Dynamic Train-Track-Ballast Interaction with Unevenly Distributed Track Properties

ABSTRACT A numerical method to simulate vertical dynamic interaction between a rolling train and a railway track has been extended to account for stochastic properties in the track structure. Here, the rail pad stiffness, the ballast stiffness, the dynamic ballast-subgrade mass and the sleeper spacing are modelled as random variables. The numerical simulations have been carried out in the time-domain with a moving mass model. Full-scale measurements in the field and laboratory experiments have been carried out to get realistic data for the selected stochastic variables. Two conceptual different methods (a perturbation and a Monte Carlo method) were used to investigate the influence of the randomness of selected stochastic parameters in the track structure. The investigated quantities have been the maximum value of the rail-wheel contact force, the maximum magnitude of the vertical wheelset acceleration and the maximum value of the sleeper displacement. Mean values and standard deviations of these quantities have been calculated. The effects of the variation of the investigated track properties are discussed.