On wayside detector measurement of wheel–rail impact loads induced by wheel flats – Data analysis, alarm levels and regulations

Paper in proceeding, 2024

Wheel–rail impact loads induced by discrete wheel tread irregularities, such as wheel flats, may lead to severe damage of vehicles and tracks. In Sweden, wheel removal regulations are applied if the wheel flat is longer than 60 mm independent of axle load and train speed. Condition monitoring of wheels is carried out via measurement of peak loads in wheel impact load detectors. If measured loads exceed the alarm level 350 kN, a train speed reduction is imposed until the vehicle with the wheel damage has been decoupled from the train. In this study, measured peak loads from six detectors along a specific freight traffic route are compared for different wheel flat lengths, axle loads and train speeds. The alarm level was not exceeded for any of the wheel flats, including those significantly longer than 60 mm. To reduce costs due to unnecessary traffic disruptions while maintaining safety, it is suggested that wheel removal criteria should strictly be based on measured loads in detectors instead of by visual inspection of wheel flat length. The detectors should be subjected to regular monitoring of track geometry and should have a robust and transparent calibration procedure for measurement of dynamic wheel loads.