gert8037 iss 1 - rssb iss 1.pdf · b2.2.2 station operator duty holders of this category of railway...

This document is the property of the Rail Safety and Standards Board Limited. It shall not be reproduced in whole or in part without the written permission of the Department Head of Railway Group Standards Management, Rail Safety and Standards Board. Published by: Rail Safety and Standards Board Evergreen House 160 Euston Road London NW1 2DX © Copyright 2003 Rail Safety and Standards Board Limited

Railway Group Standard GE/RT8037 Issue One Date December 2003

Signal Positioning and Visibility

Synopsis This document mandates the requirements for positioning signals and indicators to ensure adequate viewing and clarity of meaning for drivers.

Signatures removed from electronic version

Submitted by

Paul Woolford Standards Project Manager

Authorised by

Anne Blakeney Acting Department Head Railway Group Standards Management

Uncontrolled When Printed Document superseded by RIS-0737-CCS Iss 1 with effect from 04/06/2016

This page has been left blank intentionally



RAIL SAFETY AND STANDARDS BOARD 1

Railway Group Standard GE/RT8037 Issue One Date December 2003 Page 1 of 36

Contents Section Description Page

Part A

A1 Issue record 2 A2 Implementation of this document 2 A3 Scope of Railway Group Standards 2 A4 Responsibilities 2 A5 Health and safety responsibilities 3 A6 Technical content 3 A7 Supply 3

Part B

B1 Purpose 5 B2 Application of this document 5 B3 Definitions and acronyms 6 B4 Introduction 9 B5 Requirements 9 B6 Managing departures from best practice 11 B7 Signal sighting design requirements 12 B8 Commissioning checks 16 B9 Records 16

Part C

C1 General requirements for positioning and visibility of signals 19 C2 Colourlight main signals and associated route indicators 22 C3 Position light signals (PLS) and associated route indicators 24 C4 Semaphore signals and signs that perform the function of signals 25 C5 Use of co-acting signals and banner repeating signals 27 C6 Platform equipment 28 C7 Miscellaneous technical requirements 30

References 33



2 RAIL SAFETY AND STANDARDS BOARD


Part A A1 Issue record

Issue Date Comments One December 2003 Original document

Supersedes GK/RT0037 issue four This document will be updated when necessary by distribution of a complete replacement.

Revisions have not been marked by a vertical black line in this issue because the document has been revised throughout.

A2 Implementation of this document

The publication date of this document is 6 December 2003.

This document comes into force on 7 February 2004.

The dates by which compliance with the requirements of this document is to be achieved are set out in Part B2. Where those dates are later than the date on which this document comes into force, this is to give Railway Group members additional time to plan and commence implementation so as to achieve full compliance by the dates set out in Part B2.

This document supersedes the following Railway Group Standard, either in whole or in part as indicated:

Railway Group Standard

Issue No.

Title RGS sections superseded by this document

Date(s) as of which sections are superseded

GK/RT0037 4 Signal Positioning and Visibility

All sections June 2005

GK/RT0037 issue four is withdrawn with effect from June 2005.

A3 Scope of Railway Group Standards

The overall scope of Railway Group Standards is set out in Appendix A of GA/RT6001. The specific scope of this document is set out in Part B2.

A4 Responsibilities Railway Group Standards are mandatory on all members of the Railway Group* and apply to all relevant activities that fall into the scope of each individual’s Railway Safety Case. If any of those activities are performed by a contractor, the contractor’s obligation in respect of Railway Group Standards is determined by the terms of the contract between the respective parties. Where a contractor is a duty holder of a Railway Safety Case then Railway Group Standards apply directly to the activities described in the Safety Case.

* The Railway Group comprises Network Rail Infrastructure Limited, Rail Safety and Standards Board Limited, and the train and station operators who hold railway safety cases for operation on or related to infrastructure controlled by Network Rail Infrastructure Limited.

Network Rail Infrastructure Limited is also known as Network Rail.

Rail Safety and Standards Board Limited is also known as RSSB.





A5 Health and safety responsibilities

In issuing this document, RSSB makes no warranties, express or implied, that compliance with all or any documents published by RSSB is sufficient on its own to ensure safe systems of work or operation. Each user is reminded of its own responsibilities to ensure health and safety at work and its individual duties under health and safety legislation.

A6 Technical content The technical content of this document has been approved by:

Jeff Allan, Principal Signalling and Telecommunications Engineer, RSSB

Richard Evans, Principal, Operations, RSSB

Enquiries should be directed to RSSB – Tel: 020 7904 7518 or e-mail [email protected].

A7 Supply Controlled and uncontrolled copies of this document may be obtained from the Industry Safety Liaison Dept, Rail Safety and Standards Board, Evergreen House, 160 Euston Road, London NW1 2DX or e-mail [email protected].





Part B B1 Purpose

This standard contains mandatory requirements for positioning signals and indicators to ensure adequate viewing and clarity of meaning for drivers.

B2 Application of this document

B2.1 To whom the requirements apply This document contains requirements that are applicable to RSSB and duty holders of the following categories of Railway Safety Case:

a) infrastructure controller

b) station operator

c) train operator.

Under the Railways (Safety Case) Regulations 2000, the duty holder at a station (as defined in those Regulations) is responsible for ensuring that the requirements of Railway Group Standards are complied with. At a station, contractual arrangements (including a lease) do not of themselves relieve the duty holder of his obligations under those Regulations.

B2.2 Compliance requirements Except as provided for below, the requirements of this document are mandatory from 7 February 2004 for all fixed signals, signs that perform the function of signals, and associated indicators, where these form part of Network Rail controlled infrastructure, and apply when such signals are assessed prior to introduction or modification, or assessed as a result of an incident, allegation, or in connection with a line speed increase.

The requirements of this document are mandatory for work where Approval in Principle is given on or after 7 February 2004. When Approval in Principle is given before 7 February 2004, but the infrastructure has not yet been brought into service, the design shall be reviewed and, where reasonably practicable, brought into compliance with the requirements of this document. Where it is not reasonably practicable to do so, the situation shall be regularised by means of a non-compliance or derogation (see clause B2.2.4).

In respect of remedial action associated with signals that are the subject of a SPAD investigation, consideration shall be given to implementation of those technical requirements set out in this document which are both reasonably practicable in the circumstances, and have the potential to reduce the risk of a signal being passed at danger in the future.

Until 30 June 2005 it is permissible for committees not fully compliant with section B7.4 to continue to meet the requirements of GK/RT0037 issue 4.

B2.2.1 Infrastructure controller Duty holders of this category of Railway Safety Case shall comply with all parts of this document.

Where, in this standard, responsibilities are placed on the signal sighting committee or chairperson, the infrastructure controller shall be responsible for ensuring that these are carried out.

B2.2.2 Station operator Duty holders of this category of Railway Safety Case are required to provide competent persons to participate in signal sighting committees, as described in this standard. Competence requirements are identified in section B7.4. The





station operator shall ensure that the staff they provide for this purpose are aware of the contents of this entire document.

B2.2.3 Train operator Duty holders of this category of Railway Safety Case are required to provide competent persons to participate in signal sighting committees, as described in this standard. Competence requirements are identified in section B7.4. The train operator shall ensure that the staff they provide for this purpose are aware of the contents of this entire document.

B2.2.4 General compliance requirements Until the compliance date, or the date by which compliance is achieved (if earlier), the applicable requirements of GK/RT0037 issue four shall continue to be met (see Part A for details).

After the compliance date, or after the date by which compliance is achieved (if earlier), Railway Group members shall not deviate from the requirements set out in this document.

