Gauge-Corner Cracking
Definition
A specific RCF pattern where cracks initiate at the gauge corner of the rail head, the edge most heavily loaded by wheel flange contact in curves. The cracks are angled steeply at the surface but can turn transversely as they deepen.
- Location
- Gauge corner of the rail head
- Cause
- Wheel flange contact loading, especially in curves
- Type
- Rolling contact fatigue (RCF) pattern
- Crack path
- Steep angle at surface, can turn transverse with depth
Common questions
Why does this cracking concentrate at the gauge corner rather than elsewhere on the rail head?+
The gauge corner is the point of highest contact stress from the wheel flange as a train negotiates a curve, so repeated rolling contact loading concentrates fatigue damage there more than on the rail crown, which sees more evenly distributed contact.
Why does the crack angle matter to a failure investigator?+
A crack that stays angled toward the surface tends to shell off as surface spalling, while one that turns transverse as it deepens can propagate into the rail head and cause a sudden transverse break, so the angle and depth trajectory inform the derailment risk assessment.
How is gauge-corner cracking distinguished from ordinary wear on the rail?+
Wear removes metal gradually and smooths the running surface, while gauge-corner cracking is a fatigue crack network that can underlie an apparently intact surface, so investigators rely on ultrasonic or magnetic particle inspection rather than visual wear assessment alone to detect it.
Related terms
- 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...
- Rolling Contact Fatigue (RCF)
- 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,...
- 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...