signalling safeworking procedures · effective date: 01 april 2015 . preface . the asset standards...

Mandatory Requirements for Signalling Safeworking Procedures

T HR SC 02000 ST

Standard

Version 1.0

Issued Date: 09 December 2014

Effective Date: 01 April 2015

Important Warning This document is one of a set of standards developed solely and specifically for use on the rail network owned or managed by the NSW Government and its agencies. It is not suitable for any other purpose. You must not use or adapt it or rely upon it in any way unless you are authorised in writing to do so by a relevant NSW Government agency. If this document forms part of a contract with, or is a condition of approval by, a NSW Government agency, use of the document is subject to the terms of the contract or approval. This document may not be current. Current standards are available for download from the Asset Standards Authority website at www.asa.transport.nsw.gov.au. © State of NSW through Transport for NSW Sup

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T HR SC 02000 ST Mandatory Requirements for Signalling Safeworking Procedures

Version 1.0 Effective Date: 01 April 2015

Standard governance

Owner: Lead Signals and Control Systems Engineer, Asset Standards Authority

Authoriser: Chief Engineer Rail, Asset Standards Authority

Approver: Director, Asset Standards Authority on behalf of ASA Configuration Control Board

Document history

Version Summary of change

1.0 First issue

For queries regarding this document, please email the ASA at [email protected] or visit www.asa.transport.nsw.gov.au

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Preface The Asset Standards Authority (ASA) is an independent unit within Transport for NSW (TfNSW)

and is the network design and standards authority for defined NSW transport assets.

The ASA is responsible for developing engineering governance frameworks to support industry

delivery in the assurance of design, safety, integrity, construction, and commissioning of

transport assets for the whole asset life cycle. In order to achieve this, the ASA effectively

discharges obligations as the authority for various technical, process, and planning matters

across the asset life cycle.

The ASA collaborates with industry using stakeholder engagement activities to assist in

achieving its mission. These activities help align the ASA to broader government expectations of

making it clearer, simpler, and more attractive to do business within the NSW transport industry,

allowing the supply chain to deliver safe, efficient, and competent transport services.

The ASA develops, maintains, controls, and publishes a suite of standards and other

documentation for transport assets of TfNSW. Further, the ASA ensures that these standards

are performance based to create opportunities for innovation and improve access to a broader

competitive supply chain.

The Mandatory Requirements for Signalling Safeworking Procedures standard has been

developed from TMG J000 Signalling Safeworking Procedures (known as Manual J). It specifies

the principles of signalling safeworking and the minimum mandatory requirements for

operator/maintainer signalling safeworking procedures.

This standard supersedes the RailCorp document TMG J000 Signalling Safeworking

Procedures (Manual J) and this is a first issue.

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Table of contents 1. Introduction ............................................................................................................................................ 8

2. Purpose ................................................................................................................................................... 82.1. Scope ..................................................................................................................................................................... 82.2. Application ............................................................................................................................................................. 8

3. Reference documents ........................................................................................................................... 8

4. Terms and definitions ........................................................................................................................... 9

5. Network rules and procedures ........................................................................................................... 11

6. Principles of signalling safeworking ................................................................................................. 11

7. Authority to work on the operational signalling system ................................................................. 137.1. Signalling permit to work ................................................................................................................................... 13

8. Authority to operate signalling controls ........................................................................................... 14

9. Testing equipment, tools and radio transmitter devices ................................................................. 159.1. Calibration requirements .................................................................................................................................... 159.2. Radio transmitter devices .................................................................................................................................. 16

10. Derailments and collisions ................................................................................................................. 1710.1. Licensed signalling personnel attendance ....................................................................................................... 1710.2. Signal engineer attendance ................................................................................................................................ 18

11. Signalling irregularities and wrong side failures ............................................................................. 1811.1. Examples of signalling irregularities - wrong side failures ............................................................................. 1911.2. Examples of signalling irregularities - not wrong side failures ....................................................................... 1911.3. Effective elements of a safe condition .............................................................................................................. 2011.4. Treatment of signalling irregularities ................................................................................................................ 2011.5. Investigating signalling irregularities ................................................................................................................ 2211.6. Signalling irregularity certification requirements ............................................................................................. 2311.7. Signalling irregularity reporting requirements ................................................................................................. 23

12. Signalling failures (fail safe) ............................................................................................................... 2312.1. Analysis of signalling failures ............................................................................................................................ 2412.2. Treatment of signalling failures ......................................................................................................................... 2512.3. Temporary repairs ............................................................................................................................................... 29

13. Securing signalling apparatus out of use ......................................................................................... 3013.1. Disconnection from interlocking ....................................................................................................................... 3113.2. Requirements for securing signalling apparatus out of use ........................................................................... 3113.3. Infrastructure booking authority ........................................................................................................................ 3213.4. Signalling disconnection requirements ............................................................................................................ 33

14. Temporary bridging of signalling circuits ......................................................................................... 3714.1. Booking protecting signals into use ................................................................................................................. 3814.2. Approval for temporary bridging ....................................................................................................................... 3814.3. Jumper wires for temporary bridging ................................................................................................................ 4014.4. Testing of temporary bridging ........................................................................................................................... 4014.5. Temporary bridging left unattended .................................................................................................................. 4114.6. Reinstatement advice for temporary bridging .................................................................................................. 4114.7. Non-vital signalling circuits................................................................................................................................ 4114.8. Momentary bridging ............................................................................................................................................ 41

15. Release of track and indication locking ............................................................................................ 4215.1. Rules and types of releases ............................................................................................................................... 42 © State of NSW through Transport for NSW of 151 Sup

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15.2. Requesting a release .......................................................................................................................................... 4415.3. Precautions before releasing normal indication locks on signal levers ........................................................ 4415.4. Precautions before releasing normal/reverse locks on point or facing point lock levers ............................ 4415.5. Precautions before releasing normal/reverse indication locks on point levers ............................................ 4515.6. Precautions before releasing point lock relays at standard relay interlockings ........................................... 4615.7. Precautions before releasing signal normal indication relays at standard interlockings ............................ 4615.8. Precautions before releasing approach stick relays ........................................................................................ 4715.9. Precautions before releasing signal route normal relays at route control interlockings ............................. 4715.10. Process for releasing route holding in point lock relay circuits at route control interlockings ................... 4715.11. Providing releases for other situations including computer based interlocking .......................................... 48

16. Management of seldom used signalling apparatus ......................................................................... 4916.1. Seldom used point configurations .................................................................................................................... 4916.2. Seldom used track circuits ................................................................................................................................. 51

17. Requirements for re-railing and associated trackwork ................................................................... 5517.1. Licensed signalling personnel attendance ....................................................................................................... 5517.2. Infrastructure booking authority requirements ................................................................................................ 5617.3. Protection of rail traffic ....................................................................................................................................... 5617.4. Traction return arrangements ............................................................................................................................ 5717.5. Requirements for newly installed rails .............................................................................................................. 5717.6. Reinstatement of signalling................................................................................................................................ 5917.7. Control and issue of temporary rail bonds ....................................................................................................... 59

18. Requirements for providing adequate traction return ..................................................................... 6118.1. Exemption to providing alternative traction arrangements ............................................................................. 6118.2. Work affecting negative return at substations or section huts ....................................................................... 6218.3. Work affecting impedance bonds ...................................................................................................................... 6318.4. Temporary rail connections for overhead wiring ............................................................................................. 63

19. Minor signalling additions, alterations and renewals work ............................................................ 6319.1. Risk mitigation requirements for minor additions, alterations or renewals .................................................. 6419.2. Involvement of signal engineer for risk mitigation requirements ................................................................... 6519.3. Work not affecting the design principle ............................................................................................................ 6519.4. Like for like renewal work ................................................................................................................................... 6619.5. Work affecting the design principle ................................................................................................................... 6919.6. Rewiring and wire repair requirements ............................................................................................................. 7019.7. Documents used for the certification of signalling .......................................................................................... 7219.8. Paralleling of contacts in trackside apparatus ................................................................................................. 72

20. Requirements and scheduling of signalling maintenance .............................................................. 7320.1. Maintaining operational signalling equipment ................................................................................................. 7320.2. Safety related examinations ............................................................................................................................... 7420.3. Maintenance scheduling, reporting and recording .......................................................................................... 75

21. Inspection and testing of vital signalling relays ............................................................................... 7621.1. Precautions and requirements for vital signalling relays ................................................................................ 7721.2. Storage and reuse of vital signalling relays...................................................................................................... 7821.3. Maintenance and overhaul of vital signalling relays ........................................................................................ 79

22. Inspection and testing of signals and signs ..................................................................................... 8222.1. Requirements for periodic and responsive signal sighting ............................................................................ 8322.2. Maintenance and inspection of signals ............................................................................................................. 84

23. Gauging of trainstops ......................................................................................................................... 88

24. Inspection and testing of points ........................................................................................................ 88


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24.1. Principle of point testing .................................................................................................................................... 8924.2. Prerequisite tasks for point testing ................................................................................................................... 9024.3. Requirements for point lock testing mechanically operated points ............................................................... 9024.4. Requirements for point lock testing power operated points ........................................................................... 9124.5. Requirements for point detection testing ......................................................................................................... 9224.6. Provision for lock slide removal and wide cut notch point lock ..................................................................... 9624.7. Provision to extend point detection limits ........................................................................................................ 98

25. Inspection and testing of track circuits ............................................................................................. 9825.1. Objective of track circuit inspection, testing and maintenance ...................................................................... 9925.2. Track circuit records ......................................................................................................................................... 10025.3. Track circuit inspection and tests ................................................................................................................... 10025.4. Track circuit precautions .................................................................................................................................. 10525.5. Safety critical and safety significant track circuit tasks ................................................................................ 109

26. Inspection and testing of level crossing protection ...................................................................... 11126.1. Maintenance and inspection of level crossing protection equipment .......................................................... 11126.2. Treating reports of level crossing failure ........................................................................................................ 113

27. Inspection and testing of signalling interlockings ......................................................................... 11327.1. Authority to test signalling interlockings ........................................................................................................ 11427.2. Testing altered locking on interlocking frames greater than eight levers ................................................... 11427.3. Interlocking test certificates ............................................................................................................................. 11527.4. Periodic testing of mechanical interlockings ................................................................................................. 11527.5. Periodic testing of relay interlockings ............................................................................................................ 11627.6. Periodic testing of computer based interlockings ......................................................................................... 117

28. Inspection and testing of electrical insulation ............................................................................... 11728.1. Detecting earth leakage .................................................................................................................................... 11828.2. Minimum acceptable values ............................................................................................................................. 11928.3. Determination for further testing ..................................................................................................................... 11928.4. Analysis and test records ................................................................................................................................. 12028.5. Inspection and testing of power supply busbars ........................................................................................... 12028.6. Inspection and testing of electrical conductor insulation ............................................................................. 12128.7. Circuits exempt from periodic insulation inspection and testing ................................................................. 125

29. Specific requirements for computer based interlockings ............................................................. 12829.1. Requirements for Solid State Interlocking systems ....................................................................................... 12829.2. Requirements for Microlok II systems ............................................................................................................. 13329.3. Requirements for Westrace systems .............................................................................................................. 138

30. Surveillance inspections ................................................................................................................... 14130.1. Scope of surveillance inspections ................................................................................................................... 14230.2. Scheduling of periodic inspections ................................................................................................................. 14230.3. Surveillance inspection reports and action requirements ............................................................................ 143

31. Housekeeping and protection of signalling assets ........................................................................ 14331.1. Prevention of water ingress to signalling equipment .................................................................................... 14431.2. Prevention of fire around signalling equipment ............................................................................................. 144

32. Control of signalling documentation ............................................................................................... 14432.1. Requirements for signalling documentation control ..................................................................................... 145

33. Control of signalling security locks and keys ................................................................................ 14633.1. Lock types in use .............................................................................................................................................. 14733.2. Major signal boxes and control centres .......................................................................................................... 14933.3. Configuration and key cutting.......................................................................................................................... 149


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34. Storage and dispatch of operational safeworking keys ................................................................ 15034.1. Temporary storage of operational safeworking keys .................................................................................... 15034.2. Dispatching operational safeworking keys for repair, replacement or cancellation ................................... 151


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1. Introduction Signalling safeworking procedures are owned and operated by the operator/maintainer in

accordance with their obligations to the rail regulator as rail infrastructure managers.

This standard sets out the minimum mandatory requirements to be included in the

operator/maintainer signalling safeworking procedures.

Additionally this standard specifies the authority levels required of signalling personnel when

working on the operational or potentially operational signalling system.

It forms the basis for the operator/maintainer to develop the procedures for signalling

safeworking relevant to their domain rail environment.

2. Purpose The purpose of this document is to provide a coherent regime of work practices that aim to

ensure the continued integrity and reliability of the operational signalling system. It also aims to

safely bring into use new or altered signalling systems, equipment and wiring within the NSW

rail network as governed by TfNSW.

2.1. Scope This standard covers information on signalling safeworking which can affect the safe operation

and reliability of the signalling system and all its components, including the effect on rail traffic

and users at level crossings, when worked on by signalling personnel.

This standard does not include matters relating to work health and safety or worksite protection.

2.2. Application This standard applies to the signalling systems within the NSW rail network as governed by

TfNSW.

3. Reference documents Australian standards

AS 4292 Railway safety management Part 1: General requirements

AS 4292 Railway safety management Part 4: Signalling and telecommunications systems and

equipment

AS 1742.7 Manual of Uniform traffic control devices - Railways crossings


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Transport standards

ESG 100 Signal Design Principles

ESG 007 Glossary of Signalling Terms

SPG 0711 Inspection and Testing of Signalling

TMG A1412 Process for Signalling Personnel - Authorisations & Licensing

Train Operating Conditions (TOC) Manual

Other reference documents

Operator Network Rules and Network Procedures

4. Terms and definitions The terms defined in ESG 007 Glossary of Signalling Terms and the following definitions apply

in this standard and shall be incorporated in signalling safeworking procedures:

AEO Authorised Engineering Organisation

ASA Asset Standards Authority

CBI computer based interlocking

EMR master emergency facility

EOL emergency operation lock

EPROM erasable programmable read-only memory

ESML emergency switch machine lock

SPAD signal passed at danger (stop)

TfNSW Transport for New South Wales

authorised signalling personnel signalling personnel who are not licensed, but have been

assessed and authorised to perform specific work within a signalling environment in accordance

with the ASA signalling authorisation and licensing framework and the operator/maintainers’

competency management system; and hold suitable competency for the intended task

certification of signalling apparatus documentary evidence provided for the purpose of

booking specific signalling apparatus into operational use, following satisfactory testing in

accordance with the relevant requirements, by signalling personnel

interlocking the part of the signalling system which applies the interaction between signalling

controls, rail vehicles and trackside equipment, such as points and other signalling apparatus

including signals as applicable, to prevent conflicting and unsafe movement authorities and to

ascertain routes are set and locked correctly


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licensed signalling personnel signalling personnel who hold a valid licence for either signal

engineer, signal electrical or signal mechanical, attained in accordance with the ASA signalling

authorisation and licensing framework and the operator/maintainers’ competency management

system; and hold suitable competency for the intended task

like for like renewal the renewal or temporary removal of signalling equipment that may be

performed without a signalling design authority

operator/maintainer the entity acting as the rail infrastructure manager, accredited to operate

and maintain railway infrastructure

responsible signal engineer a licensed signal engineer (field) responsible for the integrity and

performance of signalling infrastructure within an assigned area of accountability (example, a

maintenance signal engineer, asset signal engineer or similar as determined by the contracted

AEO acting on behalf of the operator/maintainer)

signalling commissioning engineer a licensed signal engineer (field) who shall act in the

interest of TfNSW to bring into use new or altered, safe and reliable, signalling systems in

accordance with the specific signalling design and ASA requirements

signal engineer a signalling person who is licensed to the level of signal engineer (field)

signalling irregularity a failure of a signalling unit or its subsystem which is contrary to the

intended design requirement; is not fail-safe and which in combination with other failures or

circumstances may bring the system to an unsafe condition. Additionally, the definition of a

signalling irregularity is extended to items of signalling that are found with errors, where these

errors have the potential to falsely energise a vital relay or other vital function.

signalling permit to work a documented authority issued to signalling personnel by a

contracted AEO acting on behalf of the operator/maintainer to enable work within an operating

signalling environment or signalling commissioning environment

signalling personnel persons who are either licensed signalling personnel or authorised

signalling personnel

signalling safeworking procedures pertains to the operator/maintainer document for

signalling safeworking procedures


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5. Network rules and procedures Signalling safeworking procedures shall complement the applicable network rules and

procedures and shall not supersede them.

Signalling safeworking procedures shall reference the applicable network rule/procedure as

pertinent to the related paragraph.

Signalling personnel shall comply with the requirements stated in both network rules and

procedures and signalling safeworking procedures.

6. Principles of signalling safeworking Signalling safeworking procedures shall incorporate the following principles of signalling

safeworking:

• Signalling work shall be managed and performed to meet the relevant requirements of

AS 4292 Part 1 General requirements and Part 4 Signalling and telecommunications

systems and equipment.

• The movement of trains shall be protected in the following circumstances:

o when signalling equipment has failed in an unsafe manner or becomes unreliable

o when any signalling work or other work impairs or may impair the protection afforded

by the signalling system

• Signalling irregularities shall be promptly attended and thoroughly investigated. The defect

shall be rectified or addressed and the equipment tested and certified as operating safely

before being restored for operational use.

• Signalling failures shall be recorded and analysed to determine trends and the necessary

corrective actions required to provide a safe and reliable signalling system.

• Where the interlocking is disarranged or vital signalling equipment is disconnected from the

interlocking or is disarranged, renewed or has safety critical adjustments altered, its safe

operation shall be certified fit before restoring it back into use.

• Risks associated with signalling apparatus that are seldom used shall be managed and

controlled to minimise the level of risk. Human factors shall be considered when mitigating

such risks.

• Alterations or additions to the signalling system or changes to its configuration shall not be

made unless properly approved by the designated person within the contracted AEO. This

includes alterations or additions to signalling trackside equipment, control systems,

automatic train protection equipment, vital communication links and power supplies.


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Alterations or additions shall comply with SPG 0711 Inspection and Testing of Signalling

and signalling safeworking procedures.

• New or experimental equipment intended for use on the signalling system shall meet the

ASA requirements for type approval before being installed in operational areas.

• Like for like renewal determinations and performed work shall be in accordance with the

like for like work instructions contained in SPG 0711 and signalling safeworking

procedures.

• The protection defeated by contacts of vital signalling apparatus temporarily bridged shall

be provided by an effective alternate means.

• Temporary repairs of vital signalling equipment shall be done to a safe and secure

standard. Any temporary repair made shall be brought up to a permanent standard before

the temporary work presents an unacceptable risk.

• Sound asset management methods shall be applied to ensure the signalling system and its

components are maintained to provide the inherent safety and reliability aspects of the

signalling system throughout its operational life.

• Signalling equipment shall be suitably secured to minimise risks associated with

unauthorised access and vandalism.

• Signalling plans, track insulation plans, circuit books, control tables, diagrams, interlocking

data and the like shall be maintained up to date and be available to those who need them

in order to carry out their duties.

• Testing equipment, tools and items used to maintain the signalling system shall be in

proper working order and comply with ASA requirements, as applicable. Testing and

measuring equipment used for certifying the safety and reliability parameters of the

signalling system shall be suitably calibrated.

• Where line pole routes are still in use, they shall be maintained by persons holding

appropriate competency to do the work. However, licensed signalling personnel shall retain

accountability for the signalling elements of the work.

• Off-site repair and overhaul of vital signalling equipment shall be controlled in order to

ensure the equipment is restored to the relevant specification and standard before being

re-used.


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7. Authority to work on the operational signalling system Only licensed signalling personnel shall work on the operational signalling system and its

associated equipment and wiring. They shall perform signalling work only as prescribed on their

certificate of competency and signalling permit to work.

Persons who are not licensed in signalling shall not interfere with the operational signalling

system or its equipment and wiring. They shall not perform any task that may affect the

adjustment of operational signalling equipment except in the following situations:

• when they are specifically instructed by licensed signalling personnel

• when they are supervised directly and closely by a licensed signalling person who shall

take responsibility for the work being performed by the non-licensed person

Authorised signalling personnel are permitted to perform specific unsupervised work within a

live signalling environment. They shall perform work only as prescribed on their certificate of

competency and signalling permit to work. Such work may include the supervision of

non-signalling personnel during specific non-invasive tasks such as installation work, cabling,

wiring, mechanical and civil works as prescribed on the signalling permit to work.

Authorised signalling personnel may also perform or lead testing and certification of signalling

apparatus in accordance with their certificate of competency and signalling permit to work. The

affected signalling shall be first booked out of use and disconnected from the interlocking by a

licensed signalling person before the testing work can proceed.

7.1. Signalling permit to work The signalling permit to work is a documented authority granted by the operator/maintainer to

signalling personnel for work that can affect the integrity and reliability of operational signalling.

The process aligns with other signalling requirements such as interface coordination meetings

and site integrity agreements.

Additionally, the signalling permit to work is a process which establishes each signalling

person's capability to perform the tasks intended for the work. The signalling personnel's work

shall be limited to their licence/authority level and competency, taking into account their

experience and the site specific circumstance and conditions.

The signalling permit to work shall only pertain to the operator/maintainer's network.


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A signalling permit to work shall be required before work can proceed within a live signalling

environment or on operational signalling equipment, which includes the following:

• vital and non-vital signalling systems

• train control systems

• signalling trackside equipment

• signalling power supplies

• communication equipment used for signalling

• signalling air systems

• signalling mechanical equipment

• signalling cables, wires, routes and pits

A signalling permit to work shall also be required before work can proceed on new (green-field)

signalling installations that involve inspection, testing and certification of the operational

interface during the commissioning phase of a project.

The signalling permit to work shall be issued to signalling personnel by the contracted AEO

acting on behalf of the operator/maintainer. The contracted AEO acting on behalf of the

operator/maintainer may also grant overall permission to another contracted AEO to administer

the permit to work arrangements on their behalf for the duration of permitted work.

The actual granting of signalling permits to signalling personnel shall be done by a signal

engineer holding accountability.

8. Authority to operate signalling controls The operation of controls by signalling personnel for the purpose of testing signalling apparatus

shall be done only in the following conditions:

• with the signaller’s consent

• only where the operation has no potential to endanger the movement of trains or other rail

vehicles or users at level crossings

• only when the affected signalling has been booked out of use

Signalling personnel shall attain an understanding of the controls that may be operated, the

extent of the test area and the agreed time frame for the testing.

Signalling personnel shall not operate signalling controls for operational purposes.


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Note: Where devices such as releasing switches or token keys are provided for

ground operated signalling, and the work does not disconnect or disarrange the

equipment from the interlocking, there is no requirement to book out the equipment

before its operation for testing purposes; however the signaller's permission shall still

be obtained.

9. Testing equipment, tools and radio transmitter devices Only testing equipment that complies with ASA requirements shall be connected to signalling

circuits and equipment.

This requirement applies to portable monitoring, chart recording and logging devices when

directly connected to working circuits and equipment. When these devices are used, the

installation of their associated wiring shall be in accordance with temporary repair requirements

stated in Section 12.3 of this standard.

Temporary repair requirements that pertain to the connection of testing equipment may be

exempt in situations where the persons remain in attendance. Disconnections of wiring in this

case shall be avoided. However, any disconnections made shall be suitably tested.

Under no circumstances shall the feed/transmitter and the relay/receiver of the same track

circuit be fed into the same recording or logging device, even if the recorder or logger channels

are isolated. This requirement avoids the risk of the track circuit train detection being electrically

bypassed by the recorder or logger.

Test probes used for testing live signalling circuits shall be appropriately insulated and suitable

for attaching to the terminals required for test.

Test lamps or test LEDs shall not be used as they may provide a significant leakage path for

circuit currents.

Tools used for specific purposes, such as crimping tools, shall be suitable for the task and shall

comply with ASA requirements, as applicable.

9.1. Calibration requirements Testing and measuring equipment used to certify the safety and reliability parameters of the

signalling system shall require on-going calibration.

The following are examples of testing and measuring equipment that require on-going

calibration:

• multimeters

• inductive type ammeters (clamp, tong meters)


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• insulation resistance testers (meggers)

• track circuit frequency adaptors and selective frequency meters

• track shunt boxes

• lightning arrestor testers

• point and trainstop gauges

• measuring wheels

Specific tools, when used on safety critical work, shall require on-going calibration.

The following are examples of specific tools that require on-going calibration:

• lug crimping tools

• torque wrenches

All calibrations shall be in accordance with manufacturer's specification unless other relevant

specifications apply.

9.2. Radio transmitter devices Radio transmitter devices emit electro-magnetic energy that can interfere with electronic

signalling and testing equipment.

The following are examples of radio transmitter devices that emit electro-magnetic energy:

• handheld two-way radios such as GRN and CB

• mobile phones

• cordless phones

• Wi-Fi enabled devices

• automatic train protection (ATP) programming and testing equipment

To minimise the likelihood of interference, these devices shall not be used close to electronic

vital and non-vital signalling equipment or when using some testing equipment.

The following are examples of electronic signalling equipment and testing equipment that may

be affected by radio transmitter devices:

• computer based interlocking equipment

• audio frequency track circuits


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• electronic power supplies and electronic changeover units

• clamp and tong meters

• digital multimeters

When testing equipment is affected by radio interference, error readings may be displayed on

devices such as clamp meters, tong meters and digital multimeters. When these devices are

affected by radio interference, any measurements taken shall not be used for the purpose of

certification.

Most radio transmitter devices shall not be used within three metres of affected signalling and

testing equipment. Calls from mobile or cordless phones shall not be made or answered within

three metres of affected signalling or testing equipment; however, the phone may be used up to

one metre of affected signalling or testing equipment, once the call is established. Wi-Fi enabled

devices and ATP programming and testing equipment shall not be used within one metre of

affected signalling and testing equipment.

10. Derailments and collisions Derailments and collisions shall be promptly attended in order to provide appropriate protection

for trains by booking out of use the protecting signalling, including signalling on adjacent or

obstructed lines. Signalling shall be protected in accordance with signalling safeworking

procedures and the network rules and procedures. Signalling suspected of contributing to the

cause of the incident shall be booked out of use, but not disconnected. In these cases, the

protecting signals in the rear of the incident shall be booked out of use and disconnected.

Any derailment or collision where the signalling is thought to be the cause shall be treated as a

signalling irregularity and a signal engineer shall attend to the incident.

For incidents involving emergency services or otherwise where the incident has the potential to

become a crime scene, signalling personnel when attending the incident shall consider aspects

of interference, independence and access for emergency services. In these cases, signalling

personnel shall coordinate their actions in conjunction with the relevant authorities and senior

rail management.

10.1. Licensed signalling personnel attendance Licensed signalling personnel shall attend to all derailments or collisions, unless the affected

lines where the incident occurred have no signalling provided (example: non-signalled yards).

They shall ensure appropriate signalling protection, gather information and evidence and

perform other tasks as instructed by the investigating signal engineer. Care shall be taken not to

disturb any evidence.


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The position of levers/controls, indications, signals, points, relays and other trackside apparatus

which may be applicable to the circumstances shall be noted.

10.2. Signal engineer attendance When signal engineers are required to attend a derailment or collision, they shall perform the

following functions:

• ensure signalling safeworking protection arrangements are appropriate

• gather evidence and investigate the incident where signalling is suspected to be the cause

• provide safe alternate signal engineering arrangements to facilitate train running as

necessary

• facilitate incident recovery and restoration works

• lead testing and certification requirements, including the provision of an inspection and test

plan

• compile a detailed report

• make recommendations to prevent recurrence of this incident

11. Signalling irregularities and wrong side failures All signalling irregularities and wrong side failures shall be immediately attended, protected and

investigated in accordance with signalling safeworking procedures.

Note: Not all signalling irregularities result in immediate failure. Some may remain in

the system as latent defects or errors to the intended design requirement, which may

later emerge, adversely affecting the safe running of trains.

Predictable, common failure modes such as a single lamp failure (example: on a signal or level

crossing) or a trainstop that is falsely in the lowered position due to a mechanical problem are

not deemed signalling irregularities.

A wrong-side failure is where the failure is not protected by the system design or there are

insufficient effective elements of a safe condition for the particular circumstance, which could

directly endanger the safe running of trains or people. Refer to Section 11.3 for effective

elements of a safe condition.


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11.1. Examples of signalling irregularities - wrong side failures Following are examples of signalling irregularities that are wrong side failures:

• point locking: if points are released under conditions when they should be locked

• point detection: if point detection is made when the points are not in their correct position

• facing points: if a signal can be cleared over facing points when the points are not locked or

correctly detected

• signal: if a valid, less restrictive indication is displayed by a signal than is correct for the

conditions allowed

• rail vehicle detection: if a track circuit or axle counter fails to detect the presence of a rail

vehicle

• level crossing protection: if level crossing protection equipment fails to operate for

approaching trains (excluding an insignificant amount of lights out or one failed bell), and

there is no proving of the boom normal position - does not include the level crossing when

in manual operation

• interlocking: if a release can be incorrectly obtained from the locked position

• vital signalling relay: if a vital signalling relay is falsely energised due to internal or external

interference or defect, which subsequently causes a reduction in system safety

• electric lock: if an electric lock is incorrectly free

• dual control: if the restoration of any one control fails to return the signal to the stop

11.2. Examples of signalling irregularities - not wrong side failures Following are examples of signalling irregularities that are not wrong side failures:

• signal indication: if a signal displays no lights or an irregular combination of lights (invalid

indication)

• level crossing protection: if level crossing protection equipment fails to operate for

approaching trains (excluding an insignificant amount of lights out or one bell), and the

system design provides proving of the boom normal position (XNR) causing the protecting

signals to remain or replace at stop - does not include the level crossing when in manual

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• pedestrian gate: if only one pedestrian gate remains partially open due to a mechanical

problem - conditional that the remaining elements of the level crossing have activated

correctly and it is evident that trains are approaching

Refer to Section 11.3 for effective elements of a safe condition.

• vital signalling relay: if a vital signalling relay is falsely energised due to internal or external

interference or defect, and the system design provides proving of the relay's 'de-energised'

position (back contact proving) and thus protecting the system

11.3. Effective elements of a safe condition In some cases of signalling irregularity, where it is clearly evident that the system has failed,

there may still remain sufficient effective elements to provide a safe condition.

Examples of effective elements of a safe condition include the following:

• A pedestrian gate not closing when required

The possible effective elements may include the following:

o the obvious activation of the level crossing protection

o the detection of the gate not closing (XNR) and protecting signal held at stop

• No lights illuminated in a signal (invalid indication)


o the driver recognising the loss of signal indication

o the signal in rear correctly indicated the 'proceed' authority for the signal ahead

(example: 'caution' if the failed signal is at stop)

• A phantom signal indication from another light source which has caused an irregular

(invalid) signal indication


o the driver recognising the irregular signal indication

o the signal in rear correctly indicated the 'proceed' authority for the signal ahead

(example: 'caution' if the failed signal is at stop)

11.4. Treatment of signalling irregularities All reports of signalling irregularity shall be treated as factual and promptly attended to.

