Steve McKee - Pacific National - Module 6: Condition monitoring


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Steve McKee delivered the presentation at 2014 RISSB Wheel Rail Interface Forum.

The RISSB Wheel Rail Interface Forum reviewed the fundamentals of what happens between wheel and rail before focusing on the practicalities of monitoring, interventions, maintenance, management and the critical importance of the interdisciplinary cooperation.

For more information about the event, please visit:

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Steve McKee - Pacific National - Module 6: Condition monitoring

  1. 1. Wheel Rail Interface Forum Condition Monitoring Steve McKee, Pacific National: Condition Monitoring Analyst 21st May 2014 Brisbane, QLD
  2. 2. 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.
  4. 4. 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
  5. 5. 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
  6. 6. 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
  7. 7. 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
  8. 8. 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
  9. 9. 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.
  10. 10. 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.
  11. 11. 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
  12. 12. Wheel Impact Relationships with Rollingstock and Infrastructure Rail Breaks + 500 450 350 100 225 250 DynamicWheelImpactkN 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
  13. 13. 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
  14. 14. 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
  15. 15. 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
  16. 16. Datum references A.1 / A.8 A.2 A.3 A.4 A.5
  17. 17. 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
  18. 18. Key Wheel Profile Analysis
  19. 19. 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
  20. 20. 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
  21. 21. 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
  22. 22. 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
  23. 23. 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
  24. 24. Strain Gauge Array in a Reverse Curve situation
  25. 25. 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
  26. 26. 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 07/10/2012 19:52 13/10/2012 13:58 21/10/2012 07:50 01/11/2012 21:28 22/11/2012 21:11 04/12/2012 15:02 04/02/2013 14:21 27/02/2013 15:55 23/03/2013 13:14 TrackingError(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
  27. 27. 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
  28. 28. Tracking and Noise Relationships Tracking position Noise Data
  29. 29. 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
  30. 30. 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.
  31. 31. 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.
  32. 32. 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
  33. 33. 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
  34. 34. 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
  35. 35. 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
  36. 36. 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.
  37. 37. 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
  38. 38. 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
  39. 39. Track Geometry output
  40. 40. Track Geometry output
  41. 41. Rail Profile Capture
  42. 42. 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 POINTGage 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
  43. 43. Cant Deficiency Measuring Systems Instrumented bogies running in service to measure cant in curves at differing speeds
  44. 44. 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
  45. 45. Typical Defect Output 10’ Mid-Chord Offset Car Body Vertical 10’ MCO - Left Axle Box 10’ MCO - Right Axle Box
  46. 46. VTI - Track Conditions Chart for Field Staff
  47. 47. VTI - Track Conditions Chart for Field Staff
  48. 48. Combination Fault Outputs Axle Exception Car body Mid Chord Offset Exception
  49. 49. 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.
  50. 50. 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
  51. 51. Inter-Relationships Rollingstock and Track Measurements Ref: Keith Bladon
  52. 52. 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.
  53. 53. 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
  54. 54. 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