Research on Braking Safety of the Triple Locomotive in a 10,000-Tonne Heavy-Haul Train

To hill-start a 10,000-tonne heavy haul train on a mountainous railway, a triple locomotive unit is employed to provide traction power. Meanwhile, large dynamic braking forces are usually applied to control the train speed at the downhill section instead of air braking forces. The sustained dynamic braking forces influence the coupler stability, which further affects the running safety of the locomotives. To analyze the running safety of the locomotives under large dynamic braking forces, a multi-locomotive model is established and validated, and the dynamic performance of the locomotives on tangent track, curved track, and turnout under different dynamic braking forces are simulated. The results indicated that the large dynamic braking force leads to a large coupler yaw angle, which causes a large lateral component of coupler force and intensifies the wheel-rail interaction. To enhance the running safety of the locomotives, the applied dynamic braking force should be limited according to practical line conditions.