Signalling equipment suspected of causing an irregularity shall be protected by arranging

protecting signals to stop.


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The suspected signalling equipment shall only be booked out of use and not initially disturbed or

disconnected, unless instructed by the investigating signal engineer.

The immediate failed signal may be disconnected in conjunction with being booked out of use, if

it is clearly evident that the cause of irregularity is not within the signal operating circuit or its

controlling relay/module.

Where a failed signal is not disconnected (booked out of use only), the protecting signals in the

rear of the failed signal shall be booked out of use and disconnected. The protecting signals in

the rear may be restored in the intervening period until the signalling irregularity is rectified on

the following conditions:

• the actual cause of the signalling irregularity is positively determined by the investigating

signal engineer

• rail traffic can safely operate using the signals in accordance with network rules and

procedures

• the failed signal is disconnected in conjunction with being booked out of use

• the immediate protecting signal is deemed sufficient protection for the signalling irregularity

Note: The immediate protecting signals shall remain booked out until the defect is

rectified or addressed.

11.4.1. Signalling data logs Data logs from vital and non-vital signalling systems, used for the purpose of providing

information and evidence following a serious incident (such as signalling irregularity, derailment,

collision and so on) shall be reviewed by a signal engineer first before being passed on to other

parties.

Data logging systems include computer based interlockings, control systems, vital and non-vital

data recorders, and level crossing monitors. Productions from replay facilities and asset

monitoring facilities are also included in this requirement.

The log information provided shall be an unaltered download, separately interpreted and

attested by the signal engineer. This information shall be a true representation of the actual

event, supported by accurate commentary to describe the event in plain language. The logger

time shall be checked against real time to determine the difference.

The critical inputs and outputs used in logger events, supplied as evidence for serious or major

incidents shall be verified to be correct in accordance with the design requirements.


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11.5. Investigating signalling irregularities All signalling irregularities shall be investigated by a signal engineer.

A suitable independent person is required to witness the investigation, except for simple cases.

Refer to Section 11.5.1 for simple cases.

In case of serious consequences or implications, the investigation shall be conducted by a

senior, experienced signal engineer, independent of the pertaining circumstances.

The investigating signal engineer is responsible to determine the signalling system is safe to

restore for normal operational use. The investigating signal engineer shall be satisfied that upon

completion, the investigation has been properly and thoroughly conducted.

Where the cause of signalling irregularity is not immediately known, the investigating signal

engineer shall compile an inspection and test plan as part of the investigation strategy to

determine the causal factors.

Where the testing has the potential to impair the safety provided by the signalling system, or

otherwise interferes with train operations, the signalling affected by the testing shall be booked

out of use.

11.5.1. Simple cases of signalling irregularity

The term simple case refers to a signalling irregularity which includes the following:

• an incident which is not a collision, derailment or near miss

• there is no injury or damage

• there are no extraordinary circumstances pertaining

• there remained sufficient effective elements of a safe condition

• the cause found is non-contentious and obvious to the signalling personnel attending

In simple cases of signalling irregularity, it is not necessary for the investigating signal engineer

to attend on site in order to conduct the investigation. However, the investigating signal

engineer is still the person responsible to determine if the signalling system is safe to restore

and shall be satisfied that the identified cause satisfactorily explains the situation.


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11.6. Signalling irregularity certification requirements Certification of the signalling system shall be made only when the investigation has concluded,

and upon any of the following conditions:

• a genuine cause has been found or determined and the affected apparatus has been

rectified or otherwise addressed

• the alleged report is proven to be unsubstantiated by thorough testing which has verified

the signalling to be working safely and in accordance with the signalling design

The investigating signal engineer shall refer the incident to another signal engineer who holds

the accountability in any of the following cases for instructions:

• a significant incident occurs (mainline or passenger train derailment, collision or near miss)

and the signalling system is suspected to be at fault

• a recurrence of the irregularity cannot be ruled out, which may potentially result in serious

consequences

• the alleged report or confirmed irregularity cannot be satisfactorily explained and the

investigating signal engineer has deemed the apparatus to remain booked out of use

Note: The signal engineers involved should have suitable experience relative to the

complexity of the subject matter.

11.7. Signalling irregularity reporting requirements A comprehensive report shall be compiled by the investigating signal engineer for all incidents

of signalling irregularity. The report shall contain the events and details of the incident, details of

the technical investigation conducted, test results and applicable evidence such as logs, photos,

statements, and so on. The report shall also include rectification measures, either completed or

proposed, including further investigations if appropriate and any recommendations.

12. Signalling failures (fail safe) All signalling functional failures shall be attended and subsequently reported, recorded and

analysed so that the trends can be identified and appropriate measures be taken to reduce

failures to a minimum. A failure management system shall be used for this purpose.

Repairable items with unique serial numbers that have failed, such as vital signalling relays,

track transmitters/receivers, CBI equipment and so on, shall be identified in the failure

management system so that the performance can be tracked once they are returned to service.


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Signalling conditional failures which do not have an impact on functional failures or rail

operations need not be recorded in the failure management system, but shall be prioritised and

managed using a defect management system.

During a failure, the best possible arrangements shall be made in accordance with signalling

safeworking procedures and network rules and procedures. This is done in order to maximise

the safe use of the signalling system and minimise train delays, while still retaining an

appropriate level of protection for trains. Human factors leading to error shall be considered

when determining the course of action to be taken in this regard.

Under no circumstances shall signalling personnel cause a signal to display a less restrictive

indication. A signal shall not be made to clear by means of manipulation, interference, bridging

of contacts or by other similar actions except as specifically laid down in signalling safeworking

procedures.

When temporary repairs are made to correct a failure condition the responsible signal engineer

shall be advised and the temporary repair treated in accordance with Section 12.3.

12.1. Analysis of signalling failures The signal engineer responsible for handling signalling failures shall regularly analyse signalling

failure data and make recommendations as applicable.

The following list describes the analysis for the different types of signalling failures:

• Repeat and no cause found failures shall be thoroughly investigated and if required,

escalated to a higher level for investigation to determine appropriate courses of action in

preventing recurrence. A file shall be retained for these failures.

• Failures caused by vandalism shall be analysed to determine appropriate measures of

security in an attempt to minimise recurrence of these types of failures.

• Rail lines or signalling apparatus seldom used shall be analysed to minimise failures

associated with seldom use, including assessment and mitigation of associated risks.

• Failures caused by persons performing work shall be analysed to ensure the interference

caused by workers is addressed to prevent recurrence and thus not impair the safety and

reliability of the signalling system caused by these failures.

• Failures caused by signalling component defects shall be analysed to determine

appropriate measures to minimise recurrence of these failures. This analysis shall include

identification of equipment used at other locations that can be impacted by similar failure

modes.


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12.2. Treatment of signalling failures In the event of a signalling failure, it may not always be necessary to book out and disconnect

signalling apparatus. The risks associated with removal of the normal operation of signals,

points and so on shall be assessed and considered in order to maximise the safe use of the

signalling system.

However, signalling shall be made to provide protection in any of the following situations:

• the failure is a signalling irregularity

• the safety of the signalling may be impaired by an intervening action (example: signalling

equipment is disarranged or disconnected from the interlocking)

• the signalling equipment is unreliable and may result in signals inadvertently returning to

stop on approaching trains

• the failure condition remains unrectified and routes become unavailable for a considerable

amount of time

• if requested by the network operator

12.2.1. Failure of signals The loss of signal indications whether caused by a defective lamp or LED unit or caused by

other electrical or mechanical defect shall be promptly rectified.

Note: A signal displaying a less restrictive indication or a signal displaying an invalid

indication (example: multiple indication) or a running signal displaying no indication

shall be deemed a signalling irregularity and treated accordingly.

Refer to Section 22 of this standard for other procedures associated with signals and signs.

12.2.2. Failure of trainstops Where a trainstop has failed such that it no longer provides protection, an attempt to enable the

trainstop to the raised position shall be made. Where a trainstop cannot be enabled in the

raised position, the associated signal shall be booked out of use and a mechanical trainstop

fitted in place.

If a mechanical trainstop is not available, the signal in the rear of the failed trainstop shall also

be booked out of use. The failed trainstop 'Normal' contacts may be temporarily bridged. A

temporary bridging authority shall be issued for this purpose. Trainstops fitted with VCSR

functionality may be left lowered without the need for temporary bridging and signals may be left

operational.


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Note: A trainstop that falsely indicates a raised position, or due to an irregular circuit

operation (and not a mechanical problem) is falsely in the lowered position, shall be

deemed a signalling irregularity and treated accordingly.

Additionally, the associated protecting signal shall be booked out of use in any of the following

situations:

• when a trainstop is replaced

• when cabling to the trainstop is removed

• when trainstop detection wiring is interfered with

A failed trainstop provided at a signal not protecting points may have the trainstop arm lowered

to the reverse position to allow trains to progress past the signal on the following conditions:

• a VCSR function is in operation

• the failure is independent of the signal controls failing

• the integrity of the trainstop 'Normal' contacts and their circuits are not compromised or in

doubt

In these cases, there is no need to apply temporary bridging and the signal may be left

operational.

Signals may also be left operational where an indication other than stop is displayed by the

signal (as provided by the circuit design) when the trainstop is in a raised position, for example,

a low speed indication or shunt indication.

Signallers shall be advised of the operational impacts caused by failed trainstops.

Trainstop suppression

Events such as signalling system failures, control system failures, power supply failures and so

on can affect signals and retain the trainstops in the raised position. In such cases, network

operators may choose to institute 'manual block working' in accordance with the network rules

and procedures. Subsequently, network operators may request that affected trainstops be

suppressed to facilitate this operation.

In these situations trainstops may be suppressed, subject to a signal engineer assessing and

mitigating the risks that apply in each situation.

The associated signal shall be booked out of use before a trainstop is suppressed.

The signal engineer shall determine whether to apply temporary bridging or not. If temporary

bridging is required, a temporary bridging authority to bridge-out the trainstop 'Normal' contacts

shall be issued. The jumper wires shall be installed inside the trainstop. The temporary bridges

shall be removed before the signal is booked back into use.


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Trainstops at entry block posts shall not be suppressed.

12.2.3. Failure of points

When points have failed, no attempt shall be made to unlock or move the points other than from

the signal box control unless the affected points, and protecting signals have been booked out

of use.

Emergency switch machine locks (ESML) and emergency operation locks (EOL) are facilities

which are interlocked with the signalling. Licensed signalling personnel may use ESML and EOL

as permitted by the signaller to manually operate points for the purpose of diagnosing and

rectifying a failure. This may be done without booking the affected points and signals out of use.

Where electro-pneumatic points are not fitted with emergency facilities, the control valve internal

operation arrangements may be utilised for this purpose.

In all cases, the signaller shall be notified first to place the affected signals to stop. Licensed

signalling personnel shall also be assured that there are no approaching trains before the

emergency facilities are used. Upon reinstatement of the emergency facility, the position of the

points shall be left in correspondence with the signal box control and interlocking.

Where the point lock mechanism has failed such that it does not effectively lock the points, the

affected points and protecting signals shall be booked out of use. The affected points and

protecting signals shall also be booked out of use when the point detection is not in correct

adjustment or is unreliable (example: causing signals to inadvertently return to stop on

approaching trains). Facing points shall be clipped and SL locked.

The protecting signals may be left operational on failed points when the point lock (as

applicable) and point detection remains in correct adjustment and working order. In this case,

facing points shall be clipped and SL locked. The prevention of ‘point creep’ which may cause

loss of detection and potential unlocking of points shall be considered.

Where the failure is a result of damaged or defective electrical point detection components,

which may cause severe train disruption, a temporary bridging authority to bridge-out the failed

detector contacts may be issued.

12.2.4. Failure of ESML or EOL detection Where there is a failure of detection or there is a missing point handle or key pertaining to an

ESML or EOL cabinet which results in severe disruption to trains, a temporary bridging authority

to bridge-out the detector contacts of the ESML or EOL may be issued. The ESML or EOL

cabinet including the manual operation facility at the points shall be secured using signalling

Falcon 8 locks.

The point's manual operation facility shall be booked out of use; however the points and signals

may be left operational using the signal box controls. © State of NSW through Transport for NSW of 151 Sup

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12.2.5. Failure of plunger locks or isolating relays A failed plunger lock on electro-pneumatic points or an isolating relay on electric points may be

momentarily released as requested by the signaller to enable the points to be operated from the

signal box control. A separate request shall me made by the signaller for each release.

If the plunger lock or isolating relay is not effectively locking the points, the points shall be

deemed defective and the affected points and protecting signals shall be booked out of use.

Facing points shall be clipped and SL locked.

12.2.6. Failure of track circuits In the event of a track circuit failure, no attempt shall be made to clear affected signals by

manipulating the track circuit relay or by bridging across the track circuit relay contacts or

terminals.

A release of track or indication locking affected by a failed track circuit may be provided but only

as prescribed in the signalling safeworking procedures. Refer to Section 15 of this standard for

requirements associated with the release of track and indication locking.

Where a track circuit does not provide an effective track shunt, the protecting signals and any

associated points shall be booked out of use. This is done until adequate measures are

implemented to address the risks associated with the loss of effective track shunt. Facing points

shall be clipped and SL locked. The responsible signal engineer shall be advised of the situation

and shall subsequently implement adequate measures.

Where a track circuit failure is caused by a broken rail the immediate protecting signals shall be

made to remain at stop. Alterative traction return arrangements shall be provided.

Signals shall be made operational on the following conditions:

• certification of the affected rail by a competent person

• satisfactory testing of the track circuit following remedial work

12.2.7. Failure of level crossing protection equipment

Failures of level crossing protection equipment shall be protected in accordance with network

rules and procedures.

Signals interlocked with failed level crossings shall also be booked out of use whenever the

level crossing is booked out of use.

Level crossings fitted with master emergency facilities or other approved level crossing manual

override arrangements shall not be disconnected, provided they are in correct working order.

Note: The level crossing battery supply shall be checked to ensure that it has sufficient

charge following periods of prolonged power supply loss. © State of NSW through Transport for NSW of 151 Sup

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12.2.8. Failure of electric locks on signal levers When the 'Normal' electric lever lock fails on a signal lever, the lever shall be kept in the normal

position until the failure has been rectified. The associated signal shall be observed to display a

stop indication.

12.2.9. Failure of interlocking relays At standard relay interlockings, relays such as signal reverse relays, point normal/reverse relays

and releasing switch normal/reverse relays shall not be lifted or falsely energised or released.

At route control interlockings, relays such as route reverse lock relays, point normal/reverse lock

relays and releasing switch normal/reverse lock relays shall not be lifted, or falsely energised or

released.

There is an exception in the case of route holding in point lock relays as stated in Section 15.10

of this standard.

12.2.10. Failure of section control relays in single line track control sections In the event of failure of a section control relay in track controlled areas with pilot working, it may

be permissible to temporarily bridge-out the half pilot staff contacts. This can be done at one or

both ends of the section for testing purposes provided the starting signals at both ends of the

section are booked out of use. A temporary bridging authority shall be issued for this purpose.

12.2.11. Failure or damage to signalling cables and wires When failures are caused by broken or damaged signalling cables and wires, no attempt shall

be made to manipulate any relay or equipment affected by the defect. The affected signalling

shall be booked out of use until the items are effectively repaired.

The work of repairing or replacing signalling cables and wires shall be done in accordance with

Section 19.6 of this standard.

12.3. Temporary repairs Temporary repairs shall be done only where the work does not affect the design principle. The

work shall be done in accordance with Section 19 of this standard, which outlines the specific

requirements for additions, alterations and renewals work, and the level of authority required to

undertake such work. The requirement also outlines the associated risks and lists examples for

mitigation.

The testing of temporary repairs shall comply with the requirements prescribed in SPG 0711.


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The responsible signal engineer shall be notified of all temporary repairs made. A temporary

repairs register shall be kept updated by the responsible signal engineer as a record for this

purpose. The register shall include any risk mitigation requirements and the prioritisation of

permanent repairs.

All items utilised for temporary repairs, including wires, cable cores, contacts and other

components, shall be suitable for the intended purpose.

Temporary wiring shall be suitably tagged, identifying the particular circuit and associated

terminal number.

Under no circumstances shall exposed or bare wire ends be left loose or have the potential to

come into contact with live circuits.

Signalling documentation shall indicate the nature of the temporary repair. Additionally,

signalling documentation as certified by a signal engineer shall be duly sent for updating as

necessary to reflect any permanently changed arrangements.

13. Securing signalling apparatus out of use Signalling apparatus is secured in a safe, de-energised or locked state during degraded modes

in order to prevent its operation.

Situations where the signalling integrity has been impaired or may become impaired shall be

adequately protected by securing the signalling apparatus out of use.

Maximising the safe use of the signalling system shall be considered when determining the

course of action for securing the apparatus out of use. This may permit some of the signalling

apparatus to remain operational.

This consideration shall be subject to a risk assessment conducted by a signal engineer and the

implementation of an appropriate mitigation to bring any identified risk to an acceptable level.

The potential for human error shall be given due consideration during the risk assessment.

For example, where points are affected by rail contamination, the route control functionality may

be retained while still disabling the protecting signals from clearing. This enables all the points in

a route to operate as designed and eliminates the human error associated with manually

operating points. This can prevent a points run-through.

The mitigation strategy shall be discussed between the signal engineer and another signal

engineer before implementing, to ensure all risks are controlled.



Engineering works performed in track possessions shall meet the same requirements for

securing signalling apparatus out of use, as if the work was being performed on running lines.


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13.1. Disconnection from interlocking Signalling is deemed disconnected from the interlocking when the disconnection affects the

integrity provided by the interlocking for the safety of train movements.

The opening of circuit terminal links and pins or the disconnection of electrical power or air

supply to trackside apparatus alone does not constitute disconnection from the interlocking.

There is an exception in the case of signal lights and level crossing protection equipment where

it shall be deemed disconnected from the interlocking if their indication or operation is disabled.

13.2. Requirements for securing signalling apparatus out of use The requirement to book signalling apparatus out of use each time may not always be

necessary. The methodology used to prevent the operation of signalling shall be relative to the

level of protection required.

Signalling safeworking procedures shall prescribe the methods based on the following

protection requirements as a minimum:

• Signallers can apply blocking facilities to secure signalling controls in a specified position

(generally normal). This method does not provide a high level of protection as the signalling

remains potentially operable. It is suitable only for the immediate protection of a derailment,

collision or failed train or otherwise for the protection of engineering works where the work

does not affect the signalling system.

• Licensed signalling personnel can disable signalling apparatus to prevent its operation by

removing electrical power or air supply to motors, mechanisms or control devices. This

method provides an intermediate level of protection because the trackside apparatus

(example: points, releasing devices) that is disabled from operation still maintains

connection to the interlocking. Therefore, the apparatus may not require booking out of use

and the signals may remain operable.

This method applies only where work does not interfere with the safe operation of the

signalling system and does not impact the on-time running of trains.

Signallers shall be advised of the work and shall be requested to apply blocking facilities to

relevant signalling controls.


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An example of engineering works that may be suited to this type of protection is as follows:

o inspection and testing of signalling equipment to rectify a failure

o inspection and testing of signalling equipment to certify its correct operation during

periodic or reactive testing

o periodic maintenance of signalling equipment

Where disabled signalling is left unattended by licensed signalling personnel, a higher level

of protection shall be considered.

• The most secure method of protection is afforded when licensed signalling personnel book

out of use the trackside apparatus. This shall be done in any of the following situations:

o where disabled signalling equipment requires the use of hand signallers to facilitate

the movement of rail traffic or the movement of users at level crossings

o where signalling apparatus requires disconnection from the interlocking

o where signalling apparatus is disarranged

o where the safe operation of the signalling is put at risk by engineering works

o where the integrity of the signalling is in doubt

In these cases, the following approach shall be adopted:

o an understanding with the signaller is achieved of the work involved, the implications

to rail operation, and the safeworking requirements to be applied

o compiling an infrastructure booking authority in accordance with the network rules and

procedures

o requesting the signaller to place blocking facilities on specific signalling controls

o protecting signals made to remain at stop by electrical or mechanical disconnection

o disabling the operation of the trackside apparatus concerned and securing the

equipment in a safe state (example: clip and SL lock points)

o disabling and securing in a safe state, other equipment that interlocks with the

trackside apparatus concerned

13.3. Infrastructure booking authority Licensed signalling personnel are responsible for compiling the infrastructure booking authority

whenever they are involved in the booking out of signalling apparatus. The physical

disconnection of signalling apparatus shall begin only after obtaining the signallers approval.

The infrastructure booking authority may be transcribed by the parties where the worksite is

remotely located from signallers or train controllers. © State of NSW through Transport for NSW of 151 Sup

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Signing the infrastructure booking authority when restoring signalling apparatus into use shall

constitute certification that the affected interlocking and signalling apparatus has been tested to

be safe and fit to restore for normal operational use.

Signalling apparatus booked out of use for a period greater than six months shall be formerly

advertised in a weekly notice (or similar) in addition to compiling the infrastructure booking

authority.

13.4. Signalling disconnection requirements Signalling disconnections when left unattended shall be clearly labelled and made secure to

prevent the possibility of wrongful reconnection.

When disabling signalling, the isolation shall be confined to any of the following:

• removing fuses and disconnecting pins

• unplugging of coded plug couplers and the like

• turning off circuit breakers, isolating switches or air cocks

In general it should not warrant the removal of wires from terminals or relays, or the removal of

mechanical equipment. However, where this is absolutely necessary, the reinstatement shall be

suitably tested.

The disconnection of relays and devices shall preferably occur within the same location as the

relay/device; otherwise two points of disconnection (one on each leg of the relay/device circuit)

is required.

13.4.1. Disconnection of signals Any trainstop associated with a signal made inoperable, shall be electrically and pneumatically

(as applicable) isolated to prevent its operation.

Signals made inoperable shall continue to display a stop indication consistent with the design

requirements; otherwise the protecting signals in the rear shall be booked out of use. This

includes a signal that is manipulated to display a 'proceed' indication for the purpose of the

work.

The removal of power to signal lights shall constitute disconnection from the interlocking.

Where the signalling integrity is in doubt or where the integrity is affected by the work, a more

stringent means of disconnection and protection shall be considered (example, disabling the

higher indications of the protecting signals and the affected signals in the rear and other signals

affected by the work).

The following disconnection requirements pertain to situations where the signalling integrity is

not in doubt or where the integrity is not affected by the work: © State of NSW through Transport for NSW of 151 Sup

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Disconnection of signals activated by control relays

Signals shall be made to remain at stop by electrically disconnecting the control relay for the

first 'proceed' aspect (typically the HR/caution relay, low speed relay, or shunt control relay).

Where signals provide more than one route, it is permissible to disable only the affected routes

while still maintaining the functional routes to operate. Route links, where these are provided,

shall be used for this purpose.

Disconnection of signals activated by computer based interlockings

Signals shall be made to remain at stop by inhibiting the signal operating output using

technician controls at a maintainer's interface, or by electrically isolating the circuits that prevent

the signal from clearing.

Disconnection of signals activated by mechanical interlocking (large levers)

Signals shall be made to remain at stop by removing the respective signal lever catch rod pivot

pin and slackening off the signal wire.

Distant signals shall be made to remain at caution accordingly.

13.4.2. Disconnection of points Points are disconnected for the purpose of either disabling their operation or booking out of use.

Where points are disarranged then the points shall be booked out of use and the protecting

signals booked out of use. Protecting signals may be left operational when the points are not

disarranged.

Following are some typical situations where the points are disarranged:

• point lock is not effective and secure

• point detection is not in proper adjustment

• point switches are not held in their correct position and in proper condition

• any of the mechanical connections are not in working order

Points that are booked out of use shall also be clipped and SL locked. Where points are not

disarranged and the requirement is only to disable their operation, then it may not be necessary

to clip and lock the points unless required by network operators or other factors.

Points that are disabled or booked out of use for an extended period may be affected by

unreliable track circuits (which may not provide an effective track shunt) and the requirements of

seldom used signalling apparatus in accordance with Section 16 of this standard shall apply.


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When booking points out of use, the unavailability of emergency facilities for point manual

operation (EOL or ESML) shall be considered if the infrastructure (track, signalling, and

overhead wiring) is not fit for use. In such cases, the facility shall be locked with a Falcon 8 lock

and the information of the unavailability of the infrastructure shall be stated on the infrastructure

booking authority.

The following disconnection requirements pertain to the different point operating types:

Disconnection of points operated mechanically

The operation of mechanical points shall be disconnected by removing the catch rod pivot pin

for the respective point lever and FPL lever (as applicable).

Disconnection of points operated electrically

The operation of electrical points shall be disconnected by electrically isolating all ends of the

set of points concerned. On some machines, the points may require power-operation upon

restoration to ensure the mechanism has operated to its full stroke.

If motors are turned off for an extended period the prevention of 'point creep' shall be

considered.

Disconnection of points operated pneumatically

The operation of pneumatic points shall be disconnected by electrically isolating all ends of the

set of points concerned. Additionally, the pneumatic supply to each point end shall be isolated

except where it is necessary to maintain an air-on situation to prevent 'points creep'.

When isolating the pneumatic supply, maintaining the detection of air pressure switches in some

control valves shall be considered.

13.4.3. Disconnection of level crossings Level crossing protection equipment not fitted with master emergency arrangements (EMR) or

other approved level crossing manual override arrangements shall be disconnected by

electrically isolating the level crossing control relay or output. Where Up Road and Down Road

control relays are provided, the relevant relay shall be electrically isolated (depending upon the

affected approach tracks). In single line areas where Up Direction Stick and Down Direction

Stick relays are provided, both relays shall be electrically isolated. The operation of road and

pedestrian boom/gate mechanisms shall be electrically isolated (by means other than operating

the boom emergency switches) and the road booms tied in the raised position. Pedestrian

booms/gates shall not be tied in the raised/open position. Additionally, protecting signals that

interlock with the level crossing shall be booked out of use.


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Level crossings that are fitted with EMR or other approved level crossing manual override

arrangements enable full functionality of the level crossing protection equipment during manual

operation irrespective of the status of the control circuits. This maximises the availability of

warning provided by the level crossing. Master emergency switch operation (or override

function) deactivates the level crossing operation in the raised position and causes the signals

on the approach side of the level crossing where provided to display stop. When it becomes

necessary to allow rail traffic to pass, the manual operating switch or similar in override

arrangements is used to activate the level crossing protection. The signals shall clear once the

level crossing has been proved in the lowered position and the availability of other conditions.

Therefore, level crossings fitted with EMR or other approved level crossing manual override

arrangements, when booked out of use, need not be disconnected unless the level crossing

protection equipment itself is inoperable.

The removal of power to level crossing protection equipment shall constitute disconnection from

the interlocking.

13.4.4. Disconnection of track circuits Track circuits shall be disconnected to prevent the energisation of the parent track circuit

relay/output. Care shall be taken to ensure track circuit relays/output are not falsely energised

by other track circuits or power sources.

The transmitter/feed end and receiver/relay end shall be electrically isolated from the respective

trackside apparatus. Additionally, 50 Hz ac, dc and high voltage impulse (HVI) tracks circuits

such as Jeumont Schneider type shall have their transformer/battery/transmitter power supply

isolated.

For audio frequency overlay track circuits such as PSO 4000, the power supply to transmitters

and receivers shall be retained where practical. This will avoid loss of the volatile memory that

contains the date and time logs. Disconnection of audio frequency overlay track circuits shall be

done by isolating the transmitter and receiver links in the location.

Note: Where the power supply is removed from audio frequency overlay track circuit

transmitters or receivers, this will necessitate the resetting of the time and date

function.

For Microtrax coded track circuits, the power supply to master and slave cardfiles shall be

retained where practical. Disconnection of Microtrax coded track circuits shall be done by

isolating the links within the track interface panel at both ends of the track.


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13.4.5. Disconnection of releasing switches and electric lever locks Releasing switches and electric lever locks shall be disconnected to prevent their operation by

electrically isolating the coil operating circuit. A test shall be conducted to ensure that the device

is inoperative.

14. Temporary bridging of signalling circuits The principle for using temporary bridging states that the protection defeated by the bridging is

provided by an effective alternate means.

Temporary bridging of signalling circuits shall be done only in exceptional circumstances as

necessary to minimise disruption to trains caused by signalling equipment that is damaged or is

disconnected or disarranged.

Temporary bridging shall not be connected across any contacts which provide protection for the

movement of trains in either of the following cases:

• where it prevents signalling apparatus from properly returning to a more restrictive position

or locked position

• where it allows unprotected signalling apparatus to operate to a less restrictive or unlocked

position when it is not safe to do so

Temporary bridging of signalling circuits shall be performed in accordance with signalling

safeworking procedures.

Signalling apparatus with temporary bridging applied shall be booked out of use. Safe

arrangements shall be made to secure the apparatus concerned so that it cannot be moved out

of correspondence with the interlocking and the bridged-out position. Signals affected by the

apparatus temporarily bridged shall also be booked out of use except where stated in

Section 14.1.

Temporary bridging shall be confined to bridging of closed contacts of trackside signalling

apparatus that indicate the locked, fail-safe position of the apparatus. For example, the 'Normal'

indicating contacts of signals at stop or trainstops in the raised position or the detection contacts

of points in their correct position and locked. The temporary bridging of contacts shall be limited

only to failed or removed apparatus. Jumper wires shall be connected as close as possible to

the apparatus concerned.

Contacts that are temporarily bridged shall be disconnected so that the work does not interfere

with the live portion of the circuit.

Additionally, where 'Normal' detector contacts are temporarily bridged, for example at an end of

points, the circuits that provide the Reverse detection shall be disconnected. Similarly, if the

Reverse detector contacts are temporarily bridged, the circuits that provide the 'Normal' © State of NSW through Transport for NSW of 151 Sup

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detection shall be disconnected. This precaution may also apply to other apparatus such as

trainstops and level crossing mechanisms.

Only licensed signalling personnel deemed competent to perform the activity of temporary

bridging without supervision, shall lead this work.

14.1. Booking protecting signals into use In order to facilitate train running while temporary bridging is applied, the authorising signal

engineer, after due consideration of the associated risks, may permit the booking into use of

specific protecting signals. This shall be done on the following conditions:

• testing is conducted to ensure correct application of temporary bridging as stated in

Section 14.4

• point securing equipment such as point-clips, locks and spikes, as applicable, are applied

and frequently inspected

Protecting signals shall not be booked into use which would allow trains to operate over lines

where signalling equipment is moved out of correspondence with the interlocking and the

bridged-out position. Protecting signals shall also not be booked into use where the equipment

is disarranged or worked on in a way that the safety of the signalling is impaired (example:

facing points not adequately secured).

