Rolling Contact Fatigue (RCF)
Definition
Surface and subsurface fatigue damage caused by cyclic wheel-rail contact stress. Micro-cracks initiate at the rail surface, typically in the gauge-corner region, and can propagate to cause spalling or transverse rail fracture.
- Cause
- Cyclic wheel-rail contact stress
- Initiation site
- Rail surface, typically the gauge-corner region
- Damage type
- Surface and subsurface fatigue micro-cracks
- Progression
- Can propagate to spalling or transverse rail fracture
Common questions
Why does RCF concentrate in the gauge-corner region specifically?+
The gauge corner experiences the highest contact stress and lateral creep forces as wheels negotiate curves, concentrating the cyclic loading that initiates the micro-cracks characteristic of rolling contact fatigue.
How does RCF differ from ordinary wear on a rail?+
Wear removes material gradually from the running surface, while RCF develops subsurface cracks under cyclic loading that can propagate internally and cause a sudden transverse fracture even when the surface still looks serviceable.
What inspection methods are used to detect RCF before it causes a rail failure?+
Ultrasonic testing and eddy current inspection are commonly used to detect subsurface and near-surface cracks, since RCF damage is often not visible or only marginally visible during a routine visual track inspection.
Related terms
- Gauge-Corner Cracking
- A specific RCF pattern where cracks initiate at the gauge corner of the rail head, the edge most heavily loaded by wheel...
- Press-Fit Fretting
- Relative micro-motion between a wheel or disc pressed onto an axle at its interference fit, generating fretting fatigue damage and pits that...
- RAIB
- Rail Accident Investigation Branch: the independent UK body that investigates railway accidents with the objective of improving safety, operating under the same...
- Squats
- Flat-bottomed depressions in the rail running surface accompanied by internal crack systems, another manifestation of rolling contact fatigue caused by wheel slip...
- Track Geometry Measurement
- Systematic recording of gauge, cross-level, twist, alignment, and surface profile along a route using dedicated measurement vehicles, producing a continuously updated map...