Wheel Rail Interface Forum

Condition Monitoring

Steve McKee,

Pacific National: Condition Monitoring Analyst

21st May 2014

Brisbane, QLD

What is condition

Monitoring?

Is monitoring the health of assets through various means of data collection to determine the condition and degradation rates over time or kilometre, normally using specialist equipment.

example: Vibration analysis, critical parameter measurements, visual inspections, tribology and thermography.

CM information can be manually collected or automatically collected through wayside equipment, by manual methods, on-board measurements or track monitoring cars.

The information is collated such that real time data can be used by track or rollingstock maintenance personnel to take the appropriate

action.

Condition monitoring is a very useful tool in

WHEEL RAIL INTERFACE MANAGEMENT

WRIM REQUIREMENTS

DEFINE THE SYSTEM

DOCUMENT THE PROCESSES

MEASURE THE PARAMETERS

AUDIT THE COMPLIANCE

Why Manage Wheel Rail Interface

• A large portion of railway assets are the capital value of track and

vehicles.

• Unforeseen downtime on these items are commercially damaging

to the both the track owner and train operator, often resulting in

penalties from customers or loss of revenue.

• Management Information Systems must support strategies to

obtain optimal performance out of these assets and extend asset

life

• There is an overload of available data from the collation of CM data.

The best way to manage this data is to apply a multidisciplinary

approach, involving both the track and rollingstock stakeholders

How is CM data currently

being used in WRIM?

• Maintenance planning activities

• Development of new designs and components

• Review and development of materials for components

• Improved maintenance practices and asset modifications

• Auditing of contractors and maintenance practices

• Setting of intervention levels and alarms

• Strategic planning

• Continuous improvement programs

• Design for reliability and maintainability

• Hazard Studies and risk assessments

• Failure mode and effects analysis

Measure

Analyse

Adjust

Rollingstock: Wheel profiles;

Wheel conditions i.e. flats, out-of-round;

Axle alignment;

Vehicle component integrity: – Wheel structural flaws; – Axle structural flaws & bearing condition; – Bogie/Truck structural flaws & condition.

Rollingstock

What needs to be Measured?

Track Track geometry;

Rail profiles;

Rail friction;

Vertical & lateral track strength;

Track component integrity: Rail flaws & temperature; Sleeper & fastener condition ; Ballast & sub-grade condition.

Track

Vehicle/Track Interaction: Vertical and lateral wheel

loads;

Bogie & car-body accelerations;

Wheel/Rail contact stress;

Wheel climb tendency.

Poor wear characteristics

Rollingstock Parameters

• Wheel tread condition (reasons for

change out – why made codes)

• Wheel profiles and wear rates

• Bogie tracking performance and

measurements

• Ride performance

• Bearing health condition

• Noise emissions

• Coupler / knuckle components,

• Brake blocks profiles, wear rates

and temperatures

• Other component wear

Types of CM available: Preventative • Capturing of information over time that can be trended and used for

maintenance planning

• Provides the opportunity for maintenance to be planned at a chosen

location

• Allows maintainers and engineers to do root cause analysis and determine

causal factors

Reactive

• Equipment located in track that identifies rollingstock that has reached an

unsafe limit and cannot continue in operation until it has been fixed.

• This may include no-go gauges for measurement when components have

reached limits where they cannot run and require immediate attention

• Use of equipment causes large delays, and can sometimes be false alarms

Wheel Impact Monitoring

Wheel Impact Load Detectors analyse the

passage of wheelsets and measure the

impacts generated from tread defects.

The force is ranked and assigned via tag

readings to the wagon and individual

wheelsets. These can be either:

• Strain Gauges

• Acoustic

• Accelerometers

• Hybrid – Strain gauges and accelerometers

• Laser or vision based – looking at tread

surface.

Wheel Impact Detector Many rail networks have installed wheel tread impact detectors to identify

tread defects. Where these systems are installed, the impact force should be

used to assess the removal of wheels as an alternative/complement to

measurement of the physical dimensions of the tread defect.

When inspecting the

defect there may be

components of out of

round, which can

increase the impact force

to a much higher defect

classification than the

physical size, this should

always be taken into

consideration when

classing a tread defect.

