The use of multiple models to analyse railway track ground dynamics

With the increases in train speed in recent decades, it is important to define the track-ground critical velocity to prevent high track dynamic amplification. This is affected by wave propagation in the soil layers and track supporting the moving load. Therefore, this paper investigates the important variables that influence the critical velocity and dynamic amplification based on three case studies of track-ground dynamic problems, which are: the presence of low stiffness soil layer, track shakedown and soil improvement. Three modelling strategies (analytical, hybrid analytical-numerical and 2.5D numerical) are used to analyse the different track-soil problems. The findings provide a better understanding of critical velocity and dynamic amplification. These are useful when considering a new track-ground design or improving the existing railway lines.