In order to investigate the effect of track supportfailure on dynamic response of tangent track, a vehicle-track couplingdynamic model is established, in which the rails are assumed to beTimoshenko beams resting on the discrete sleepers. The failure situation oftrack components under the tangent track is simulated by the abrupt changesof track stiffness along the track. The effect of the discrete sleepersupports on the coupling dynamics of the vehicle and track is taken intoconsideration by the excitation model of moving sleeper supported. As to theinteraction of wheel and rail system, the creepage formulas of wheel/railrolling contact are deduced, in which the lateral, vertical and torsionalmotions of rail are taken into account. The normal forces of wheel/rail arecalculated by Hertzian contact theory and the creep forces of wheel/rail inrolling contact are decided by the nonlinear creep theory of Shen et al. Themotion equations of the vehicle/track coupling system are solved with thenew explicit integration method. Effect of zero, two, four and six tracksupports in failure situation on tangent track dynamic response is analyzedand evaluated. The numerical results indicate that track support failuregreatly affects dynamic response of tangent track. With the increasing offailure number, the wheel/rail normal forces, displacement and accelerationof track components increase quickly, which will deteriorate the track.