Where it is considered not reasonably practicable to comply with the requirements set out in this document, authorisation not to comply shall be sought in accordance with GA/RT6001, GA/RT6004 or GA/RT6006.

B2.3 Exclusions from the application of this document The requirements of this standard are not applicable to the positioning of buffer stop lights.

B2.4 Related requirements in other documents Other requirements relating to the provision and positioning of signals and signs are contained in GK/RT0031, GK/RT0032, GI/RT7033, GK/RT0034, and GK/RT0044.

Requirements for the maintenance of signal visibility and for the reassessment of the visibility of existing signals in connection with alterations to other assets or following allegations of poor visibility are contained in GE/RT8034.

Requirements for the reassessment of the visibility of existing signals following an overrun (Signal Passed at Danger - SPAD) are contained in GO/RT3252.

Requirements for the positioning of signal post telephones are set out in GE/RT8048.

B2.5 Supporting documents This document is supported by the Railway Group Guidance Note GE/GN8537, Guidance on Signal Positioning and Visibility.

B3 Definitions and acronyms

Achievable reading distance The maximum reading distance that can be reasonably practicably achieved.

Alignment The horizontal and vertical relationship between the centre-line of an element of a signal and the railway infrastructure.

Assessed minimum reading time The assessed minimum reading time is the sum of the times assessed to be essential in order for a driver approaching a signal to:

a) detect the presence of the signal

b) identify the signal as being applicable to the driver





c) observe the information presented by the signal

d) interpret the information to determine what action, if any, is required.

AWS Automatic Warning System.

CD Close door.

Centre-line The line (usually extending out perpendicularly from the face of a signal) forming the optical axis of the beam.

DOO Driver only operation.

Driver’s eyelevel The height above rail level that is assumed for the driver’s eye. This will vary according to the design of the cab, the seat adjustment and the driver. For the purposes of signal sighting, the driver’s eyelevel shall normally be assumed to be 2.75 m above rail level unless sighting exclusively for trains of a non-standard height.

Driving position The normal position from which the driver controls the train, by operating the primary controls (see GM/RT2161 for further details).

Element An element of a signal is any of the following:

a) a single aspect of a main signal (a double yellow counts as one element)

b) a position light junction indicator

c) the number/character displayed by an alphanumeric route indicator

d) a single arm/disc of a semaphore signal or, during darkness, the illuminated spectacle

e) an aspect of a position light signal (the two white lights counts as one element).

Form of signal The combination of elements used to create a signal, and their positions relative to each other.

Lateral position The horizontal distance from the running edge of the nearest rail of the line to which the signal applies at a specific location on the track, and the vertical position above rail head level.

Longitudinal position The position along the track.

Normal stopping position Any position within the range of positions at which drivers are expected to stop on the approach to a signal at danger.

OLE Overhead line equipment.





Permissible speed The highest permitted speed (including any enhanced permissible speed) of a train on the approach to a signal.





Platform starting signal A signal is defined as a platform starting signal if either:

a) the longest passenger (or empty coaching stock) train authorised to use the platform would, if stopped at the signal, still have a portion of the passenger accommodation alongside the platform, or

b) the leading end of the train passes over the automatic warning system (AWS) equipment associated with the signal before it is dispatched from the station.

PLS Position light signal.

PLJI Position light junction indicator.

RA Right away.

Readable An aspect or indication is readable if, under clear weather conditions by day and by night, persons meeting the minimum eyesight requirements of Railway Group Standards GO/RT3251 or GO/RT3255 are always able to identify the aspects and indications displayed when viewed from the driving position.

Clear weather conditions means daylight visibility of 1000 m or better, where visibility is measured in accordance with guidelines such as those set out in the British Meteorological Office Observer’s Handbook. GK/RT0031 sets out the minimum requirements for signals.

Required reading distance The distance before the signal determined by the signal sighting committee that is to be provided and maintained (see GE/RT8034) for sighting a signal by the driver of an approaching train.

SAS SPAD Start against signal SPAD.

Signal A visual display device which conveys instructions or provides prior warning of instructions regarding the driver’s authority to proceed. For the purposes of this standard it includes level crossing indications to train drivers, points and SPAD indicators, and signs or boards that perform the function of a fixed signal.

Signal file The records associated with all signal sighting issues for each signal.

SOY SPAD Start on yellow SPAD. SPAD Signal passed at danger.

SSC Signal sighting committee.

Other definitions and acronyms are as defined in GK/RT0002 (due to be re-issued as GK/GN0802 on 3 April 2004)



1 0 RAIL SAFETY AND STANDARDS BOARD


B4 Introduction On a railway where driver observation of lineside signals and signs is essential for the correct control of trains, driver cognition and response factors have the potential to introduce some significant risks. Even in the case of a perfectly positioned signal there is a finite risk of a Signal Passed at Danger (SPAD).

In situations where there are particular risk factors associated with the signal (such as conspicuity problems, restricted approach view, interruptions to the view), then each of these factors constitutes a departure from the ideal and thereby increases the SPAD risk.

Where it is necessary to position signals in a manner which departs from the ideal, the signal sighting committee shall assess the risk implications of each departure from the ideal and shall recommend the form and position of the signal that:

a) most nearly meets the requirements of this standard

b) reduces the risk of SPAD to ‘as low as reasonably practicable’

c) ensure that no intolerable risks are introduced.

This standard supports HM Railway Inspectorate Safety Principle 20: ‘The signalling system should provide for the safe routing, spacing and control of trains.’

B5 Requirements B5.1 Principal requirements Signals shall be positioned and aligned so as to ensure that:

a) the driver of an approaching train has sufficient time to identify, observe and interpret the information being displayed

b) the information being presented is clear and unambiguous

c) the risk of reading the wrong signal is minimised

d) the presentation of information displayed to the driver is such as to avoid information overload.

B5.2 Assessed minimum reading time B5.2.1 Determining when an assessed minimum reading time is required Except as permitted below, the assessed minimum reading time, as defined in section B3, shall be determined for each signal.

An assessed minimum reading time is not required for the following types of signal:

a) signals where trains can only start from rest (for example a terminal platform starter)

b) signals that can only display a stop aspect (for example a fixed red or a stop board)

c) signals where all approaching trains are required to proceed at a speed which allows them to stop on sight (for example, independent PLS).

For signals not requiring an assessed minimum reading time, a minimum reading distance shall be determined that ensures that any approaching train is capable of stopping at the signal.



RAIL SAFETY AND STANDARDS BOARD 1 1


B5.2.2 Determining the assessed minimum reading time The assessed minimum reading time shall be no less than eight seconds travelling time before the signal.

The assessed minimum reading time shall be greater than eight seconds where there is an increased likelihood of misread or failure to observe. Circumstances where this applies include, but are not necessarily limited to, the following:

a) the time taken to identify the signal is longer (for example, because the signal being viewed is one of a number of signals on a gantry, or because the signal is viewed against a complex background)

b) the time taken to interpret the information presented by the signal is longer (for example, because the signal is capable of presenting route information for a complex layout ahead)

c) there is a risk that the need to perform other duties could cause distraction from viewing the signal correctly (for example, the observance of lineside signs, a station stop between the caution and stop signals, or DOO (P) duties)

d) the control of the train speed is influenced by other factors (for example, anticipation of the signal aspect changing).

The assessed minimum reading time shall be determined using a structured format approved by the infrastructure controller.

B5.3 Interruption of view So far as is reasonably practicable, there shall be no interruption of the driver’s view of a signal during the minimum reading time. An assessment shall be made of any remaining interruptions to demonstrate that they do not give rise to an unacceptable risk of the driver disregarding or misreading the signal.

When determining where the minimum reading time commences, referred to as the minimum reading distance (MRD), a distance equivalent to the length of any interruptions shall be added.

