Development of a real-time wheel/rail contact model in NUCARS® 1 and application to diamond crossing and turnout design simulations

A new, stable, multi-point penetration wheel/rail (w/r) contact algorithm has been developed for the NUCARS® vehicle/track interaction multi-body simulation program. This algorithm resolves previous problems with integration instabilities during wheel flange contact. Contact geometry comparisons using both the standard rigid and new penetration contact models show that the new penetration model correctly calculates the constrained contact geometry for a range of wheel dia-meters and contact angles. The critical conditions for multiple solutions for w/r profile combinations with steep flanges and the methodologies to account for this problem in NUCARS are also discussed. Applications of the new w/r contact algorithm to diamond crossing and turnout design simulations are presented and compared with test data. These results show that the revised real-time w/r penetration contact model and the flexible track model with rail profile variation capability in NUCARS provide a promising tool for the advanced analysis of special track work.