Track model validation for simulation of train–turnout dynamics

Conference poster, 2011

Based on track stiffness and wheel–rail contact forces measured in a demonstrator turnout (switch & crossing, S&C), a viscously damped track model for simulation of vehicle dynamics is developed and validated. Track stiffness at nominal wheel loads, in the frequency range up to 20 Hz, was measured using a rolling stiffness measurement vehicle (RSMV). Vertical and lateral contact forces were measured by an instrumented wheelset mounted in a freight car featuring Y25 bogies. The measurements were performed for traffic both in the through and diverging routes, and in the facing and trailing moves. The full set of test runs was repeated with different types of rail pad to investigate the influence of track stiffness on contact forces. It is concluded that wheel–rail impact loads at the crossing can be reduced by using more resilient rail pads. The track model is a mass-spring-damper model that is moving with each wheelset in the vehicle model. Reasonable agreement between simulated and measured vertical contact forces at the crossing can be obtained when using a track model with one vertical degree of freedom (dof) per rail, each with neglected inertia, coupled to one track mass with one vertical and one rotational dof. This model can be tuned to capture the large phase delay in dynamic track stiffness at low frequencies, as measured by the RSMV, and remaining sufficiently resilient at higher frequencies.