The decision to allow protecting signals to operate over disarranged facing points which have

been secured by alternate means, shall be discussed between the authorising signal engineer

and a signal engineer who holds accountability to ensure all the risks are controlled before

implementation.



14.2. Approval for temporary bridging Temporary bridging to signalling circuits shall be granted either by an approved circuit design or

by a documented process and a bridging authority form issued by the authorising signal

engineer. The authorising signal engineer shall discuss the bridging arrangements with the

person applying the bridging and with the person removing the bridging. The testing

requirements shall also be discussed.

In both cases, the responsible signal engineer shall be notified of the temporary bridging

arrangements.

Where it is impractical for the authorising signal engineer to directly issue the bridging authority

form, the authorising signal engineer may delegate the issuing of the form to a licensed

signalling person who is independent of the work. This person shall transcribe the instructions © State of NSW through Transport for NSW of 151 Sup

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for the bridging as provided by the authorising signal engineer. The name of the authorising

signal engineer shall suffice until a signature is obtained.

Temporary bridging granted by an approved circuit design shall be performed in accordance

with SPG 0711.

14.2.1. Approval of temporary bridging by authorising signal engineer Where temporary bridging is granted by an authorising signal engineer, it shall be performed in

accordance with a documented process and a temporary bridging authority form stating at least

the following information:

• unique temporary bridging authorisation number

• location and listing of signalling equipment to be bridged

• planned date and time for the application and removal of bridging

• reason for the temporary bridging

• a photocopied diagram of circuits to be bridged

• authorising signal engineer approval (name, signature and date approved)

• the responsible signal engineer's advise (name and date advised)

• person nominated to apply bridging (name, signature, time and date bridging applied)

• identification numbers of jumper wires applied

• person nominated to remove bridging (name, signature and time and date bridging

removed)

• identification numbers of jumper wires removed

• time and date of removal advice provided to authorising signal engineer

• authorising signal engineer final sign-off (signature and date)

The bridging authorisation number shall be noted on the infrastructure booking authority as

stated in the network rules and procedures. Additionally, the word 'BRIDGED' in brackets shall

be written along side each of the equipment listing that has bridging applied.

When booking the affected signalling back into use, signing the infrastructure booking authority

shall constitute certification that all the temporary bridging has been removed and the affected

signalling has been tested to be safe and reliable.


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14.3. Jumper wires for temporary bridging Jumper wires used for temporary bridging shall be of suitable length and the insulation of bright

colour to ensure that the jumper wires are noticeable. The temporary nature of the wiring

installation shall be made obvious.

Conductors shall have a minimum cross section of 1.5 mm² with an insulation 0.6/1 kV

standard. The connecting lugs, plugs or clips shall be insulated and suitable to its application.

The connection shall be secure to ensure that there is no possible connection to an inadvertent

terminal or circuit.

Precautions shall be made to ensure jumper wires used for temporary bridging are not

interfered with during the time of their application.

Where the authority of temporary bridging is not provided by an approved signalling design, the

jumper wires shall be controlled by the authorising signal engineer, individually numbered for

identification, registered and stored in a secured box. Issuing of jumper wires shall be limited to

the amount required as authorised on the temporary bridging authority form.

Temporary bridging used as part of an approved signalling design shall be in accordance with

the relevant design.

In an emergency, the authorising signal engineer may approve the making up of an improvised

jumper wire for temporary bridging. The emergency jumper wire shall be fitted with an

identification label. The authorising signal engineer shall write down a description of this jumper

wire in the temporary bridging authority form. The improvised jumper wire shall be destroyed

immediately after the emergency use.

14.4. Testing of temporary bridging Testing shall be performed to ensure that all contacts not intended for bridging remain effective

in the circuit while the temporary bridging is applied. Testing of entire affected circuits shall also

be performed upon removal of temporary bridging to ensure all temporary bridges are removed

and all contacts are effective in the circuit. This test shall include a correspondence test, an out

of correspondence test (as applicable), a wire/null count and an apparatus function test.

Signals affected by the work shall remain booked out of use until the satisfactory completion of

all relevant tests, both upon applying temporary bridges and then upon subsequent removal of

temporary bridges.


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14.5. Temporary bridging left unattended Where the temporary bridging is likely to be left unattended for some time, additional

precautions shall be made to ensure the jumper wires are not tampered with.

Any facing points clipped shall be XL locked and spiked to prevent an unauthorised movement

of the points causing an out of correspondence with the interlocking and the bridged-out

position. Any attempt to manually operate the points using an ESML or EOL facility shall be

prevented using Falcon 8 locks to secure the equipment.

Precautions of a similar nature shall be applicable to other apparatus temporarily bridged as

necessary.

14.6. Reinstatement advice for temporary bridging The authorising signal engineer shall be notified of the removal of temporary bridging and

subsequent testing. These notification arrangements shall be discussed and agreed at the time

of authorisation. The authorising signal engineer shall pursue advice of removal if not notified

once the agreed notification time has elapsed.

Any required extension of time for the application of temporary bridging shall be approved first

by the authorising signal engineer.

14.7. Non-vital signalling circuits Where non-vital signalling circuits are physically separate from vital signalling circuits, they may

be exempt from these temporary bridging requirements.

14.8. Momentary bridging Momentary bridging is the bridging of specific circuit contacts for the purpose of releasing

track-locking or indication-locking when performed by licensed signalling personnel. The jumper

wire shall be hand held (at least at one end) at all times and never be left connected. The bridge

shall be applied momentarily for just sufficient time to allow the release to be given.

The jumper wire and issuing criteria used for momentary bridging need not meet these

temporary bridging requirements; however the jumper wire and connection means used shall be

suitable for its application.


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15. Release of track and indication locking Release of track and indication locking is provided to manage train movements when the

interlocking is locked and unable to become ‘free’ due to specific situations.

Examples of such situations include the following:

• a failure of electric locks or circuitry

• an incorrect route set for an approaching train

• a rail vehicle that has failed on a particular section of track

Most track and indication locking is designed to be automatically released by the interlocking;

however there are occasions where licensed signalling personnel are required to provide a

manual release when requested by network controllers.

15.1. Rules and types of releases The interlocking between conflicting signals and/or points and/or level crossings shall not be

released.

At standard relay interlockings, relays such as signal reverse relays, points normal/reverse

relays and releasing switch normal relays shall not be released.

At route control interlockings, relays such as route reverse relays, point normal/reverse lock

relays and releasing switch normal/reverse lock relays shall not be released; however in

exceptional circumstances, the route locking in point lock relay circuits may be released.

Manual releases are permitted in accordance with signalling safeworking procedures when

either of the following occurs:

• track locking (approach locking and route holding) is locked

• indication locking on mechanical levers (signal normal indication and point normal/reverse

indication) is locked

At some installations, circuits may combine interlocking with track locking, or track locking with

indication locking and it is necessary to ensure that only the specific locking is released.

15.1.1. Locking principles used in interlockings The following principles of locking relate to the release of interlockings:

Approach locking

Approach locking is provided to prevent the alteration of a route in the face of a train which has

received a 'proceed' signal indication for the route.


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This provides an assurance of the following:

• all facing points are in correct position and locked

• trailing points are set for the non-conflicting position (and hence no converging routes can

be set)

• opposing signals are retained at stop

Route holding

Route holding is provided to prevent the following for a train that has entered a valid route:

• the unlocking or movement of facing points within the route

• the alteration of facing points in the overlap to an obstructed overlap

• the alteration of trailing points within the route and in the overlap

• the clearing of opposing signals

Indication locking

Indication locking is provided to ensure all safe conditions are met for train movements before

allowing a signal or points lever to enter (or relevant relay to indicate) its full position, which may

then free the locking for other signals or points.

15.1.2. Manual releases Manual releases are only permitted on the following:

• normal indication (NI) electric locks on mechanical signal levers

• normal/reverse (N/R) electric locks on mechanical point and facing point lock levers

• point normal/reverse indication (NI/RI) electric locks on mechanical point levers

• point lock relays at standard relay interlockings

• signal normal indication relays at standard relay interlockings

• approach stick relays at standard relay interlockings and at route control interlockings

• signal route normal lock relays at route control interlockings

• route holding in point lock relay circuits at route control interlockings

The manual releasing methods shall be limited to the following:

• momentarily lifting an electric lock on mechanical levers while the lever is moved


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• momentarily energising a signal normal indication relay at standard relay interlockings, or a

point lock relay at standard relay interlockings (not route control interlockings), or a signal

route normal lock relay at route control interlockings

• momentarily bridging the track stick contact of the approach stick circuit at standard relay

interlockings or at route control interlockings, or the affected track circuit contacts proving

the track locking element in a point lock relay circuit at route control interlockings

15.2. Requesting a release A formal 'request for release' shall be obtained from the signaller before a manual release is

provided. Details of the release shall be entered in the train register book or other permanent

record or by using an infrastructure booking authority. The details of the release shall be signed

by both the signaller and the licensed signalling person.

The signaller shall be requested to place the associated signals to stop and ensure they remain

at stop by applying appropriate blocking facilities before a release is provided. Licensed

signalling personnel shall also receive an assurance from the signaller (recorded on the request

for release document) that all approaching trains have come to a stand and shall remain so.

A separate request shall be obtained for every release given, requiring either a separate entry in

the train register book or other permanent record or a separate infrastructure booking authority.

15.3. Precautions before releasing normal indication locks on signal levers Normal indication (NI) locks on signal levers incorporate indication locking and track locking for

approach locking and in some cases route holding.

The following precautions shall be observed before providing a release of normal indication

locks on signal levers:

• ensure the associated protecting signals are at stop and the trainstops where provided are

in the raised position

• ensure any train approaching the signal involved has been brought to a stand

• ensure any train occupying track circuits included in the normal indication lock circuit has

been brought to a stand and is clear of any points in the route ahead of the signal

15.4. Precautions before releasing normal/reverse locks on point or facing point lock levers Normal and reverse ('N/R') locks on mechanical point or facing point lock levers incorporate

track locking generally for both approach locking and route holding.


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The following precautions shall be observed before providing a release of normal/reverse locks

on point or facing point lock levers:



• ensure any approaching train has been brought to a stand

• ensure no train is foul of any of the points worked by the points lever

At hybrid installations containing both mechanical and relay interlocking, ensure that all relay

interlocked functions are non-conflicting with the mechanical interlocking. This shall be done

before a normal or reverse electric lock is released on a point or facing point lock lever.

Where it is intended to by-pass a train occupying route holding circuits with another train, the

licensed signalling person giving the release shall be assured by the signaller that both train

drivers are aware of the intended move.

15.5. Precautions before releasing normal/reverse indication locks on point levers Normal or reverse indication (NI/RI) locks on point levers apply indication locking and do not

incorporate track locking.

The following precautions shall be observed before providing a release of normal/reverse

indication locks on point levers:

• ensure the points are lying in correspondence with the point lever and the point switch

blades are in their respective fully closed/fully open positions as applicable, and that facing

points where provided are securely locked by the point lock

• ensure the points will not be unlocked or moved before giving the release - if necessary clip

and SL lock the points

Points that remain out of use following an initial release of the indication lock shall not be

released again unless the points are booked out of use, clipped and SL locked. The failed

indication lock may then be permanently released if necessary. This is done to enable the lever

to be placed in correspondence with the points position in order to obtain the sequence of the

interlocking.

Rail traffic shall not be permitted to pass over facing points while the point lever is in the NI or RI

position; unless the points are secured by clip and SL lock.


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15.6. Precautions before releasing point lock relays at standard relay interlockings Point lock relays in standard relay interlockings apply track locking, generally for route holding

and in some cases approach locking.

The release of point lock relays at standard relay interlockings may be provided except in cases

of track locking (approach locking). Such approach locking is released by the approach stick

relay.

The following precautions shall be observed before providing a release of point lock relays at

standard relay interlockings:



• ensure any approaching train has been brought to a stand

• ensure no train is foul of any points worked by the points control




15.7. Precautions before releasing signal normal indication relays at standard interlockings The release of signal normal indication relays at standard relay interlockings may be provided

except in cases of track locking (approach locking); such approach locking shall be released by

the approach stick relay.

The following precautions shall be observed before providing a release of signal normal

indication relays:

• ensure the associated protecting signal is at stop and the trainstop where provided is in the

raised position

• electrically disconnect the associated signal to prevent its operation



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15.8. Precautions before releasing approach stick relays Approach stick relays are provided for approach locking of signals that protect points.

The following precautions shall be observed before providing a release of approach stick relays:


raised position


15.9. Precautions before releasing signal route normal relays at route control interlockings The release of signal route normal relays at route control interlockings may be provided except

in cases of track locking (approach locking); such approach locking shall be released by the

approach stick relay.

The following precautions shall be observed before providing a release of signal route normal

relays:


raised position

• electrically disconnect the associated signal to prevent its operation


15.10. Process for releasing route holding in point lock relay circuits at route control interlockings In route control interlockings, point lock relays incorporate interlocking functions and shall not be

released except in the following cases and only as permitted by a signal engineer:

• a failure occurs of the track locking element in a point lock relay circuit

• the route holding tracks are occupied by a failed rail vehicle

In these cases, the release of track locking shall be performed in accordance with the process

for energising the applicable point lock relay. This process allows the point lock relays to be in

correspondence with the intended lie of the points. The specific release details shall be fully

explained to the signaller.

The following process shall be observed to provide a release of route holding in point lock relay

circuits at route control interlockings:

1. ensure all signals that interlock with the points are at stop and the trainstops where

provided are in the raised position


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2. ensure any train that has entered the route concerned has come to a stand

3. ensure any points or releases which interlock with the points concerned are in non-

conflicting positions

4. ensure no train is foul of the points concerned

5. instruct the signaller to operate the point control to the position in correspondence with the

current lie of the points (and the interlocking) and apply a block to the point control

6. manually operate the points concerned to the intended (opposite) position and secure by

clip and SL lock (this will temporarily place the points out of correspondence with the

interlocking and point control)

7. momentarily bridge the appropriate track locking relay contacts in the relevant point lock

relay circuit and instruct the signaller to operate the point control to the centre position and

observe the points 'free' indication

8. instruct the signaller to operate the point control to the intended position (normal or

reverse) in correspondence with the lie of points

9. remove the bridge immediately upon the respective point lock relay becoming energised

10. check that the opposite point lock relay is in the de-energised position

No attempt shall be made to operate the point lock relay or points by operating route set

buttons.

Contacts in the point lock relay circuit, other than those applying track locking, shall not be

bridged.

Point lock relays shall not be manually lifted or replaced with a relay in the 'energised' position.




15.11. Providing releases for other situations including computer based interlocking Other situations may arise when the signalling interlocking has been locked and may require a

release. An example of this is at computer based interlockings where a loss of track circuit input

may cause the interlocking to be locked.

In such cases, where the procedures for providing a release are not prescribed by this standard,

the risks of providing such a release shall be first identified by a signal engineer.

The decision to release the signalling interlocking shall be decided by the signalling engineer

holding accountability for providing assurance.


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The principles prescribed in this section shall be applied when permission is granted to provide

the release.

16. Management of seldom used signalling apparatus Signalling apparatus which is rarely or never used due to a change in rail traffic conditions shall

be managed in accordance with signalling safeworking procedures.

Signal boxes and associated apparatus which are normally closed shall be suitably maintained

and tested before the signal box is brought back into use.

Licensed signalling personnel shall take every opportunity to inspect the rail surface of track

circuits to evaluate the capability of an effective track shunt, particularly at sections of track

which are prone to seldom use, such as sidings, refuge lines, crossovers and so on.

Signalling apparatus seldom used that has the potential to impair the safety of the signalling

system shall be immediately booked out of use including the associated protecting signals.

The responsible signal engineer shall be immediately advised of seldom used signalling that

pose a risk to the safety of signalling. The responsible signal engineer shall assess and mitigate

the risks associated in such situations to an acceptable level and shall retain a register of

seldom used apparatus for this purpose. The responsible signal engineer shall liaise with the

network operators, with an aim to ensure sufficient trains are tabled through the track circuits

and the affected points that are seldom used to maintain the condition of the rail surface.

The reinstatement of signalling affected by apparatus seldom used shall be conditional upon the

signalling (including points) being tested to ensure that they are in working order. The track

circuits shall be tested to ensure that they are capable of providing an effective track shunt.

Alternatively where the risks associated in such situations are assessed and mitigated by a

signal engineer, the specific signalling may remain operational.

16.1. Seldom used point configurations Following are examples of point configuration which may cause the points to be seldom used:

• emergency crossovers

• power worked double-ended crossovers provided for out of course working

• points at sidings or refuges operated from a remote signal box

• points at sidings or refuges locally operated from a ground frame or adjacent control panel

• installed points pending commissioning or removal


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Points affected by seldom use for a period greater than nine weeks shall be clipped, XL locked

and spiked.

Points that are inoperable or have other constraints due to seldom use shall be listed at the

relevant signal box.

The portion of a turnout that is rarely used forming part of a run-off not governed by a signalled

approach may be exempt from 'seldom used' requirements and the points may be left

operational.

Where seldom used points become impractical to operate for maintenance purposes and the

points are booked out of use, the maintenance may be reduced to the specific tasks stated in

Section 16.1.4 of this standard.

16.1.1. Specific requirement for emergency crossovers Emergency crossovers, whether operated by ground frames released by a releasing switch,

duplex lock or similar arrangement, shall be clipped and XL locked in the normal position when

the emergency crossover is not in use.

16.1.2. Points at sidings or refuges operated from a ground frame or adjacent control panel Points at sidings or refuges operated from a ground frame or adjacent control panel may remain

operational where the operator can clearly observe the clearance point or other end of points.

16.1.3. Installed points pending commissioning or removal Where a set of points is installed pending proper connection to the interlocking or where the

interlocking is removed from points pending removal, the point switch blades shall be

adequately secured in accordance with ESG 100 Signal Design Principles.

The periodic maintenance of point securing devices for points not properly connected to the

interlocking shall be scheduled as if they were operational points. The maintenance tasks shall

be performed in accordance with Section 16.1.4 of this standard.

The checking of XL locks, point-clips and point-spikes used to secure installed points that are

not connected to the interlocking shall be included in the signal engineer's periodic testing of

signalling interlockings in accordance with Section 27.4.

16.1.4. Specific maintenance tasks where points are impractical to operate due to seldom use Where it is impractical to operate points for maintenance purposes due to seldom use, the

specific tasks listed below shall be scheduled at the same frequency as operational points.


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These tasks provide the integrity for the signalled routes that remain operational through the

points retained in the normal position.

The specific tasks do not preclude other maintenance activities from being performed on the

affected point equipment such as insulation testing or cleaning and lubrication. Full

maintenance services shall be resumed before points are made fully operational.

The minimum tasks (as applicable) to be performed for points that become impractical to

operate for maintenance purposes due to seldom use include the following:

• check that releasing arrangements and manual operating levers are securely locked

• check for damage to the point equipment including point rods

• check the fastenings are secure and are of the correct type (example: nyloc nuts)

• check that the point-spikes, point-clips and locks are securely fitted

• ensure the point lock is securely plunged and effectively locking the points

• check the closed-switch is secured against the stock rail throughout its entire length and

that the back-drive is not moving or flogging during train passage

• ensure the detection mechanism is in its proper position and is secure

• check that the stretcher rods securely maintain the open-switch in its correct position and

ensure the minimum flange-way clearance is provided

• check for evidence of excessive movement or wear to the points channel iron or points

mechanism and ensure there is no drifting of the motor/operating bar (points motor latched

for EP Claw Lock & EP Spherolock)

• check for evidence of excessive movement or wear to the permanent-way at the points

• inspect condition of parallel bonds including rail connections and retaining clips

16.2. Seldom used track circuits Network control officers treat the operation of track circuits that have not been travelled over by

rail traffic for 72 hours or more as unreliable (seldom used) and shall manage rail traffic in

accordance with the network rules and procedures.

Note: Where installations provide inherent protection from the risks of rusty rail

(example: axle counters), the signalling may be left fully operational irrespective of the

track shunt condition.

16.2.1. The 72 hour rule

The 72 hour period calculation assumes a base-line at which the rail surface condition was

relatively free of contaminants and was frequently utilised by rail traffic, such that it provided an © State of NSW through Transport for NSW of 151 Sup

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effective track shunt, before the 72 hour period commenced. Where the rail condition is in a

lesser state, then consideration to reduce the 72 hour period nominated in the network rules

and procedures may be proposed as an exception to the general requirement. In such cases,

the exception shall be documented and duly issued to the designated network control officer

and relevant signalling personnel.

In certain circumstances, the responsible signal engineer may deem it acceptable to extend the

72 hour period, conditional upon an assessment of the engineering risks and operational

implications being appropriately mitigated. The determination shall take into account the factors

for consideration stated in Section 16.2.3 of this standard. The matter shall then be raised for

acceptance with the signal engineer holding accountability on behalf of the operator/maintainer

and the appropriate network control officer.

16.2.2. Identifying and testing track circuits at risk Where rail traffic has stopped operating for periods greater than 72 hours affecting large areas

of track circuited lines, suitable arrangements shall be put in place to identify and test the track

circuits at risk.

Periods of non-use may be instigated by possession work, industrial dispute, alteration to

normal timetables or varied freight operations.

Proper and timely notification, liaison and planning with the relevant parties are required to

ensure that risks associated with loss of track shunt are managed effectively so as to not cause

a reduction in signalling safety.

Examples of trackwork or possession situations which may cause track circuits to be at risk of

not providing an effective track shunt include the following:

• track circuits directly worked on during trackwork (example: installation of new or rusty

rails)

• track circuits inside a possession area that are not part of any trackwork

• track circuits outside a possession area that are not traversed due to an operational

variance caused by the possession

An inspection and test plan shall be arranged as part of a strategy for testing track circuits for an

effective track shunt following periods of non-use greater than 72 hours.

The method and scope of testing shall vary depending upon the reason for the event, length

and track configuration, type of trains in operation, weather conditions and the period of

non-use.

Testing strategies may require re-evaluation if the scope of work or possession arrangements

alter throughout the period of non-use.


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Certification of the track circuits and subsequent running of train services shall not exceed

24 hours from the conclusion of testing.

16.2.3. Risk assessment - factors for consideration The decision to allow signalling to operate over seldom used track circuits relative to the

potential loss of effective track shunt due to rail surface contamination needs to be determined

on site by a signal engineer.

Signalling safeworking procedures shall prescribe the factors for consideration required when

determining the option for allowing the signalling system to operate when track circuits are

seldom used.

Examples of factors for consideration include the following:

• capability of an effective track shunt

o type of track circuit used

o random or loose contaminants causing intermittent loss of shunt

o new or seldom used rusty rail, causing high likelihood for the loss of shunt

• location of contaminated rail

o proximity to clearance points and tuned loops

o length of contamination (equal to a whole train or light engine)

o contamination spanning the entire track circuit

o contamination spanning several track circuits

• environment and configuration

o long straight or tangent track allowing smooth rolling of wheels on rails

o contaminated rails affecting part of a siding or refuge

o contaminated turnout rails which form part of a mainline crossover

o contaminated rails in both turnout and straight rails of points

o points operated remotely or locally from a control panel or adjacent ground frame

o seldom used track circuits that operate level crossing protection equipment

o areas prone to high humidity, excessive rainfall or temperature extremes

o rail susceptible to rusting due to environmental contaminants including ocean salt

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• rolling stock operating on affected line

o electric trains

o mixed trains

o freight only trains

o light engines

o typical rolling stock length and consist

o speed of rail vehicles, especially short or light vehicles

o axle loading, number of axles per train and gross tonnage

o time and frequency between rail vehicles

o rolling stock with tread conditioning from brake shoes or only disk brakes used

o wheel and rail profile, variance of wheel to rail contact band, risk of 'hollow' wheels

o rail contaminants emanating from rail vehicle

o track circuit shunt assistors used on certain rolling stock to enhance track shunt

capability

• maintenance and administrative controls

o effective monitoring

o regular grinding

o utilisation of a temporary stop-block to reduce risk

o specific signal routes left operational subject to an acceptable level of risk

o the arrangement of more frequent services

o determining if manual safeworking operation would cause a higher risk

o determining if blocking facilities applied to signalling controls in lieu of apparatus

disconnection would cause a higher risk

o determining if a change to the Train Operation Conditions (TOC) Manual would

provide an acceptable risk

Where adverse conditions continue or where infrequent or light weight traffic services

permanently operate, options for engineering design solutions that mitigate the risk of an

effective track shunt in these situations shall be sought.


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17. Requirements for re-railing and associated trackwork When re-railing is performed that involves breaking the rails of track circuited or electrified lines,

certain elements shall be considered to ensure all the risks associated with the work are

understood and controlled. These considerations shall include the following elements:

• protection of trains

• provision of alternative traction return

• testing of track circuits and associated signalling

• ensuring an effective track shunt

• certification of infrastructure for operational use

Note: For the purpose of this standard, re-railing includes any trackwork that involves

breaking the rail.

17.1. Licensed signalling personnel attendance Licensed signalling personnel shall attend re-railing when it occurs in any of following situations:

• within interlocked areas, except where outer home signals are provided and the intervening

track circuits do not impact the operation of the interlocking

• in the vicinity of points located at intermediate sites outside an interlocking

• in plain track areas where the length of re-railing is six metres or more

• at any location on electrified single lines

• in the vicinity of insulated joints, tuned loops or any other track interface, including short

sections of rail in the vicinity of converging track clearance points

• adjacent to substations or sectioning huts

• wherever there is potential for traction bonding or track circuit cabling to be interfered with

by the work

In all other cases, licensed signalling personnel may be exempt from attending re-railing. In

such cases, temporary rail bonds shall be issued by signalling personnel to qualified track

workers for them to apply. This is done to allow the trackwork, which would otherwise affect

operational signalling, to proceed with minimum disruption to rail traffic. The track circuits

remain operable by the placement of temporary rail bonds around the rail break. Temporary rail

bonds and their placement shall be in accordance with the requirements stated in Section 17.7

of this standard.


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When licensed signalling personnel are required to attend re-railing, they shall protect rail traffic

and signalling equipment from the work by undertaking the following tasks:

• considering the effects caused on the signalling system by the re-railing

• compiling the infrastructure booking authority

• booking protecting signals out of use

• providing an alternative path for traction return current, as necessary

• disconnecting affected track circuits

• disconnecting associated signalling equipment

At the end of re-railing, licensed signalling personnel shall reinstate and test the affected track

circuits. They shall also ensure the rail surfaces are sufficiently clean to provide an effective

track shunt. Associated signalling shall be functionally tested before restoring the signalling

back into use.

17.2. Infrastructure booking authority requirements Before commencing the re-railing, an infrastructure booking authority shall be compiled in

accordance with network rules and procedures. Licensed signalling personnel shall be

accountable for compiling the authority. Qualified representatives from track and electrical shall

also sign the authority as applicable. The signaller shall sign the authority, permitting the work to

proceed.

Signalling apparatus shall not be disconnected until the infrastructure booking authority has

been signed by the signaller. Trackwork that affects signalling shall not commence until

authorised by licensed signalling personnel. This is required to confirm the protecting signals

are booked out of use and alternative traction arrangements are in place, as applicable.

Signatures shall again be obtained at the completion of work before the signalling is deemed

operational.

17.3. Protection of rail traffic The requirements for securing signalling, for the purpose of protecting rail traffic from the

re-railing, shall be as follows:

• track circuits affected by the re-railing shall be disconnected

• protecting signals that immediately lead toward the tracks affected by the re-railing shall be

booked out of use and disconnected

• signals in the rear of the protecting signals shall also be booked out of use where the

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• trainstops provided at protecting and affected signals shall be retained in the raised

position

• automatic level crossing protection affected by the re-railing shall be booked out of use

Level crossing protection shall be disconnected if not fitted with master emergency or other

similar manual override facilities. Whenever level crossing protection is disconnected, it

shall be functionally tested by operating each approach track circuit in turn, before the level

crossing is booked back into use.

Where an affected level crossing is situated on double line areas with automatic signalling,

the signals approaching the level crossing on lines that are not affected by the re-railing

may be left working if required.

• other trackside signalling equipment affected by the re-railing shall be booked out of use,

disconnected and removed clear of the trackwork as necessary, for example, points

equipment, balises used for automatic train protection

17.3.1. Re-railing on bi-directional lines On lines where the signalling is bi-directional, the immediate protecting signals in each direction

shall be booked out of use and disconnected. Signals other than the immediate protecting

signals, where affected by the re-railing shall be booked out of use, but may be left connected.

This alleviates the need to physically disconnect each intermediate signal within the

bi-directional section where it is impractical to do so.

Starting signals that are not directly affected by the re-railing may be left operational.

17.4. Traction return arrangements The requirements for providing adequate traction return shall be in accordance with Section 18

of this standard. This provision relates to traction return arrangements for work such as

re-railing, disconnection of traction bonding or disconnection of negative return cables at

substations and section huts.

17.5. Requirements for newly installed rails The surfaces of newly installed rails are most likely to be contaminated with protective coatings,

rust and other contaminants. Where track circuits are in operation, this poses a risk that trains

may not provide an effective track shunt and as such, may not be detected by the signalling

system.

Therefore, the surfaces of rails, including the running face, shall be made sufficiently clean

along the entire length of track circuit in order to provide an effective track shunt. This shall be

done before the protecting signals are restored for operational use.


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Following re-railing, the rails shall be cleaned to provide a shiny metallic surface to achieve a

good electrical wheel to rail interface. This shall be achieved by the following methods, as

applicable:

• Mechanised profile-grinding long sections of newly installed rail. The grinding shall clean

any protective coating, rust or other contaminates for the full width of the rail head and

along the running face for the entire section of newly installed rail.

• Hand operated rail-grinding short sections of newly installed rail. The grinding shall clean

any protective coating, rust or other contaminates for the full width of the rail head and

along the running face for the entire section of newly installed rail.

• Utilising the passage of trains or other rolling stock to provide a satisfactory wear band on

the rail surface and running face to achieve an effective track shunt. The trains shall not

operate on signals until an effective track shunt is obtained.

A train shunt check shall be performed following the installation of newly installed rails. The

trains shall operate under a manual system of safeworking, such as manual block working and

not under signals, until an effective track shunt is obtained.

An exemption to the train shunt check requirement may apply in any of the following situations:

• On sections of newly installed rail not exceeding 15 metres, where the newly installed rail is

at a distance greater than 15 metres from any clearance point or adjacent track circuit

(insulated rail joint or tuned loop).

In addition to the train shunt exemption, there is no requirement to clean the rail surface.

• On sections of newly installed rail not exceeding 15 metres, where the newly installed rail is

at a distance of 15 metres or less from any clearance point or adjacent track circuit

(insulated rail joint or tuned loop).

