Wheel-Rail Interface Management
in
Heavy Haul
D R Welsby
Senior Research Fellow
Wheel-Rail Interaction & Track Design
Inst...
Content
• Overview of Operating Conditions
• Issues & Objectives
• Influencing Parameters
• Interface Management
• Interfa...
Overview of Heavy Haul Operating Conditions
• Definition of Heavy Haul (IHHA):
• Regularly operates trains ≥ 5000t gross m...
Overview of Heavy Haul Operating Conditions
• Track:
• Usually minimum head hardened rail, 60 or 68kg/m section
• CWR – li...
Issues & Objectives
• Issues of concern:
• High wheel and rail wear
• Rolling Contact Fatigue (RCF) preventing UT (shieldi...
Issues & Objectives
• Objectives:
• Reduce risk of rail break and derailment
• Limit RCF development, growth and associate...
Influencing Parameters (RCF & Wear)
• Contact stress
• Traction/adhesion & creepage
• Rail and wheel material
properties &...
Influencing Parameters
• Contact stress:
• Simplified elliptical contact (Hertz)
• Highly dependent on contact
geometry
• ...
• Contact stress:
• Non-hertzian contact more realistic
• Dynamic modeling software, such as Universal Mechanism, used to
...
2 point contact (new)
Towards Conformal (worn)
Contact Evolution
Influencing Parameters
• Traction/adhesion & creepage:
• At a macro level adhesion is defined as the “ratio
of tangential ...
Influencing Parameters
• Traction/adhesion & creepage (cont..):
• Three creep forces and creepages are generated:
• Longit...
Influencing Parameters
• Traction/adhesion & creepage (cont..):
• Impact:
• Wear ≈ energy dissipation ≈ Ʃ [creep forcei x ...
Influencing Parameters
• Material properties & characteristics:
• Quality of manufacture:
• Avoid; inclusions, segregation...
Influencing Parameters
• Material properties & characteristics (cont..):
• Work hardening:
• Desirable characteristic wher...
Influencing Parameters
• Material properties & characteristics (cont..):
• Wear resistance:
• Suitable hardness to reduce ...
Influencing Parameters
• Combined effects:
• Best represented in terms of „Shakedown‟ theory (concept of first yield
and r...
Influencing Parameters
• Combined effects (cont..):
• Shakedown diagram used to help predict
the onset of RCF
• Shakedown ...
Interface Management
Effective
Management
Traction/
Adhesion
Contact
Stresses
Material
Characteristics
Maintenance
Practic...
Interface Management
• Contact stress:
• Implement and maintain appropriate wheel and rail profiles
• Work within wheel an...
Interface Management
• Traction/adhesion and creepage:
• Consider friction management (lubrication, friction modifiers)
• ...
Interface Management
• Rail material:
• Generally minimum head hardened rail grade for heavy haul
• Current move towards p...
Interface Management
• Rail material (simplistic e.g.):
• 30t axle load moderate curve
• SC rail – ratchetting, surface an...
Interface Management
• Rail material:
• Estimated rail life
Interface Management
• Rail material:
• However, harder rails are sensitive to:
• High adhesion/creepage effects
• Rail pr...
Interface Maintenance
• Rail grinding:
• Clean-up fatigued material
• Control crack growth
• Install and maintain correct ...
Thank You
Federal Railroad Association (2011), Rolling contact fatigue a comprehensive review, Report No. DOT/FRA/ORD-11/24, Novembe...
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Darrien Welsby - Institute of Railway Technology - Monash University - Wheel rail interface management in heavy haul

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Darrien Welsby 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: http://www.informa.com.au/wheelrailinterface14

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Darrien Welsby - Institute of Railway Technology - Monash University - Wheel rail interface management in heavy haul

  1. 1. Wheel-Rail Interface Management in Heavy Haul D R Welsby Senior Research Fellow Wheel-Rail Interaction & Track Design Institute of Railway Technology 20 May 2014 Brisbane, QLD.