B5.4 Calculating the location at which the assessed minimum reading time commences The location on the train’s approach to the signal at which the assessed minimum reading time commences (known as the minimum reading distance) shall usually be calculated using the permissible speed applicable at that location.

Where the maximum attainable speed of all trains on the approach to the signal is less than the permissible speed, it is permissible to calculate the minimum reading distance based on attainable speed.

It is permissible to determine separately the assessed minimum reading time (and hence minimum reading distance) for each aspect that the signal can display. With the signal displaying a clear or first caution aspect the permissible speed (or attainable speed if justified) shall be used to determine the minimum reading distance. For other aspects it is permissible to determine the minimum reading distance based on the attainable speed of trains as appropriate to the aspect being displayed (see also clause B5.2.1).

It is permissible to determine the minimum reading distance of semaphore stop signals based only on the approach speed to the red aspect.

B5.5 Maximising the reading distance achievable As far as is reasonably practicable, hazards (identified in the requirements set out in clause B5.2.2) and obstructions to the driver’s view of the signal shall be removed so as to maximise the reading distance achievable (known as the





achievable reading distance) and minimise hazards that could increase the risk of driver error.

Where alterations have been made that affect hazards identified, the assessed minimum reading time shall be reviewed.

B5.6 Form of signals The form of approved signals are set out in GK/RT0031.

B5.7 Longitudinal positioning of signals The longitudinal position of signals shall be selected so as to ensure that they meet the readability requirements set out elsewhere in this standard, whilst also taking into account the requirements for:

a) signal spacing (see GK/RT0034)

b) the provision of signals (see GK/RT0032)

c) the positioning of signals used to control movements onto occupied lines (see GK/RT0044).

B5.8 Structural and electrical clearances Requirements for structure clearances relating to the positioning of new, altered and temporary infrastructure are set out in GC/RT5212. Additional requirements for personal safety in respect of clearances are set out in GC/RT5203.

Signals and signal structures shall be positioned so as to meet the requirements of GE/RT8025.

B5.9 Restrictions on use of co-acting signals The co-acting signal shall be of the same style (colourlight or semaphore) as the primary signal. Section C5.2 identifies further factors to address when considering the use of a co-acting signal.

B5.10 Maintainability The design of the signal and associated structure shall take into consideration the proposed arrangements for the maintenance and alignment checks of the signal, and shall incorporate any features necessary to allow access to the equipment for such purposes.

B6 Managing departures from best

practice The contents of Part C of this standard represent current best practice for the appearance, sighting and alignment of signals. Signals shall usually be positioned in accordance with Part C; however, it is permissible not to comply with all the details stated, but any departures from the requirements of Part C shall be permitted only if:

a) supported by all disciplines represented on the signal sighting committee

b) approved by the infrastructure controller

c) the details and justification of the departures from the requirements of Part C are recorded in the signal file.

The infrastructure controller shall review all such departures to ensure that the rationale being applied is consistent, logical, justified and complies with the principal requirements identified in clause B5.1.

The application of this clause B6 does not absolve Railway Group members from seeking derogations, temporary non-compliances or non-compliances pending standards change from other relevant Railway Group Standards.





B7 Signal sighting design requirements

B7.1 Concept design stage requirement Consideration of signal sighting issues shall be properly co-ordinated with the overall scheme design process and shall take place sufficiently early in a scheme that the options available to a committee to optimise the readability of signals are not restricted by actions or decisions already made.

As a part of the signalling design production and overrun risk assessment processes (see GK/RT0207 and GI/RT7006 respectively), as much detail as possible about the proposed position and form of each new and altered signal (and each indicator and sign performing the function of a signal) shall be produced during the concept design phase.

These details shall be submitted to a signal sighting committee in order for an on-site evaluation of the proposals to be undertaken.

It is also permissible to use equipment such as virtual reality simulation or video facilities to support the signal sighting design process.

B7.2 Role of signal sighting committees B7.2.1 New, modified or repositioned signals For all new, modified and re-positioned signals, indicators, and signs that perform the function of signals, the infrastructure controller shall ensure that a signal sighting committee is convened to verify the proposed position and form. The committee shall:

a) review any preliminary sighting proposals produced by the designers and the signalling scheme plan

b) identify any alterations or additions required

c) make recommendations as to the position and form of each signal in order to optimise the driver’s approach view.

The infrastructure controller shall ensure that where multiple signals are involved, a consistent approach to signal sighting is taken for all signals. Wherever practicable this shall be achieved by using the same personnel for sighting all the signals.

When satisfied, each committee member shall indicate in writing their agreement with the proposed sighting details, and the committee shall recommend the sighting details for approval by the infrastructure controller (see clause B7.6).

B7.2.2 SPAD investigations For existing signals subject to a SPAD investigation, the infrastructure controller shall ensure that the investigation remit set by the Inquiry Panel Chairperson (see GO/RT3252) is performed by personnel competent in signal sighting.

It is permissible for the committee membership to be restricted below that set out in clause B7.4.1 so long as the committee is capable of fulfilling the investigation remit set.

B7.2.3 Linespeed increase For existing signals subject to a proposed linespeed increase, the infrastructure controller shall ensure that a signal sighting committee is convened to:

a) assess the signal for compliance with this standard at the proposed speed

b) where necessary, make recommendations regarding improvements that shall be made to the signal before introduction of the higher speed.





When satisfied, each committee member shall indicate in writing:

c) their agreement that no change is required, or

d) their agreement with the proposed changes.

See also GK/RT0007 and GI/RT7006.

B7.3 Additional responsibilities of the signal sighting committee A signal sighting committee shall also be required to consider the positioning of the following items of infrastructure equipment:

a) signal post telephones (see GE/RT8048)

b) permanent speed boards (see GK/RT0038)

c) AWS inductors (see GE/RT8035)

d) platform/track mounted monitors and mirrors to be used by drivers (see GE/RT8060).

B7.4 Signal sighting committee core competence requirements B7.4.1 Committee membership The signal sighting committee shall collectively include all the expertise (engineering, operations, train driving, local knowledge) necessary to assess the signals in question. In particular, the infrastructure controller shall ensure that the committee includes:

a) representatives of the infrastructure controller, with both operations and signal engineering experience. Other engineering expertise shall be included where necessary

b) a representative with knowledge of the signalling scheme design, unless the committee has been convened to assess a SPAD incident

c) representatives of all train operators using the route, with experience in driving the relevant types of trains

d) one or more representatives of station operators on the route, if the signals under consideration include platform starting signals.

The infrastructure controller shall consider including other specialist skills within the committee, such as human factors, where the membership would otherwise not contain sufficient skills for the specific task in hand.

The infrastructure controller shall consider including members of an investigation/inquiry panel within the committee where the committee is formed as a result of an accident or incident.

B7.4.2 Competence standards Those members who bring expertise of signal engineering, drivers’ skills or operations requirements to the committee, together with the chairperson, shall be assessed as competent in the core requirements of a signal sighting committee.

The signal sighting committee chairperson shall, additionally, be assessed as competent in the core requirements of a signal sighting committee chairperson. It is permissible for a SSC chairperson to be the representative of an area of expertise in addition to the chairperson’s duties.

The infrastructure controller shall set and monitor competence standards for the core requirements of a signal sighting committee and for the core requirements of a signal sighting committee chairperson.





The infrastructure controller shall maintain a central register of personnel assessed as competent in the core requirements of a signal sighting committee or the core requirements of a signal sighting committee chairperson.

