BACK TO THE FUTURE Biennial Symposium: 10 11 October 2012 Wheel / Rail Interaction Georg Hettasch
Presentation overview Why railways work The goal The wheel / rail interaction universe Acknowledgements: Dr. Robert Fröhling Danie Fourie Ulrich Spangenberg
Why railways work: high speed passengers
Why railways work: heavy haul freight
Why railways work: wheelset steering
Why railways work: wheelset steering Small Wheel / Rail contact angle Small rolling radius on inner wheel Lateral wheelset displacement Large rolling radius on outer wheel Large Wheel / Rail contact angle Rail reaction force direction on inner wheel Transnet no. 23 wheel profile on Coal Line High and Low leg rail profiles Rail reaction force direction on outer wheel
Why railways work: interface stresses 3 s 3 s 2 s 1 s 1 s 2 1 2 s 3 iform pressure m all directions
Contact stress [MPa] Why railways work: interface stresses 2500 40 30 2000 20 1500 10 0 1000-10 500-20 -30 0-40 -40-35 -30-25 -20-15 -10-5 0 5 10 15 20 25 30 35 40 Contact location relative to rail [mm] Pair 167 Extracted maximums Reference
The goal: limiting wear Coal Line Jumbo wheel (no. 23 profile) 18E Locomotive wheel (original no. 22 profile)
The goal: Rolling Contact Fatigue management Gauge side false flange contact Field side false flange contact
The goal: vehicle / track interaction force management
The goal: vehicle / track interaction force management
The goal: derailment mitigation
The goal: derailment mitigation
The goal: derailment mitigation
The goal: derailment mitigation Wheel 4 Wheel 3 Direction of travel Wheel 4 Wheel 3 Distance reduced by 900 mm Gauge assumed 1065 mm Back-to-back assumed 987 mm 620 mm 544 mm 340 mm 326 mm Left stock rails Left wing rails Movable V Right wing rails
The wheel / rail interaction universe Gauge Face Wear Corrugations Longitudinal Rail Wear Limits Rail Profile Track and Rail IM2000 Measurements Rail Profile Track Geometry Geismar Gauge Rail MiniProf Rail Profile Measurements Transverse Rail Profile Turnout Geometry Track Structure Load Transfer Track Cant Track Gauge Open Track Ballast Rail Fastenings Railway Track Fishplates Turnouts Rail Inclination Stiffness Rail Pads Manual Lubrication Application Solid Stick Lubrication Spray Lubrication Adhesion Friction Management Grease Pots Gauge Face Lubrication Derailments Top-of-rail Friction Trolley Based Rail Lubrication Management Locomotive Sanding Wheel Re -profiling Flange Tip -profiling Re Decision Making Wheel Diameter Tribology Profile Wheel Profile Wear Measurements Wheel Profile Maintenance Combo Exchange Wheel Re -profiling Portal Wheel Lathe Time Friction Management Friction Wheel Profile Maintenance Wheel Re -profiling Procedure Inertia Mechanics Railway Track Under Floor Wheel Lathe Wheel / Rail Forces Mass Time Lubrication Wheel Lift Wheel Climb Friction Specifications Procedures Bogies VI Rail (Adams) Curving Forces Vehicle Stability Suspension Design Track Loading Derailment Ratio (Y/Q) Out-of-round Wheels Ride Quality Index Medyna Wheel / Rail Wheel Wear Patterns Wheel Wear Trends Variables Force Limits Wheel Unloading Hollow Wear Flange Wear Vehicle Dynamics Wheel Wear Impact Forces Wheel Wear Limits Tread Wear Fundamental Normal Loads Creep Forces Wheel Wear Vehicle Hunting Wheel Wear Rates Force Lateral Loads Circumferential Wheel Profiles Displacement Wheel Squeal Displacement Rolling Noise Load Measuring Wheelset Skew Bogie Detector Fundamental Wheel / Rail Interaction Noise Gauge Spreading Force Mass Wheel / Rail Forces Flanging Vibrations Weigh In Motion Lateral Forces Fundamental Sciences Wheel Impact Monitor Track Shift Force Mechanics Sciences Inertia Derailments Point of Derailment Wheel Drop Wear Tribology Laser -based Wheelset Shadowgraph Wheelset Measuring Machine Measuring Machine Documentation Track and Rail Measurements Wheel Profile Measurements Tyre Thickness Gauge Field Gauge Wheel MiniProf Digital Wheel Gauges Wheel Profile Monitoring Systems (MRX, WPMS) Mechanical properties Mechanics Variables Force Displacement Geometry mechanics Mass Normal stress Inertia Fundamental Wheel Sciences / Rail Shear stress Time Mechanics Contact Interaction / Rail mechanics Creepage Lubrication Wheel / Rail Vehicle Friction Tribology Vehicle Creep Interaction Dynamics Dynamics Wear Fatigue Metallurgy Tribology Mechanical properties Mechanical properties Microstructure Sciences Variables Metallurgy Microstructure Chemical properties Rim Quenching Pealite Bainite Metallurgy Hypereutectoid Steel Microstructure Cementite Austinite Microstructure Martensite Head Hardened Rail Heat treatment Wheelset Handling Solid wheels Tyred Chrome Manganese F Type wheels Rail Wheelset AP Bearings Microstructure Metallurgy Components Documentation Manganese Crossing Rail Sections Reports Drawings 60 kg/m 57 kg/m Wheel / Rail Interaction Rail Handling 48 kg/m Management system (WRIM) User Manuals Force Geometry Contact Chemical properties Components D Type Wheelset Geometry Fracture Analysis Shelling Metal Flow Wheel Failure Spalling Wheel Tread Fatigue Rim Splitting Dipped Welds Contact Rail Head Wear Grinding Quality Index (GQI) Track Quality Index (TQI) Rail Grinding Metal Removal Rate Profile Quality Index (PQI) Machine Rail Grinding Grinding Facets Grinding Patterns Grinding Intervals Hand Rail Grinding Shear stress Rail Profile Deviation Class Magic Wear Rate Shear mechanics Corrective stress Grinding Preventative Grinding Normal stress Contact mechanics Vehicle Fatigue Dynamics Heat treatment Chemical properties Vehicle Dynamics Creepage Creep Normal stress Rail Fatigue Shakedown Diagram Transverse Contact Rolling Mechanics Contact Fatigue Wheel Profiles RS Geo Conformal Contact Equivalent Conicity Contact Mechanics Wheel / Rail Contact Patch Crack Angles Angle of Attack Wheel Creep Failure Rolling Radius Difference Single Point Contact Stresses Two Point Contact Lateral Creep Electric Traction Ratcheting Spin Creep Vehicle Current Return Heat Input Tread Brakes Rail Welding Dynamics Alumo-Thermic (Thermit ) Welding Pre-heating Rail Welding Creepage Fatigue Heat treatment Traffic Characteristics Wheel / Rail Interaction Noise Machine Rail Grinding Longitudinal Creep FlashbuttWelding Operational Practices Vehicle Loading Skew Loading Train Speed Locomotive Million Gross Tons Braking Effort Traffic Characteristics Tons per Axle Locomotive Train Length Over Loading Tractive Effort
Conclusion Railways work because: of the ability of profiled wheelsets to steer the wheel / rail interface can operate at very high material stresses We strive to: control Rolling Contact Fatigue and wear minimise Vehicle / Track interaction forces, and eradicate derailments The discipline of Wheel / Rail Interaction is dominated by the study of: Contact Mechanics Tribology Vehicle Dynamics Metallurgy