  2. 2. Content • Overview of Operating Conditions • Issues & Objectives • Influencing Parameters • Interface Management • Interface Maintenance
  3. 3. Overview of Heavy Haul Operating Conditions • Definition of Heavy Haul (IHHA): • Regularly operates trains ≥ 5000t gross mass • Annual haulage of 20MGt over at least 150km • Regularly carries axle loads ≥ 25t • Australian Heavy Haul (examples): • Pilbara Iron Ore: 36-40tal, 30-45,000Gt trains  • Queensland Coal: 26tal, 7-10,000Gt trains  • NSW Coal: 25-30tal, ~10,000Gt trains  Must Satisfy at Least Two
  4. 4. Overview of Heavy Haul Operating Conditions • Track: • Usually minimum head hardened rail, 60 or 68kg/m section • CWR – limited use of aluminothermic welding over mob. flashbutt • Heavy concrete sleepers • Varying lubrication strategies (wayside – solid stick – none) • Rollingstock: • High adhesion AC locomotives • Maximum speed ≤80km/h • Wagon bogies usually 3-piece design (simple/cost effective) • Includes passive, steering and non-steering types
  5. 5. Issues & Objectives • Issues of concern: • High wheel and rail wear • Rolling Contact Fatigue (RCF) preventing UT (shielding) • RCF initiated defects (e.g. transverse defect) • Vehicle hunting & instability • Broken rails and derailment (Wear) (Shielding) (Transverse Defect)
  6. 6. Issues & Objectives • Objectives: • Reduce risk of rail break and derailment • Limit RCF development, growth and associated defects • Maintain surface condition suitable for effective UT inspection • Limit wear and maximise rail and wheel life • Maintain rails and wheels in the safest & most economical manner • Maintain vehicle stability No. 1 objective is to prevent this !! (Smith, 2009)
  7. 7. Influencing Parameters (RCF & Wear) • Contact stress • Traction/adhesion & creepage • Rail and wheel material properties & behaviour • Maintenance practices (Magel, 2011)
  8. 8. Influencing Parameters • Contact stress: • Simplified elliptical contact (Hertz) • Highly dependent on contact geometry • Not directly proportional to axle load • In reality non-hertzian (Rovira et. al., 2012) (Innotrack, 2009)
  9. 9. • Contact stress: • Non-hertzian contact more realistic • Dynamic modeling software, such as Universal Mechanism, used to analyse contact conditions Contact patch Normal pressure distribution -11 -6 -1 4 9 -5 0 5 10 0 500 1000 1500 p(x,y), MPa y, mm x, mm
  10. 10. 2 point contact (new) Towards Conformal (worn) Contact Evolution
  11. 11. Influencing Parameters • Traction/adhesion & creepage: • At a macro level adhesion is defined as the “ratio of tangential to normal traction” transmitted at the wheel-rail interface (Fletcher & Lewis, 2012) • At a micro level adhesion “depends on elastic deformation of the rail and wheel surfaces at their contact which produces partial slip [creepage] with distinct sticking and slipping regions” (Fletcher & Lewis, 2012) • Directly affected by the friction characteristics (interfacial layer) (Olofsson & Lewis, 2006)
  12. 12. Influencing Parameters • Traction/adhesion & creepage (cont..): • Three creep forces and creepages are generated: • Longitudinal: velocity difference, yaw • Lateral: lateral velocity, yaw, roll • Spin (moment): contact angle, yaw • Combined effect changes the stick/slip characteristics (Vollebregt, 2013)
  13. 13. Influencing Parameters • Traction/adhesion & creepage (cont..): • Impact: • Wear ≈ energy dissipation ≈ Ʃ [creep forcei x creepi] • RCF develops from high creep forces and resulting shearing action at the surface. RCF damage increases with increasing surface shear Position of Maximum Shear Stress (Pointner, 2008)(FRA, 2011)
  14. 14. Influencing Parameters • Material properties & characteristics: • Quality of manufacture: • Avoid; inclusions, segregation & impurities • Reduce; residual stresses in rolled section • Modern techniques generally produce good quality steel • Strength (yield / tensile): • Shear strength  resistance to RCF/deformation • Fatigue strength  fatigue life in bending • Ductility: • Ability to withstand the high plastic strains without fracture • Can be measured through tensile testing (reduction of area) – indicative, or through complex twin disk testing
  15. 15. Influencing Parameters • Material properties & characteristics (cont..): • Work hardening: • Desirable characteristic where the hardness of the surface material increases due to strain • Increases resistance to wear, deformation and development of RCF • Often ~10mm deep into the head in heavy haul railways • Toughness: • Resist high impact loads & inhibit fatigue crack initiation • Measured as the energy required to rupture per volume of material
  16. 16. Influencing Parameters • Material properties & characteristics (cont..): • Wear resistance: • Suitable hardness to reduce wear • Can be considered in conjunction with lubrication strategy • Weldability: • Suitable for flashbutt and aluminothermic welding processes • Aim to maintain a relatively uniform hardness across joint
  17. 17. Influencing Parameters • Combined effects: • Best represented in terms of „Shakedown‟ theory (concept of first yield and residual stress effects) a. Fully elastic = No deformation occurs b. Elastic shakedown = elastic limit is reached in the first few load cycles, but the steady state is entirely elastic (load carrying capacity increased) c. Plastic shakedown = steady state strain cycle consists of a closed cycle of plastic deformation d. Ratchetting: Incremental collapse (Johnson, 2000)
