Track Geometry Measurement
Definition
Systematic recording of gauge, cross-level, twist, alignment, and surface profile along a route using dedicated measurement vehicles, producing a continuously updated map of track condition.
- Parameters measured
- Gauge, cross-level, twist, alignment, surface profile
- Method
- Dedicated measurement vehicles
- Output
- Continuously updated track-condition map
- Use
- Rail and infrastructure failure investigation
Common questions
Why measure track geometry continuously rather than at fixed intervals?+
Rail wear and ground movement are progressive, so continuous measurement catches developing defects such as twist or misalignment before they reach a threshold that could cause a derailment.
How is track geometry data used after a derailment?+
Investigators pull the measurement history for that section of track to check whether a known defect had already exceeded maintenance thresholds and whether it was flagged but left unaddressed.
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...
- 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...