Abstract:
This paper investigates the consequences of railway track stiffness variations and explores potential countermeasures using dynamic Finite Element Analysis. The study highlights that abrupt changes in track stiffness—caused by hanging sleepers, transitions from embankments to bridges, or switches—lead to increased dynamic wheel-rail contact forces, which in turn accelerate track degradation and settlement. To analyze these effects, time-domain computer simulations are performed using three-dimensional Finite Element models of the track structure, which include the rail, sleepers, pads, ballast, and subgrade, subjected to a moving wheel load. The FEA is employed to conduct parametric studies on various scenarios, such as the severe impact loading caused by a wheel passing over an unsupported "hanging" sleeper, where the FE model simulates the large force variations. The Finite Element simulations are then used to evaluate the effectiveness of countermeasures like under-sleeper pads and subgrade grouting, demonstrating that these solutions can significantly smooth out stiffness transitions and reduce the detrimental dynamic forces, thereby mitigating track deterioration.