In such cases the exemption shall only apply where the rail surface and running face have

been cleaned using a hand operated or mechanised profile grinder. Additionally, an

inspection of the newly installed rail surface shall prove the rail surface and running face

are free of contamination. A fixed shunt check shall then be performed on each track circuit

affected by the newly installed rail section.

• On sections of newly installed rail exceeding 15 metres, where a mechanised profile

grinder is used to clean the rail surface and running face and the grinding was completed

no more than 72 hours from the time of certification.

In such cases, an inspection along the entire length of the newly installed rail shall prove

the rail surface and running face are free of contamination. A fixed shunt test shall be

performed on each track circuit affected by the newly installed rail.


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Note: Short sections of newly installed rail pose a risk of loss of track shunt. For

example, a short section of newly installed rail (two metres or longer) that is located 15

metres or less from a clearance point or adjacent track circuit (insulated rail joint

placed or tuned loop). In this case, there is a risk that a bogie of a train may stand on

the rusty portion of the new rail and be foul of the converging line or adjacent track

circuit. The train may not be detected by the signalling system.

These dimensions are derived from a wheel base of a single bogie that is approximately two

metres and the centre line between bogies is approximately 15 metres.

17.6. Reinstatement of signalling Following the re-railing work, the affected track circuits shall be tested in accordance with the

track circuit inspection and testing requirements stated in Section 25.3 of this standard. The

tests shall be done only after the traction return arrangements are reinstated.

The requirements of a train shunt check in accordance with Section 17.5 of this standard shall

apply.

Testing shall ensure the track circuits operate in accordance with their design requirement and

that the polarities, where applicable, comply with the track insulation plan. Additionally, the track

circuits shall be tested to ensure they de-energise with the correct shunt resistance applied

(track shunt check) and also when the feed-end power supply is removed (zero feed test).

Where the re-railing affects parallel bonds, the parallel bonds shall be ensured for correct and

effective connection after re-railing. The portion of track circuit connected via the parallel bonds

shall be shunt tested before the signalling is restored for operational use.

All affected signalling shall be checked to be operational before certifying its use.

The infrastructure booking authority shall be signed by the relevant disciplines to certify their

respective infrastructure and then signed by the licensed signalling person to certify the

signalling infrastructure. The authority shall then be provided to the signaller for sign-off.

Note: Signing the infrastructure booking authority back into use constitutes certification

that the infrastructure is safe for operational use.

The responsible signal engineer shall retain a copy of the completed infrastructure booking

authority.

17.7. Control and issue of temporary rail bonds Temporary rail bonds referenced in this standard are the bonds applied by non-signalling track

workers during re-railing. Temporary rail bonds are used when the work necessitates rails to be

broken and licensed signalling personnel are not required to attend, in accordance with this


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standard. These bonds are intended to keep the track circuits working, and maintaining the

traction return current, in order to minimise disruption to rail operations.

The following are examples of trackwork where temporary rail bonds are required to be fitted:

• pulling back for expansion or creeping

• welding rail joints

• renewing defective fishplates

• replacing a section of rail less than six metres long

The responsible signal engineer shall issue the temporary rail bonds to track workers on

request. The responsible signal engineer shall gather an understanding of the intended scope of

work and then provide clear instruction to the track worker for the correct use and placement of

the bonds. The responsible signal engineer shall ensure the track worker is competent to apply

the temporary rail bonds before permitting their issue.

The issue of temporary rail bonds to each trackwork team shall be limited to the following:

• two temporary rail bonds, of a maximum length of two metres each

• two temporary rail bonds, of a maximum length of six metres each

Temporary rail bonds shall be of an approved design, fitted with approved rail clips. Each bond

and its associated rail clips shall be uniquely numbered and tagged. The bonds and tags shall

be inspected every six months to assess their condition and effectiveness. The responsible

signal engineer shall retain a register specifically for the purpose of recording these details.

The responsible signal engineer may delegate these duties to other signalling personnel who

are competent to do so. However, the responsible signal engineer shall retain accountability.

17.7.1. Specific restrictions for use The instruction to track workers applying temporary rail bonds shall include the following

restrictions where applicable:

• In double rail ac track circuit areas, temporary rail bonds shall only be placed around the

rail break when done in conjunction with shorting bonds. These shorting bonds shall be

placed across the rails on both sides of the break.

• In electrified track circuited areas, only one rail of a track shall be broken at any one time.

For example, it is not permissible to break both rails of the same track at the same time. It

is also not permissible to have more than one break in each rail.

• In non-electrified track circuited areas, no more than two rails of a track shall be broken at

any one time. However, it is not permissible to have more than one break in each rail at the


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same time. For example, it is permissible to have a break in both (opposite) rails of a track

simultaneously, but no other breaks can be made at that time.

18. Requirements for providing adequate traction return Adequate provision for the safe return of traction return current shall be considered and

implemented before performing work that affects its path to the substation or section hut.

The following types of work have the potential to impact the return path of overhead traction

current:

• re-railing in electrified areas

• disconnection of traction bonding including impedance bonds

• disconnection of negative return cables at substations and section huts

Alternative traction return arrangements shall be made to mitigate the risks associated with rail

breaks, disconnected traction bonds or negative return cables. This is done to ensure unsafe

voltages do not develop across the rails or cables.

Similarly, signalling equipment shall be safeguarded against damage caused by the potential

rise in traction return voltage.

In many cases, particularly where complete tracks are removed, the alternative arrangements

may include isolation of the overhead. Where this is the case, the effects of live overhead that

may be adjacent to the isolated section shall be considered.

18.1. Exemption to providing alternative traction arrangements Implementing alternative traction arrangements may be exempt in certain circumstances on the

following conditional requirements:

• ensure traction bonding in the vicinity (on both sides) of the intended work complies with

the specific track insulation plan

• ensure traction bonding in the vicinity has sufficient capacity to safely return the additional

traction return current

These conditions shall be validated by physical inspection of the traction arrangements to

confirm their condition and compliance.

Where the exemption applies, only one rail break shall be permitted in each traction rail.


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The following circumstances state where the exemption from providing alternative traction

arrangements may apply:

• On lines where there are three or more traction rails in the same corridor that provide the

traction return path to a substation or section hut. In this case, one traction rail may be

broken without providing alternative traction arrangements.

• On lines where there are six or more traction rails in the same corridor that provide the

traction return path to a substation or section hut. In this case, two traction rails may be

broken without providing alternative traction arrangements.

18.2. Work affecting negative return at substations or section huts Where re-railing, or disconnection of traction or negative return cables is done adjacent to

section huts or substations, at least one effective negative return cable shall be retained during

the work. This is to ensure unsafe voltages do not develop across rail or cable breaks.

The following requirements shall be met for undertaking re-railing, or disconnecting traction

bonding or negative return cables adjacent to substations or section huts, as applicable:

• Where substation or section hut negative return cables connect to both sides of a

mechanical joint in single rail track circuits, the re-railing shall be done in two stages. The

first stage shall include re-railing only to one side of the mechanical joint. After the negative

return cable of that portion is reinstated, the remainder of the re-railing shall be carried out

as the second stage.

• Where substation or section hut negative return cables connect to plain rail (no mechanical

joint) in single rail track circuits, the rail shall be first cut so both negative return cables are

not disconnected simultaneously. The first stage shall include re-railing only to one side of

the rail cut. After the negative return cable of that portion is reinstated, the remainder of the

re-railing shall be carried out as the second stage.

• Where substation or section hut negative return cables connect to impedance bonds in

double rail track circuits, the re-railing shall be undertaken on only one rail at a time. During

this time, the other rail shall remain fully bonded with its negative return made via the

impedance bond.

Where the above requirements are impractical, the overhead traction shall be first isolated

before commencing the work. For example, when the complete track is required to be removed.

The electrical operation control centre shall be notified of the intention to disconnect any

substation or section hut negative return cables before the work commences.


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18.3. Work affecting impedance bonds Before an impedance bond is disconnected, the feed and relay of the affected track circuit shall

be isolated from the track. Temporary bonding shall be provided for the traction return path

between the affected track circuit and the adjacent track circuit traction path.

18.4. Temporary rail connections for overhead wiring Temporary rail connections are permitted for temporary earthing of overhead wiring. This shall

be in addition to permanent rail connections where these are provided in accordance with

signalling designs for installed overhead sectioning and earthing switches.

When temporary rail connections are requested, a signal engineer shall nominate the location

for the connection and provide a marked-up copy of the specific track insulation plan. The

connection shall be made only on the traction rail of a single rail track circuit or the neutral point

of a double rail track circuit. Where the operation of the track circuit is not required, the

connection may be made on any of the traction rails.

In cases where the operation of a track circuit is affected by the temporary earth connection, the

track circuit shall be disconnected and the associated signalling shall be booked out of use.

Temporary rail connections shall be made by a secure connection and located clear of any

trackwork taking place.

19. Minor signalling additions, alterations and renewals work Sustaining the integrity of the operating signalling system at all times is an unconditional

requirement. This is particularly relevant during signalling additions, alterations and renewals

work where the risks from interference caused by the work are increased.

Note: Alteration work includes the installation of any temporary repairs.

All persons performing such work shall be aware of the potential impact of the work they

perform, including the effect on adjacent running lines or operational equipment in close

proximity to the work area. Signalling that has been tested and certified, pending being brought

back into use, shall be secured and treated similarly as if it were operational equipment.

Any work which has the potential to impair the integrity of the signalling shall be booked out of

use, including the signals in the rear of the affected equipment.

Work on signalling equipment which involves disconnection, disarrangement, disassembly,

adjustments, alterations or additions shall be planned and performed with adequate controls in

place. This shall include thorough testing at the completion of the work commensurate with

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assembly, incorrect type or configuration, improper adjustment and so on. This shall be

assessed and then mitigated by suitable testing in accordance with SPG 0711.

A functional test of the apparatus shall always be included in such testing.

19.1. Risk mitigation requirements for minor additions, alterations or renewals Risk mitigation requirements for minor additions, alterations or renewals shall be prescribed in

signalling safeworking procedures.

The following are examples of risk mitigation requirements to be included in signalling

safeworking procedures for minor additions, alterations or renewals, as applicable:

• electrically isolate the live circuitry of affected signalling from the worked-on portion

• correlate the existing arrangement, which includes apparatus inspection, wire and null

count to ensure it reflects the specific as-built design before commencing work

• ensure the signalling documentation used reflects the latest design

• secure and insulate unterminated wires, including spare cable cores in such a way that

they are unable to make contact with any conductive surface or electrical component

• not connect wires or equipment pending commissioning to working circuits, and as such

shall require two points of connection to take effect

• not leave connected wires and equipment decommissioned from use, to working circuits or

power supplies

• label and tag wires and corresponding terminals before connecting or removing

• treat metal links as wires, particularly when wire/null counting

• disconnect and reconnect only one single wire or one cable type (where the individual

cores can be easily identified) at a time, where possible

• mark matching sides of equipment including air hoses before disassembly

• provide a unique and distinct colour for temporary wiring used on each stage or testing

purpose

• comply with the required standard for the specific location including wires, cable cores,

contacts and other items of equipment which will be utilised in new or altered circuits

• update accordingly, the signalling documentation at the end of each stage

• ensure personnel are competent for the task

• comply with the testing and certification requirements of SPG 0711


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• ensure adequate lighting and access

• remove distractions or causes of pressure

• apply a methodical and systematic approach

• maintain proper housekeeping of the work area and ensure the housing and all equipment

are made secure when vacated

19.2. Involvement of signal engineer for risk mitigation requirements A signal engineer shall be associated with every signalling addition, alteration or renewal. The

level of association shall be dependent upon the risks associated with the work and the

authority level of the signalling personnel performing the work, which includes inspection, testing

and certification.

Examples of such cases are listed below:

• signal engineer signs off the scope and authorisation form for a like for like renewal

• signal engineer authorises a like for like renewal where the equipment is not exactly

identical

• signal engineer is advised of rewiring

• signal engineer performs inspection and testing of signalling additions or alterations

• the responsible signal engineer is consulted when adjustment made beyond specified or

expected limits

• the responsible signal engineer consulted when temporary repairs are effected

• the signalling commissioning engineer commissions new or altered signalling

19.3. Work not affecting the design principle Licensed signalling personnel are permitted to perform some alteration work on the signalling

system, without the direct involvement of a signal engineer, where the work does not alter the

design principle. The following are the tasks that can be performed by licensed signalling

personnel:

• Transfer of a circuit from a defective contact, terminal, cable core or wire to an equivalent

spare in order to rectify a failure scenario. The wiring work shall be limited to removing one

single wire or cable type at a time. This work shall be treated as a temporary repair in

accordance with Section 12.3 of this standard.

• Replacement of signalling equipment with an identical type. The like for like renewal

requirements stated in Section 19.4 of this standard shall be observed. © State of NSW through Transport for NSW of 151 Sup

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• Replacement of consumable or sub component items, where there is minimal risk of error.

These items include pluggable apparatus that are indexed against incorrect insertion. This

work may be exempt from meeting the like for like renewal requirements.

The following are examples of consumable or sub component items that may be exempt from

the like for like renewal requirements:

• fuses and terminals

• power supply units, transformers, capacitors, rectifier units

• mechanical pins, bushes, fasteners and minor mechanical components such as cranks,

rods, economical movements, detector ball joints, extension irons

• contacts where fitted with a pluggable wiring loom or individually wired

• plug-in relays, track circuit transmitters and receivers

• trainstop limit switches, motors, older style contact fingers, trip arms, detector arms

• electric point motors, capacitors, clutches, mechanisms, older style contact fingers

• signal lamps, signal LED boards, signal lenses

• level crossing booms, lights and bells

• signalling controls and indications such as push buttons, switches and diagram lights

Precautions and adequate testing shall be prescribed in signalling safeworking procedures to

ensure that there is no alteration to the circuit, or changes to polarity, operating parameters or

settings, configuration or design principle. Additionally, a functional test shall be performed

before certifying every case.

Whenever a signalling power supply or related wiring to polarity sensitive equipment, for

example, 50 Hz ac track circuits; is worked on, care shall be taken to ensure the polarities are

not reversed.

Adjustments made to vital signalling equipment beyond the specified or expected limits shall be

first approved by the responsible signal engineer or signalling commissioning engineer before

bringing the equipment back into use. All adjusted equipment shall be tested in situ.

19.4. Like for like renewal work Like for like renewal refers to the replacement of an item with an identical item. It can also refer

to an item that is not identical where it is deemed acceptable by a signal engineer on the

following basis:

• the replacement item is of similar characteristic, footprint

• where the difference does not diminish the intended design principle


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The like for like renewal requirements shall generally pertain to the renewal of trackside

apparatus such as electric point mechanisms, electro-pneumatic point equipment, mechanical

point components, signals, trainstops, vital shelf relays, releasing switches, level crossing

mechanisms and similar items.

Examples of electro-pneumatic point equipment include detectors, escapement slides, plunger

lock assemblies, indication boxes, air motors, and control valves. Mechanical point components

include point lock assemblies, detectors and compensators.

The like for like renewal requirement shall also pertain to trackside equipment that is temporarily

removed such as work that involves the removal of the wiring or cable which connects the

equipment to the interlocking. For example, a trainstop that is disconnected from its cable (and

air supply if applicable) and removed clear of its mountings to facilitate trackwork.

Only licensed signalling personnel deemed competent to perform the activity of like for like

renewal without supervision, shall lead this work.

Like for like renewal procedures shall be included in signalling safeworking procedures to

provide licensed signalling personnel with suitable documentation. This aims to ensure all the

required tests and checks are complete before permitting the replaced signalling equipment

back into use.

Like for like renewal work shall be performed in accordance with the scope and authorisation

form and relevant work instructions contained in SPG 0711. A separate work instruction shall be

compiled for each asset. Where a work instruction for the equipment type is not available, a

signal engineer shall provide the necessary instruction pertaining to the work to mitigate the

associated risks.

19.4.1. Work package for like for like renewal A work package shall be compiled for like for like renewal work.

This work package shall consist of the following documents:

• scope of work and authorisation form

• relevant work instruction

• signalling plan extract as applicable

• circuit diagram and analysis pages as applicable

• infrastructure booking authority

• bridging authority form with its own circuit diagrams as applicable

• certification returns and other required certificates as applicable


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Each page of the work package shall be numbered and the total number of pages shall be

shown on the cover.

The circuit diagrams and signalling plans shall be copies of the as-built circuit book or signalling

documentation for the area and not hand drawn copies. Care shall be taken to ensure these

reflect the latest installed design, including any interim maintenance copies that may apply. Part

circuit diagrams shall be marked with the circuit book page and identification number, or job

number if an interim maintenance copy is used. Disconnection of circuits shall be marked on the

circuit diagrams.

All work shall follow the work instruction procedure, and all testing shall be documented on the

work instruction, circuit diagram and/or analysis page, or signalling plan as appropriate.

All inspection and tests stated in the work instructions shall comply with the suite of tests

prescribed in SPG 0711 and signalling safeworking procedures (example: point lock testing

requirements).

The completion time shall be noted on the scope and authorisation form upon completion of the

work. The work instruction and any document where testing notations have been made, such as

the signalling plan or circuit diagram, shall also be signed. The completed package shall be

forwarded to the authorising signal engineer for reviewing, taking action on any asset update

requirements, and archiving.

19.4.2. Authorisations required by signal engineer Where an item intended for installation is not exactly identical as the item being replaced, the

difference between the equipment types, the effect on the design principle, and the risks

associated with the changed configuration shall be assessed. A signal engineer shall be

required to assess and authorise the renewal work in these circumstances.

The following are examples of items that are not exactly identical but may be authorised as a

like for like renewal:

• newer version of a point machine replaces an earlier version

• similar equipment where later versions alter the terminal arrangement

• trainstop with enclosed contacts replaces trainstop with open contacts

• point machine changed on a triple-end or independent switches (additional out of

correspondence test required)

• more than one point machine is changed within the layout


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• shelf relay replaced by a plug-in relay conversion unit

• partial renewal where not all elements are replaced and only a subset of the work

instruction may be applicable

• where a work instruction does not cater for the particular type of work

Where an authorisation is granted, the scope of work and authorisation form shall include a

description of the difference between the equipment types and a listing of any subsequent

actions. The subsequent actions can include updating the asset register, marking-up and

signing the field certified office copy, submission of the certified office copy for updating, and

arranging additional training for signalling personnel. Any pending actions following the

authorised renewal of not exactly identical equipment shall be promptly closed out.

Additionally, the scope and authorisation form shall be signed by the signal engineer before

commencing the work. In cases of emergency, the signal engineer may provide the

authorisation remotely, and provide the signature at the earliest opportunity.

19.4.3. Granting pre-authorisation for like for like renewal work A signal engineer may consider pre-authorising routine equipment changes in advance of an

event. The pre-authorisation shall be documented by providing appropriate local procedures

attached to the relevant work instruction. The local procedures shall mitigate the additional risks

associated with the equipment difference.

The following are examples where pre-authorisation may be granted for a like for like renewal:

• newer version of equipment replaces an earlier version (including trainstops and point

machines)

• a point machine is changed on a triple-end or at independent switches

• shelf relay replaced by a plug-in relay conversion unit

19.5. Work affecting the design principle Additions, alterations, or renewal work that do not meet the like for like renewal requirements, or

any other work that affects the intended signalling design principle or configuration shall

proceed only when issued with an approved design. Approved designs are issued by the

contracted AEO accountable for approving signalling design. A signalling commissioning

engineer shall be assigned to lead this work and the work done in accordance with SPG 0711.

The following are examples where work shall be treated as an alteration, done in accordance

with SPG 0711, and not as a like for like renewal:

• conversion of incandescent signal to LED type

• replacement of LED signal with a different LED type © State of NSW through Transport for NSW of 151 Sup

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• upgrade of conventionally operated points to Claw Lock or Spherolock type

• change of track circuit type

• installation of repeat relays

19.6. Rewiring and wire repair requirements Whenever wires or cables are in need of replacement or repair, extreme care shall be taken to

ensure the conductors are not cross connected or the circuits not interconnected.

The affected signalling equipment and protecting signals shall be first booked out of use before

commencing rewiring or repairs to wiring that may affect working circuits.

Licensed signalling personnel are permitted to perform rewiring or repair of working circuits to

alleviate a failure situation. The work shall be carried out on one single wire or cable type at a

time. The different cable types shall be easily recognisable by licensed signalling personnel so

as to avoid confusion when reconnecting.

Only signal engineers or authorised signalling personnel holding the level of circuit tester are

permitted to lead testing where the work exceeds repairing or replacing one single wire or cable

type at a time.

In any case, the affected signalling and protecting signals shall be booked back into use only by

a licensed signalling person.

Wires and cables shall be correlated to ensure that there are no unintended intermediate

contacts, terminals or cables entering intermediate locations and thus is in accordance with the

specific design. The old and new wires shall be labelled accordingly with the identity of their

respective terminals.

All wiring connections shall be made secure, reliable and electrically insulated from other

conductors, live terminals and earth. Rewiring and repairs not performed to the required

standard for the specific location shall be treated as a temporary repair in accordance with

Section 12.3 of this standard.

The rewiring or repair shall be inspected and tested in accordance with SPG 0711 before

returning the affected signalling back into use.

Signalling safeworking procedures shall contain wire replacement and repair procedures for

licensed signalling personnel to follow, where permitted by this standard to perform such work.


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19.6.1. Additional testing requirements for specific situations In addition to the normal testing requirements stated in SPG 0711, the requirement of specific

testing shall be included in signalling safeworking procedures to mitigate risk that pertain to the

situations stated below:

Signalling cables damaged by excavation works

Where multi-core cables are damaged by excavation works or similar, there is a risk that the

insulation between the conductors can get damaged. This can cause a short circuit current flow

over a sustained period which can lead to deformed Q type relay contacts.

Where the sustained short circuit period exceeds one hour, a signal engineer shall consider the

consequential risk of the sustained short circuit current flow. If determined necessary, the signal

engineer shall mandate, in addition to the normal testing requirements, the testing of all relay

contacts in the affected circuits on the fuse or supply side of the damaged cable. This testing

shall be conducted by either of the following two methods:

• test the affected relay in a relay test panel to ensure all contacts operate (open and close)

in accordance with their configuration type

• functionally operate the relays in the affected circuits to ensure that they are effective in

each circuit function as designed (circuit function test)

Track circuit wires replaced

Licensed signalling personnel are permitted to repair or replace two or more track circuit leads

to a track circuit location by changing over one single wire or associated pair at a time.

The work shall be tested to ensure the following:

• wires have not been cross connected

• track circuit relay de-energises with the correct shunt applied across the rails

• polarity of the track circuit, where applicable, is in accordance with the track insulation plan

A shunt test of adjacent track circuits shall also be performed.

Where cut tracks are involved, a shunt test shall be performed to ensure the track voltage of the

adjacent cut track is removed during the shunt.

Signalling data communication links replaced

Data communication links are utilised to connect vital and non-vital systems such as Microlok II,

Solid State Interlocking, Dupline, Kingfisher, SCADA and other such systems. These links

consist of either copper communication type cables or optical fibre conductors.


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When changing a spare pair in a copper communication type cable or optical fibre conductor,

the logically correct pair at both ends shall be first established, followed by an end-to-end

continuity test, before certifying the signalling back into use.

19.7. Documents used for the certification of signalling Except as provided for in the like for like renewal requirements, provision for the certification of

signalling shall be achieved by completion of the following signed documents as applicable:

• infrastructure booking authority

• interlocking certificate, design integrity test certificate

• maintenance record; for example, point lock return, insulation test record, track circuit

record, relevant inspection and test form (ITF)

• certified office copy circuit book, signalling plan, track insulation plan, control table, locking

table or working sketch

• other documents used by the contracted AEO for the purpose of certification

19.8. Paralleling of contacts in trackside apparatus The paralleling of contacts used for the detection or operation of signalling apparatus, with

associated spare contacts, is permitted and may be performed ahead of obtaining approved

signalling documentation.

Licensed signalling personnel are permitted to perform such work where it is deemed necessary

to improve the reliability of trackside signalling. The wire and termination means used to parallel

the contacts shall be consistent with the wiring already in use with a limit of two wires terminated

at each terminal. The parallel wires shall be labelled with the letters 'PC' to identify their purpose

until specific circuit books are updated accordingly.

A test shall be performed to ensure the original design function of the contact has not been

defeated by the work and also to ensure the effectiveness of the paralleled contacts.

The responsible signal engineer shall be notified of all such contacts paralleled and

subsequently shall make the necessary arrangements to update the specific circuit books. The

local circuit book shall be duly marked-up to indicate the paralleled contacts until the updated

circuit books are issued.


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20. Requirements and scheduling of signalling maintenance The signalling system and its associated equipment shall be maintained to ensure the

availability of the asset and its reliable operation to safely and efficiently regulate train

movements in accordance with its design.

Signalling maintenance shall be performed on the whole signalling system and where

applicable, shall include trackside communication equipment. The work shall be done in

accordance with signalling safeworking procedures, network rules and procedures, signalling

technical maintenance plans, engineering instructions, equipment manuals and transport

standards as published on the ASA website.

The responsible signal engineer shall be advised of any maintenance or signalling safeworking

matter requiring their attention or escalation. The urgency of the advice shall be treated

accordingly.

The responsible signal engineer shall be accountable for ensuring all aspects of signalling

maintenance are executed. This shall be done by taking into account the asset condition and

site specific conditions that may require the asset to receive more rigorous, frequent

maintenance, inspection and testing. This is particularly required where these conditions have

the potential to impair the safety of the signalling system.

Where the safety provided by an asset is impaired, the responsible signal engineer shall take

the necessary action to mitigate such risk associated with the situation or otherwise arrange to

book the affected signalling out of use.

20.1. Maintaining operational signalling equipment When intending to perform maintenance work on operational signalling equipment that may

affect its safety or reliability, the licensed signalling person shall advise the signaller of the

nature of the work and nominate the equipment affected. This shall be done before

commencing such work.

Examples of effect to signalling caused by maintenance work include the following:

• indications of signals changing for approaching trains

• indications of signalling displayed incorrectly at signal boxes or control centres

• level crossing protection operation is restricted or activated without an approaching train

Maintenance work that impairs the safety of the signalling shall be protected, in accordance with

securing signalling apparatus out of use as stated in Section 13 of this standard, before

commencing the work.


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Any signalling equipment worked-on shall be functionally tested before leaving the worksite to

ensure there are no adverse effects on its operation at the end of the work. This requirement

extends to the removal or disturbance of any signalling apparatus such as ESML or EOL keys,

relays, fuses, links, switches, opening of electrical contacts and so on.

During maintenance visits, signalling personnel shall be vigilant of any potential failure

situations. This shall include a check of signalling equipment where there is reasonable cause to

suspect the reliable operation has been jeopardised by construction activity, mechanised track

maintenance or similar activities. Track circuit parallel bonding, obvious signal sighting

obstructions and the rail surface condition shall form part of this vigilance.

20.2. Safety related examinations Signalling safeworking procedures shall include a system of managing and reporting

compliance for nominated signalling maintenance tasks defined as 'safety critical' and 'safety

significant'. These tasks aim to manage a situation where functional failure or secondary

damage of an asset can result in a signalling irregularity.

20.2.1. Safety critical task A safety critical task is one that protects against a wrong side failure mode in a safety related

asset or component, such that if a failure were to occur it would have a high probability of

causing an outcome of severe consequence.

For example, points are identified as safety critical assets and are allocated safety critical tasks

of gauging the gap between switch and stock rails to check the go/no-go settings of the point

lock and point detection. These tasks are done to ensure the point lock and point detection

settings have not drifted beyond their specified limits.

The risk increases when the safety critical tasks are extended beyond the specified period

without defined and approved risk mitigation measures in place.

Signalling safeworking procedures shall classify the following tasks as safety critical:

• periodic safety inspection of 50 Hz ac double rail track circuits

• periodic testing of point locks and point detection

• periodic testing of selectors and bolt locks

• periodic testing of unproved electric locks

• periodic inspection of unproved vital signalling relays - ac vane and dc shelf types


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20.2.2. Safety significant task A safety significant task is one that protects against a wrong side failure mode in a safety

related asset or component, such that if a failure were to occur it would have a medium to low

probability of causing severe consequences. This is enabled by the provision of additional

safety barriers.

For example, track circuits are identified as safety significant assets and are allocated safety

significant tasks of performing a shunt test, zero feed test and polarity test (where applicable).

These tasks are done to ensure the track circuit characteristic has not drifted beyond its

specified limits, and ensure that it cannot be falsely fed from another source.

Safety significant assets are slower to manifest themselves and are less likely to be adverse

following the breach of the defined conditional criteria.

Signalling safeworking procedures shall classify the following tasks as safety significant:

• signal engineer’s periodic inspection and testing of signalling interlockings and mechanical

locking items

• signal engineer’s periodic inspection of level crossing protection equipment

• periodic testing of signalling electrical conductor-insulation resistance

• periodic testing of electro-mechanical and thermal type time limit relays

• periodic overhaul of non-proved vital signalling relays - ac vane and dc shelf types

• periodic testing of dc type track circuits

• periodic inspection of parallel bonds

• periodic track circuit shunt testing, zero feed testing and polarity testing where applicable

• periodic testing of slip detectors and rain-fall detectors

20.3. Maintenance scheduling, reporting and recording A maintenance management system shall be used to schedule all signalling safety critical,

safety significant, and other signalling periodic maintenance tasks. Work orders shall be

generated by the maintenance management system in accordance with the signalling technical

maintenance plan.

The maintenance management system shall highlight in particular, the compliance of signalling

safety critical and safety significant tasks.

Apart from the compliance requirements, safety critical and safety significant tasks shall require

specially attested returns from licensed signalling personnel to provide verification of

certification. A specific format for the return shall be arranged by the contracted AEO


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accountable for providing the maintenance. Returns shall be duly submitted to the responsible

signal engineer for review of the certification and compliance elements and actioning any

necessary items.

An additional return shall be required for any out of course safety critical or safety significant

adjustment or test made between periodic maintenance inspections.

Other such records, for example, relay records, battery records, track circuit records, insulation

test records, signal inspection and test records shall be kept on-site as applicable and also with

the responsible signal engineer or maintenance depot.

20.3.1. Maintenance schedule period latitudes The signalling technical maintenance plan defines the tasks and schedules for signalling

infrastructure maintenance. Maintenance frequencies shall comply with the frequencies stated

in the signalling technical maintenance plan and this standard where defined for safety critical

and safety significant tasks. Each task may have a planning latitude which reflects the permitted

variation around the task due date. Planning latitudes shall be no greater than 20% for tasks

with a frequency of up to 42 days, and no greater than 10% for tasks with a frequency of above

42 days, unless authorised by the ASA.

Safety critical and safety significant tasks shall be completed within the defined planning

latitude.

