Investigation on How Rail Surface Self-cleaning Changes the Locomotive Traction Dynamics

Railway locomotive traction performance is strongly dependent on the friction condition between wheel and rail at the contact interface. One of the major factors affecting the friction condition at that interface is the third body layer. This layer as experienced by each wheelset of a locomotive is partially if not fully eliminated from the contact zone when the subsequent wheelsets run on the rail. Such a self-cleaning phenomenon is generally ignored in classical locomotive dynamics studies, assuming it should not introduce a significant effect. Thus, a constant dynamic friction coefficient is used for all sequential wheels. However, recent investigations show that consideration of the phenomenon is important to accurately reflect the actual physical process at the wheel-rail interface and the exclusion of such phenomenon may result in a significant cumulative error in locomotive dynamics studies.