Optimisation of turnout rail profiles based on equivalent conicity

Abstract

This paper presents a method for the optimisation of wheel–rail profiles, and this is based on the relationships between the equivalent conicity, RRD curve and rail profile slope. This method can be used to improve the riding stability of trains when rolling across turnouts, and to optimise the equivalent conicity. The measured profile of a straight switch rail, i.e. a 60D40 rail laid in a high-speed turnout switch area, was taken as a sample for optimisation. The existing curve of equivalent conicity was lowered for reverse-reasoning calculation of the optimised profile. The optimised profile of the 60D40 rail was taken as the optimal design for an in-service straight switch rail. The effectiveness of the optimised design was then evaluated based on static wheel–rail contact and vehicle-turnout coupling dynamics. The conclusions show that, for an in-service straight switch rail, profile optimisation can effectively improve the wheel–rail relationship, thus enhancing the riding stability of trains in turnout switch areas.