Safety critical and safety significant tasks not achieved by the due date and latitude period shall

be risk assessed by the responsible signal engineer and the risks appropriately and promptly

mitigated. Failure to secure prompt appropriate risk mitigation shall warrant the particular asset

and associated assets to be booked out of use.

The non-compliance of other signalling maintenance tasks that are not safety critical or safety

significant shall be managed in accordance with the contracted AEO's engineering management

system. However the risks associated with the safety elements of these tasks shall be

considered and prioritised by the responsible signal engineer.

21. Inspection and testing of vital signalling relays Vital signalling relays are integral to the safety and reliability of interlockings. Their critical

applications include control, indication, locking, operation, detection and timing. The safety

assurance aspect of vital signalling relays requires a thorough understanding and management

of the various failure modes and associated risks. Persons working on vital signalling relays

shall take the necessary precautions when wiring, inspecting and maintaining, replacing, and

overhauling. These safety assurance requirements shall be included in signalling safeworking

procedures.


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Vital signalling relays exist in various forms and configurations, but all are categorised as either

proved (proved in the de-energised position by the signalling design) or unproved. Unproved

relays pose a greater risk, as a wrong side failure associated with these relays may go

undetected by the system.

All vital signalling relays shall be supplied sealed to prevent unauthorised tampering. Any vital

signalling relay in service that is not sealed shall be treated as sealed and not opened. The seal

shall not be broken in the field except in exceptional circumstances and only as directed by a

signal engineer.

Plug-in conversion units, using Q type BRB 930 relays, are available as a replacement for ACVL

relays and any ACVL relay determined for replacement shall be replaced with the conversion

unit. For each replacement, a notice of installation advice shall be completed and submitted for

the purpose of circuit book update. Once installed, the conversion unit may be considered as a

plug-in relay for maintenance purposes.

Note: Conversion units have a contact current capacity of only three amperes.

21.1. Precautions and requirements for vital signalling relays Precautions and requirements for vital signalling relays shall be prescribed in signalling


The following are examples of precautions and requirements for vital signalling relays:

• Vital signalling relays shall be inspected and tested before they are placed into service for

correct operation and configuration (voltage, type, contact configuration, and coding) in

accordance with the specific signalling design. The relay shall also be closely inspected for

any transit damage.

• The tampering of coding holes in bases or coding pins in relays is strictly forbidden.

• The signalling associated with circuits that pass through shelf relays that are not fitted with

a detachable top shall be booked out of use before replacing.

• The circuits that pass through replaced relays shall be functionally tested. Any wiring

disturbed shall be wire and null counted.

• The replacement task of shelf relays shall be wholly performed by one person and not

transferred to another person part way through the work.

• The change details of replaced shelf relays, VT1 relays, electro-mechanical and thermal

timer relays, and large plug-in relays shall be duly recorded and a notice of relay change

submitted to the responsible signal engineer.

• Relay wiring shall not be altered contrary to the specific signalling design unless

transferring to a spare contact for the purpose of temporary repair during failure situations.


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Care shall be taken to ensure the contact configuration is not changed by the transfer.

Temporary repair requirements stated in Section 12.3 shall apply.

• Timer relays shall not be adjusted contrary to the time noted on the specific signalling

design.

• Magnetically latched relays shall only be inserted into service while in the de-energised

position. Under no circumstances shall they be inserted while in the energised position.

Before interfering with these relays (typically NLR/RLR), the protecting signals and any

other affected signals shall be placed at stop, and all approaching trains ensured to have

come to a stand at the signals, with no train foul or passing over any affected points.

• Double element ac line relays may be replaced with a single element type and vice versa

provided the local and control coils are correctly bridged in parallel as required in the

specific signalling design.

• DC shelf relays and dc large plug-in relays shall be bench tested for pick-up, drop-away

and working currents before being placed into service.

• AC shelf relays fitted with black coils without coil formers shall not be used, as these relays

may release wax from the coils when hot.

• Signal branch type dc shelf relays shall not be used.

• Flexible stranded wire (9/0.40 mm or similar) may be used on shelf relays fitted with

detachable tops. However, single stranded wire (1/1.70 mm or similar) shall only be used

on shelf relays where a detachable top is not fitted.

21.2. Storage and reuse of vital signalling relays Vital signalling relays shall be handled, transported and stored with care and not subjected to

any damage or deterioration. The relays shall be stored in an upright position and not placed on

floors prone to dust particles and contamination.

The armature securing screw provided on shelf relays to prevent transit damage shall be

removed before use.

Refurbished vital signalling relays shall be re-tested for correct operation and contact

effectiveness when they have exceeded their storage period. Re-testing shall be conducted

using an approved relay go/no-go tester that cycles the relay operation while measuring the

contact resistance.

The storage period for refurbished relays is as follows:

• Q type BRB 930 relays – seven years

• plug-in ac relays – three years


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• dc shelf relays – five years

• ac shelf relays – three years

New Q type BRB 930 relays, stored in original packaging may be exempt from re-testing

requirements subject to the relays passing a visual inspection and operation in a conventional

relay test panel (which indicates relay contact status).

Used Q type BRB 930 relays with up to 10 years service may be considered for reuse, on

condition that the relay is inspected to be in proper condition (including seals intact, coding pins

straight, plug in contacts not bent, no evidence of corrosion or foreign matter, and transparent

cover). Additionally, the relay shall pass a functional test in an approved relay go/no-go tester.

Q type BRB 930 relays with a contact resistance greater than 2 ohms shall not be used except

in cases of emergency, as a temporary measure, on condition that the resistance is not greater

than 7.5 ohms. In such cases, temporary repair requirements in accordance with this standard

shall be complied with.

21.3. Maintenance and overhaul of vital signalling relays The periodic inspection of unproved vital signalling ac vane and dc shelf relays shall be treated

as a safety critical task in accordance with Section 20.2 of this standard.

The testing of electro-mechanical and thermal type timer relays shall be treated as a safety

significant task in accordance with Section 20.2 of this standard.

The replacement for overhaul of unproved ac vane and dc shelf relays shall be treated as a

safety significant task in accordance with Section 20.2 of this standard.

Any vital signalling relay, including spare relays, found with a defect having potential to impact

on its safe operation shall be promptly brought to a signal engineer's attention and the signalling

shall be protected accordingly.

21.3.1. Inspection requirements for ac vane relays (all types)

AC vane relays shall be periodically inspected for abnormal operation in accordance with the

signalling technical maintenance plan. However, the period between inspections shall not

exceed 52 weeks.

The following inspection criteria for ac vane relays shall be included in signalling safeworking

procedures:

• ensure correct operation, condition of contacts, terminals and pigtails

• inspect for correct release (not sluggish or jerky) and not failing to return fully to the stop

position due to defective bearings, warped bakelite tops, wax or other foreign matter in the

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• inspect for foreign matter, flaky plating or paint inside the relay

• inspect for deposits of wax, varnish or paint on the vane which may indicate overheating of

coils or contact with pole faces

• inspect for scratches or abrasions on the vane which may indicate that the vane is distorted

or air gap tolerances are incorrect

• inspect vane for spread due to striking the bottom of the relay case (detected by a mark in

the paint of the case bottom or jamming on the pole faces)

• inspect vane spindle for any accumulation of dust or discolouration which may be attributed

to wear of the bearings or evidence of wax deposits

• inspect roller stops for evidence of grooving

• inspect for evidence of grooving on spring type stops to ensure that the spring is effective

and not fouled by its bracket when the relay is energised

• ensure vane is positioned centrally between (and clear of) pole faces

• ensure ends of split pins are properly spread

• ensure counter weight lock nut is locking the counter weight and it has not shifted

21.3.2. Inspection requirements for dc shelf relays DC shelf relays shall be periodically inspected for abnormal operation in accordance with the

signalling technical maintenance plan. However, the period between inspections shall not

exceed 52 weeks.

The following inspection criteria for dc shelf relays shall be included in signalling safeworking

procedures:

• ensure correct operation, condition of contacts, terminals and pigtails

• inspect for correct release and ensure the armature is operating freely and drops away

promptly when the relay is de-energised – check for defects or wax or foreign matter in the

bearings

• inspect for foreign matter or flaky plating or paint inside the relay

• ensure ends of split pins are properly spread

• inspect for any other unusual condition


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21.3.3. Inspection requirements for large plug-in and Q type BRB 930 relays Large plug-in and Q type BRB 930 relays shall be periodically inspected for abnormal operation

(to the extent practical without removal) in accordance with the signalling technical maintenance

plan. However, the period between inspections shall not exceed 52 weeks.

The following inspection criteria for large plug-in and Q type BRB 930 relays shall be included in

signalling safeworking procedures:

• ensure clear plastic covers not fouling the contact assembly due to warping or cracking

• inspect for contact burning, or pitting of the carbon contacts

• inspect for displaced or worn carriers

• inspect for rust on plated components or signs of excessive deterioration of the plating

• ensure retaining clip is securing relay in base

21.3.4. Inspection requirements for time limit relays

Electro-mechanical and thermal type timer relays shall be periodically tested for the correct

time-out duration (not exceeding 10% of the specified time) and operation in accordance with

the signalling technical maintenance plan. However, the period between inspections shall not

exceed two years.

Electronic time limit relays such as QTD5 or similar may be exempt from periodic testing.

21.3.5. Replacement requirements for vital signalling relays The procedure for shelf relay replacement shall be in accordance with the like for like renewal

requirements as prescribed in this standard.

Unproved ac vane and dc shelf relays shall be periodically inspected and overhauled in

accordance with the signalling technical maintenance plan. However, the period between

overhaul shall not exceed 15 years, except for relays used on cut-tracks which will not exceed

10 years.

Proved ac vane and dc shelf relays and other relay types shall be replaced on a needs basis.

Samples of Q type BRB 930 relays from typical installations shall be inspected after 20 years in

service to assess the need for replacement. The inspection shall be performed in suitable

workshops by persons competent to do so, jointly with licensed signalling personnel. A report of

the sample relays inspected shall be compiled and sent to the responsible signal engineer for

review and determination.


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All vital signalling relays shall be fitted with suitable labelling to identify the relay as overhauled.

The label shall include relevant information such as the date of overhaul, workshop and tester's

identification and any specific values pertaining to the relay type.

21.3.6. Programming the replacement and overhaul of vital signalling relays The responsible signal engineer shall have an effective program for the replacement and

overhaul of vital signalling relays as required by this standard. The program shall include

relevant details of ac vane and dc shelf relays in service. The program shall also include details

of ac vane and dc shelf relays that were replaced due to defect or periodic overhaul.

21.3.7. Treatment of safety related relay faults Any vital signalling relay that fails to de-energise, or falsely indicates an energised or

de-energised state, or has a fault which may impact upon the safety of the signalling system

shall be immediately protected in accordance with signalling irregularity requirements as

prescribed in this standard. The relay shall not be initially disturbed. The responsible signal

engineer shall be promptly advised to provide further instruction. The failure and investigation

shall be treated as a signalling irregularity.

Vital signalling relays identified with defects shall be analysed jointly by a signal engineer and a

relay manufacturer or overhaul expert in a suitable workshop environment. The pending actions,

including the addressing of any potential effects for similar relays in service or spares, shall be

promptly attended to and closed out.

22. Inspection and testing of signals and signs Signals and signs referenced in this standard are those shown on signalling plans, track plans

and working sketches. These are viewed by train drivers or by users at level crossings for the

purpose of safeworking and operation of the railway.

Signals display either a colour light or semaphoric indication. Signs may be passive,

retro-reflective or active.

Running signals shall be maintained to display the optimal indication from the lens system and

the applicable sighting of the indication shall be as long and continuous as practical.

The focus of signals shall be maintained not to cause an ambiguous or read-through indication.

The door of colour light signals shall not be opened where the risk of light penetrating through

the open lamp case, can affect approaching trains (causing an irregular signal indication).

Signal doors shall be checked to ensure they are securely closed and locked before leaving the

signal site.


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22.1. Requirements for periodic and responsive signal sighting Signals and signs shall be periodically inspected and maintained for optimum visibility and

acceptable sighting distance in line with signalling design principles. The frequency of this work

shall be in accordance with signalling technical maintenance plans and whenever the

opportunity exists during the course of other site visits.

An inspection of sighting for obstructions shall include vegetation growth, new or altered

structures, and changes to the background and lighting conditions, whether on or off the rail

corridor. Any pending actions from these inspections shall be promptly addressed.

In difficult cases where the signal indication cannot be distinguished due to sunlight shining

directly onto the lenses, the responsible signal engineer shall be notified to provide an

appropriate solution. Any configuration change required in this regard shall be approved by the

contracted AEO accountable for approving signalling design.

For Type F and passive type level crossing signals and signs, similar action is required to

ensure that road and pedestrian users receive good sighting of the level crossing lights and

signs. The signal focus and intensity shall be checked as part of periodic maintenance. This will

necessitate viewing the signals on all approaches to the level crossing from a distance in

accordance with signalling design principles.

Running signals shall be regularly checked from the driver's cabin by a signal engineer or other

competent representative for correct focus, optimum light intensity, sighting obstructions, and

the potential for phantom or ambiguous indications. The inspection also provides an opportunity

to liaise with the driver to obtain their perspective of the signal sighting and shall preferably be

done in collaboration with a lead train crew representative.

The signal sighting inspection shall be conducted in accordance with the signalling technical

maintenance plan. However, the period between inspections shall not exceed 26 weeks on

passenger lines and 52 weeks on non-passenger lines.

Where a phantom signal indication is possible, arrangements shall be made to have

anti-phantom filters fitted to the lens modules concerned.

The lights displayed by mechanical signals shall be checked at night while colour light signals

shall be checked during daylight.

Where a signal sighting committee is formed to review the sighting of a signal due to a SPAD or

other sighting issue, the committee shall use the signal sighting checklist and compile the signal

sighting form contained in SPG 0711.


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22.2. Maintenance and inspection of signals Signals shall be periodically inspected to ensure the whole profile is in accordance with the

specific signalling design and in proper condition. The signal profile includes the following

elements:

• signal post, structure and ladder

• hoods and backgrounds

• lamps or LEDs, lenses and lamp cases

• mechanical arms

• identification and notice plates

• termination boxes

The frequency of maintenance and inspection for signals shall be in accordance with the

signalling technical maintenance plan.

22.2.1. Maintenance of lamp cases, hoods and backgrounds The coating of lamp case interiors shall be checked to be coloured matt black to minimise

reflection of external light.

The matt black coating on hoods and front of backgrounds shall be checked to be in good

condition and not capable of reflecting external light.

22.2.2. Maintenance of lamps All lamps used in signals shall be of the correct type, voltage, wattage and filament-arrangement

in accordance with the specific signalling design.

New lamps shall be kept in their wrapping and stored in a dry place until they are put into

service, to prevent any damage or deterioration due to corrosion.

Multi-filament lamps such as SL35 type shall be a good fit in the lamp holder and properly

seated with the main filament at the focal point of the lens. Multi-filament lamps shall be inserted

in the holder so that the main filament is normally illuminated. The lamp shall also be checked

that on breaking the main filament circuit, the auxiliary filament becomes illuminated. When

replaced, new lamps shall be observed to light up before being left in service.

Signal lamp voltages shall be checked on installation, when replaced or as necessary due to

regular failure.

Lamp voltages shall be measured across the terminals of the lamp holder.


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Level crossing lamp voltages shall be measured with the level crossing battery supply operating

with the charger turned off.

To maximise lamp life, the lamp voltage shall be adjusted towards the minimum voltage.

Table 1 provides the maximum and minimum voltage settings for signal lamps.

Table 1 - Signal lamp settings

Lamp rating Maximum setting (volts)

Minimum setting (volts)

10 volt 5 watt 9. 7 9.4

10 volt 11 watt 9. 7 9.4

10 volt 13/3.5 watt 9. 7 9.4

10 volt 18 watt 9.5 9.0

10 volt 18/3.5 watt 9.5 9.0

10 volt 25 watt (level crossing lights)

9.7 9.4

12 volt 2/2 watt 10.7 9.0

12 volt 24/24 watt 11.7 / 11.5* 11.3 / 11.1*

12 volt 24/24 watt (subsidiary and marker lights)

10.7 / 11.3+ 10.2 / 11.1+

12 volt 36 watt 11.2 10.7

12 volt 36 watt (subsidiary lights)

10.1 9.5

120 volt 15 watt busbar value busbar value

130 volt 60 watt busbar value busbar value

* applies to lamps where separate voltage taps are not provided for the main and auxiliary filaments and the auxiliary filament is not subject to voltage drop across the filament changeover relay coils

+ applies to lamps in Solid State Interlocking installations


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22.2.3. Maintenance of LED modules LED modules used in signals shall be of the correct type, voltage and current in accordance

with the specific signalling design.

LED modules shall be appropriately packaged against damage during transportation.

LED modules shall display no less than 50% of the applicable individual LEDs contained within

the module or otherwise they shall be promptly replaced.

LED modules that display between 50% and 75% of the applicable individual LEDs contained

within a module shall be managed for change-out.

Care shall be taken to ensure any replacement LED module is of the correct type by checking

the voltage, colour, model and conditioning resistors to be in accordance with the specific signal

design.

Whenever a LED module is replaced, or the wiring to a LED module altered, a functional test of

the signal shall be performed to ensure the signal displays the correct aspect and focus.

Additionally, the voltage at the LED module shall be checked and an inspection made for any

defective LEDs. Where current proving is in force, the current shall be measured and the

proving circuit checked for functionality by breaking the circuit to the lit LED module. The light

intensity shall be compared with other lights of the same signal.

22.2.4. Maintenance of lenses Lenses shall be cleaned during periodic maintenance and as necessary. Cleaning products

which contain abrasives or solvents shall not be used to clean lenses.

Lenses shall be inspected to ensure they are not cracked, damaged or faded, such that it may

impair the optimum light intensity or appear as another colour (example: 'red' appearing as

'amber').

Where lenses are regularly subjected to graffiti, an acceptable graffiti protective coating may be

applied.

Whenever lenses are replaced, a functional test of the signal shall be performed to ensure the

signal displays the correct aspect and focus.

Where the outer lenses of running incandescent signals are partially or completely missing, the

lens shall be either immediately replaced, or otherwise the lens removed or securely covered

with dark non-reflective material. Additionally, the lamp shall be removed and the respective

controlling relay disconnected.

In such cases, the more restrictive indications of the signal may be left working. For example, if

the full clear (green) indication is missing, then the signal medium and caution indications may


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be left working. However, if the caution or low speed lens is missing, then the signal shall be

retained at stop and booked out of use. In either case, the signaller shall be advised of the

situation.

22.2.5. Maintenance of mechanical signals The signal operating structure, including its signal wire length and supports shall be periodically

inspected to ensure the signal arm movement is not restricted by corrosion or any obstacle

which may impact the signal's ability to display a stop indication.

Signal stay wires and associated mechanical items shall be checked to ensure they remain

clear of the structure gauge.

The back-spectacle shall be adjusted to enable the back-light to be seen only when the signal

arm is horizontal.

22.2.6. Maintenance of signs Signs shall be inspected periodically in accordance with the signalling technical maintenance

plan to ensure the wording remains in accordance with the signalling design.

Signs shall be cleaned and observed for damage, legibility, colour fade, retro-reflectivity and

clear sighting. Where such legibility and retro-reflectivity is significantly diminished, the sign

shall be replaced.

Where signs are regularly subjected to graffiti, an acceptable graffiti protective coating may be

applied.

22.2.7. Signal structural inspection The structural integrity of posts, mounting brackets and gantries used for signals, warning lights,

buffer stop lights, level crossings, guard indicators, signs, and associated equipment shall be

periodically inspected in accordance with signalling technical maintenance plans.

The whole structure shall comprise its supporting components, ladders, gateways, walkways,

handrails, signal cages, fall-arrest devices and foundations.

Examinations beyond the competency of signalling personnel shall be referred to others holding

such structural competency. Signalling safeworking procedures shall nominate the responsibility

of inspection requirements accordingly to ensure clear accountability.

Signalling safeworking procedures shall contain a suitable check list to assist inspection

personnel when compiling suitable reports where rectification work is necessary.


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23. Gauging of trainstops Trainstops may be exempt from periodic gauging. However, trainstop gauging shall be triggered

by specific events which may cause the trainstop trip arm to become out of gauge.

The following are examples of typical events that may affect the gauge of the trainstop trip arm:

• occurrence of re-railing adjacent to the trainstop

• renewal of the trainstop

• reinstatement following temporary removal of the trainstop such as facilitating trackwork

• renewal or adjustment of the trainstop trip arm

• renewal or adjustment of a trainstop component affecting the height of the trip arm

• renewal or refastening of the trainstop mounting

• where signs or evidence indicates the trip arm is out of gauge such as non-aligned trip

marks on the trip arm face

• where the adjacent track alignment has changed or the rail fixings replaced or adjusted

Whenever trainstops are gauged, an attested return shall be duly submitted to the responsible

signal engineer.

24. Inspection and testing of points Points referenced in this standard are the power operated layouts and layouts operated from a

mechanical frame. Non-interlocked points, including ball lever and throw-over types, or spring

switch types such as Thompson, Thornley, or similar, are not covered by this standard.

Point operating mechanisms and layouts shall be periodically maintained, tested and certified to

ensure their operation is safe and reliable. The point lock, point detection and switch openings

shall be certified to ensure they remain within their specified limits. The rear flangeway of

open-switches shall be checked to have sufficient clearance. The frequency of this certification

shall not exceed 30 days, excepting specific Spherolock point layouts which shall not exceed 90

days. The periodic certification of points is a safety critical task and shall be treated in


Note: The specific requirements for Spherolock points that permit their safety critical

task frequency to be extended to 90 days are prescribed in the technical maintenance

plan.

Before commencing work on points, consideration shall be given to risks associated with the

work, having the potential to impair or disrupt the safe and reliable operation of trains. The

arrangement to perform this work shall be in accordance with Section 20.1 of this standard.


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For testing purposes, mechanical points shall be operated by means of the lever in the

interlocking machine. Power operated points shall be preferably operated using the manual

operation facilities provided, such as EOL or ESML, or the actuator arrangements in air control

valves where manual operation facilities are unavailable. Otherwise they can be operated from

the signal box control.

Where the point-lock locks the points both ways, each switch rail shall be tested.

The closed-switch opening gaps stated in this standard for the purpose of point lock and

detection testing shall be effective between the switch-tip and up to 75 mm from the switch-tip. It

shall be otherwise in line with the respective point lock or detector rod as specified by the

respective equipment manual.

Signalling safeworking procedures shall prescribe the applicable methodologies for the testing

of point lock and point detection that complies with the settings specified in this standard. The

methodologies prescribed may include effective novel methods of testing that are in accordance

with signalling principles, ASA.

24.1. Principle of point testing The principle of point testing is to prove the safety critical elements of points are effective and

will remain so until at least the next scheduled certification.

The following safety critical elements are to be proven effective during point testing:

• the closed-switch is closed and locked against the stock rail

• the open-switch is in the open position to the specified opening

• the open-switch rear flangeway has sufficient clearance

• the positions of point switches are correctly detected

• the positions of point drives, lock drives and other critical movements are correctly

detected, for example, plunger lock, indication box, pneumatic shuttle valve, control valve

pressure switch

The closed-switch shall be checked to be closed against the stock rail along its machined length

and without switch-roll having sufficient spring applied where applicable. The open-switch shall

be checked to be securely connected that it remains fully open and provides sufficient rear

flangeway clearance. The associated point rodding and fastenings shall be checked to ensure

they are effective and in proper condition.


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24.2. Prerequisite tasks for point testing Certain tasks are required to be done as a prerequisite to point lock testing and point detection

testing. These are done to confirm the satisfactory condition of the various elements before

testing for certification.

The following are examples of prerequisite tasks required before point testing:

• checking the layout for excessive movement that may alter the correct track gauge,

including any excessive lateral movement of switch and stock rails

• checking the stock and switch rail conditions for rail overflow and evident rail defects

(including rail surface defects) that may affect the integrity of the turnout

• cleaning and lubricating, as applicable, the switch plates and switch rollers (where fitted) to

remove contaminants and permit uninhibited operation of the switch rails

• checking the switch plates or rollers for even loading from switch rails

• checking the back-drive equipment (where fitted) for correct and smooth operation

24.3. Requirements for point lock testing mechanically operated points Mechanically operated points shall be tested to ensure the closed-switch cannot open by

3.2 mm or more. This requirement shall be reliant on achieving the following conditions:

• completion of the prerequisite tasks described in Section 24.2

• the point switches lying in correct position

• the point lock has fully entered

The point lock shall not enter if the closed-switch is open by 3.2 mm or more.

For reliability, the point lock shall be adjusted to fully enter with a closed-switch opening of at

least 1.6 mm.

Each open-switch opening (at the switch-tip) shall be checked and adjusted if necessary, in

accordance with their respective point type specification.

The rear flangeway clearance of each open-switch shall be checked to have sufficient

clearance. Any event causing the rear flangeway clearance to become altered (example, worn

switch rail, loose back-drive nuts, bent rodding) shall be suitably tested to ensure the clearance

is to specification.

The point lock plunger travel shall be 200 mm, except in cases where double lock plungers are

worked by one lever the travel shall be 175 mm. When the point lock plunger is withdrawn, the


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clearance between the end of the lock plunger and the slotted lock rod or the locking rod block

shall be 20 mm.

24.3.1. Other requirements for mechanically operated points On mechanically operated catch points, a fully entered point lock shall not permit the

open-switch to close by less than 100 mm. Additionally, the point lock shall not enter if the

open-switch is open by less than 100 mm.

On mechanically operated points fitted with a wide cut notch point lock for the trailing-only

switch, the point lock specification may be exceeded. In this case a fully entered point lock shall

not permit the closed-switch to open by 6.4 mm or more. Additionally, the point lock shall not

enter if the closed switch is open by 6.4 mm or more. Refer to Section 24.6.2 for requirements

that relate to the provision of wide cut notch point locks.

On mechanically operated points fitted with point lock detectors, the point lock shall enter into

the slide notch with sufficient clearance on both sides. Where a wider notch is used in point lock

detectors (example: at Lithgow), the point lock settings may be altered so that the point lock

does not enter with a closed-switch opening of 4.8 mm or greater. However, the point lock shall

fully enter with a closed switch opening of 3.2 mm or less.

24.4. Requirements for point lock testing power operated points Power operated points shall be tested to ensure the closed-switch cannot open by 3.2 mm or

more. This requirement shall be reliant on achieving the following conditions:

• completion of the prerequisite tasks described in Section 24.2

• point switches lying in correct position

• point lock has fully entered

The point lock shall not enter if the closed-switch is open by 3.2 mm or more.


least 1.6 mm.

Each open-switch opening, at the switch-tip, shall be checked and adjusted if necessary, in

accordance with their respective point type specification.

The rear flangeway clearance of each open-switch shall be checked to have sufficient

clearance. Any event causing the rear flangeway clearance to become altered (example, worn

switch rail, loose back-drive nuts, bent rodding) shall be suitably tested to ensure the clearance

is to specification.


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24.4.1. Requirements for Claw Lock points On Claw Lock points, the point lock specification may be exceeded such that a fully entered

point lock shall not permit the closed-switch to open by 4.8 mm or more. Additionally, the point

lock shall not enter if the closed-switch is open by 4.8 mm or more.


least 3.2 mm.

24.4.2. Requirements for swing nose points The point lock settings of swing nose crossings are the same as for Claw Lock points.

A swing nose crossing where operated by a Claw Lock electro-pneumatic mechanism fitted with

HLM point lock detector, shall lock the Claw Lock operating bar at the extremities of its 180 mm

travel. The HLM lock shall enter each notch centrally with equal clearance on both sides.

24.4.3. Other requirements for power operated points On power operated catch points, a fully entered point lock shall not permit the open-switch to

close by less than 100 mm. Additionally, the point lock shall not enter if the open-switch is open

by less than 100 mm.

On power operated points fitted with a wide cut notch point lock for the trailing-only switch, the

point lock specification may be exceeded such that a fully entered point lock shall not permit the

closed-switch to open by 6.4 mm or more. Additionally, the point lock shall not enter if the

closed-switch is open by 6.4 mm or more. Refer to Section 24.6.2 of this standard for

requirements that relate to the provision of wide cut notch point locks.

On power operated points where a HLM style point lock detector is used to secure the operating

bar, the lock shall be checked to operate in the middle of the notch provided. The maximum

no-go tolerance of the closed-switch opening is 6.4 mm.

24.5. Requirements for point detection testing Upon completion of the prerequisite tasks described in Section 24.2, and with the point switches

in their correct position, the point detector contacts shall be tested for the following:

• to be opened with a closed-switch opening of 4.8 mm or more

• to be closed when the closed-switch opening is 3.2 mm or less

• to be opened when the open-switch opening is less than 100 mm

Point detector contacts shall be visibly observed or otherwise checked using a voltmeter.


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24.5.1. Requirements for detection testing mechanisms where detection is interlocked with point lock On some point mechanisms the point detection is interlocked with the point lock, such that the

point lock is required to enter before enabling the detector contacts to close.

In these cases, the point detection setting shall be correct such that the detection contacts will

open and close in accordance with the specifications prescribed in this standard.

Accordingly, the periodic certification of the point detector shall be done for mechanisms that

provide visual sighting of the detector actuator roller and also for mechanisms that do not

provide visual sighting of the detector actuator roller.

For mechanisms that provide visual sighting of the detector actuator roller, the following

requirements shall be complied with:

• The point detection settings shall be assured by checking the proximity of the detector

actuator roller relative to the detector slide notch. The relevant contacts shall open and

close in accordance with the go/no-go specifications prescribed in this standard. This may

be achieved without the need to slacken (float) the point lock.

• The point detector contacts shall be checked to be open while the point lock is tested at the

'no go' specification.

For mechanisms that do not provide visual sighting of the detector actuator roller, the following

requirements shall be complied with:

• The point lock shall be accordingly slackened (floated) to allow the lock to enter. This

provides the opportunity to check the point detection settings.

• The point detector contacts shall be checked to be in accordance with the go/no-go

specifications prescribed in this standard.

• The point lock shall then be readjusted and certified in accordance with the go/no-go

specifications prescribed in this standard.

Other methodologies that assure the correct detection of point switches in these circumstances

may be applied; however, the methodologies used shall be in accordance with signalling

principles, ASA.

24.5.2. Requirements for testing point operating bar detection on Claw Lock and Spherolock points

Point operating bar detection (also known as point lock coverage detection) on Claw Lock and

Spherolock points is tested to ensure adequate point lock coverage is achieved at the moment

detection of the point operating bar is broken.


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Point operating bar detection is tested and certified during the initial set-up of points when

commissioned.

Subsequently, point operating bar detection shall be tested and certified whenever an event has

affected any of the following:

• open position of the open-switch

• detection of the open-switch

• detection of the operating bar, where separate detectors are used

The method and specification for testing point operating bar detection is different depending on

the type of arrangement in use.

