The Influence of Local Irregularities on the Vehicle–Track Interaction

Abstract

Local track irregularities such as mud spots generally cause a sudden variation in track stiffness, which leads to the track geometry degradation in a short period. The interaction of the moving train with such track defects induces additional dynamic stresses in the track system that may prove harmful for the structural health of the track structure. In this paper, an analytical approach is proposed to simulate the vertical track acceleration caused by a local track irregularity when subjected to a uniformly moving load. The railway track is modeled as an infinitely long continuous Euler–Bernoulli beam lying over a Pasternak-type viscoelastic foundation track model. At any given location along the rail beam, the stiffness and thickness of the considered foundation model, respectively, denote the track substructural stiffness and track geometry. To simulate the effects of local irregularities, a pre-defined variation of the stiffness and thickness is considered in a particular section of the foundation model. The time-domain deflection/acceleration responses are obtained for the railway track subjected to a uniformly moving (a) point load and (b) two-mass oscillator system. The results show that the local irregularities may cause significant damage to track structure, which may lead to poor ride comfort or in some cases, even derailment.