The committee shall be led by a chairperson, appointed and approved in advance by the infrastructure controller. The infrastructure controller shall select the signal sighting chairperson ensuring that the person’s previous experience indicates that the person is capable of resolving the anticipated complexities of the planned work. The infrastructure controller shall maintain records of the signal sighting chairpersons’ previous experience.

B7.5 Signal sighting committee general competencies B7.5.1 General requirements The infrastructure controller shall ensure that, collectively, the signal sighting committee possesses all of the following:

a) all necessary general competencies (see clauses B7.5.2 – B7.5.4)

b) sufficient local knowledge for the route and signals under consideration

c) a working knowledge of the requirements of this standard, and of other associated documents and sources of information (for example, gauge requirements).

B7.5.2 Factors for consideration relating to overrun risk The signal sighting committee shall be collectively competent to consider the effects of the following factors on the likelihood of an overrun occurring:

a) gradients and permissible/attainable speeds

b) aspect sequences and form of junction signalling, including those of existing signals

c) routes by which a driver could approach a signal

d) grouping of parallel signals and the potential for drivers to be confused as to which one applies to the line they are on

e) train working arrangements (including running and shunting movements, and movements onto occupied lines)

f) normal stopping positions of trains

g) train dispatch arrangements

h) complexity of infrastructure (for example, station areas, overhead line equipment, curved approaches, bridges)

i) types of trains authorised or planned to operate over the route and in particular their cab sightlines (see also GM/RT2161)

j) irregular or excessive spacings of signals

k) potential driver distractions (for example, station stops, speed restrictions, neutral sections)

l) ambient lighting conditions (including effects of reflected or background sunlight)

m) effects of artificial lighting (reflected and background)

n) reading through to other signals

o) signals unusually positioned (for example, on right-hand side of line)





p) position of AWS in relation to signal (see GE/RT8035)

q) train radio coverage.

B7.5.3 Other issues for consideration The signal sighting committee shall be collectively competent to consider the following issues:

a) structure gauge, clearances and other matters related to the infrastructure and proposed signal structures, including any alterations to the infrastructure that are planned to take place

b) the compatibility of signals and electric traction equipment, for example any conflicts between the positions of neutral sections and the positions of signals (see GK/RT0032), and potential interruptions to signal visibility

c) local problems or special conditions, for example a previous history of overruns in the vicinity; driver’s complaints regarding the approach view; areas of high vandalism; signs with the potential to obstruct signal visibility.

B7.5.4 The choice, position and visibility of new or modified signals The signal sighting committee shall be collectively competent to make recommendations concerning:

a) form of new or modified signals

b) longitudinal and lateral position of each signal

c) the reading time for each signal (including the acceptability of any interruptions)

d) alignment and close-up viewing requirements for each signal

e) measures for overrun risk control

f) train dispatch arrangements from platforms and associated train dispatch equipment (see section C6)

g) arrangements for maintainability of signals.

B7.6 Checking and approval of committee recommendations Sighting recommendations for new, modified or repositioned signals shall be checked by an individual competent to act as a signal design engineer. It is not permissible for the recommendations to be checked by a member of the committee that produced them. Assessments of an existing signal, subject to a linespeed increase shall be similarly checked even if no changes are recommended.

The sighting details, as recommended by the signal sighting committee, shall be approved by the infrastructure controller when satisfied that the recommendations are adequate to control the risk of an overrun by poor sighting (SPAD).

The infrastructure controller’s approval process shall review and assess all proposed departures from the requirements of Part C of this standard (see section B6).

Where the infrastructure controller does not approve the recommendations, the signal sighting committee shall be reconvened to review its previous proposals, in the light of the reasons for non-approval, and make appropriate alternative recommendations. The infrastructure controller is not permitted to approve any sighting details unless they are supported by the sighting committee (as indicated by the signature of the members – see section B7.2).





The infrastructure controller shall ensure that the checker has signed the sighting details before giving written approval for the recommendations produced. Details of any departures from Part C of this standard shall be clearly identified and kept with the recommendations.

Signal sighting details shall be approved before the production of dependent engineering details commences (except as permitted by GK/RT0207).

B7.7 Review of overrun risk assessment Where the form or position of a signal, as proposed by the designers, is subsequently altered as a result of the signal sighting committee’s recommendations, the relevant parts of the overrun risk assessment (see GI/RT7006) shall be reviewed to ensure that the assessment is still valid.

B8 Commissioning checks

B8.1 Pre-commissioning checks The requirements for the testing and commissioning of signals are set out in GK/RT0209. The infrastructure controller shall ensure that the tests include:

a) a compliance check of the installed signal against the approved sighting details

b) an adequacy check to ensure that the driver’s view is adequate to reliably identify and observe the signal and correctly interpret the signalling information.

The adequacy check shall be carried out from the driving cab using rolling stock appropriate to the line of route or from the track using a periscope or equivalent device. If it is not reasonably practicable to observe every aspect combination from all possible approaches; a representative sample of all combinations shall be observed, selecting, where possible, for this sample, those giving the greatest potential for misreading or incorrect driver response. Where reasonably practicable, these checks shall be conducted before the signals are brought into service. Where this is not reasonably practicable, it is permissible for the checks to be carried out (or completed) within seven days after the signals are brought into service.

B8.2 Post-commissioning checks The infrastructure controller and train operators shall ensure that train drivers are consulted and thus given the opportunity to identify any problems or concerns about the sighting of signals that have become apparent by day or night after the introduction of the new or altered signals. This consultation shall be completed no later than three months after commissioning.

Any remedial actions identified between bringing the signals into service and the driver’s review shall not be delayed awaiting the results of the review.

Any remedial actions shall be implemented on a timescale agreed by the infrastructure controller and train operator(s), commensurate with the risks. Where necessary, special measures shall be applied to control the risk pending the implementation of the remedial actions.

The general reporting of deficiencies in signal sighting is set out in GE/RT8034.

B9 Records B9.1 Information to be retained A record (also called the signal file) shall be created for each signal. The infrastructure controller shall ensure that, as a minimum, it contains:





a) all the current approved sighting details, together with details of the modification history of the signal, including any changes or additions that affect its position, appearance, alignment point or light output

b) a record of the approval by the infrastructure controller (see clause B7.6)

c) details of assessments, calculations, assumptions and justifications associated with the chosen form, position and alignment of the signal

d) reports of problems with the sighting of signals, including those raised at the post-commissioning consultation (see clause B8.2)

e) dated photographs of the signal at commissioning and after any alterations to the form or position of the signal. As a minimum, two views of each signal shall be required, one from alongside the most restrictive aspect looking back along the approach to the signal, and a close-range view of the signal, showing clearly the arrangement of the signal elements and signal structure

f) details (for example, in diagrammatic form) of any partial or complete obstructions to the driver’s viewing of signals that occur within the required reading distance

g) details of any derogations, temporary non-compliances or temporary non-compliances pending standards change relating to Railway Group Standards

h) details of any departures from the requirements of Part C of this standard

i) all ongoing risk assessments involving the signal.

The information required in a), c), f) and h) shall be recorded in a standard format approved by the infrastructure controller.

GI/RT7001 sets out the general requirements for infrastructure records.

B9.2 Availability of information The infrastructure controller shall ensure that records of signals be made accessible for the purposes of:

a) investigating sighting complaints (see GI/RT7006 or GE/RT8034)

b) overrun investigations (see GO/RT3252)

c) planning alterations to signalling or linespeed (see GI/RT7006)

d) maintenance and visibility checks (see GE/RT8034).





Part C C1 General

requirements for positioning and visibility

of signals C1.1 Longitudinal positioning of signals C1.1.1 Signals on parallel lines Where lines running parallel to each other are signalled in the same direction and drivers on one line can see the signal(s) on the parallel line(s), the signals for each line shall normally be placed so as to be at the same longitudinal positions as those on the parallel lines. This is called ‘parallel positioning’ of signals.

