A rail fleet experienced a sudden increase in reaction link failures, creating a significant safety and availability concern. The failed component formed part of a critical assembly, and its failure had the potential to result in equipment dropping out of gauge.

INTERFAIC supported a structured root cause investigation using failure evidence, historical test data, instrumented on-train measurements and finite element assessment. Strain gauges and accelerometers were used to understand the dynamic behaviour of the assembly during service conditions. Modal analysis identified a bending mode that aligned with the observed failure mechanism.

Outcome: the investigation identified vibration-driven fatigue as the likely failure mechanism, with recommendations developed to manage immediate risk and inform future redesign.