Following is a list of different arrangements in use that prove the position of the operating bar to

ensure adequate point lock coverage is achieved:

• electro-pneumatic Claw Lock & Spherolock points, using the open-switch detector contacts

• electro-pneumatic Claw Lock & Spherolock catch points or independent switches using a

separate detector (typically U5A or HM) fitted at the end of the operating bar

• electro-pneumatic Claw Lock points using separate micro switches fitted at the motor

• electric Claw Lock & Spherolock points, including catch points and independent switches,

using the operating/drive bar detection contacts incorporated within the point mechanism

(example: Siemens 84M type)

The method and specification for testing the point operating bar detection for each arrangement

is as follows:

• electro-pneumatic Claw Lock & Spherolock points, where the open-switch detector

contacts are used

The open-switch detector contacts shall be checked to be open when the operating bar has

travelled 20 mm or less from the full normal or full reverse position. This will provide at

least 25 mm (20 mm for 53 kg rail) of point lock coverage for the closed-switch at the

moment the open switch detector contacts are opened.

• electro-pneumatic Claw Lock & Spherolock catch points or independent switches where a

separate detector (typically U5A or HM) is used at the end of the operating bar

The operating bar detector contacts shall be checked to be open when the operating bar

has travelled 20 mm or less from the full normal or full reverse position (as applicable). This

will provide at least 25 mm (20 mm for 53 kg rail) of point lock coverage for the

closed-switch at the moment the operating bar detector contacts are opened.


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• electro-pneumatic Claw Lock points where separate micro switches are fitted at the motor

The micro switch contacts shall be checked to be open when the motor and operating bar

have travelled 5 mm from the full normal or full reverse position. This will provide the

maximum amount of point lock coverage for the closed-switch at the moment the motor

detector contacts are opened.

• electric Claw Lock & Spherolock points, including catch points and independent switches,

using the operating/drive bar detection contacts incorporated within the point mechanism

(example: Siemens 84M type)

The operating/drive bar detector contacts (N-RI/R-NI) shall be checked to be open when

the operating/drive bar has travelled 20 mm or less from the full normal or full reverse

position (as applicable). This will provide at least 25 mm (20 mm for 53 kg rail) of point lock

coverage for the closed-switch at the moment the operating/drive bar detector contacts are

opened.

Testing of point operating bar detection during normal train running may be impractical.

Therefore, periodic testing of point operating bar detection may be exempt. This is based on the

following reasons:

• the point operating bar detection is a relatively course setting

• the detection contacts are back-proved in the circuit design and thus the operation is

'checked' from one position to the other

• the causes for out-of-adjustment situations are mitigated by maintenance tasks and event

driven tasks

24.5.3. Requirements for detection testing point locking mechanisms on mechanical points

Mechanical facing points fitted with a type D point lock are provided with a cross-slide or

detection slide. The slides are operated by the point lock plunger and are connected to an

electrical or a mechanical detector. The detector proves the locked position of the type D point

lock.

The detector contacts shall not make until the point lock plunger has completed two thirds of its

stroke. This specification equates to a dimension between 130 mm and 140 mm of its 200 mm

stroke towards the locked position.

Detection of mechanical facing points fitted with a HDLM type point lock is achieved internally

within the HDLM unit by two changeover contacts. The lock bar has slots machined on each

side which the lock bolt will drop into when the lock bar slides to the locked position. The locked

position is detected by cut-outs on the detector slides via bell cranks and rollers. The detector

contacts prove the locked position of the HDML point lock.


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The detector contacts shall not make until the point lock bolt has dropped into the locked

position.

24.5.4. Requirements for detection testing swing nose crossings The point detection settings of swing nose crossings are the same as that of other points.

24.5.5. Requirements for detection testing derailers The detector shall prove the position of the derailer, for example, derail position and clear

position.

Derailer detector contacts shall be made to close when the derailer is in a position to effectively

derail a train. The same contacts shall be made to open when the derailer is not in an effective

derail position.

Where contacts are used to also prove the derailer in a clear and safe position for the passage

of a train, the contacts shall only make when the derailer is in the fully cleared position.

Similarly, the same contacts shall be open when the derailer is not in the fully cleared position.

The detector contact settings can be adjusted slightly coarse because of the latitude between

the effective derail position and the fully cleared position.

24.5.6. Requirements for detection testing point back-drives The detector contacts of back-drive detectors (where fitted) shall be opened at approximately

6.4 mm for the closed-switch opening. This is measured at the back-drive detector. The detector

contacts shall be closed with a switch opening of 4.8 mm or less.

24.6. Provision for lock slide removal and wide cut notch point lock The provision to remove lock slides from point machines applies only to the points that are

trailing-only in both directions and operated by combined electric switch machines.

The provision to allow a wide cut notch in a point lock applies only to the following

configurations:

• open-switch catch points operated by combined electric switch machines

• open-switch catch points operated by signal branch electro-pneumatic or mechanical

mechanisms

• trailing-only position of points operated by signal branch electro-pneumatic or mechanical

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24.6.1. Providing approval for lock slide removal and wide cut notch point lock Where the reliability of trailing-only points can be improved by the removal of point lock slides or

by the provision of a wide cut notch point lock, then it is permissible to implement such

arrangement in accordance with signalling design principles.

The responsible signal engineer shall approve these provisions and control a register of all

points with point lock-slides removed or with a wide cut notch point lock.

Note: Points fitted with wide cut notch point lock slides shall be inspected every two

years by a signal engineer as part of their mechanical interlocking inspection to ensure

the integrity of the arrangement is maintained and that the inscriptions remain in

accordance with the signalling plan or working sketch.

24.6.2. Requirements for lock slide removal and wide cut notch point lock Signalling safeworking procedures shall include the following requirements for the removal of

point lock slides in points operated by combined electric switch machines:

• the unused guide-ways on both sides of the machine are plugged to prevent entry of dust

and grit

• the points shall be identified as 'non-locked points' to network operators, for the purpose of

yard working

Signalling safeworking procedures shall include the following requirements for the provision of a

wide cut notch point lock for the open-switch catch point of points operated by combined electric

switch machines:

• the wide cut notch point lock shall be machined at an engineering machine shop

• the allowable cut out for the wide cut notch in the point lock shall not exceed 13 mm wider

than the respective locking dog

• the point lock slide shall be stamped with the words 'wide cut notch' together with the

applicable point end number, all in 6 mm letters

• the stamped text shall be adjacent to the wide cut notch on one side of the lock slide, and

on the top and bottom face at the end between the elongated slot and second hole

• an additional set of lines shall be inscribed on the opposite face corresponding to the new

wide cut notch point lock, and the old marks shall be stamped with a cross

• installation of wide cut notch point lock-slides shall be certified by a signal engineer


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• the lock slide with a wide cut notch shall always belong to its respective point end at the

specified location, or otherwise when made redundant shall be destroyed

Signalling safeworking procedures shall include the following requirements for the provision of a

wide cut lock for the open-switch catch point or the trailing-only position of points operated by

signal branch electro-pneumatic or mechanical mechanisms:

• the allowable cut-out for the wide cut notch shall not exceed 13 mm wider than the

respective locking dog

• the trailing-only position of points shall be identified as 'non-locked points' to network

operators for the purpose of yard working

24.7. Provision to extend point detection limits On trailing-only points, signalling safeworking procedures may permit an increase to the

detection setting for reliability reasons to extend the detection limit of the closed-switch opening

from 4.8 mm to 6.4 mm.

This arrangement shall be conditional upon all of the following requirements:

• there is no signalled move through the trailing points in the facing direction

• there is no reversing move where part of the train would set back through the points in a

facing direction

• the arrangement is duly updated on the relevant signalling plan or working sketch

• a register of the arrangement is controlled by the responsible signal engineer

25. Inspection and testing of track circuits Track circuits provide a means of rail vehicle detection as utilised by the signalling system.

Track circuits require inspection, testing and maintenance, periodically and sporadically; for

example, following planned works such as re-railing, or unplanned events such as responding to

failures. The safety critical and safety significant tasks prescribed in this standard shall not be

exceeded. Additionally, signalling personnel shall be vigilant for evidence of potential track

circuit problems whenever the opportunity permits.

Any condition found with the potential to cause a track circuit to incorrectly indicate an

unoccupied state shall be treated as a signalling irregularity and the responsible signal engineer

be promptly notified.

Any condition found with the potential to reduce the reliability of a track circuit shall be actioned

in accordance with the operator/maintainers' requirements and relevant network rules and

procedures.


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25.1. Objective of track circuit inspection, testing and maintenance The objective of track circuit inspection, testing and maintenance is to find and remove any

potential failure condition, and ensure as far as practicable that the track circuit will function

safely and reliably. The track circuit shall comprise all the necessary components required to

enable its safe and reliable operation.

The following are examples of track circuit components:

• track circuit power supplies

• transmitter/feed units

• receiver/processer units

• trackside units and interfaces

• track circuit resistor and capacitor units

• track circuit relays

• rail surface, track and ballast condition

• impedance bonds

• insulated rail joints

• equipment wiring, track wiring and cabling

• traction bonds and parallel bonds

• wiring connections, including rail connections

• lightning protection

The following are examples of specific tasks that pertain to track circuits:

• performing inspection and maintenance of track circuit components

• recording of power supply and track circuit voltages, currents and settings

• performing shunt tests, including train shunt test where applicable

• performing polarity tests, where applicable

• performing zero feed tests

Track circuits that fail safety testing criteria shall be immediately reported to the responsible

signal engineer or other relevant signal engineer. In the absence of prompt, effective remedial

action, the protecting signals shall be booked out of use. Track circuits shall not be left operating

in an unsafe condition.


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25.2. Track circuit records Track circuit records (track circuit history cards) shall be used to record observations, test

values, adjustments and events that pertain to the track circuit. The records provide a means of

detecting trends. Gradual consistent variations may indicate the imminent deterioration of a

track circuit component. These variations shall be identified and resolved.

Track circuit records shall be made available at the receiver/relay location of the track circuit.

The relevant tests and information shall be recorded thereon. The current track circuit record

shall indicate the first and last full details of any previous record used. This provides a long term

baseline to compare variations.

A separate track circuit record shall be used for each track circuit and also for the following

applications:

• pin-point detectors (DPU)

• centre-fed track circuits

• common transmitter track circuits

• two receiver track circuits

• cut track circuits

• master and slave ends of Microtrax coded track circuits

• overlay track circuits

25.3. Track circuit inspection and tests The track circuit tests prescribed in this standard shall be performed as necessary during

periodic maintenance. Examples of other events that require track circuit testing include the

following:

• in response to an associated failure or incident

• following re-railing or trackwork

• following periods of track disuse

• whenever track circuit components are interfered with or replaced

25.3.1. Drop shunt test A drop shunt test proves the resistance value of the track circuit shunting characteristic. The

drop shunt resistance is measured using a variable shunt device called a shunt box. The drop

shunt value shall be the highest value of resistance that is obtained when the shunt box is

placed across the rails, which cause the track circuit relay/output to drop away.


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When taking the drop shunt measurement, the leads of the shunt box shall be connected across

the rails at the relay/receiver end of the track, set at a high value at which the relay/output is

energised. The resistance is then decreased until the track circuit relay/output drops away. At

that point, the drop shunt value is then measured. The drop shunt test shall be repeated three

times until consistent results are obtained. This result is recorded on the track circuit record.

The drop shunt value shall be in accordance with the specific track circuit equipment manual.

However, the drop shunt resistance value shall not be less than the value specified in Table 2

for the relevant track circuit type.

A fixed shunt test proves the track circuit shunting characteristic is within the specified limit. A

fixed shunt test shall be carried out by connecting a resistive shunt across the rails while

observing that the track circuit relay/output drops away with the shunt applied. The shunt

resistor shall be connected across the rails at all extremities of the track circuit (including within

crossovers) and at the mid point of the track circuit. At each point, the track circuit relay/output

shall be observed to drop away.

The value of the resistive shunt used for this test shall be in accordance with the specified

resistance for the relevant track circuit type specified in Table 2.

The fixed shunt check proves that the track circuit will shunt at a given point along the track,

usually at the receiver/relay end. The shunt check is done by using a fixed shunt resistor while

observing that the track circuit relay/output drops away with the shunt applied.

The value of the resistive shunt used for this test shall be in accordance with the specified

resistance for the relevant track circuit type.

Table 2 provides the minimum shunt resistance for different track circuit types.

Table 2 - Minimum shunt resistance

25.3.2. Fixed shunt test

25.3.3. Fixed shunt check

Track circuit type Minimum shunt resistance

dc track circuit (4 ohms/shelf relay) 0.15 ohms

dc track circuit (4 ohms/BT1B relay) 0.25 ohms

dc track circuit (4 ohms/QT1 relay) 0.25 ohms

dc track circuit (4 ohms/QT2 relay) 0.25 ohms

dc track circuit (9 ohms shelf relay) 0.50 ohms

HVI Jeumont Schneider track circuit (double rail) (1xBRTCA2-Rx)

0.25 ohms


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Track circuit type Minimum shunt resistance

HVI Jeumont Schneider track circuit (double rail) (1xRVT600-Rx)

0.50 ohms

HVI Jeumont Schneider track circuit (double rail) (2xRVT600-Rx)

0.25 ohms

HVI Jeumont Schneider track circuit (single rail) (Normal/TV-TH1)

0.50 ohms

HVI Jeumont Schneider track circuit (single rail) (TV-THD2 or TV-LV)

0.25 ohms

ac track resistor fed - signal branch track circuit (single rail)

0.25 ohms

ac track resistor fed – WB&S track circuit (single rail)

0.50 ohms

ac track circuit resonant impedance bond 0.25 ohms

ac track circuit AAR standards (double rail)

0.06 ohms

UM71 audio frequency track circuit (CSEE)

0.15 ohms

TI21 audio frequency track circuit (ML)

0.15 ohms

WB&S audio frequency track circuit (FS2500)

0.15 ohms

WB&S FS2600 track circuit 0.50 ohms

USS Microtrax coded track circuit 0.25 ohms

audio frequency overlay track circuit Safetran PSO 4000

0.15 ohms

25.3.4. Train shunt check

A final test of the proper operation of a track circuit is the train shunt check. This test is

performed to prove that there is effective wheel to rail contact and that a train is effectively

detected during its entire passage over the track circuit. A train shunt check shall be required

whenever there is doubt about the conductivity of the wheel to rail contact surfaces, for

example, after re-railing or after an extended period of disuse.

The train shunt check is carried out by monitoring the track circuit relay/receiver input voltage

while a train passes over the whole length of the track circuit. The input voltage is observed to

ensure it does not exceed the maximum train shunt value in accordance with the relevant

values specified in Table 3.


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25.3.5. Polarity test A polarity test is performed to prove the polarities across insulated rail joints of like track circuits

conform to the polarity shown on the specific track insulation plan. In most cases, the polarity of

rail voltages across insulated rail joints will be opposite. This requirement avoids an unsafe

condition arising, caused by a track circuit being fed from an adjacent track circuit in the event of

an insulated rail joint becoming short circuit.

The existence of like polarities is only acceptable at a track feed to track feed interface, or

where a short circuit insulated rail joint would result in both adjacent track circuits becoming

de-energised. Polarity reversal does not apply to audio frequency track circuits.

A polarity test is conducted by checking the rail voltage polarities to ensure that the polarity

across all insulated rail joints between adjacent like track circuits conform to the specific track

insulation plan.

Following are examples of adjacent track circuits affected by like polarity:

• dc track circuit adjacent to dc track circuit

• 50 Hz ac track circuit adjacent to 50 Hz ac track circuit

• high voltage impulse (HVI) track circuit adjacent to HVI track circuit

• Microtrax coded track circuit adjacent to Microtrax coded track circuit

The responsible signal engineer shall be advised of incorrect polarities between track circuits as

soon as possible. Where incorrect polarities are evident, the condition of insulated rail joints

shall be checked to ensure that they are not liable to breakdown before the situation is

corrected. Any track insulation reconfiguration shall first require an approved signalling design.

25.3.6. Zero feed test A zero feed test is performed to prove that the track circuit relay or receiver is not fed from any

other source other than its own track feed or transmitter. Zero feed tests require the track circuit

feed or transmitter power supply to be temporarily disconnected. During this time, the relay

voltage or receiver input is measured to be near zero and shall not exceed the maximum zero

feed values specified in Table 3. The track circuit relay/output shall also be observed to have

de-energised.

Any track circuit that exceeds the maximum train shunt or zero feed value shall be disconnected

and the protecting signalling booked out of use.

Notwithstanding the specified maximum zero feed value, test readings above 10% of the drop

away test value or above one third of the other values specified in Table 3 shall be investigated

and immediately reported to the responsible signal engineer.


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Note 1: The drop away test value for shelf relays is the drop away value shown on the

manufacturer's or workshop's test label on the relay. The drop away test value for

plug-in relays is the standard drop away value for that type of relay.

Note 2: On ac vane relays, the supply to the local coil shall be opened. On audio

frequency track circuits, the transmitter for the track adjacent to the receiver shall also

have the supply fuse removed unless a frequency selective voltmeter is utilised.

Note 3: Where a rail vehicle is fitted with a track circuit actuator (TCA), used to

enhance the wheel to rail shunt capability, the vehicle cannot be used for a train shunt

check unless the TCA is first turned off.

Table 3 provides the maximum train shunt and zero feed resistance values for different track

circuit types. It also provides the threshold that requires advising the responsible signal

engineer.

Table 3 - Maximum train shunt and zero feed values

Track circuit type

Test point Unit of measure

Maximum train shunt or zero feed value (see note 1)

Advise responsible signal engineer

DC (shelf relay) relay coil V dc <30% of drop away test value

>10% of drop away test value

DC (plug-in relay)

R1/R2 V dc <30% of drop away test value


50 Hz ac control terminals

V ac <30% of drop away test value


CSEE UM 71 receiver R1 R2 mV ac (with filter)

<90 >30

ML TI 21 input resistor (1 ohm) terminals

mV ac (with filter)

(mV x gain) <100 (mV x gain) >35

WB&S FS2500 receiver monitor mV ac <400 >135

HVI Jeumont Schneider

receiver terminals

V dc (with integrator)

<100 >35

HVI Jeumont Schneider

C+/C1 (RVT-600) 3/C1 (BRT-CA2)

V dc (with integrator)

<100 >35

USS Microtrax coded track circuit

slave end - track interface panel terminals

mV dc <80mV (pulse) >50mV (pulse)

WB&S FS2600 receiver monitor mV ac <500 >100


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Track circuit type

Test point Unit of measure

Maximum train shunt or zero feed value (see note 1)

Advise responsible signal engineer

Audio frequency overlay Safetran PSO 4000

signal display receiver signal level

<40 (train shunt) <20 (zero feed)

>20

25.3.7. Inspection of traction bonding Traction bonding includes parallel bonds between rails, tie-in bonds, cross bonds (example: rail

to rail and rail to impedance bond), and traction bonds from rails to section hut or substation

busbars. Traction bonding shall be inspected to ensure it is in good condition.

Any open circuit traction bonds or high resistance connections found shall be promptly rectified

or replaced.

25.3.8. Inspection of parallel bonds Parallel bonds on track circuits extending over points to a clearance point on another line, shall

be inspected along their entire length to ensure the bonding has not been damaged or removed

by trackwork, vandals, or other causes. This may result in loss of train detection.

Any open circuit parallel bond or high resistance connection found shall be immediately rectified

or replaced.

25.3.9. Inspection of track circuit relays

Track circuit relays shall be inspected in accordance with Section 21 of this standard.

25.4. Track circuit precautions Track circuit precautions for the following tasks shall be prescribed in signalling safeworking

procedures:

• adjustments

• circulating currents affecting 50 Hz ac track circuits

• polarity of power supplies

• interference or repairs to track circuit wires

• contaminated (rusty) rails


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• CSEE/HVI Jeumont Schneider receiver rack position

• Microtrax coded track circuits

• audio frequency overlay track circuits

These are stated in detail in Section 25.4.1 through Section 25.4.8.

25.4.1. Adjustments Track circuit feed voltages shall not be increased to compensate for open circuit or high

resistance bonding. In electrified areas, high track feed voltages may increase the probability of

circulating currents through traction tie-in bonding or earth paths.

Track circuits adjusted in wet or poor ballast conditions shall be retested when the track has

dried out and the ballast conditions improved to ensure correct shunting of the track circuit.

Licensed signalling personnel are permitted to make minor adjustments. However the

responsible signal engineer shall be accordingly notified.

Intended large adjustments, or adjustments required for unaccountable reasons shall be

immediately referred to the responsible signal engineer or other relevant signal engineer for

instruction. Large adjustments shall not be made without the authorisation of a relevant signal

engineer.

Following any track circuit adjustment, a fixed shunt test (for minor adjustments), or drop shunt

test (for large adjustments) shall be performed. A record of the values and reason for the

adjustment shall be made on the track circuit record. Additionally, the track circuit shall be

monitored accordingly and readjusted immediately when the conditions improve. The

responsible signal engineer shall ensure the timely reinstatement of any adjustment.

25.4.2. Circulating currents affecting 50 Hz ac track circuits

Fault conditions with 50 Hz ac track circuits may enable currents to circulate via traction tie-in

bonds, earth paths, and so on through other track circuits which may pose a potentially unsafe

condition. Where unbalanced ac rail currents are detected, the responsible signal engineer shall

be promptly notified and the cause of the imbalance investigated and rectified without delay.

Open circuit or high resistance rail bonds, series bonds, impedance bond side leads, and their

connections, shall be rectified promptly. Jumper bonds, in good condition and installed correctly

may be utilised in an emergency. However these will be replaced by permanent bonds as soon

as possible.

The rail current balance shall be determined by measuring the signalling current in both rails, at

both the feed and relay ends of the track, using an induction meter set at 50 Hz frequency. For

double rail 50 Hz ac track circuits, an imbalance of rail current greater than 0.5 amps shall be

considered significant. For single rail 50 Hz ac track circuits, an imbalance of rail current greater


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than 1.25 amps shall be considered significant. The currents measured in each cable of a side

lead pair should be within 10% of each other. Uneven current sharing indicates a high

resistance side lead or connection. The voltage drop across a side lead connection to the rail

should be less than 10 mV ac.

Note: While it is not expected to experience stray 50 Hz ac currents emanating from

balanced double rail 50 Hz ac track circuits, this may not be the case with single rail

50 Hz ac track circuits. This is because the traction rails of parallel single rail track

circuits are generally connected by tie-in bonds. This provides an alternate low

resistance path for the stray currents. Therefore it is not unusual to measure

unbalanced 50 Hz ac currents in single rail 50 Hz ac track circuits.

25.4.3. Polarity of power supplies Whenever power supplies or their associated wiring are worked on, there is a risk that the

polarity of 50 Hz ac track circuits may become swapped, potentially causing an unsafe

condition. This is also true when the supply phasing is altered by supply authorities or the

location normal or emergency power supply changes state.

Adjacent 50 Hz ac track circuits, fed from different power supplies are mostly at risk.

Consequently, the polarities of these adjacent track circuits shall be tested whenever an 'at-risk'

event occurs at the power supply level.

Note: Where feed and relay ends of the same 50 Hz ac track circuit are fed from

different power supplies these track circuits shall be promptly reconfigured so that they

become fed from the same power supply.

25.4.4. Interference or repairs to track circuit wires A fixed shunt check or train shunt check shall be performed whenever two or more track circuit

wires to or from track circuit equipment are disconnected and reconnected. A polarity test

between the affected track circuit and adjacent track circuits shall also be performed, where

applicable.

25.4.5. Contaminated (rusty) rails Rust and other contaminants that form on the rail surface may affect the wheel to rail interface,

potentially causing an ineffective track shunt. Where the rail surface condition is in doubt, a train

shunt check shall be performed. Track circuits that fail to provide an effective track shunt shall

be treated as seldom used apparatus in accordance with Section 16 of this standard.

Similarly, track circuits that are prone to excessive sanding shall be treated as seldom used

apparatus.


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25.4.6. CSEE and HVI Jeumont Schneider receiver rack position The task of plugging CSEE and HVI Jeumont Schneider track circuit receivers into their correct

rack positions is critical. The misalignment of a receiver by one module space can have unsafe

consequences, resulting in the permanent energisation of the track circuit relay.

These units shall be checked to be in their correct position whenever they are plugged into their

base. Additionally a check shall be made to ensure every vacant module position above and

below these units is fitted with obturation fittings and coding plugs.

25.4.7. Microtrax coded track circuits The Microtrax card file shall be securely mounted with all plug-in modules fully inserted and the

front panel holding down screws securely tightened.

Vacant positions on the cardfile shall have cover plates fitted at all times.

The boards, modules or vital power failure relay shall not be removed or replaced with the

Microtrax unit powered up.

Wiring from the Microtrax unit to the track interface panel should not be short-circuited or open-

circuited while the Microtrax unit is in operation. The Microtrax unit shall be turned off at both

ends before interfering with this wiring. Failure in doing so will place the Microtrax unit in

selective shut down mode.

When performing shunt tests, the slave end unit condition shall be monitored. The slave end

unit shall indicate its de-energised state by displaying '0000' in the 'TRK MARGIN' display. To

ensure the occupancy indication displayed remains constant, the track shunt shall be applied for

at least 30 seconds.

Microtrax operator keys for crossing loops may be issued to licensed signalling personnel for

the purpose of engineering work only and not for operational use. Where the keys are issued to

licensed signalling personnel, the keys shall be numbered and issued to the person who shall

be accountable for the security of the key. The key shall not be lent to other persons unless the

transfer is approved and documented by the responsible signal engineer.

Microtrax diagnostic and configuration software shall not be copied onto third party machines or

supplied to unauthorised persons. Under no circumstance shall the vital erasable programmable

read-only memory (EPROM) be duplicated or altered by field personnel.

The configuration of modules including associated EPROM shall be permitted only by the

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The storage of Microtrax configuration data, for example, EPROM and version information shall

be registered and kept secure. This shall be managed by the contracted AEO who holds

accountability for the maintenance of signalling design records and data.

Note: A zero feed test is not required for Microtrax coded track circuits.

25.4.8. Audio frequency overlay track circuits (PSO 4000) The Safetran PSO 4000 audio frequency overlay track circuit receiver indicates its de-energised

state by the 'Rx-Int' led in the receiver occupancy display being extinguished. This shall be

monitored in conjunction with the signal display level on the receiver which indicates its

de-energised state by displaying a number less than '100'.

The track circuit relay shall also be observed to be in a de-energised state during this time.

25.5. Safety critical and safety significant track circuit tasks The safety critical and safety significant tasks for track circuits are mandatory and shall be

treated in accordance with Section 20.2 of this standard.

25.5.1. Safety critical tasks for double rail 50 Hz ac track circuits Double rail 50 Hz ac track circuits in electrified areas shall be periodically tested and certified for

unbalanced rail currents and voltage drop across connections to ensure their safe operation.

The frequency of this certification shall not exceed 30 days.

The values of these tests shall be documented on a track circuit record specific for this purpose.

The following tasks shall be included in signalling safeworking procedures for the testing and

certification of double rail 50 Hz ac track circuits:

• test track circuit relay coil voltage when unoccupied

• test current in each rail for balance at relay end

• test current in each rail for balance at feed end

• test current in each cable of impedance bond side lead for balance at up rail

• test current in each cable of impedance bond side lead for balance at down rail

25.5.2. Safety significant tasks for track circuits installed with parallel bonds Parallel bonds shall be periodically inspected for continuity and integrity. The frequency of this

inspection shall not exceed three months, except where parallel bonds are surface run, have

hypalon insulation and have welded rail connections. In this case, the inspection frequency can

be extended to 6 month intervals. In any case, signalling personnel shall take every opportunity


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to inspect parallel bonds whenever opportunities arise, for example, when working in the vicinity

of points.

The results of this inspection shall be recorded on the track circuit record.


certification of parallel bonds:

• inspect parallel bonds for electrical continuity in accordance with track insulation plan

• inspect parallel bonds for effective rail connection

• inspect parallel bonds for sound condition

25.5.3. Safety significant tasks for dc track circuits

DC track circuits shall be periodically tested to ensure the battery voltage and battery condition

is within specified limits. The frequency of this testing shall not exceed three months.

The results shall be documented on the track circuit record.


certification of dc track circuits:

• test track circuit relay coil voltage when unoccupied

• test battery supply voltage and current (with charger off, drain or charge as applicable)

• inspect battery condition

25.5.4. Safety significant tasks for all track circuits

All track circuits shall be periodically tested to ensure their shunting capabilities are within

specified limits. The frequency of this testing shall not exceed two years.

The results shall be documented on the track circuit record.


certification of track circuits:

• test track circuit relay/receiver input voltage when unoccupied (except double rail 50 Hz ac

and dc track circuits as these are certified separately)

• perform fixed shunt test

• perform drop shunt test

• perform polarity test as applicable

• perform zero feed test


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26. Inspection and testing of level crossing protection Level crossings are interfaces where rail corridors and road/pathways intersect. This interface

poses a risk which may result in a collision between users of level crossings and trains. This risk

increases as rail and road vehicle speeds and volumes increase over time.

Level crossing protection takes the form of either active or passive types as referenced in this

standard. Users at level crossings refer to road vehicles, pedestrians or cyclists, as applicable.

In some cases, dedicated pathways for pedestrians or cyclists are provided at level crossings.

Active level crossing protection includes type F flashing lights, bells and signage (for track and

road), and may include road boom barriers, pedestrian boom barriers or swing gates, pedestrian

lights, and pedestrian tone generators (sirens). Level crossing protection activation can be

controlled locally or remotely, or enabled automatically.

Passive level crossing protection is generally provided for roads that are less utilised or for

private roads and usually consists of stop or give-way and warning signage only.

At some level crossings, the activation equipment is interfaced with adjacent road traffic signals

to enable efficient management of road traffic. This aims to reduce the likelihood of road vehicle

queuing across the rail corridor or the road intersection.

The requirements for road signage provided for level crossing approach warning is not covered

by this standard.

26.1. Maintenance and inspection of level crossing protection equipment Signalling safeworking procedures shall prescribe the precautions and procedures necessary to

perform inspection, maintenance and emergency response while ensuring the safety

requirements of level crossing protection is afforded at all times. Additionally, signalling

personnel shall be vigilant when in the vicinity of level crossings, to observe for faults, damage

or vandalism that may affect its safe operation.

The moving parts of level crossing boom barriers and swing gates, including pedestrian

emergency access gates where provided, shall be kept clean, lubricated and checked for

efficient operation.

The operational time taken for the booms and gates to descend and ascend shall be checked to

be in accordance with the design requirements. Where these times are excessive, the

responsible signal engineer shall be notified and the matter investigated.

The balancing of boom barriers and swing gates shall also be checked and adjusted as

necessary. © State of NSW through Transport for NSW of 151 Sup

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In some ac electric type gate mechanisms, particular attention shall be given to the magnetic

brake and armature, to ensure they are adjusted as necessary to compensate for brake shoe

wear. The friction drive or clutch shall also be checked and adjusted as necessary.