  18. 18. Influencing Parameters • Combined effects (cont..): • Shakedown diagram used to help predict the onset of RCF • Shakedown ratio P0/ky = Maximum contact pressure / Shear strength of the material • Traction coefficient = Adhesion (macro) • Lower bound not applicable to rail steels • ~0.3 adhesion transition point
  19. 19. Interface Management Effective Management Traction/ Adhesion Contact Stresses Material Characteristics Maintenance Practices
  20. 20. Interface Management • Contact stress: • Implement and maintain appropriate wheel and rail profiles • Work within wheel and rail wear limits • Implement and monitor appropriate profiling practices and quality Wear RCFOptimum ? “Magic Wear Rate” (Magel et. al., 2004)
  21. 21. Interface Management • Traction/adhesion and creepage: • Consider friction management (lubrication, friction modifiers) • Maintain good track geometry • Maintain appropriate wheel and rail profiles • Consider vehicle curving performance (design / maintenance) • Consider environmental conditions (high/low rainfall, leaf debris etc.) www.dipostel.fr www.lbfoster.com > Steering in curves < RCF & wear < Stability in tgt < Steering in curves > RCF & wear > Stability in tgt
  22. 22. Interface Management • Rail material: • Generally minimum head hardened rail grade for heavy haul • Current move towards premium (hypereutectoid) grades in the Pilbara – why?:  Higher load carrying capacity  Harder material = less wear and longer service life  Shallower crack propagation  Lower maintenance requirement
  23. 23. Interface Management • Rail material (simplistic e.g.): • 30t axle load moderate curve • SC rail – ratchetting, surface and subsurface damage • Std. HH – Elastic shakedown to stable condition • Prem. HH – Fully elastic (no deformation/damage)
  24. 24. Interface Management • Rail material: • Estimated rail life
  25. 25. Interface Management • Rail material: • However, harder rails are sensitive to: • High adhesion/creepage effects • Rail profile anomalies (not meeting target profile) • Metal removal during grinding • Ground surface finish • Due to the low ductility of premium rail material its ability to accommodate profile anomalies by plastic deformation is less than that of HH rail • Care is therefore needed to maintain high grinding quality and sufficient metal removal to control damage
  26. 26. Interface Maintenance • Rail grinding: • Clean-up fatigued material • Control crack growth • Install and maintain correct profile • Maintain appropriate surface finish • Ultrasonic testing: • Frequent inspection to improve defect detection and reduce risk of rail break and possible derailment • Wheel profiling: • Remove hollow wheels responsible for rail damage • Prevent instability and track/vehicle damage
  27. 27. Thank You
  28. 28. Federal Railroad Association (2011), Rolling contact fatigue a comprehensive review, Report No. DOT/FRA/ORD-11/24, November. Innotrack (2009), D4.3.4 – Calculation of contact stresses, Integrated Project No. TIP5-CT-2006-031415, International Union of Railways (UIC), Paris;15 February. International Heavy Haul Association (2013), accessed 15 May 2013, http://www.ihha.net/. Johnson, K.L. (2000), „Plastic deformation in rolling contact‟, in Jacobson, B and Kalker, J (ed.), Rolling contact phenomena, Springer-Verlag Wien/New York, Udine, pp. 164-201. Jönsson, P. (2007), Dynamic performance of freight wagons and their influence on cost for track deterioration, Presentation at Elmia Nordic Rail Conference, Jönköping, Sweden; Oct. 9-11. Magel, E., Sroba, P., Sawley, K. & Kalousek, J. (2004), Control of rolling contact fatigue of rails, Proc. 2004 Annual AREMA Conference, Nashville, TN; Sept. 19-22. Magel, E. (2011), Rolling contact fatigue: A comprehensive review, Federal Railroad Administration, Washington DC. Olofsson, U & Lewis, R. (2006), Tribology of the wheel-rail contact, in Iwnicki, S. (ed.), Handbook of railway vehicle dynamics, CRC Press; Boca Raton FL. Pointner, P. (2008), „Impact of wear and rolling contact fatigue on rails – A pragmatic approach‟, ZEVrail Glasers Annalen, vol. 132, pp 304-312. Rovira, A., Roda, A., Lewis, R. & Marshall, M.B. (2012), Application of fastsim within variable coefficient of friction using twin disc experimental measures, Wear 274-275, pp. 109-126. Smith, L. (2009), Derailed iron ore train, Australian Broadcasting Corporation, accessed 22 April 2013, http://www.abc.net.au/news/2009-01- 30/derailed-iron-ore-train/278956 Vollebregt, E. (2013), The frictional contact problem Part 1 the creep phenomenon, Notes on Introductory CONTACT Course, WRI2013, Chicago IL; 6-7 May. Welsby, D. R. & Zheng, D. (2008), „A fast algorithm for rail subsurface stress calculation due to wheel/rail contact load‟, Proc. Conference on Railway Engineering 2008, Railway Technical Society of Australasia, Perth, pp. 61-72. Welsby, D. R. (2009), Characteristics & performance of hypereutectoid rail steels, Presented at the Railway Technical Society of Australasia AGM, Melbourne, 19 August. References:
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