Typical Wheel Impact Plot Typical developing

defect

• Deep metal damage

• Machining at this late

stage will not remedy

fault and may hasten

other vehicle damage;

• will also cause much

shorter lifespan for the

wheels on this bogie

Wheel Impact

Relationships with

Rollingstock and

Infrastructure

Rail Breaks

+

500

450

350

100

225

250

Dyn

am

ic W

he

el Im

pa

ct kN

Wheel Cracks

Bearing degradation:

Component failure

Bogie and Wagon

degradation

Time In Service / km travelled

Static Load

Track Damage

(Ballast & sleeper

degradation)

Grease

breakdown

Bearing

Fatigue

Prevention of Wheel Defects

The identification of wheel defect patterns has assisted in the

reduction of wheel defects in service.

Multiple skids: - Undertake Brake System Tests

/ repeat skids - Grade control valves

- triple valve failures

- slack adjuster set-up

Spalling patterns: Check for bogie steering and

tracking problems

Check brake application forces and brake adjustments

Wheel Profile Monitoring Wheel profile measurement can either be done in track automatically or through manual methods such as through wheel profile measuring, or through using hand gauges to take critical measurements

In Shop: - Manually Gauge checking

- Through profile measuring

- Manual measurement of

critical dimensions

In Operation

- Video Imaging

- Laser capture

In-track wheel profiling monitoring systems capture the passing wheel profiles to detect those wheelsets that do not meet specification.

The profile it then trended for profile parameters to predict the wheelset optimum removal time and identify poorly wearing wheelsets.

In track Wheel Profile Monitors

Datum references

A.1 / A.8

A.2

A.3

A.4

A.5

Key Wheel Profile Analysis

Being able to obtain the wheel tread profile enables the user to

- Indentify and rectify accelerated wear rates and take remedial

measures

- Compare wear profiles against routes travelled

- Compare mating wheel and rail profiles.

- Identify abnormal wear profiles

- Identify asymmetrical wear and causes

- Predict life in service

- Estimate wheel use in service

- Identify wheelsets that have reached

condemning limits

Key Wheel Profile Analysis

Brake Shoe Module

Unlike the wheel profile units only one measure taken:

Thickness of brake shoe at top and lower section.

This one measurement can then be trended for:

• rapid wear flags for brake system attention

• when reaching condemn

• or abnormal wear

Sliding Wheel Detectors

The development of sliding wheel detectors has assisted in the prevention of wheel defects in service.

Placed at the exit of terminals / major junctions for low speed operations. The system detects wheel turning at different speeds to others passing the system

MRX Technologies - Australia

Cracked Wheel Detection

• In track or via hand held ultrasonic

probes:

• Detects internal or surface wheel

cracks via ultrasound technology

• The system will detect shattered

rim cracks and tread surface

thermal cracks.

TTCI – AAR Strategic Research Initiatives Projects – Advanced Rail Management Conference

Wayside Noise

Monitoring Stations

Using similar technology to acoustic bearing detectors the system

reviews passing trains to determine the individual wheelset creating the

noise emissions.

Noise Monitoring Systems

Bogie Performance and

Tracking Monitors Bogie tracking angle of attack or

hunting detection may be obtained

via:

- Strain gauges fitted in curves or

straights line

- Laser / optical derivation

- On-board monitoring

- Wheel profile derived

Strain Gauge Array in a

Reverse Curve situation

Bogie Geometry Definitions

Base measurements:

Angle of Attack – the angle to

the rail itself

Tracking Error: How the mid

section of the axle is offset from

the rail centre

Derived Measurements

Rotation – the bogie is rotated

about it’s centre: Warped

Shift: The whole bogie is

shifted off the centreline

IAM: the bogies are angled

opposing

The following graph illustrates 10 bogies from a 5 pack, showing trended tracking error,

before and after wheelset & bogie removal

Bogie Geometry Bad Actors

-35

-30

-25

-20

-15

-10

-5

0

5

10

07/10/201219:52

13/10/201213:58

21/10/201207:50

01/11/201221:28

22/11/201221:11

04/12/201215:02

04/02/201314:21

27/02/201315:55

23/03/201313:14

Trac

kin

g Er

ror

(mm

)

A

B

C

D

E

F

G

H

I

J

Bogie

changeout

Wheelset

change-out Note how TE

increased and this

would increase

flange wear

The following graph illustrates 10 bogies from a 5 pack, showing

trended tracking error, before and after wheelset & bogie removal

The following graph illustrates 10 bogies from a 5 pack, showing trended tracking error,

before and after wheelset & bogie removal

Straight vs. Curve

Measurements There are some bogie

geometry systems

installed on curves but

experience in different

countries and different

conditions have proven

that the geometry outputs

are highly variable due to:

- Speed

- Braking

- And particularly friction at

the wheel rail interface.

