Transportation Technology Center, Inc., a wholly owned subsidiary of the Association of American Railroads, has developed a double rail model for special trackwork simulation in the NUCARS® vehicle/track interaction multibody dynamic simulation program. The double rail model consists of a primary rail and a secondary rail on each side of the track. it It permits one wheel to contact two rails so that the effects of their relative movements on wheel/rail contact can be investigated. It also allows rail profile and track suspension stiffness and damping to vary on the track.
This paper presents simulation results of a freight car running on a No. 20 turnout. Simulation results showed that the double rail model improved the integration stability and simulation accuracy for high frequency wheel/rail (W/R) impacts by capturing the simultaneous multiple W/R contact point situations and transitions under various discontinuous track running surface conditions.
Parametric studies of W/R impacts on frog points showed the frog point geometry designs have conflicting requirements for dynamic performance for vehicles equipped with with new wheels and hollow-worn wheels; the NUCARS double rail model provides a useful tool for frog and switch point geometry optimization.