Investigation on Running Safety of Empty Wagons in Long Freight Train Passing a Worn Switch Rail

According to the field investigation of a climb derailment accident occurred at a switch rail area, the measured switch rail profiles are employed to establish a wagon-switch rail interaction model. Based on the numerical simulations, the characteristics of the wagon-switch rail interaction were studied. Meanwhile, the influences of the train speed, the coupler force and the coupler yaw angle on the running safety of the middle wagon of the 3-pack freight train were investigated. The simulation results indicate that fierce impacts occur in the transitional area between the stock rail and the switch rail accompanied with instantaneous wheel-rail separation. The wheel-rail interactive forces increase rapidly with an increase in the train speed, and the vertical interaction is fiercer than that in the lateral direction under the coasting condition. The synthetic effect of large lateral component of coupler force and variable cross-sections of switch rail can intensify the lateral wheel-rail interaction, and increases the operating risks of wagons. To enhance the running safety of the empty wagons in switch area, the train operation regulation should be optimized to reduce the longitudinal impulse, and the maintenances of the track structure and wagons should be strengthened to improve the running stability of the wagons.