Dynamic responses of vehicle ballasted track interaction system for heavy haul trains

In this study, the dynamic responses of ballasted tracks subjected to heavy haul trains are investigated. The vehicle ballasted track interaction (VTI) model can be divided into three parts, which are vehicle model, ballasted track model and wheel/rail contact model. The vehicle is modelled as a multi-body system with 10 degrees of freedom. The ballasted track consisting of rail, sleeper, ballast, sub-ballast and sub-grade is modelled as four elastic components. The vehicle model and ballasted track model is linked by the wheel/rail contact model, which is determined by the nonlinear Hertzian theory. The VTI model is solved by an iterative procedure and validated with some field experiments. The dynamic responses of the vehicle/track system are compared with those from the moving load model. Moreover, the wheel/rail contact force, the force from rail to sleeper and the force from sub-ballast to subgrade are computed for different axle loads of 25t, 30t, 35t and 40t. It is deduced that maximum values of these forces increase in a linear form with the increasing of axle load.