Torsional Effect on Track-Support Structures of Railway Turnouts Crossing Impact

Abstract

The introduction of special crossings and rail turnouts provides flexibility in the rail network as it allows for vehicles to switch between various tracks, thereby maximizing the utilization of current infrastructure. Turnouts are a costly and critical feature to a rail system as they suffer adverse operational loads, compared with a straight rail track, and thus require regular maintenance. This leads to the question of whether a turnout can be justified for flexibility against upkeep costs throughout the life of the turnout. Therefore, great consideration is given to the interaction between the turnout components and reducing wear in service, as failed components may have adverse effects on the performance of neighboring components. This paper presents a development of three-dimensional (3D) finite-element (FE) model, fostering nonlinearities in materials’ behaviors, to analyze the forces and reactions in a railway turnout system. The analysis provides new findings of critical sections in the turnout and further enables alterations to be made to the initial design of members to accommodate for the increased effects. The FE model is composed of standard concrete sleepers with 60-kg/m rail and a tangential turnout radius of 250 m. The turnout structure is supported by a ballast layer, which is represented by a deformable solid. The FE model is the first in the world to predict the torsional behavior of the turnout and its fragile support by considering multiwheel impacts, which would simulate in-service and cyclic loading and will be adapted as a set of concentrated loads to represent a coupled locomotive negotiating the turnout. The simulations demonstrate the significance of the third medium to suppress the torsional effect of the crossing forces on supporting bearers.