Simulation and experiment based investigations of squat formation mechanisms

In this work, possible formation mechanisms of squats were investigated based on field and laboratory measurements, full-scale wheel-rail test rig experiments and a newly developed simulation tool. Wheel-rail contact conditions were found, which can lead to cracks in or to outbreaks of a white etching layer (WEL) on a rail surface. Under certain condition this also can lead to cracks growing into the bulk material. Furthermore, according to the simulation results, geometrical deviations of the rail surface - as for example outbreaks of WELs - can remain at the rail surface and grow up to a size comparable to that of squats. It has been shown, that the crack initiation potential in the area of such permanent geometrical deviations can be increased. •Development of a new squat simulation tool.•Cyclic loading of white etching layers can lead to outbreaks at the rail surface and cracks.•Geometrical deviations of the rail surface can remain permanently on the rail surface.•Small geometrical deviations of the rail surface do not remain permanently.•Geometrical deviations of the rail surface can lead to an increased crack initiation potential.