Risk assessment of flange climb derailment of a rail vehicle

Abstract

We study the wheel flange climb onto the railhead, which is one of the most dangerous regimes of motion and can lead to derailment. The tangential components of the wheel-rail interaction forces are described by the creep model with small slips taken into account. We pass to the limit of infinite rigidity of the interacting bodies (zero slip velocities). It is shown that, in the actual service conditions of rail vehicle motion, neglecting the wheel-rail slip is not justified; namely, the limit model is determined by the primary Dirac constraints, i.e., finite relations between coordinates and momenta arising owing to the system Lagrangian degeneration. The obtained nonclassical model allows one to study the efficiency of some railway motion safety criteria and analytically estimate derailment conditions, which depend on the flange shape, the track curvature radius, the height of the vehicle center of mass, the wheel-rail interaction forces, the coefficients of friction of the interacting surfaces, and the external perturbation forces and moments.