Experimental and numerical study on wheel-rail lateral forces for a locomotive negotiating sharp curves under variable speed conditions

Abstract The wheel-rail lateral force acting on the high rail during curve negotiation constitutes a critical indicator for assessing the running stability and ride comfort of rail vehicles. This paper investigates the impact of a locomotive’s speed, acceleration, and push/pull operation modes on the wheel-rail lateral force through vehicle dynamics simulations and field tests. In the rail vehicle-track dynamics model, the coupler and buffer system are accurately modeled to evaluate the interactions between car and locomotive during negotiating a small curve. Under push operation conditions, the wheel-rail lateral force exhibits significantly higher sensitivity to locomotive acceleration than to operating speed. Specifically, a 50% increase in acceleration yields an 8.2% increase in lateral force at constant speed, whereas a 50% increase in speed only produces a 4.1% increase at constant acceleration. Furthermore, under the same operating speed and acceleration, the wheel-rail lateral force is 18% greater under the push operation condition compared to pulling operation condition. These findings offer valuable guidance for optimizing locomotive operation strategies to reduce excessive wheel-rail lateral forces and thus mitigate abnormal wear in curved track sections.