A Fundamental Study on Derailment of Wheel Flange Under Rolling-Sliding and Pure Sliding Conditions

A newly developed full scale wheel-rail contact testing machine is used to obtain detailed data on flange climb behavior with covering various loads and displacements at the wheel flange and rail contact under both rolling-sliding and pure sliding conditions. The effects of different surface roughness of the wheel flange on coefficient of friction at the contact point in wheel flange climb mechanism were investigated. A correlation between different state of the interface (i.e. surface of dry, wet, rust, oily and different lubricated condition by solid lubricant) and wheel flange surface roughness with rail were drawn. The coefficient of friction was significantly influenced in pure sliding conditions than that of rolling-sliding conditions by the degree of the asperities on the wheel flange surface. Moreover, solid lubricant showed better performance to reduce coefficient of friction. However, the rust on the rail surfaces was one of the important factors to destabilize the friction behavior.