The effect of the secondary lateral stopper on the compressed stability of the couplers and running safety of the locomotives

This paper aims to study the effect of the secondary lateral stopper on the compressed stability of the couplers in order to improve the running safety of the heavy-haul locomotives. The influence mechanism of the secondary lateral stopper on the compressed stability of the couplers is theoretically analyzed. To verify the effect of the secondary lateral stopper, both the simulation and the field braking tests are conducted. The multi-body dynamic model consists of two eight-axle locomotives, one dummy of freight vehicle and four detailed connected couplers. The field braking tests are conducted on the tangent line using three eight-axle locomotives. The results indicate that decreasing the free clearance and increasing the stiffness of the secondary lateral stopper both have a positive effect. However, when the free clearance decreases from 20？mm to 10？mm, there is no remarkable decrease in the yaw angles of the coupler and the car body, and the maximum lateral force of the wheelset is still out of the standard in the simulation. When the stiffness of the secondary lateral stopper increases by five times, the yaw angles of the coupler and the car body are reduced significantly and the running safety of the locomotives is also enhanced