Signals shall be regarded as parallel if they are within 20 m of each other longitudinally. Where lines running parallel to each other are signalled in the same direction but signals are not provided on each line, particular consideration shall be given to ensure that the risk of driver confusion or misread is minimised.

Where lines that are operated as separate routes run parallel (for example, the DC lines alongside the West Coast Main Line, or LUL lines adjacent to Network Rail controlled infrastructure), this section applies to each route individually, and not to the set of parallel routes. Nevertheless, consideration shall be given to the risk of drivers on either route erroneously obeying signals that apply to the adjacent route.

A departure from the requirement for signals to be positioned to appear in parallel shall demonstrate, as a minimum, that:

a) during the approach to the signals, the driver is unlikely to be confused as to the position of the signals or which signal to obey. In particular, the ‘crossing-over effect’ (in which the relative positions of the signals appears to change during the approach) shall not occur

b) the overrun risks associated with the non-parallel positions are acceptably low.

C1.1.2 Train radio coverage Consideration shall be given to the adequacy of train radio coverage when positioning signals. If necessary, the coverage shall be improved to suit the positioning of the signal.

Where the radio system automatically routes calls to the appropriate signaller, the radio system shall be checked to ensure that routing is applied correctly (see GE/RT8080).

C1.2 Lateral positioning of signals C1.2.1 General requirements Each signal shall be positioned laterally as follows:

a) on the left-hand side of the line as seen in the direction of travel to which the signal applies, except as permitted by clause C1.2.2

b) so that drivers on all lines readily associate the signal with the line to which it applies and not with any other line.

C1.2.2 Positioning of signals on right-hand side of line A departure from the requirement for signals to be positioned on the left-hand side of the line shall demonstrate, as a minimum, that:

a) the readability is improved for trains approaching the signal and SPAD risk is reduced





b) for stop signals, the signal is readable by drivers of trains stationary in the normal stopping position at the signal (clause only applicable to stop signals)

c) there is no line immediately to the right of the signal, such that drivers on either line might associate the signal with that line rather than with the line to which it actually applies (signals on lines separated by an island platform can usually be regarded as meeting this criterion).

C1.3 Visibility of signals C1.3.1 Determining the required reading distance Where the achievable reading distance (see clause B5.5) is initially assessed as less than the minimum reading distance (see clause B5.4), then mitigating measures shall be considered in order to increase the reading time available or to reduce the minimum required.

Consideration shall be given to hazards generated by the introduction of the mitigating measures. Where the hazards introduced are considered more significant than the improvements to reading distance generated, the mitigating measure shall not be introduced and other options shall be developed.

A departure from this requirement to permit an achievable reading distance less than the minimum reading distance, shall demonstrate, as a minimum, that:

a) it is not reasonably practicable to increase the achievable reading distance

b) the difference between that which is achievable and the minimum reading distance is tolerable.

When an acceptable achievable reading distance has been determined this shall be recorded as the required reading distance. (GE/RT8034 sets out requirements to maintain the required reading distance for the life of the signal.) C1.3.2 Close-up viewing of the signal For signals capable of displaying a stop aspect, all elements of the signal shall be readable from the driving cab with no interruption of view between 40 m from the signal and the closest point at which a driver is expected to bring his train to a stand at the signal at danger. It is permissible to apply other measures, such as described in section C5.2, in order to meet this requirement.

Where the signal is fitted with a device that offers a means of enhanced close-up viewing (for example a close up viewing segment) the device shall be orientated to optimise the readability over this distance.

Where planned stopping points are to be closer than 15 m before the signal, a vision plot, identifying the limitations caused by cab sightlines of the relevant types of rolling stock, shall be carried out.

Section C6 sets out the special requirements for platform starting signals.

C1.3.3 Visibility of signals on other lines So far as is reasonably practicable, signals shall be positioned and aligned so as not to cause confusion in the correct observation and interpretation of other signals by drivers on other lines, whilst ensuring that a driver has adequate visibility of signals on their line.

On parallel lines signalled in the same direction, consideration shall be given to the provision of a means by which a driver can more readily identify the signal that is applicable to their train. This is particularly important on lines with three or more parallel signals, or where a junction is unusually complex.





C1.3.4 Read-through Consideration shall be given to the risk of a driver reading-through to a signal beyond that which should next be obeyed and which might reasonably be expected to be displaying a less restrictive aspect (typically beyond a junction or level crossing). Where this risk is considered unacceptable, measures shall be introduced (such as reducing the conspicuity of the forward signal or applying special controls to the signal aspect) to mitigate the risk (see GK/RT0060).

C1.4 Consistency of form C1.4.1 Form of signals Successive signals for the same direction of traffic flow shall be reasonably consistent in form, in order to facilitate correct observation by the driver of the information presented.

Consideration shall be given to the form of new, modified and existing unaltered signals preceding/following the new or modified signals. The following factors shall be considered:

a) the relative position of elements of signals

b) the choice of route indicator types

c) the lateral position of signals

d) the relative position of parallel signals.

Colourlight and semaphore elements shall not be intermixed on a signal, except that it is permissible to use alphanumeric route indicators in conjunction with semaphore stop signals.

A departure from this requirement to permit inconsistent signal forms shall demonstrate, as a minimum, that:

e) the resulting signals do not introduce any foreseeable driver error

f) the inconsistency has been introduced to improve drivers’ understanding.

C1.4.2 Form of structures Consideration shall be given to the advantages, from a driver’s perspective, of consistency in the type of structures on which successive parallel signals are mounted. The inconsistent use of gantries, cantilevers and straight posts for successive groups of parallel signals can contribute to the misreading of signals by drivers.

C1.5 Lineside signs in the vicinity of signals Lineside signs, required to be observed by a driver for the purpose of controlling the train, shall be positioned so as not to create unnecessary distraction from the driver’s primary role of observing signals.

So far as is reasonably practicable, signs shall not be positioned between the signal and its associated AWS or within 50 m beyond the signal. If the sign has AWS equipment associated with it, the sign shall be positioned such that the AWS for the sign does not fall between the signal and its AWS equipment.

Where this is not achievable, the sign shall be positioned at the signal and consideration shall be given to the size, lateral position and reflective properties, to ensure that all the information displayed is proportionate and that no part is so prominent as to make other parts appear insignificant.

GK/RT0038 sets out requirements for positioning signs associated with permissible speeds. GE/RT8035 sets out requirements for the positioning of AWS track equipment.





C2 Colourlight main signals and associated

route indicators C2.1 Form of signals C2.1.1 Main colourlight signals Main colourlight signal heads comprising more than one element shall usually be mounted vertically. Where necessary, for visibility purposes or because of constraints on space, it is permissible to mount the elements other than in a vertical array, provided that any double yellow aspect, and any flashing double yellow aspect, continues to be displayed vertically.

If more than one element is used to display aspects, the order of proximity of lights to the driver’s eye as he passes the signal shall be as follows:

a) red aspect light closest

b) first yellow aspect light

c) green aspect light

d) second yellow aspect light (required only for double yellow aspect and flashing double yellow aspect).

Where any of the four elements listed above are not provided, or are combined into a single unit, the order described above shall be maintained by the remaining elements.

Exceptionally, it is permissible for a signal required to show red, yellow and double yellow only, to have the red light separating the two yellows, but only if the red aspect remains near driver’s eye level so that the sighting of the aspect cannot be obscured by signal hoods.

C2.1.2 Positioning of route indicators Position light junction indicators (PLJIs) shall usually be positioned with the pivot light directly above the main aspects. It is permissible for the indicators to be positioned immediately to the side of the main signal (left or right), but only where there is no other way of ensuring adequate readability.

