A rail squat is a subsurface crack caused by rolling contact fatigue that leads to a dip in the surface of a rail. Squats can cause deep defects requiring relatively new rail to be discarded. Current practice is to grind out rail squats and weld back material to replace that missing. A 3D model of wheel-rail contact is created to examine the formation of rail squats, with an aim to identify formation mechanisms, and to investigate methods of prevention of rail squats. The project will also seek to identify the effects of changes in operating conditions on squat formation.
Existing data from industry partners have been collated. At selected sites, testing will be carried out to identify the load spectra and variation of wheel rotation speed associated with a wheel traversing a squat. The project will also involve development of modelling tools as appropriate to understanding the conditions in the early development of a squat.