Development and application of a calculation method for the equivalent conicity in high-speed turnout Zones

Abstract

ABSTRACT Equivalent conicity is an equivalent mean parameter for reflecting the effects of lateral wheel-rail forces on passenger comfort on trains. Based on the asymmetry of the variable cross-section rails in the turnout zone, this paper views the equivalent conicity of a wheelset in the turnout zone as an equivalent conicity of a wheelset in which the wheels match all constant-section asymmetrical rails. A calculation method is established for the equivalent conicity of the turnout zone according to the hunting motion wavelength formula of wheelsets; considering the Rolling Radius Difference (RRD) curve of several ‘zero-crossings’, the principle of minimum gravitational stiffness is used as reference for determining the point ye at which the equivalent conicity of a large lateral displacement is calculated. For fluctuating RRD, the equivalent conicity is calculated using the zoning method; the paper also proposes to evaluate wheel-rail contact geometry in the turnout zone based on the nominal equivalent conicity of the most probable lateral displacement of the wheelsets. Using the matching of wheelsets of different service lengths and the No.18 turnout switch zone as an example, this paper studies the effects of a changing wheel profile on the equivalent conicity of the turnout zone.