Where a PLJI is positioned to the side of the main signal, the pivot light shall be positioned adjacent to the red aspect. Position indicators 1, 2 and 3 shall be placed only to the left of the main signal, and position indicators 4, 5 and 6 only to the right (see GK/RT0031 for details of position notation).

It is permissible for alphanumeric route indicators to be positioned either above, or immediately to the side of the main signal, whichever gives the optimum readability. Where an alphanumeric route indicator is positioned to the side of the main signal, it shall be positioned to the left of the main signal if the signal is on the left-hand side of the line, and to the right of the main signal if the signal is to the right-hand side of the line.

C2.2 Alignment of signal The signal shall be aligned so as to optimise the readability of the signal by the driver of an approaching train, taking into account the need for all illuminated elements of the signal to:

a) be readable at the start of the required reading distance

b) remain readable throughout the required reading distance (except during those interruptions to the view considered acceptable by the process set out in clause B5.3).





C2.3 Lateral position of signal C2.3.1 Height of signal above rail level The centre of the element that displays the most restrictive element shall be as close as possible to, but not usually less than, 3.3 m above rail level.

Where necessary, to provide adequate visibility, it is permissible for the most restrictive element of the signal to be up to 5.1 m above rail level. In deciding whether it is acceptable to use a height greater than 3.3 m, attention shall be given to:

a) the difficulty that a driver might have in relating the signal to the line to which it applies (especially where the approach to the signal is curved, with signals on parallel lines)

b) the readability of the signal during the driver’s approach (see clause C2.2)

c) the readability of the signal when the driver is close to it (see clause C1.3.4)

d) possible problems with incident or background sunlight, or with the background against which the signal is viewed, preventing the aspect from being discerned

e) the risk of reading through to another signal ahead, instead of obeying the correct signal.

It is also permissible, where necessary, to provide adequate visibility, because of space constraints, or to assist with the association of signal with line, for a signal to be positioned with some or all of its elements below 3.3 m. In deciding whether it is acceptable to position a signal below the height specified in this section, particular attention shall be given to:

f) the readability of the signal during the driver’s approach (see clause C2.2)

g) lines where the driver’s eye level on all trains is lower (for example, LUL stock)

h) the readability of the signal when the driver is close to it (see clause C1.3.4)

i) risk of obscuration of the signal (for example, by the signal head hoods, signs, persons on the track)

j) the presence of a co-acting signal.

C2.3.2 Horizontal displacement of signal relative to rails Signals to the side of the structure gauge (for example, post mounted) shall usually be positioned as close as reasonably practicable to the nearest running rail of the line to which they apply whilst still maintaining clearances as specified in clause B5.5. It is permissible to position signals further away from the nearest running rail if, by doing so, the driver’s view is improved.

Signals above the structure gauge (for example, gantry or cantilever mounted) shall usually be positioned with the centre-line of the most restrictive aspect approximately 900 mm to the left of the running edge of the left-hand rail. It is permissible for such signals to be positioned further to the right if by doing so:

a) the readability throughout the required reading distance is improved, or

b) the association of the signal with the correct line is improved.

Signals positioned to the right of the track centre-line shall be considered as right-hand mounted signals and therefore require a departure from clause C1.2 of this standard.





C2.4 Partial failure of a signal aspect Consideration shall be given to the possible effect on the displayed aspect during a partial failure such as a filament failure. Where this is considered to have a noticeable effect on the appearance, position or alignment of the lit aspect, an assessment shall be carried out to determine whether the consequent change is acceptable.

C3 Position light signals (PLS) and associated route

indicators C3.1 Form of signals C3.1.1 Subsidiary signals Except as permitted below, subsidiary PLSs shall be positioned immediately below the red main aspect. It is permissible for the subsidiary PLS to be positioned immediately to the left of the main red aspect when the signal is to the left of the line to which it applies, or to the right if the signal is to the right of the line to which it applies, if either:

a) route indicators are associated with the PLS, or

b) the effect of placing the PLS beneath the red aspect would be to make the red aspect less readable, because of its increased height.

Where route indicators are associated with a subsidiary signal, they shall usually be positioned immediately above the PLS.

A PLS used as a Proceed on Sight Aspect (PoSA) shall be positioned in accordance with this clause C3.1.1.

A departure from the requirements of this clause shall demonstrate that the form of the signal as a whole is improved or that limitations such as the structure gauge make compliance impractical.

C3.1.2 Independent PLS Route indicators associated with an independent PLS shall usually be positioned immediately above the PLS.

A departure from the requirements of this clause shall demonstrate that the form of the signal as a whole is improved or that limitations such as the structure gauge make compliance impractical.

C3.2 Visibility requirements C3.2.1 Required reading distance The required reading distance for an independent PLS shall be sufficient for a driver to brake to a stand at the signal from the permissible speed applicable to the train movement.

Additional requirements for a subsidiary PLS used for controlling movements onto an occupied line are set out in GK/RT0044.

The requirements in this section are not applicable when an independent PLS acts as a preset shunt signal.

C3.2.2 Alignment PLSs and associated indicators shall be aligned towards a train standing at the normal stopping position on the approach side of the signal.





C3.3 Lateral position of independent PLSs C3.3.1 Height of signal above rail level Independent PLSs shall usually be positioned below driver’s eye level so as to be clearly differentiated from main signals. The selection of the height shall be determined by:

a) limitations of structure gauge

b) achieving consistency of height within a junction area

c) cab sightline limitations.

C3.3.2 Horizontal displacement of signal relative to rails Independent PLSs shall be positioned in accordance with the requirements of clause C2.3.2.

C4 Semaphore signals and signs that perform the function of signals

C4.1 Form of signals and signs C4.1.1 General requirements In meeting the requirements of this standard, all semaphore signal arms, discs and indicators mounted on a common structure and applying to the same line shall be treated as elements of a single signal.

Arms shall be of the upper quadrant type, unless existing signals in the area are wholly or largely lower quadrant. All arms on a structure shall be of the same type.

Semaphore shunt signals shall be of the disc type, unless existing shunt signals in the area are wholly or largely miniature arm type.

C4.1.2 Signals with multiple arms Where multiple routes exist from a main signal, a separate arm shall be provided for each route, arranged horizontally. The position of each arm from left to right shall correspond to the direction of the route from left to right. Routes which differ in speed shall be stepped in height; the highest arm shall apply to the fastest route and subsequent arms to either side shall be progressively lower. The dolls shall be a minimum of 1830 mm apart and the arms stepped in height by a minimum of 760 mm increments.

The following alternative forms of junction signal are permitted if their use improves clarity or consistency:

a) Junction signals arranged with multiple routing arms arranged vertically above one another. The position of each arm from top to bottom shall correspond to the direction of the route from left to right. Arms shall be a minimum of 1680 mm apart. This arrangement shall be used only where the speed differential between the fastest and slowest route is no greater than 10 mph and where the permissible speed is no greater than 40 mph.

b) Junction signals arranged with a single arm and a standard alphanumeric route indicator positioned directly underneath. Consideration shall be given to the risk of a bright route indicator obscuring a relatively dim signal lamp.

Where stop and distant arms applying to the same route are to be mounted on the same post, the distant arm shall be positioned 1680 mm (+/- 200 mm) below the stop arm.

Where stop and subsidiary arms applying to the same route are to be mounted on the same post, the subsidiary signals shall be fitted 1070 mm (+/- 200mm)





below the arm next above. Where a distant signal is fitted below a stop signal, any subsidiary signal shall be fitted below the distant signal arm.

