Study on curving performance of heavy haul train under braking condition

In order to study train curving performances, 1D and 3D train dynamics models were built by numerical method. The 1D model was composed of 210 simple wagons allowed of only longitudinal motions, while the 3D train model included three complicated wagons of which longitudinal, lateral and vertical DOF could be considered. Combined with calculated results under braking condition from 1D model, behaviours of draft gear and brake shoe could be added into 3D model. The assessment of train curving performance is more focused on making a comparison between idling and braking conditions. Some results indicate as follows: When train braking is operated on a curved track, wheel-rail lateral force and derailment factor are larger than those under idling condition. Because yawing movement of wheelset is limited by brake shoe, the zone of wheel contact along wheel tread is wider than that under idling condition. Besides, as curvature gets tighter, traction ratio shows a nonlinear increasing trend, whether under idling or braking condition.With brake shoe pressure increasing, train steering gets more difficult.