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In this study, the dynamic response of ballasted tracks subjected to heavy haul trains will be investigated. The vehicle/track interaction model can be divided into two sub-systems, which are vehicle sub-system and ballasted track sub-system. The heavy haul vehicle is composed by one car body, two bogies and four wheel sets, and these components are connected by secondary and primary suspension system. The vehicle is modeled as a multi-body system with 10 degree of freedoms. The ballasted track consisting of rail, sleeper, ballast, sub-ballast and sub-grade is modeled as four elastic components, in which the rail system is treated as an Euler-Bernoulli beam supported by discrete fasteners and sleepers, the ballast and sub-ballast subsystem is regarded as a series of lumped masses, and the spring-damping elements are used to link the fastening system, the elastic layer between ballast and sub-ballast, and the visco-elastic layer of the subgrade. To take into account the separation phenomenon between moving wheels and the track, a nonlinear Hertzin spring between them is presented, as shown in Fig 1. An iterative procedure is performed to compute the response of the vehicle/track system, and the validation of the present vehicle/track model will be examined by field experiments. Moreover, the dynamic responses of the vehicle, contact force, and ballasted track are computed for different freight vehicles, including C64, C70, C80 and C96 with corresponding axle loads of 21t, 23t, 25t and 30t.