STRAIGHT

TRACK

CURVE

TRACK

Tracking and Noise Relationships

Tracking position

Noise Data

Train 2002-06-14-03-45 @ 80 km/h

-20

-10

0

10

20

177 181 185 189 193 197 201 205 209 213 217 221 225

axle #

tracking

position,

mm

tp1 tp2 tp3

Hunting Detection System

Hot Bearing/

Hot Wheel Detectors An infrared thermal system

that identifies the wheel disc

and bearing temperature.

Benefits to wheel interface:

- Ability to identify wheels that

have abnormal brake

application or stuck on

brakes, which can create

thermals and skidded wheels.

Locating New Wayside Equipment

• Co-locate as many systems as economically beneficial at one location to be able to analyse the inter-relationships between defect and wagon conditions under the same operating parameters.

Optimise location of the mix of devices for best fleet coverage

• Some equipment is sensitive to the environment and physical attributes about the track. Consider:

– Noise based systems, you may get noise reflection from nearby structures

– Remoteness – also increases expense in maintaining and installing equipment and access to utilities – such as power and communications.

• Density and type of traffic running through the site – has the equipment got the capabilities with dealing with differing rollingstock and operating conditions?

• Takes measurements that are immune to as many variables as possible. (eg: speed, load, rail‐top condition and weather)

• The location is capable of producing results that are repeatable at the inspection point and reproducible at other locations.

Track Maintenance requirements

for Wayside Equipment

Maintaining track infrastructure either side and through out the location of the

wayside equipment is critical in obtaining accurate and repeatable results.

Track Condition Wayside Equipment Result

Top of rail alignment / mud hole Increase wheel impact results

Create false bearing noise

Inaccurate weigh cell reads

Corrugations False impact results

Create noises representative of bearing

faults

Loose Sleeper Fastenings Optical geometry inaccuracy

Lateral alignment False AOA and hunting conditions

Additional Noise sources

Lubrication Changes to steering in sites, or too much

and get on to optical sensors

Speed restrictions in section Making passage through the site too slow

to obtain a read or prevent condition

On-Board Monitoring Systems • Use of onboard sensors located at strategic positions to obtain

parameters on the asset position, reporting back to a central processor

• Alarms and conditions are communicated to the locomotive or through

mobile networks.

• Current data collection:

• Wheel impact, derailed vehicle, bearing temperature and vibration,

handbrake left on, track vibration, loaded/empty, noise monitoring, wagon

instability, brake pipe pressure, etc.

• Many more in future development

Infrastructure Condition

Monitoring Data that is currently collected:

• Track Inspections – Visual / Planned and Automated

• Track Geometry Measurement

- Specialised Track Geometry Cars

– Unattended Geometry Measuring Fitted to Service Wagons

• Ride Performance

• Rail Profiles

• Sub-grade Conditions

• Point and Crossing Condition

• Lubrication

• Sleeper and Fastening Condition

• Major structure condition

Track Inspection Systems

• Current methods for track inspection include either visual inspection by track inspectors or automated inspection from dedicated inspection cars.

• The use of autonomous inspection technologies will result in earlier detection of track defects and changes in maintenance practices from reactive to preventative

Track Recording Cars

The following are typical parameters measured:

Alignment - Alignment is the projection of the track geometry of each

rail or the track center line onto the horizontal plane

Cross-level - The variation in cant of the track over the length of a

predetermined "chord" length

Curvature - The amount by which the rail deviates from being

straight or tangent. The geometry car checks the actual curvature (in

Degree of curvature) of a curve versus its design curvature.

Rail gauge - The distance between the rails. Over time, rail may

become too wide or too narrow.

Rail profile - Looks for rail wear and deviations from standard profile.