Good visibility of lights and signs at level crossings is essential. To achieve this requirement,

signal lights shall be maintained in accordance with Section 22 of this standard.

Signalling personnel shall arrange to notify the local road authority of situations where road

signs at level crossings positioned outside the railway boundary are obscured, missing, or

damaged. Additionally, such advice shall be reported to the responsible signal engineer.

Maintenance records shall be utilised to record test values, observations and events pertaining

to level crossing protection equipment. These shall be available at each level crossing site for

later reference.

26.1.1. Signal engineers periodic inspection A signal engineer shall periodically inspect each active level crossing to ensure the following:

• level crossing protection equipment performs in accordance with its intended design

requirement

• level crossing configuration is effective for specific circumstances

The signal engineer's inspection is a safety significant task and shall be treated in accordance

with Section 20.2 of this standard. The frequency of these inspections shall not exceed the

specified period stated in Table 4.

Table 4 – Inspection frequency for level crossing protection equipment

Level crossing protection equipment Inspection frequency

Lights and bells with no boom barriers/gates, not remotely monitored and tested

3 months

Lights and bells with no boom barriers/gates, remotely monitored and tested

6 months

Lights, bells with boom barriers/gates, not remotely monitored and tested

6 months

Lights, bells with boom barriers/gates, remotely monitored and tested

12 months

26.1.2. Level crossing daily operation test Active level crossing operation shall be tested daily, unless the level crossing is fitted with an

effective remote monitor and testing device.

This daily test shall consist of a two minute load test (battery charger disconnected), checking

for the correct operation of all lights, bells and boom barriers or gates as applicable. The power


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supply indicator (PSI) lights where available shall be observed to be turned ON at the

conclusion of the test.

This daily test shall be performed by licensed signalling personnel or qualified rail workers in

accordance with the network rules and procedures.

In addition to periodic maintenance, licensed signalling personnel shall perform a level crossing

operation test whenever they investigate reports of defective level crossing protection

equipment which includes associated power supply.

26.1.3. Reinstatement actions following maintenance or failure response Fault or warning conditions, detected by a level crossing monitor, shall be cleared before

leaving the level crossing site.

Whenever level crossing lamps are replaced or re-adjusted, the level crossing shall be operated

for sufficient time to confirm that the level crossing monitor’s lamp detection system (where

fitted) is working correctly.

At the conclusion of maintenance, testing or investigation, it shall be ensured that the level

crossing is fully operational and that nothing has been left switched off, disconnected or

unlocked including battery chargers, power supplies, test switches, emergency switches and

manual operating or overriding switches.

26.2. Treating reports of level crossing failure All reports of level crossing protection failure shall be duly investigated by licensed signalling

personnel. This includes any report of power supply defect associated with the level crossing, or

any fault or warning indication provided by a level crossing monitor.

Reports of signalling irregularity pertaining to level crossing protection shall be promptly

investigated by a signal engineer. The response to level crossing irregularities shall be in

accordance with Section 11 of this standard.

27. Inspection and testing of signalling interlockings New or altered signalling interlockings are tested when commissioned to ensure they comply

with their design requirement. Subsequently, the signalling commissioning engineer is required

to provide a copy of the associated design documentation to the responsible signal engineer to

indicate the altered locking details as commissioned. These design documents may include

locking tables, control tables, locking diagrams, signalling plans and working sketches.

The responsible signal engineer shall be accountable for retaining the most up-to-date versions

of signalling documentation relevant for the purpose of interlocking testing.


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Periodic testing of mechanical and relay interlockings shall then be performed to ensure they

remain effective and in accordance with their design requirement. The responsible signal

engineer shall be accountable for ensuring these interlockings are periodically tested.

Signalling interlockings may also require testing in the following situations:

• when investigating a signalling irregularity or incident

• where there is doubt with the integrity of the interlocking

• whenever mechanical locking or associated covers are interfered with

The inspection and testing of signalling interlockings shall be done in accordance with

SPG 0711.

27.1. Authority to test signalling interlockings Interlocking testing, including signalling principles testing, shall only be performed by signalling

personnel who hold the competency for such testing.

Signalling personnel, holding a specific competency for interlocking tests (equivalent to an

interlocking certificate), are permitted to test mechanical interlocking items and mechanical

frames. These mechanical frames may include frames greater than eight levers. They are also

permitted to test relay interlockings and computer based interlockings.

Signal design engineers required to perform design integrity testing (principles testing) following

related new or altered work, shall also meet these competency requirements for testing

interlockings.

Signal engineers, who do not have the specific competency for interlocking tests, may perform

interlocking tests on mechanical interlocking items and mechanical frames of up to eight levers.

However, as part of an investigation which is in response to a signalling irregularity or incident,

or where there is doubt with the integrity of an operating interlocking, signal engineers are

further permitted to perform such interlocking tests on all types of interlockings.

Licensed interlocking fitters are permitted to test annett locks, duplex locks and other similar

mechanical items following maintenance of these items.

27.2. Testing altered locking on interlocking frames greater than eight levers Where a mechanical interlocking frame greater than eight levers is tested to certify an altered

locking arrangement, two testers shall be required to jointly conduct the test. Both testers shall

meet the same competency requirements for testing interlockings as stated in Section 27.1 of

this standard.


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The testing methodology shall require one tester to test the levers in accordance with the

locking table as usual. The other tester shall simultaneously observe the layout plan to ensure

that the relevant signalling principles are effective during the test, for example, checking that

levers pulled do not clear opposing signals.

Both testers shall sign the test certificate to certify the interlocking is correct.

27.3. Interlocking test certificates Interlocking test certificates shall be provided in the following situations:

• upon certification of related new or altered works

• upon certification of periodic interlocking testing

• upon certification of interlockings subsequent to a related signalling irregularity or incident

The responsible signal engineer shall retain a file of interlocking test certificates.

27.4. Periodic testing of mechanical interlockings Periodic testing of mechanical interlockings is a safety significant task and shall be treated in

accordance with Section 20.2 of this standard. The frequency of this testing shall not exceed

two years.

Mechanical locking items and frames are subject to wear and tear. Generally, the mechanical

locking does not contain any redundant locking.

Therefore, the method of testing used is important to identify any fault or flaw. For example,

mechanical locking that may be inappropriately defeated, or where the inscription or indexing of

items is impaired or is inappropriate.

The testing shall ensure mechanical locking items are effectively operational, safe and secure,

and in accordance with specific locking tables, control tables, locking diagrams, signalling plans

and working sketches as applicable.

The following are examples of mechanical interlocking items that shall require testing:

• mechanical lever frames

• releasing switch locks

• annett locks

• duplex locks

• half pilot staff locks

• emergency locks

• emergency switch machine locks and emergency operation locks © State of NSW through Transport for NSW of 151 Sup

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• token boards or similar devices including associated equipment as shown on signalling

plans or working sketches

• bolt locks and bracket locks

• loose keys

• XL locks, point-clips and point-spikes used on installed points not connected to the

interlocking

• wide cut notch point lock slides

Signalling notice boards shall also be checked as part of this interlocking certification to ensure

they conform to the signalling plan or working sketch.

27.5. Periodic testing of relay interlockings Relay interlockings consist of both standard relay and route control types.

Periodic interlocking testing on relay locking is a safety significant task and shall be treated in

accordance with Section 20.2 of this standard. The frequency of this testing shall not exceed

five years.

Relay interlockings contain some safety redundancy over the interlocking and control circuitry.

However, their integrity may be reduced by mechanical deterioration of electromechanical

relays, or by deterioration of wiring insulation through aging, termites, rodents, overheating, fire,

lightning and so on. Additionally, electrical leakage paths could cause tracking across insulating

surfaces which could impair the electrical integrity.

Some defects may be identified by the system. For example, where relays are back-proved or

cross-proved in the de-energised position or where the equipment fails to operate. However,

other defects such as the inadvertent bridging of an interlocking circuit may not necessarily

come to attention.

Therefore, the method of testing used is important to identify any fault or flaw where the relay

locking may be inappropriately defeated.

The following elements assist to ensure the integrity of relay interlockings:

• reliable earth leakage detection equipment

• testing of busbar voltage leakage to earth

• inherent design of relay back-proving and cross-proving


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Relay interlockings that fully comprise the following elements may be exempt from periodic

interlocking testing:

• plug-in type vital signalling relays

• PVC insulated and sheathed wires and cables

• double switched external interlocking circuits

• power supplies for vital interlocking circuits fitted with reliable earth leakage detection

Note: Mechanical items that form part of the relay interlocking are tested in


27.6. Periodic testing of computer based interlockings Computer based interlockings may be exempt from periodic interlocking testing. The safety

integrity level required of these interlockings provides the necessary safety assurance

requirements for the signalling system.

However, validation and testing may still be required when commissioning new or altered works,

or otherwise in response to a signalling irregularity or incident.

Following are some computer based interlocking systems used in TfNSW:

• Solid State Interlocking (SSI)

• Microlok II

• Westlock

• Westrace

• Smartlock

Note: Mechanical items that form part of the computer based interlocking are tested in


28. Inspection and testing of electrical insulation The integrity of electrical insulation used on vital signalling circuits forms an important aspect of

the safety assurance requirements for the signalling system. Electrical conductors used for

internal wiring, external cables and single-wires, power supplies and equipment are exposed to

many elements and forces that subject them to deterioration and damage. This may lead to vital

signalling functions being incorrectly activated by electrical leakage currents, which may result

in a signalling irregularity.

Therefore, the periodic testing of insulation properties of these conductors is important to ensure

they are adequately insulated from one another and from earth.


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Conductors and equipment of new or altered signalling installations are initially insulation tested

when commissioned in accordance with SPG 0711.

Subsequently, insulation inspection and testing shall be performed periodically to identify any

insulation degradation that may be caused by damage or fatigue over time. This provides a

timely opportunity to action any emerging faults that are found and avoid the impairment to

signalling integrity or reliability.

Periodic insulation inspection and testing is a safety significant task and shall be treated in

accordance with the requirements stated in Section 20.2 of this standard. The frequency of this

inspection and testing shall not exceed the period specified in Table 5.

Table 5 – Maximum periodic insulation inspection and testing frequency

Testing category

Insulation type

Inspection and testing frequency

Internal wiring PVC 4 years

Non-PVC 2 years

External cables and single-wires

PVC 4 years

Non-PVC 2 years

Additionally, signalling personnel shall be vigilant during other opportunities to observe the

condition of wiring, cables, terminals, racking, cable routes and equipment.

The responsible signal engineer shall be accountable to ensure all the required vital signalling

wires and cables as shown in specific signalling documents are identified for testing. The

responsible signal engineer shall also be accountable to ensure all the electrical conductors

nominated for testing are completed in accordance with the periodic insulation inspection and

testing schedule.

Insulation testing of operational signalling shall be led by a licensed signalling person. However,

where the signalling is first booked out of use and disconnected from the interlocking (by a

licensed signalling person), the inspection and testing may be led by an authorised signalling

person holding appropriate competency.

The methodology and test equipment used for insulation inspection and testing shall be in

accordance with SPG 0711.

28.1. Detecting earth leakage Earth leakage may be caused by two individual earth faults which are significant enough to

cause an unsafe situation. Additionally, earth leakages may be made up of cumulative effects of

many less-significant earth faults. The intent is to detect and rectify a single fault before another

fault arises. © State of NSW through Transport for NSW of 151 Sup

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The following are examples of the various means used to detect circuit electrical leakage paths:

• monitoring of power supply busbars using reliable earth leakage detectors

• measuring of power supply busbars to earth using test instruments

• testing of conductor insulation using test instruments

• function testing of signalling circuits

• examining the wiring, cables, terminals, racking, cable routes and equipment for damage

and deterioration

28.2. Minimum acceptable values A signal engineer shall be notified to provide instruction upon any of the following findings:

• insulation test resistance values found at or below 1 M ohm

• abnormal earth leakage values

• evidence of abnormal deterioration or insulation damage

The requirements of Section 28.3 shall also apply where these conditions are evident.

Conductors of vital signalling circuits that are found to have an insulation test value of

200,000 ohms or less shall have the associated signalling apparatus booked out of use. The

decision to permit signalling to remain operational in these circumstances shall be discussed

between the responsible signal engineer and another signal engineer holding appropriate

accountability before implementation, to ensure all risks are controlled.



28.3. Determination for further testing Periodic insulation testing of external cables and single-wires is based on samples of nominated

conductors. This provides an effective and efficient assessment of integrity for the conductors in

use within the signalling system.

However, comprehensive testing over and above the initial sample shall be required when a

defect is found with a tested conductor. This comprehensive testing shall determine the actual

condition of the cable or single-wire group.

A single-wire group is defined as the number of single conductors that are grouped together

within the same routing.

Where any of the sample tested conductors are found at or below 1 M ohm, all the conductors

within the cable or single-wire group shall be completely tested.


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Where the conductive sheaths, screens or drain wires of external cables are tested and found at

or below 1 M ohm and the associated busbar is not monitored by a reliable earth leakage

detector, the following testing requirements shall apply:

• where all working conductors of the cable are double switched, at least 20% of the cable

cores shall be tested

• where any of the working conductors of the cable are not double switched, all the cable

cores shall be tested

Working cables or single-wires that are left in these conditions shall be tested more frequently

than stated in Table 5. The frequency shall be based upon the residual risk. The responsible

signal engineer shall be accountable for this determination.

28.4. Analysis and test records Specific insulation test records shall be provided and kept on file along with the insulation

inspection and test program for future reference. These records shall pertain to a signalling

interlocking or block section as applicable. The responsible signal engineer shall be

accountable for these records including the initiation of any subsequent actions that are derived

from the findings.

The values recorded from insulation testing shall be duly analysed by a signal engineer to

determine if there are any risks involved and also to evaluate the urgency and extent of any

remedial action required.

The signal engineer shall recommend to address any degrading trend in insulation resistance

values.

28.5. Inspection and testing of power supply busbars Voltage to earth leakage tests on power supply busbars shall be performed periodically. The

frequency of this test shall not exceed three months. Each leg of the power supply shall be

tested.

Under no circumstances shall an ammeter be connected between any busbar and earth.

Power supply busbars that are fitted with reliable earth leakage detectors may be exempt from

periodic voltage leakage to earth testing. In these cases, the earth leakage detector shall be

tested for reliable operation in conjunction with maintenance of the associated signalling

location.

Records shall be provided for power supply busbar voltage to earth leakage tests. These shall

be kept in the relevant signalling location.


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28.6. Inspection and testing of electrical conductor insulation The treatment of operational signalling when performing periodic insulation testing shall be done

in accordance with the maintenance requirements stated in Section 20.1 of this standard.

Wires or cable cores shall not be removed from their terminals for the purpose of insulation

testing unless necessary. Where it is necessary, only one wire shall be removed at a time and

the reconnection shall be suitably tested. The use of disconnection links or the unplugging of

coded type plug couplers shall be the preferred means to conduct this test.

Electronic equipment shall be disconnected before insulation testing to avoid damage caused

by the testing equipment.

The following are examples of such equipment that may be affected:

• power supplies

• electronic track circuit equipment

• timers and timer relays

• flashing relays

• solid state modules

• computer based interlocking equipment

• control system equipment

• telemetry equipment

28.6.1. Requirements for insulation testing of internal wiring Internal wiring referred in this standard is the wiring of vital signalling that is contained within

signal boxes, relay rooms and trackside signalling housings. It excludes trackside cable junction

boxes and the like, which only include through-connection terminals and not any internal wiring

for vital signalling equipment.

The internal wiring of circuits shall be preferably tested complete with all associated relay

contacts closed. Where this is not practical, the internal circuit shall be tested thoroughly by

testing all the individual parts of the circuit arranged when the relay contacts can be closed.

The circuits shall be first disconnected from their respective power supply (at all ends) before

commencing testing.

All internal wires used for vital signalling shall be tested to earth and to its associated metal

frame. The frequency of this test shall be in accordance with Table 5.


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Where metal frames are earthed, the earth point used for insulation testing shall be the earth

that is connected to the frame.

Where reliable earth leakage detectors monitor the associated power supply busbar of internal

wiring, the requirement for periodic insulation inspection and testing of internal wiring may be

exempt.

28.6.2. Requirements for insulation testing of external main cables and single-wires External cables and single-wires referred in this standard are the conductors that provide the

external electrical connection for vital signalling that lie between signal boxes, relay rooms,

trackside housings and trackside equipment.

Signalling safeworking procedures shall categorise external cables and single-wires as follows:

• external main cables and single-wires – which connect signalling equipment housings to

one another

• external tail cables and single-wires – which connect signalling equipment housings to

trackside signalling equipment

• external power cables and single-wires – which supply electrical power to vital signalling

equipment

The frequency of these tests shall be in accordance with Table 5.

Periodic inspection and testing of external cables and single-wires shall include observation and

assessment of wiring terminations at trackside junction boxes and equipment. The condition of

conductor insulation shall also be observed, where the conductors are visible, for damage or

degradation. For example, evidence of verdigris or other corrosion.

Additionally, cable routes shall be observed for any likely damage or degradation. For example,

where earth works have taken place in the vicinity of buried cable routes or where trackwork has

taken place near cable troughing and pits.

External cables and single-wires shall be isolated from the live (working) portion. Computer

based interlocking equipment and other similar electronic equipment shall be turned off before

testing associated wiring. Lightning arrestors and surge protection apparatus associated with

external cables and single-wires shall be isolated during testing.


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The insulation testing requirements for external cables and single-wires shall be as follows:

• All spare conductors of external cables and single-wires shall be tested to earth and to the

other conductors nominated for testing within the same cable or single-wire group. Spare

conductors of tail cables and single-wires shall also be tested to the metal case of their

associated trackside equipment.

• A minimum amount of conductors as specified in Table 6 shall be tested to earth and to the

other conductors nominated for testing within the same cable or single-wire group. The

nominated amount of conductors of tail cables and single-wires shall also be tested to the

metal case of their associated trackside equipment.

• A cable that is fitted with a conductive sheath, screen or drain wire shall be tested to earth

and to each conductor nominated for testing within the same cable.

• Conductors nominated for testing including sheaths, screens or drain wires shall also be

tested for continuity.

• Where any working conductor of external tail cables or single-wire group is not double

switched, a functional test shall be performed on the whole cable or single-wire group. This

shall be done by corresponding all the input and output circuits of trackside equipment to

their respective interlocking indications or controls.

An example of testing an input circuit is to open and close the contacts of a point detector while

checking that it corresponds to the indications at the signaller's diagram. An example of testing

an output circuit is to observe all the aspects of a signal, in correspondence to its respective

control, while checking for erroneous indications.

Alternatively, where the trackside equipment is provided with disconnection links, a core to core

test of all the conductors may be done in lieu of performing a functional test.

Note: The functional test or the utilisation of trackside equipment disconnection links

avoids the risk of disconnecting the wires.

Table 6 provides the periodic insulation inspection and testing requirements for external cables

and single-wires.


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Table 6 - Periodic insulation inspection and testing requirements

External cables and single-wires category

Insulation type

Reliable ELD fitted

Double switched circuit

Minimum conductors nominated for testing

Additional testing requirements

External main cables and single-wires

PVC Yes Yes Nil Nil

No 2 core to core test the conductors nominated for testing

No Yes 2 Nil

No All core to core test the conductors nominated for testing

Non-PVC Yes Yes 3 Nil

No 3 core to core test the conductors nominated for testing

No Yes 3 Nil

No All core to core test the conductors nominated for testing

External tail cables and single-wires

PVC Yes Yes Nil Nil

No 2 functionally test the associated trackside equipment or core to core test

No Yes 2 Nil

No All functionally test the associated trackside equipment or core to core test

Non-PVC Yes Yes 3 Nil

No 3 functionally test the associated trackside equipment or core to core test

No Yes 3 Nil

No All functionally test the associated trackside equipment or core to core test


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External cables and single-wires category

Insulation type

Reliable ELD fitted

Double switched circuit

Minimum conductors nominated for testing

Additional testing requirements

External power cables and single-wires

PVC Yes Not applicable

Nil Nil

No Not applicable

All Nil

Non-PVC Yes Not applicable

Nil Nil

No Not applicable

All Nil

The following information provides the criteria for nominating conductors for testing:

• A spare conductor may be deemed as counting towards the minimum amount of

conductors nominated for testing.

• Where there are fewer spares than the minimum amount of conductors nominated for

testing, working conductors from the outer layer of a cable shall be chosen for the testing.

Where the outer layer is directly connected to monitored busbars the next layer shall be

chosen for testing.

• External power cables and single-wires are exempt from the 'minimum amount of

conductors' requirement where the associated power supply busbar is monitored by a

reliable earth leakage detector. This should generally limit the scope of testing for external

power cables to the cable sheaths only.

28.7. Circuits exempt from periodic insulation inspection and testing Conductors that are used in circuits exclusively in the circumstances stated in Section 28.7.1

through to Section 28.7.4 of this standard may be exempt from periodic insulation inspection

and testing.

However, while conductors that are exempt from periodic insulation testing do not pose a risk to

signalling integrity, they may still pose a risk to reliability, personnel safety or cause a fire, in the

event of insulation breakdown.

For these reasons, the requirement to periodically inspect these conductors to assess their

insulation condition shall be considered by the contracted AEO.


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28.7.1. Exemptions for Solid State Interlocking (SSI) and Westlock systems Following are the specific circuits and items of Solid State Interlocking and Westlock systems

that may be exempt from periodic insulation inspection and testing:

• central interlocking cubicle wiring and equipment

• technician's terminal wiring and equipment

• long distance terminal and data link module wiring and equipment

• data link wiring and cables

• isolation transformers and secondary wiring

• trackside functional modules and associated input/output wiring, including external

conductors where directly connected to inputs/outputs of trackside functional modules

Note: Circuits not directly connected to trackside functional modules, such as circuits

emanating from relay operated circuits, are not exempt from periodic insulation

testing.

28.7.2. Exemptions for Microlok II systems Following are the specific circuits and items of Microlok II systems that may be exempt from

periodic insulation inspection and testing:

• Microlok II cardfile and cards

• conductors of output circuits between Microlok II equipment and steering diodes or

controlled equipment where steering diodes are not fitted

• communication link wiring and equipment

• conductors of vital relay output circuits where isolation modules are fitted

• conductors of 50 V input circuits where the associated power supply busbar is monitored

by a reliable earth leakage detector

• conductors of vital relay output circuits between the duplication diodes and relays of

duplicated systems where the associated power supply busbar is monitored by a reliable

earth leakage detector


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28.7.3. Exemptions for Westrace systems Following are the specific circuits and items of Westrace systems that may be exempt from

periodic insulation inspection and testing:

• Westrace cardfile and cards

• conductors of circuits from vital lamp output modules to signal lights where either of the

following conditions are met:

o the associated power supply busbar is monitored by a reliable earth leakage detector

o an isolation transformer is fitted

• conductors of circuits from vital relay output modules

• conductors of vital inputs where either the associated power supply busbar is monitored by

a reliable earth leakage detector

• communication link wiring and equipment

28.7.4. Exemptions for telephones circuits, non-vital circuits and track circuits Following are the additional specific circuits that may be exempt from periodic insulation

inspection and testing:

• signalling communication (telephone) circuits

• non-vital signalling wiring and equipment where the non-vital signalling circuits are

physically separated from vital signalling circuits, or otherwise where the associated power

supply busbar is monitored by a reliable earth leakage detector

• track circuit cables and single-wires which meet the following conditions:

o there is no combination of feed-end and relay-end of like track circuits that are run in

the same routing

o there is no more than one relay-end of like track circuits that are run in the same

routing

Note: Where the track circuit exemption condition is not met, and the track circuit

cable has a conductive sheath, screen or drain wire, then the insulation testing

requirement can be achieved by testing only the sheath, screen or drain wire, as

applicable.


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29. Specific requirements for computer based interlockings Computer based interlockings referred in this standard apply to the following systems:

• Solid State Interlocking (SSI) systems

• Microlok II systems

• Westrace systems

• emerging computer based signalling systems

The specific requirements and precautions prescribed for computer based interlockings shall

supplement the general requirements prescribed in this standard as they pertain. They shall be

read and applied in conjunction with each other as necessary. For example, when securing

signalling apparatus out of use that is interlocked by a Solid State Interlocking, both the specific

Solid State Interlocking requirements and the general requirements stated in Section 13 of this

standard shall apply.

Signalling safeworking procedures shall prescribe the specific procedures and precautions

associated with each computer based signalling system that is in operation within their network.

29.1. Requirements for Solid State Interlocking systems The specific requirements that pertain to Solid State Interlocking systems are stated in Section

29.1.1 through Section 29.1.7.

Solid State Interlocking equipment includes the following items:

• central interlocking multiprocessor

• panel processor

• diagnostic multiprocessor

• data link and long distance modules

• trackside functional module

• technician’s terminal and logger

• panel multiplexer


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29.1.1. Security of Solid State Interlocking components and configuration data Solid State Interlocking module seals shall not be broken by field personnel. Only persons

authorised and competent for the specific work shall be permitted to interfere with the internal

components of these modules. Generally, this task is conducted by the equipment manufacturer

or other authorised agent. Defective modules shall be tagged with the date, defect details and

location.

Any such equipment found in the field with a broken seal or no seal shall be reported to the

responsible signal engineer for attention.

The configuration of memory modules including associated EPROM and subsequent sealing

shall be permitted only by the contracted AEO providing the design assurance accountability.

The storage of Solid State Interlocking configuration data (such as memory modules) and

associated spare items (such as EPROMs) shall be registered and kept secure. The contracted

AEO who holds accountability for the maintenance of signalling design records and data shall

manage the storage of Solid State Interlocking configuration data.

29.1.2. Handling and storage of Solid State Interlocking equipment Solid State Interlocking equipment contains electronic components that may be damaged by

misuse. Modules shall be handled, transported and stored with care and not subjected to

damage or deterioration.

The modules shall be stored on racks in enclosed housings in a clean, dry and non-corrosive

environment below 60 °C.

29.1.3. Interfering with operational Solid State Interlocking equipment

When it is necessary to remove multi processor modules, diagnostic modules or panel

processor modules from the central interlocking for replacement purposes, they shall be

removed in conjunction with their associated memory module. The replacement modules shall

be pre-fitted with the correct memory module.

Modules shall not be disconnected unless first powered down. The powering down of a

trackside functional module shall first necessitate the removal of the '110v NX' disconnect pin.

A module's compatibility and correct configuration shall be assured before replacing any module

in operation with another module.

When the central interlocking has been stopped, switched off and restarted, any technician’s

control that was previously applied may be lost (removed). Therefore the technician's control log

book shall be checked to determine if any controls are missing as a result of the central


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interlocking's 'off state'. Any controls noted missing, shall be reinstated upon re-starting the

central interlocking.

Module retaining screws and plug couplers shall be secured before restoring the power.

Note: Points will not show a detection status to the signaller when a points module is

replaced or powered off and on. Subsequently, upon restoring power to a points

module, the signaller is required to key the points to the last known position so that

detection can be restored.

29.1.4. Maintainer's interface to Solid State Interlocking The maintainer's interface to the central interlocking is provided by the technician’s terminal and

associated peripheral equipment. This equipment provides access to review interlocking data

and events, and enables specific control functions of the central interlocking.

The facility generally comprises the following equipment:

• technician's terminal, keyboard, monitor and tracker ball

• fault and event printer

• logger pc, monitor, keyboard and mouse

• remote access hardware and telephone line

The facility is connected to the system's diagnostic module which processes the fault and

diagnostic information.

The technician's terminal may be accessed locally or remotely. The responsible signal engineer

shall manage the access requirements as necessary, including administering the access

passwords.

Information from the technician's terminal and associated equipment can be used as evidence

when investigating serious incidents and signalling irregularities. Therefore any failure of such

equipment shall be promptly actioned and rectified.

The technician's terminal enables specific interlocking controls that can be applied or removed

to the central interlocking by a maintainer.

The following is a list of controls enabled by the technician's terminal:

• aspect disconnect

• temporary approach control

• track circuit occupy

• route bar

• points disable


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• start and stop interlocking

• disable MPM (multi processor module)

• select interlocking

All controls enabled from the technician's terminal shall be recorded on a specific technician’s

terminal control log. This log shall be compiled by the relevant signalling person operating the

control. The log shall be kept on-site for future reference.

Signalling safeworking procedures shall prescribe the procedures for applying maintainer

operated controls for Solid State Interlocking systems. These procedures shall complement the

general requirements of this standard for securing signalling out of use.

Note: An alternate means of restricting a signal from clearing in Solid State

Interlocking systems is by disabling its associated trackside functional module. In this

case, protecting signals disabled in the stop position by this means shall have their red

lights retained at all times.

29.1.5. Solid State Interlocking site records Each central interlocking location shall have an ‘Installed SSI Software' record which shall detail

the compatible hardware types and versions in use. It shall also record the fixed program and

site specific data identification for the interlocking.

The site copy shall be securely attached to the inside of the rear door of each central

interlocking cubicle.

These records shall be compiled by the contracted AEO providing the design assurance

accountability and kept up to date by the contracted AEO who holds accountability for the

maintenance of signalling design records and data. The responsible signal engineer shall

ensure the records are available and kept in good order.

Records of interlocking failures and events which are produced by the fault and event printer

shall be retained on-site for future reference.

29.1.6. Solid State Interlocking trackside functional module testing

Trackside functional modules of Solid State interlocking system shall be tested using a type

approved go/no-go tester before they are put into operational use. The same requirement shall

apply before the trackside functional module is placed into the local spares holding.

A go/no-go test shall again be performed on trackside functional modules and a satisfactory

result achieved before placing any trackside functional module into service. This also ensures

any trackside functional module used from another interlocking has been cleared of its previous

data identity and history.


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Trackside functional modules associated with a signalling irregularity or other similar incident

shall not be placed in a go/no-go tester until the matters are resolved. Otherwise, the contents

of the module's memory will be erased.

29.1.7. Test equipment for Solid State Interlocking Only test equipment specifically designed for Solid State Interlocking shall be used. This shall

be done in conjunction with the manufacturer's specific instructions in relation to the type of

interlocking in use.

A data link telegram generator is a portable testing device which simulates vital interlocking data

to trackside functional modules for the purpose of testing, typically at commissioning. If used

inappropriately, false information can be transmitted to the signalling system. Before using a

data link telegram generator, the affected and protecting signalling shall be first booked out of

use. The data link telegram generator shall only be used as authorised by the responsible signal

engineer or signalling commissioning engineer. The use of data link telegram generators on

operational systems is strictly prohibited.

Data link telegram generators shall not be kept on-site. They shall be stored in a similar manner

to storing critical computer based interlocking design records and data. These items shall be

managed by the contracted AEO who holds accountability for the maintenance of signalling

design records and data.