The discs / arms of shunting signals shall be arranged directly above one another and their positions from top to bottom shall correspond to the direction of the route from left to right. Where more than one disc / arm is mounted on a single structure, all such discs / arms shall be of uniform type (that is, all discs or all arms), size and design. Where arms are used, they shall be spaced 1070 mm (+/- 200 mm) apart.

C4.1.3 Lighting of semaphore signals Except as permitted below, the light intensity of all main semaphore signals shall be reasonably consistent within the area controlled by a signal box.

It is permissible for the light intensity of a semaphore signal to be significantly greater than that of other signals controlled by the same signal box, if by doing so it improves the readability of that signal and does not increase the likelihood of drivers misreading or disregarding other signals.

C4.2 Visibility requirements C4.2.1 Main signals The visibility requirements set out in section C1.3 apply to both the day and night indications of the signal.

C4.2.2 Shunting and subsidiary signals The required reading distance for an independent shunting signal shall be sufficient for a driver to brake to a stand at the signal from the permissible speed applicable to the train movement.

Additional requirements for a subsidiary shunt signal used for controlling movements onto an occupied line are set out in GK/RT0044.

The requirements in this section are not applicable when an independent shunt signal acts as a preset shunt signal.

C4.3 Lateral positioning C4.3.1 Main and subsidiary signals The centre of the lowest element of the signal shall be as close as reasonably practicable to, but not below, driver’s eye level, except as permitted below.

Where essential to provide adequate visibility, it is permissible for the signal height to be increased. In deciding whether it is acceptable to use a greater height, attention shall be given to:

a) the difficulty that a driver could have in relating the signal to the line to which it applies (especially where the approach to the signal is curved, with signals on parallel lines)

b) the readability of the signal when the driver is close to it

c) the risk of reading through to another signal ahead, instead of obeying the correct signal.

It is permissible for subsidiary shunting signals to be ground mounted.

C4.3.2 Shunting signals Shunting signals shall usually be positioned below driver’s eye level so as to be clearly differentiated from main signals. The selection of the height shall be determined by:

a) limitations of structure gauge

b) achieving consistency of height within a junction area





c) cab sightline limitations.





C4.3.3 Signs The horizontal centre of the distant board or the red target of a stop board shall usually be positioned 2.5 m (+/- 0.1 m) above rail level.

C5 Use of co-acting signals and banner

repeating signals C5.1 Applications where co-acting and banner repeater signals should be considered Co-acting and banner repeating signals shall be considered for use in situations where there is an identified need for the driver to see signal aspect information but is unable to see the main signal.

C5.2 Co-acting signals C5.2.1 General requirements The use of a co-acting signal shall be considered where it is impractical to position a main signal such that it is visible at long range (the start of the required reading distance) without compromising readability at close range or at the normal stopping position.

Co-acting signals shall not usually be provided at a splitting distant signal unless the primary and co-acting aspects are never seen together.

C5.2.2 Form of co-acting signals It is permissible to use co-acting signals with both colourlight and semaphore forms of signal. It is not permissible to use a combination of colourlight and semaphore signals to form co-acting signals.

The main aspects/arms of the co-acting signals shall be the same. Any other indications required (for example route, subsidiary or RA indications) shall be positioned on either or both signals, depending on the driver’s need to see the indications.

The equipment performance requirement (see GK/RT0031) of the close-range signal shall be sufficient for the viewing range it is designed for.

C5.2.3 Positioning of co-acting signals The longitudinal separation of the co-acting signals shall be no more than 2 m.

It is permissible for co-acting signals to be positioned on opposite sides of the line to which they apply. The lateral position of the co-acting signals shall be such that there is no possibility of a driver mistakenly thinking that either applies to another line.

It is permissible for a co-acting signal that is intended to be seen at long range to exceed the maximum height requirement set out elsewhere in this standard, where necessary to provide adequate visibility so long as the other signal is positioned to provide adequate visibility at short range.

C5.2.4 Identification numbers GK/RT0032 sets out requirements for the unique numbering of co-acting signals. The signal head designed for close-range viewing shall usually be identified as the primary signal.

C5.3 Banner repeater signal C5.3.1 General requirements Banner repeater signals provide only limited information about the aspect of the signal ahead, which in turn restricts their usefulness as a means of improving the reading time of main signals.





Any proposed application of a banner repeater signal shall either:

a) be supported by an assessment that identifies specific hazards to the correct observance of the signal that can be mitigated by the introduction of a banner repeater signal, or

b) be to provide a performance enhancement to some or all trains.

C5.3.2 Visibility requirements for banner repeater signals Where a banner repeater signal is provided, it shall be readable by the driver for a minimum of five seconds. It is permissible to determine the minimum reading distance for the banner repeater signal based on the attainable speed of those trains for which the banner repeater signal has been provided.

Where a banner repeater signal is to be used in association with a signal capable of displaying a flashing aspect, the achievable reading time of the main signal shall be sufficient to ensure that the signal can be observed to be flashing.

Usually the main signal shall become visible when the driver loses sight of the banner repeater. However, it is permissible to have a gap between losing sight of the banner signal and the main signal coming into view, if the effect is to significantly increase the total reading time. The gap shall be as brief as possible, subject to achieving good sighting of the banner signal, (typically no more than three seconds).

C5.3.3 Lateral position of banner signal The requirements of clause C1.2 shall be applied to determine the lateral position of a banner repeater signal.

C6 Platform equipment C6.1 Position and visibility of signals on platforms C6.1.1 Visibility of platform starting signals for drivers All elements of a signal designated as a platform starting signal shall usually be readable by a driver in the driving position of any train authorised to use the route, from all normal stopping positions of trains at the platform. Where this is impracticable, banner repeaters shall be provided which are readable from the normal stopping positions. Where permissible speeds allow, miniature banner repeaters meeting performance category 3 of GK/RT0031 (or, as a non-preferred option, ‘OFF’ indicators) can be used.

C6.1.2 Lateral position of signals on platforms Where signals on platforms are positioned below the normal height (see clauses C2.3.1 and C4.3.1), specific consideration shall be given to the risk of elements being obscured by people on the platform, as well as to other factors associated with signals positioned below the normal height.

It is permissible for miniature banner repeater signals to be positioned to the right of the line to which they apply if the platform is on the right-hand side and they are readable from the associated stopping position(s).

C6.2 Train dispatch equipment C6.2.1 Switches and plungers Switches or plungers required for train ready to start (TRTS), right away (RA) or close doors (CD) functions on a platform shall be co-located and shall be positioned where staff carrying out train dispatch duties can adequately observe the train they are dispatching.

Where platforms are bi-directional or have mid-platform signals, the layout and labelling of the switch/plunger units shall be such as to minimise the risk of operation of the wrong switch/plunger.

It is permissible for duplicate switch/plunger units to be provided where more than one dispatch position is required.





C6.2.2 ‘OFF’ indicators ‘OFF’ indicators shall be provided in situations where the guard or person in charge of the platform is unable to see the platform starter signal or banner repeater signal from all designated dispatch positions. They shall be positioned so as to be readable by the dispatch staff from the dispatch position(s). GO/RT3475 sets out requirements for assessing methods of dispatch.

A banner repeater signal is not a suitable substitute for an ‘OFF’ indicator if it is replaced to danger by occupation of the signal berth track circuit.

Where ‘OFF’ indicators are provided on bi-directional platforms or platforms equipped with mid-platform signals, the OFF indicator shall additionally indicate the signal or direction of movement to which it applies.

C6.2.3 CD / RA indicators CD and RA indicators, where required, shall meet all of the following requirements:

a) be co-located with any platform starting signal provided and with any banner repeater signals (see clause C6.1.1)

b) be positioned such that they are readable by the driver when stationary at any normal stopping position

c) be positioned such that they are readable by the person in charge of the platform.

