Comparative analysis of rail pad lateral dynamic performance in metro systems

The lateral stiffness and damping of rail pads significantly influence train performance on curves, yet their effects are not well understood. This study investigates the lateral dynamics of three rail pad structures: groove (GRP), mesh-type (MTRP), and mesh-type with high damping (MTHDRP), and their impact on train curve performance. Results from lateral loading tests indicate that MTHDRP pads exhibit the highest lateral static stiffness, dynamic stiffness, and damping ratio, while GRP pads have the lowest, highlighting significant performance disparities. Finite element analysis reveals substantial deformations in GRP pads under high lateral loads, leading to increased stress levels. Strategies to increase the lateral stiffness across these pad types involve structural parameter adjustment and integration of harder materials, detailed further in the conclusions. Multibody dynamic simulations suggest that decreasing lateral stiffness while increasing damping not only increases train safety on curves but also reduces track system vibration. Under varying conditions of speed, curve radius, rail slope, and superelevation, MTHDRP consistently demonstrates favorable performance, underscoring the importance of lateral dynamics in the design, manufacturing, testing, and dynamic analysis of rail pads to optimize vehicle and track performance on curves.