The use of conventional test equipment such as multimeters, data readers, recorders and

oscilloscopes shall only be used where they do not pose a risk to input circuits. Test equipment

shall not potentially bridge-out or bypass an input, which may result in a less restrictive input

and consequently, an unsafe output.

The following restrictions shall apply for the use of conventional testing equipment on Solid

State Interlocking systems:

• digital multimeters, including the addition of shunts units, with an input impedance of less

than 100 k ohm shall not be used

• digital multimeters which have a low ac impedance mode for voltage measurements shall

not be used for fault finding the inputs, for example, Fluke brand types 114, 116, 117 and

289

• oscilloscopes that do not have floating, isolated input channels shall not be directly

connected to a data link as this will earth one leg and could cause the data link to fail

Note: Oscilloscopes that have floating, isolated input channels may be permitted for

use.


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29.2. Requirements for Microlok II systems The specific requirements that pertain to Microlok II systems are stated in Section 29.2.1

through Section 29.2.8.

Microlok II equipment includes the following items:

• Microlok II cardfile and boards

• CPU board

• vital input and output board

• non-vital input/output board

• lamp driver board

• vital control output relay

• object controller module

• power supply board

29.2.1. Security of Microlok II system configuration data The configuration of application data of Microlok II systems shall be permitted only by the

contracted AEO providing the design assurance accountability.

Under no circumstances shall any Microlok II maintenance and configuration software be copied

onto third party machines or supplied to unauthorised persons.

The storage of Microlok II system configuration data (such as executive, application and

network configuration files) and associated spare items (such as compiled central processor unit

(CPU) boards) shall be registered and kept secure. The contracted AEO who holds

accountability for the maintenance of signalling design records and data shall mange the

storage of Microlok II system configuration data.

29.2.2. Handling and storage of Microlok II system equipment Microlok II equipment contains electronic components that may be damaged by misuse. Boards

and modules shall be handled, transported and stored with care and not subjected to damage

or deterioration.

The boards and modules shall be stored on racks in enclosed housings in a clean, dry and non-

corrosive environment below 60 °C.

Anti-static protection handling procedures shall be applied when handling Microlok II boards and

modules.


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29.2.3. Microlok II system time setting Microlok II system clocks shall be set to Australian Eastern Standard time only. The clock times

shall not be adjusted to align with daylight saving time.

Where the Microlok II architecture provides for multiple cardfiles, all the cardfile times shall be

set using the same time reference. For example, the same laptop clock shall be used to set all

the Microlok II cardfiles.

29.2.4. Authority to configure and upload Microlok II files When replacing a CPU module or object controller in operation, licensed signalling personnel

are permitted to perform the following tasks:

• upload executive software file, in accordance with the installed data form

• upload application data file, in accordance with the installed data form

• check and set adjustable items, in accordance with the site specific maintenance

procedure

• upload object controller network configuration files for the 'COM1', 'COM2' and 'Web Tool

Ethernet' ports, in accordance with the installed data form

• program new EPROM serial dongle to replace a damaged or lost EPROM serial dongle, in

accordance with the installed data form

Note: Incorrect uploading of network configuration files for the 'Web Tool Ethernet' can

fail the object controller. Confirm the correct file and process before performing this

action.

The following tasks may be performed only by a signal engineer competent to do such work on

behalf of the contracted AEO providing the design assurance accountability:

• alter adjustable configuration items to a value other than that detailed in the site specific

maintenance manual

• upload executive software file with a file other than that detailed on the installed data form

• upload application data file with a file other than that detailed on the installed data form

• upload object controller network configuration file with a file other than that detailed on the

installed data form


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29.2.5. Interfering with operational Microlok II equipment The Microlok II system shall be first powered down before removing or replacing associated

boards, modules or the vital cut-off relay. The system shall be powered down using the 'B12'

fuse or switch if provided. The 'N12' connections to the equipment shall not be disconnected

without the system first powered down.

Earthed metalwork shall be touched with both hands before replacing any board or module

unless an earth strap is utilised.

All boards and modules shall be plugged in and fully secured before powering on the Microlok II

cardfile for operational use.

Care shall be taken not to swap Microlok II cardfile external connections. Otherwise, the

equipment may display different indications to the intended design.

The restrictive coded fixtures, fittings and wiring of modules, dongles and plug couplers shall be

periodically checked to ensure their security is effective, thus permitting the insertion of only the

correct item. They shall also be checked to ensure the connections are working in proper order.

Additionally, associated labelling shall be checked to be in proper condition. The frequency of

these checks shall be done in accordance with the technical maintenance plan.

Where signal lamp driver boards are used, disconnection of the signal outputs shall be made by

removal of the applicable Elsafe modules before working on signal bleed resistors and LED

modules.

Note: Loose terminations or disconnections made in signal head terminations and

associated bleed resistors without first removing Elsafe modules, may cause the

system to reset and enter conditional power supply (CPS) shutdown.

The Microlok II cardfile shall not be made operational with a disabled vital lamp driver module

(LP16) or Microtrax coded track circuit board.

In the event of a CPU failure, the replacement CPU module shall be configured with the correct

executive software version and correct application data for the location. The circuit book

verification sheet, file size, date, checksum and version number shall match the application data

file used to configure the replacement CPU. The responsible signal engineer shall be notified of

CPU module replacements.

The inputs and outputs shall be checked for correct operation when replacing a board or

module. This shall be done by exercising a sample of each function and observing the correct

operation of the indication LED’s provided on the panel face.

Object controllers shall be replaced as a complete unit when failed. The replacement unit shall

be properly configured with the correct executive software, application data and network

configuration files before placing into operation. The configuration shall be verified against the


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installed data form within the specific circuit book. The responsible signal engineer shall be

notified of object controller replacements.

Where it is necessary to replace the EPROM dongle in conjunction with an object controller, it

shall be necessary to obtain independent verification of the object controller's configuration files.

The responsible signal engineer shall be notified of EPROM dongle replacement.

Internal repairing of Microlok II plug-in modules, track interface modules and object controller

modules shall not to be carried out in the field. These items shall be returned to the

manufacturer or other authorised agent for repairs. Defective board and modules shall be

tagged with the date, defect details and location.

29.2.6. Maintainer's interface to Microlok II system

The maintainer's interface to the Microlok II system is provided by the maintenance and

diagnostic workstation and in and some cases, by a replay facility. These maintenance tools

provide access to review error and event logs.

The maintenance tools also enable specific controls to the interlocking for the purpose of

applying blocks that prevent specific signalling from operating.

Diagnosis is also provided by LED indications displayed at the Microlok II cardfile.

The diagnosis of information displayed by LED indications on boards and modules is not fail

safe. Therefore, this shall not be used as sole information for a critical test. The information

provided by the LED indications shall only be used as an aid for diagnosis.

Microlok II systems provide different arrangements for the disconnection or disabling of

signalling.

The following arrangements are in use at various installations across the network:

• interlocking workstation facility

• blocking pins

• relay interface

• lamp driver output boards

• Microtrax coded track circuit, when housed within a Microlok II cardfile

In all cases, the disabling or disconnection of signalling that is enabled from Microlok II systems

for the purpose of securing signalling out of use shall be suitably recorded. The application for

signalling reinstatement shall also be recorded. These records shall be left where they can be

readily referenced by maintainers.

Signalling safeworking procedures shall prescribe the procedures for disabling and

disconnecting signalling from specific Microlok II systems that correspond with the


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configurations applicable to their network. These procedures shall complement the general

requirements of this standard for securing signalling out of use.

Where Microlok II diagnostic workstations utilise the communications network for safety critical

communications, the diagnostic workstation connection shall be disconnected from the safety

critical communications network while not in use. This requirement may be exempt where fully

duplicated Microlok II systems are used. In such cases, one diagnostic workstation may be left

connected.

29.2.7. Microlok II system site records System event and error logs shall be downloaded and examined for any abnormal occurrences.

These abnormalities shall be accordingly investigated. The logs files shall be retained for future

reference.

User data log shall be checked to ensure it is operating correctly and that the logger memory

has the capacity to hold the data for the required duration.

Note: Required log files need to be captured within four hours following the removal of

the CPU module from its Microlok II cardfile. This is required because the back-up

power will discharge and the logs will be unrecoverable.

Logs that indicate a potential safety problem shall be immediately brought to the responsible

signal engineer's attention.

Any unexpected activity noted of the Microlok II system shall be recorded on a specific log book

which shall be provided at each Microlok II location.

The log book shall also be used to list any disconnection made to the Microlok II system for the

purpose of securing signalling out of use.

29.2.8. Test equipment for Microlok II system

Only test equipment specifically designed for Microlok II systems shall be used. This shall be

done in conjunction with the manufacturer's specific instructions in relation to the type of


Write-enabler equipment is used to program the EPROM dongle of an object controller. It shall

be removed from site at the end of the programming work and stored in a similar manner to

storing critical computer based interlocking design records and data.

The security of write enablers, EPROM dongles, Microlok II executive software, application data

and network configuration files shall be managed by the contracted AEO who holds

accountability for the maintenance of signalling design records and data.


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29.3. Requirements for Westrace systems The specific requirements that pertain to Westrace systems are stated in Section 29.3.1 through

Section 29.3.6.

Westrace equipment includes the following items:

• Westrace cardfile and boards

• vital parallel input module

• vital relay output module

• vital lamp output module

• hot standby vital logic card and module

• diagnostic module

• S2 and Westcad panel processor

29.3.1. Security of Westrace system configuration data The vital interlocking application data for Westrace systems is stored on EPROM. The

configuration of application data of Westrace systems shall be permitted only by the contracted

AEO providing the design assurance accountability.

Under no circumstances shall a Westrace EPROM be copied onto third party machines or

supplied to unauthorised persons.

The storage of Westrace system configuration data (such as application files) and associated

spare items (such as EPROM) shall be registered and kept secure. The contracted AEO who

holds accountability for the maintenance of signalling design records and data shall manage the

storage of Westrace system configuration data.

29.3.2. Handling and storage of Westrace system equipment Westrace equipment contains electronic components that may be damaged by misuse. Boards

and modules shall be handled, transported and stored with care and not subjected to damage

or deterioration.

The boards and modules shall be stored on racks in enclosed housings in a clean, dry and non-

corrosive environment below 60 °C.

Anti-static protection handling procedures shall be applied when handling Westrace boards and

modules.


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29.3.3. Interfering with operational Westrace equipment The Westrace system shall be powered down before removing or inserting any module. An

effective anti-static protection handling procedure shall be used.

Westrace modules shall not be removed unless necessary. However, when it is necessary to

remove a module, the Westrace cardfile backplane shall be inspected for damage and to ensure

the backplane connectors are not loose or damaged.

Replacement modules shall be of the correct version relevant to the specific installation. When a

module is replaced, the associated inputs/outputs shall be checked for correct operation.

When a lamp driver module is replaced, the lamp voltages for the associated signal lamps shall

be checked and adjusted if necessary. When other modules are replaced, ensure the Westrace

system as a whole is operating correctly with no errors.

When a vital logic card is replaced, the EPROMs containing the application data shall be reused

from the defective module into the new module. This shall be done by inserting one EPROM at

a time. Care shall be taken to ensure the EPROMs are inserted into the correct place and that

the notch position is correct, for example, not installed backwards. Ensure the EPROMs are not

damaged during replacement. Only approved EPROM removal and insertion tools shall be used

for this work.

The configuration DIP switch on the replacement vital logic card shall be adjusted in accordance

with the configuration documentation for the specific circuit book. The diagnostic module

technician terminal interface shall be checked to confirm that the Westrace has been configured

as specified by the documentation.

Where an EPROM containing application data is replaced, a signal engineer shall be required to

attest this work. The details of the replacement EPROM label shall be checked against the

failed EPROM and the circuit book documentation. The correct version number, date and

checksum shall be verified.

A specific EPROM change report shall be provided to the contracted AEO who holds

accountability for the maintenance of signalling design records and data at the time of

replacement.

The failed EPROM shall be labelled as defective on its underside and topside, leaving the

version details visible. The EPROM shall be returned to the contracted AEO who holds

accountability for the maintenance of signalling design records and data for cancellation.

Where the application logic for vital data (contained in an EPROM) is required to change, this

work shall be done only by the contracted AEO providing the design assurance accountability.

The update of EPROM version numbers and other such requirements shall be done only in


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conjunction with a full design integrity test. This work shall include updating the configuration

DIP switch on the vital logic card module and associated signalling documentation.

Field repairs shall not be carried out on Westrace vital or non-vital modules. These items shall

be returned to the manufacturer or other authorised agent for repairs. Defective modules shall

be tagged with the date, defect details and location.

29.3.4. Maintainer's interface to Westrace system

Some signals operated by the Westrace system are driven from vital lamp output modules.

When disabling these signals in the stop position, the pins that output to the 'proceed' aspects

shall be removed. The signal is retained in the stop position because the interlocking's Boolean

logic is arranged to provide cold lamp proving of the yellow and green lamps.

When reinstating the 'proceed' aspects, the higher aspects shall be functionally tested.

Additionally, the error messages that indicate that the lamps were out shall be cancelled.

29.3.5. Westrace system site records The system event and error logs shall be examined for any abnormal occurrences. These

abnormalities shall be accordingly investigated. The logs files shall be retained for future

reference.

The event data log shall be checked to ensure it is operating and that the logger memory

capacity will hold the data for the required duration.

Logs that indicate a potential safety problem shall be immediately brought to the responsible

signal engineer's attention.

Any unexpected activity noted of the Westrace system shall be recorded on a specific log book

which shall be provided at each Westrace location.

The log book shall also be used to list any disconnection made of the Westrace system for the

purpose of securing signalling out of use.

29.3.6. Test equipment for Westrace system Only test equipment specifically designed for Westrace systems shall be used. This shall be

done in conjunction with the manufacturer's specific instructions in relation to the type of


A Westrace go/no-go tester shall be used to functionally test all Westrace modules before they

are installed into the system. Spare modules shall also be tested using the go/no-go tester.

The go/no-go tester may not fully test all the functions of all modules. Some modules may work

correctly in the tester but may still fail to operate in a Westrace system. Where this is the case


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for a module that has failed in service, the module shall be continuously cycled through the

tester for a period of seven days.

30. Surveillance inspections Surveillance inspections shall be performed to meet the primary and secondary objectives as

prescribed in this standard. The primary objectives are directed towards signalling safety,

reliability, and technical capability. The secondary objectives are directed towards signalling

operational efficiency, sustainability and its environmental impact. Additionally, surveillance

inspections provide an opportunity to effect stakeholder relations along with prompting

consideration for initiatives of continual improvement.

The following is a list of primary objectives:

• monitor the standard of signalling maintenance

• monitor the condition of signalling assets

• monitor the level of compliance to relevant signalling standards, technical maintenance

plans, engineering instructions and other such documents

The following is a list of secondary objectives:

• monitor the efficiency and effectiveness of maintenance

• monitor the efficiency and effectiveness of the signalling system

• monitor any adverse environmental impact caused by signalling infrastructure

• communicate directly with signalling personnel in the course of their work, giving them the

opportunity to directly raise issues and receive feed back on signalling matters

• communicate directly with network operators and other signalling stakeholders

Surveillance inspections shall be conducted by experienced signal engineers. Other signalling

personnel may be engaged as enablers for meeting the inspection requirements. However, this

shall not negate the requirement for a signal engineer to personally conduct periodic

inspections.

The responsible signal engineer shall be accountable to ensure surveillance inspections are

conducted accordingly.

The surveillance inspections shall form part of the contracted AEO's assurance regime for the

provision of safety, integrity and reliability of the signalling system.


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30.1. Scope of surveillance inspections Surveillance inspections shall include in-depth examination and tests of judiciously selected

items and activities from selected areas of aging or brand new installations. The inspections

shall include checks of point locks and detector adjustments, track circuit history records and

level crossing records as applicable.

The following is an example of specific signalling that may be targeted for inspection:

• assets that are difficult to access

• assets that are awkward to maintain

• assets that are maintained by inexperienced persons

• assets that have a poor performance history

Surveillance inspections shall include observation of signalling safety critical and safety

significant tasks. This shall be done to determine elements of compliance to procedures and

standards and to ascertain technical capability.

Surveillance inspections shall also include visits to signal boxes and control centres to liaise

with network operators on the effectiveness of the signalling system from their perspective.

Note: Liaison with train crew is achieved during front of train signal sighting inspection

done in accordance with Section 22.1 of this standard.

30.2. Scheduling of periodic inspections Periodic surveillance inspections shall be performed on an annual basis as a minimum.

The scheduling shall be such that an adequate inspection sample is conducted of no less than

20% of the area of accountability, eventually covering the whole area over a five year period.

While it may not be practical for surveillance inspections to cover every single asset over the

five year period, the scope of inspections and observations shall adequately achieve the

objectives listed.

Apart from scheduled inspections, other opportunities may exist for signal engineers to

capitalise on fulfilling the scope of surveillance inspections.

An example of these opportunities includes the following tasks:

• mechanical interlocking testing

• signal sighting inspections

• level crossing inspections


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• project site integrity meetings and practical completion inspections

• signalling irregularity and failure follow-up investigations

30.3. Surveillance inspection reports and action requirements The results of surveillance inspections shall be recorded in a specific report. The report

outcomes shall contain an itemised asset list of the inspection area, details of inspectors and

the details of any personnel observed or stakeholders engaged. The report shall also include

action requirements for the rectification of defects. These actions shall be priority based and

time scaled. A defect management system shall be used to manage this requirement.

The report shall also contain recommendations as applicable to the inspection. The

recommendations may include increased supervision or local instructions to correct

deficiencies, asset renewal programs, training plan requirements and improvements to

procedures, standards and so on.

Signal engineers shall also record occasions where they have directly observed personnel

performing signalling related tasks, particularly safety critical and safety significant tasks.

The responsible signal engineer shall be accountable to ensure surveillance inspection reports

are duly produced and actioned accordingly.

31. Housekeeping and protection of signalling assets Signalling trackside apparatus and equipment housings shall be kept clean and tidy, and left in

a secured state when not being worked-on.

Equipment housings shall include relay rooms, walk-in enclosures, location cupboards, and

lower floors of signal boxes. These shall be kept locked whenever possible to prevent

unauthorised access and vandalism. Spares and materials shall not be stored in these places,

unless they are appropriately placed on racks or cupboards provided specially for the purpose.

Highly inflammable material shall not be stored in these places. Locking arrangements shall be

maintained in good condition.

Before securing signalling apparatus or housings, signalling personnel shall check that

everything is in order and properly connected and that nothing has been left loose, foul of

standard clearances, or in a potentially unsafe condition.

Access pathways, ladders and other such items shall be maintained in good order, so as to

provide adequate access to signalling apparatus and housings. Excess vegetation, rubbish or

surplus materials shall be removed during maintenance visits.

Lighting of relay rooms and cupboards shall be maintained in good order to ensure adequate

visibility is available. © State of NSW through Transport for NSW of 151 Sup

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The responsible signal engineer shall be advised of any security breach, water ingress or fire or

any other significant matter that requires escalation and their attention.

31.1. Prevention of water ingress to signalling equipment Maintenance of signalling equipment shall be performed to keep insulating surfaces between

electrical terminals clean and free from water to prevent leakage currents.

Trackside signalling apparatus, housings, conduits and the like shall be properly sealed to

prevent the ingress of rainwater. The drainage around electrical signalling apparatus shall be

examined to ensure water does not build up and enter the equipment.

Signalling personnel when performing maintenance shall look for signs of water leakage and

take corrective action.

Maintenance during wet weather, which would allow water to enter the equipment, should be

avoided.

Signalling housing and vulnerable equipment shall be checked for water leaks following heavy

rain. Equipment shall be cleaned, dried and lubricated as necessary and where evidence of

water ingress is evident, the equipment shall be checked for correct operation.

31.2. Prevention of fire around signalling equipment Maintenance of signalling equipment shall be performed to prevent fires occurring in and around

signalling equipment and signal boxes.

Combustible materials shall be cleared from trackside signalling equipment such as signal

boxes, relay rooms, trackside equipment housings, trackside equipment, cables, air lines, air

reticulation equipment, pits and ducts.

The underside portion of elevated relay huts and equipment cupboards shall be enclosed to

prevent the accumulation of rubbish.

32. Control of signalling documentation Signalling safeworking procedures shall set out the responsibilities and requirements for the

control of signalling documentation. These documents pertain to maintenance documentation

issued to the field which include as-built copies, interim maintenance copies, commissioned

stage-work copies, modification sheets, as well as marked-up copies of temporary repairs,

paralleled contacts, and like for like renewals that are pending update.

The following are examples of typical signalling documents as referenced in this standard:

• circuit books

• signalling plans, track plans and working sketches © State of NSW through Transport for NSW of 151 Sup

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• track insulation plans

• locking tables, locking diagrams, lever nameplates diagrams

• control and indication panel layouts

• control tables

• interlocking data

• modification sheets

• air system diagrams and air reticulation plans

• detailed site survey diagrams

• equipment layout diagrams

32.1. Requirements for signalling documentation control All personnel involved with the production, installation, maintenance, and use of signalling

documentation shall have a responsibility for ensuring that the documents accurately depict and

correspond to the as-built status, as applicable. They shall promptly advise of any discrepancies

and arrange to have them corrected without delay.

All copy holders shall ensure that they utilise the latest version of controlled documents.

The despatch and receipt of all field issued signalling documentation shall be supplemented by

a transmittal notice.

The responsible signal engineer shall be accountable for maintaining a document control

system for all field issued signalling documentation.

The following are examples of the responsible signal engineer's accountabilities for signalling

documentation control in this regard:

• identifying appropriate location and quantity requirements such as signalling housings,

signal depots, office copies and so on

• managing the distribution of new and updated documents, destroying of superseded copies

and the management of transmittals for issued copies

• auditing the versions of all field issued copies every 12 months

• certifying corrections and updates as necessary including corrections emanating from like

for like renewals, field paralleling of contacts, temporary repairs that become permanent

changes, known discrepancies and so on

• arranging updates for as-built signalling documents


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Field issued signalling documentation shall be treated as an asset and duly maintained in good

condition.

Accountabilities for licensed signalling personnel in this regard shall be stated in signalling


The following are examples of licensed signalling personnel's accountabilities for signalling

documentation control:

• maintaining signalling documents in a satisfactory condition, keeping them bound and

secure, ready for use, and updated with the latest amendments

• retaining signalling documents when not in use, at their nominated location and available

for use for failures and other referencing needs

• advising the responsible signal engineer to arrange replacement copies as required

• marking-up and signing (in red pen), signalling documentation following like for like

renewals, paralleling of contacts, temporary repairs, or known and obvious corrections to

remedy a discrepancy with the ‘as built’ installation, pending the issue of updated copies

• advising a signal engineer of any discrepancies between the signalling documents and the

'as built' installation, or red mark-ups as a result of work

• booking out of use vital signalling equipment, where a discrepancy poses an imminent risk

to the safety of the signalling system, until instructions are received from a signal engineer

• destroying superseded copies as directed

• ensuring the availability or temporary retention of issued maintenance copies along with

interim maintenance copies and commissioned stage-work copies while project works are

in progress

33. Control of signalling security locks and keys Signalling housings and equipment, including trackside apparatus and cable pits shall be

secured and locked when not being worked-on to prevent unauthorised access and vandalism.

Some cable pits and older type trackside apparatus that cannot be locked due to their design,

such as signal branch EP plunger lock boxes or indication boxes/escapement slides, may be

exempt from this requirement.

The Falcon series locking system is generally used to secure signalling infrastructure, including

the provision of dual access locks for entering common signalling and communication housings

and common signalling and electrical housings. At some locations, older style locks may still be

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Railway specific locks such as SL and XL are used to prevent unauthorised operation of

signalling apparatus. The design requirement of these locks and keys is not covered by this

standard.

Signalling housings shall be locked using Falcon 4 locks. Signalling equipment shall be locked

using Falcon 8 locks. Access doors to interlocking machines where electric locks are in use,

shall be locked using Falcon 8 locks.

Signalling security locks shall be maintained such that they remain effective and in proper

condition. Damaged or defective locks shall be immediately replaced.

Note: Falcon series and older style locks used within the NSW rail network as

governed by TfNSW may be in use across other operated railway networks in NSW.

33.1. Lock types in use The following system of locking is used for securing signalling equipment housings and

apparatus:

• Falcon 4 (signalling housings)

• Falcon 8 (signalling apparatus)

• Falcon 17 (dual access lock for common signalling and communication housings)

• Falcon 22 (dual access lock for common signalling and electrical housings)

Older style locks that may still be in use in some areas include the following key types:

• Best series 7 and 8

• Yale series 6, 9 and R

• SWI (safeworking instrument) - old and new

• Staff instrument - old and new

• PIM (power interlocking machine)

• ESML (emergency switch machine lock)

• STEL

• Corbin - old and new

33.1.1. Falcon series The Falcon locking series is a hierarchical arrangement utilising a plurality of locks and keys

wherein each key series can engage the lock tumbler for a defined set of locks. The lock

tumbler uses an interchangeable core with a restricted key broaching.


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The Falcon series has a capability of being extended by adding further locks and keys.

However, only the nominated keys for Falcon series locks, as listed in Section 33.1, shall be

used within the NSW rail network as governed by TfNSW. Any requirement to extend the series

of locks and keys within the hierarchy shall require approval from the ASA.

33.1.2. Locktech series An approved alternate supplier of lock cylinder cores and keys exists with Locktech Industries.

The profiles of Locktech and Falcon keys are slightly different. The Locktech cores can be

pinned similar to Falcon locks and can be opened by either a Locktech key or Falcon key;

however, Falcon locks cannot be opened by Locktech keys.

33.1.3. Older style locks Older style locks, as listed in Section 33.1, should be phased out in favour of the Falcon series

as appropriate.

33.1.4. SL and XL locks

SL locks are used to control operational access to signalling apparatus, for example, when the

apparatus is booked out of use. SL keys are issued to network operators for the purpose of

operation and to licensed signalling personnel for the purpose of engineering.

XL locks provide a higher level of security by restricting the issue of XL keys. For signal

engineering, only responsible signal engineers and signalling commissioning engineers shall be

issued with XL keys.

XL locks are used to control operational access to signalling apparatus in the following

situations:

• when the apparatus is seldom used (example: emergency crossovers)

• when the apparatus is booked out of use for extended periods

• where installed points, pending removal or commissioning, are not connected to the

interlocking

• where a higher level of security is required

Responsible signal engineers and signalling commissioning engineers may temporarily transfer

their issued XL key to specific signalling personnel. The method of transfer shall be prescribed

in signalling safeworking procedures and is permitted in accordance with a valid signalling

permit to work. A transmittal stating the reason for the transfer and period of issue shall be

provided on each occasion. The transmittal shall be kept by the relevant party.

The XL key holder shall be accountable for its safe custody.


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33.2. Major signal boxes and control centres Major signal boxes and control centres are fitted with proprietary card type security access

systems. The management of these systems is not covered by this standard. Only persons

authorised for access shall be issued with access cards to signalling rooms within these

buildings.

33.3. Configuration and key cutting The contracted AEO acting on behalf of the operator/maintainer shall be responsible for the

configuration control of all signalling security locks and keys.

The contracted AEO shall use a system to control and record the configuration of locks and the

cutting of signalling security keys.

The configuration and cutting of Falcon locks and keys and other signalling security locks and

keys (excluding SL and XL) shall be performed by a qualified locksmith who is a member of the

Master Locksmiths Association. Appropriate supervision from a licensed signal engineer shall

be afforded to the work to ensure the security of the pinning charts is retained.

The contracted AEO acting on behalf of the operator/maintainer shall hold all Falcon and other

signalling security key and lock blanks (excluding SL and XL) and arrange for the cutting and

numbering of keys, ensuring that the allocation of numbers are unique and in accordance with

the contracted AEO's key control system.

Each new key issued shall be stamped with the key series number, a unique allocation number

and with the words, 'TfNSW DO NOT COPY'.

33.3.1. Control and distribution The contracted AEO acting on behalf of the operator/maintainer shall be responsible for

controlling the distribution of keys.

The contracted AEO shall utilise a system to control and record the distribution of signalling

security keys. Signalling security keys shall only be issued to signalling personnel and only in

conjunction with a valid signalling permit to work.

The contracted AEO may permit an allocation of signalling security keys to another contracted

AEO for signalling works as permitted by the operator/maintainer in accordance with signalling

safeworking procedures and applicable network rules and procedures. This arrangement shall

be agreed by all parties and shall be duly documented by the contracted AEO allocating the

keys.

Lost, stolen or improper use of signalling security keys shall be considered as a breach of

signalling safeworking and shall be dealt with accordingly by the relevant contracted AEO.


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Dual access keys for common signalling, electrical and communication housings may be

provided to signalling personnel in accordance with a valid signalling permit to work. Dual

access is provided by a Falcon 17 lock and key for common signalling and communication

housings and a Falcon 22 for common signalling and electrical installations. The contracted

AEO responsible for the respective discipline shall issue these keys.

34. Storage and dispatch of operational safeworking keys Operational safeworking keys and tokens are used by network operators to operate specific

signalling apparatus for the purpose of train running.

The following are examples of keys types as referenced in this standard:

• half pilot staffs

• bank engine keys

• shunting keys

• annett keys

• guards keys

• closing keys

• token board keys

• ESML or EOL keys

• XYZ keys

• fortress keys used on signalling apparatus

• level crossing emergency operation keys

Signalling personnel may also use these keys for the purpose of maintenance but not for train

operations.

34.1. Temporary storage of operational safeworking keys The storage requirements for operational safeworking keys when taken temporarily out of use

by licensed signalling personnel shall be prescribed in signalling safeworking procedures.

The following are examples of storage requirements:

• keys stored in a suitable locked safe, or appropriate lock-up area under the control of the

responsible signal engineer


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• keys clearly labelled, giving full particulars

• detailed records of keys in storage or transit, kept up to date in regards to movements,

controlled by the responsible signal engineer

34.2. Dispatching operational safeworking keys for repair, replacement or cancellation A specific record shall be used when despatching operational safeworking keys for repair,

replacement or cancellation, for the purpose of transmittal and tracking. The following details

shall be included on the record:

• reason for the dispatch

• key details

• name of all dispatchers

• name of all recipients

• date of transactions

The record shall be progressively compiled by the relevant stakeholders throughout the various

stages of dispatching and receiving. Abbreviations shall not be used to describe station names

or other details. The record shall be controlled by the responsible signal engineer.

Operational safeworking keys shall be dispatched in a suitable box locked with an SWI padlock

(or similar) accompanied by the record.

The responsible signal engineer shall account for the content of keys when dispatched and

received. When operational safeworking keys are returned, the responsible signal engineer

shall inspect the key inscription and number, and if correct, permit the distribution of the keys for

operational use.

The end receiver shall forward the completed record back to the responsible signal engineer for

retaining the file.


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