Track Recording Cars

Frequent Data Provides:

Ability to trend geometry data giving the opportunity for

predicative asset management

Defect types, growth rates, and sizes pertaining to detection

and safety criticality

Ability to monitor actual maintenance needs

Ability to monitor the quality of specific maintenance crews

Ability to monitor the durability of specific maintenance

activities

Ride Performance Measurements

Ride Performance-based track geometry (RPBTG) inspection

• Identify track segments that will likely produce undesirable vehicle

responses

• For the segments identified, recommend what track geometry

maintenance actions need to be taken

RPBTG is intended to help prioritise track geometry maintenance to

• Reduce track geometry caused derailment incidents

• Reduce vehicle/track dynamics, leading to reduced track and

vehicle degradation (the stress state)

Benefits of Track recording Cars

Track Geometry output

Track Geometry output

Rail Profile Capture

Rail Profile Capture

• General Features

– Captures rail profiles in transit

– Automatic rail type recognition

– Accepts pre-defined rail type files (by rail/track location)

– Result: Real time exception processing, off the car reports, less time/money reprocessing data to call rail types.

Rail Cant

GAGE

POINT Gage Face

Angle

Gage/Field

Side Lip

Gage/Field

Face Wear

Vertical Head Wear

REFERENCE

PROFILE

MEASURED

PROFILE

Total Head

Loss

Available/Not pictured:

-Rail Head Width

-Rail Height

Cant Deficiency Measuring Systems

Instrumented bogies running in service to measure cant in curves at differing speeds

Vehicle / Track Interaction Systems

– Vehicle Track Interaction Monitors (V/TI) are autonomous track inspection systems that utilise acceleration measurements mounted on a vehicle (typically a locomotive) with real-time reporting.

– Standard V/TI product, which includes two axle sensors to measure wheel/rail impacts, one bogie sensor to measure lateral bogie movement, and one car-body sensor to measure lateral & vertical car-body movements.

Antenna

Main CPU

Carbody Sensor

Truck Sensor

Axle Sensors

Typical Defect Output

10’ Mid-Chord Offset Car Body Vertical

10’ MCO - Left Axle Box

10’ MCO - Right Axle Box

VTI - Track Conditions Chart for Field Staff

VTI - Track Conditions Chart for Field Staff

Combination Fault Outputs

Axle Exception

Car body

Mid Chord Offset

Exception

Combination Track Faults • The current theory to why combination clusters correspond to

derailment risk is the following:

• These low level exceptions begin to repeat at a single location when

wheel/rail impacting, elevated rail stress from increased dynamic

wheel load, and defection from fouled ballast are present.

• This activity begins to accumulate such that it begins to create an

environment for fatigue and longer term deterioration, causing a

catastrophic failure such as broken rail, broken joint, bolt hole breaks,

sub grade failure, etc…

• Or in recent derailments undesirable vehicle behavior causing wheel

climb.

Track Condition Vs.

Ride Performance • Alarm and restriction levels need to be

developed for differing wagon types ,lengths,

and operating environments.

• New rollingstock have:

• Lower decks

• Longer, lighter frames and faster

• Increased axle loads

• Double stacking

• High adhesion locomotives

• New wagons exhibit very different behaviour to

older, stiffer, heavier wagons

• Need geometry constraints need development

to cope with variations in operations

Inter-Relationships Rollingstock

and Track Measurements

Ref: Keith Bladon

Development of Alarm Limits

• Alarm levels need to be set for the wheel / rail interface

not just rollingstock and track separately

• In recent years the development of alarm limits and

maintenance standards have separated in many areas in the

rail industry.

• These changes do not consider the effects on infrastructure /

rollingstock

• This has resulted in abnormal wear conditions, incidents and

in some cases derailments

• A multi-disciplinary approach to the development of alarm

limits is required for the Australian Rail Industry.

Benefits in the Multidisciplinary

use of Condition Monitoring Data Obtaining data from multiple different systems enables the user to:

• Measure rail and wheel conditions to determine maintenance needs

• Develop rail and wheel wear projection rates and limits and life projection

• Develop target rail and wheel profiles

• Perform economic/strength evaluation of different premium rail and wheel

materials

• Implement lubrication practices where necessary

• Implement a condition based maintenance plan for wheels and rail

Improve

& Enhance

Asset

Performance

Reduce

Downtime

Contain

&

Reduce

Maintenance

Costs

WRIM CM Summary

• Define what information you require to improve your system

• Identify equipment, systems or parameters to be measured and the

means of data collection

• Identify processes, standards and resources available

• Identify constraints on gathering information either electronically

or manually.

• Collate Information into a database that can interface the

parameters and data formats

• Identify information that cannot be obtained through applied data

collection processes, and determine other means of gathering data

for condition monitoring processes

• Use the information for effective wheel /rail management