Where necessary, duplicate indicators shall be provided to achieve the requirements of this clause.

C6.3 DOO monitors and mirrors Monitors and mirrors for DOO shall be positioned:

a) so as not to obscure the view of any signal for drivers of stopping or non-stopping trains

b) so as to minimise the risk of a SAS SPAD.

Technical requirements for DOO monitors and mirrors are set out in GE/RT8060.

C6.4 Train stopping positions No car stop marker or DOO monitor unit shall be positioned such that a train is required to stop within 25 m of the platform starting signal, except as permitted below.

It is permissible for the normal stopping position of a train to be within 25 m of the platform starting signal where the signal is sufficiently conspicuous such that a driver in the driving position is aware of the aspect displayed while looking at the route ahead. Where there is doubt as to whether this is achievable, consideration shall be given to the use of additional control measures to reduce the likelihood or consequence of a SPAD. Such measures include, but are not limited to:

a) use of RA indicators as part of the train dispatch process

b) a train protection system to stop trains short of any area of conflict (as set out in GI/RT7006)

c) a suitably positioned co-acting signal.





C7 Miscellaneous technical requirements

C7.1 Colour of structures and fittings The colours usually applied to signal structures and fittings are set out in GK/RT0031. It is permissible to paint signal structures in a distinctive colour to aid drivers in locating a signal, and the line to which it applies, in a complex area. Permitted arrangements are:

a) black for the horizontal part of a gantry or cantilever, where this will distinguish it from other structures that are coloured grey (for example, OLE)

b) white and black hoops for a post.

Overuse of such a measure can render it ineffective.

C7.2 Countdown markers It is permissible to provide countdown markers, as set out in GI/RT7033, on the approach to signals where this is felt to be beneficial. Such markers shall be provided as a sequence of three signs, positioned nominally 100 m apart with the last one nominally 100 m before the signal. Other arrangements are permissible where it is considered that this will be of greater benefit to the driver.

The use of countdown markers shall usually be determined as part of the risk assessment process required by GI/RT7006. Overuse of countdown markers can render them ineffective.

C7.3 Signal reminder signs It is permissible to provide a signal reminder sign, as set out in GI/RT7033, on the approach to signals where there is a significant risk of a driver forgetting that he is approaching a signal at danger (for example, due to distractions after passing the previous signal at caution, such as a station stop). The position of such signs shall be selected on a site-specific basis such that the driver, having been reminded, is able to take action to stop at the signal.

The use of signal reminder signs shall usually be determined as part of the risk assessment process required by GI/RT7006.

Overuse of signal reminder signs can render them ineffective.

C7.4 Sighting boards, hoods and blinds It is permissible for sighting boards, extended hoods or vertical blinds to be used where it will improve the readability of signals under some or all ambient lighting conditions. The effect shall be assessed to avoid any reduction in readability from any driving position of the driver of a train approaching the signal.

Consideration shall be given to the need to ensure that such measures do not degrade the readability of other signals in the area.

Consideration shall be given to masking a source of interference where this is more readily achieved.

C7.5 Line identifiers C7.5.1 Form and use of line identifiers The use of line identifiers, as set out in GI/RT7033, is permitted on parallel lines where this will reduce the risk of confusion as to which signal applies to which line. Where line identifiers are used they shall be applied to all parallel lines, numbered or lettered in a fashion that is logical to drivers, and positioned in a





consistent manner. They shall be positioned so as to be visible to drivers as follows (one, or more than one, of the arrangements can be applied):

a) above the signals

b) on the rear of gantries carrying signals for opposite direction movements, or on other structures

c) between the running rails, in the area known as the ‘four foot’

d) on posts.

The use of line identifiers shall usually be determined as part of the risk assessment process set out in GI/RT7006.

C7.5.2 Application of line identifiers when alphanumeric route indicators are also in use Where alphanumeric route indicators are also in use, the characters for the line identifiers shall be the same as those displayed by the route indicators (that is, the route indicators shall indicate the line identifier character for the line on which the next signal is to be found).

C7.6 Arrow signs The use of an arrow sign fitted close to the signal head and pointing to the left or right to indicate to which track the signal applies, is permitted. Its use shall be limited to signals where a risk of confusion about which track it applies to has been identified and no other measures to reduce the risk are practicable.

C7.7 SPAD indicators The SPAD indicator shall be aligned and positioned so as to:

a) maximise the likelihood of an unauthorised movement being brought to a stand before reaching any point of conflict

b) bring authorised movements to a stand, where indicators are provided at more than one conflicting signal, in the event of a SPAD being detected at another signal.

The use of a co-acting indicator is permitted if conflicts arise in meeting these requirements.

The requirements of clauses B5.2, B5.3, B5.4 and C1.3 shall not apply to SPAD indicators.

C7.8 Point indicators and crossing indicators Visibility requirements shall be as set out in clause C1.3 so far as they are applicable.

The lateral position shall be as set out in clause C2.3.

C7.9 Anti-vandalism measures The readability of a signal shall not be affected by any anti-vandalism measures applied to the signal.

C7.10 Use of new designs of signs GI/RT7033 sets out requirements associated with proposals to introduce new designs for signs.





C7.11 Positioning signalling equipment not identified in GK/RT0031 Where signalling equipment is to be provided that has not been identified in GK/RT0031, it shall be:

a) positioned in accordance with clause B5.1

b) approved for the intended use by the infrastructure controller

c) positioned in accordance with any requirements specified by the infrastructure controller.





References Railway Group Standards and other Railway Group Documents

GA/RT6001 Railway Group Standards Change Procedures

GA/RT6004 Temporary Non-Compliance with Railway Group Standards

GA/RT6006 Derogations from Railway Group Standards

GC/RT5203 Infrastructure Requirements for Personal Safety in Respect of Clearances and Access

GC/RT5212 Requirements for Defining and Maintaining Clearances

GE/RT8025 Electrical Protective Provisions for Electrified Lines

GE/RT8034 Maintenance of Signal Visibility

GE/RT8035 Automatic Warning System (AWS)

GE/RT8048 Positioning and Labelling of Lineside Telephones

GE/RT8060 Technical Requirements for Train Dispatch

GE/RT8080 Technical Requirements for Dispatch of Trains from Platforms

GI/RT7001 Management of Safety Related Records of Elements of Infrastructure

GI/RT7006 Prevention and Mitigation of Overruns – Risk Assessment

GI/RT7033 Lineside Operational Safety Signs

GK/RT0002 Glossary of Signalling Terms

GK/RT0007 Alterations to Permissible Speeds

GK/RT0031 Lineside Signals and Indicators

GK/RT0032 Provision of Lineside Signals

GK/RT0034 Lineside Signal Spacing

GK/RT0038 Signing of Permissible Speeds and Speed Restrictions

GK/RT0044 Controls for Signalling a Train onto an occupied Line

GK/RT0060 Interlocking Principles

GK/RT0207 Signalling Design

GK/RT0209 Testing and Commissoning of Signalling and Operational Telecommuncations Systems

GM/RT2161 Requirements for Driving Cabs of Railway Vehicles

GO/RT3251 Train Driving

GO/RT3252 Signals Passed at Danger (SPADs)

GO/RT3255 Train Working – Competence and Fitness

GO/RT3475 Operational Requirements for the Dispatching of Trains from Platforms (proposed issue date February 2004)

The Catalogue of Railway Group Standards and the Railway Group Standards CD-ROM give the current issue number and status of documents published by RSSB.

Other References British Meteorological Office Observer’s Handbook
