Comparative study on the causes of rail corrugations in long steep-grade sections under traction and braking conditions

Abstract

There are significant differences in rail corrugations between the uphill and downhill sections in long steep-grade sections. Comprehensive field investigations and numerical simulations are conducted to investigate rail corrugations under traction and braking conditions. Firstly, field investigations of rail corrugations in long steep-grade sections are carried out. Secondly, the dynamic models of the vehicle-track system under uphill traction and downhill braking conditions are constructed, and the dynamic characteristics of the vehicle-track system are explored. Then, the finite element models of wheel-rail-traction/brake systems are constructed, and the friction self-excited vibration characteristics of the wheel-rail system are studied by the complex eigenvalue method. Finally, the influences of key parameters of traction and brake friction pairs on rail corrugation are studied, and suppression methods of rail corrugations are proposed. The results show that (1) rail corrugation more easily occurs on the transition positions of the easement curve and circular curve, with slope changing. (2) Under the traction and braking conditions, rail corrugations are induced by the friction self-excited vibration of the wheel-rail-traction/brake system. (3) Reducing the traction speed or increasing the gear mesh stiffness, reducing the brake friction coefficient or the brake force can suppress the rail corrugation.