An investigation into rail corrugation due to micro-slip under multiple wheel/rail interactions

The formation of short pitch corrugation on the railhead is studied by using an approach combining wheel/track dynamics, contact mechanics and wear. Multiple wheel/rail interactions are taken into account in the wheel/track dynamics. A quasi-static method based on a two-dimensional contact model is used to solve the unsteady rolling contact problem where the normal contact force and the surface curvature vary. The longitudinal slip due to traction is considered. Corrugation growth rate is calculated at different wavelengths and at two train speeds using parameters from a British Class 87 electric locomotive and typical track. It has been found that the corrugation growth rate becomes largest when the phase of the normal dynamic contact force is such that its peak occurs about 135° after the corresponding trough in the roughness. The wear is found to be heavier at shorter wavelength and proportional to the amplitude of the dynamic contact force. In addition corrugation is shown to develop more quickly using stiffer pads than softer pads, whereas growth occurs at several frequencies for softer pads.