A dynamic ballasted track model for buckling failure analysis

Traditional analyses on track buckling failure have primarily focused on the static structural mechanics of railway tracks under thermal stress. However, to better understand the dynamic buckling failure phenomenon, it is essential to consider variable factors within the computational modelling framework. This study addresses this gap by simulating ballasted track buckling failure while incorporating dynamic force inputs and rail stiffness adjustments due to both thermal and longitudinal forces. The rails are modelled as Euler-Bernoulli beams using the Finite Element Method (FEM), and other tack components are represented as equivalent rigid bodies connected by flexible force elements. A friction model at the sleeper-ballast interface is integrated, and rail stiffness—primarily in the lateral direction—is adjusted to reflect the influence of longitudinal forces. This computational modelling of railway tracks enables a comprehensive view of the forces and displacements experienced by the individual track components, offering insights on total track behaviour. By incorporating dynamic forces into the buckling analysis, this FEM-enabled rail components significantly enhance the simulation capability of track buckling in the time domain. Additionally, track model is scalable and configurable, enabling simulations using a wide range of track parameters. The effectiveness of the developed ballasted track model is demonstrated through case studies, where a 30-meter track section under thermal compression and application of dynamic lateral loads exhibits a nonlinear buckling response.