Effect Analysis of Coupler Force onHeavy-Haul Train Safety Under Eccentric Loads

To analyze the safety of the train under eccentric loads running on a small-radius curve track, its safety indexes are analyzed, on the basis of the longitudinal dynamic model of heavy-haul trains and a 3D dynamic train-track coupling model with short marshaling. First, with the use of the longitudinal dynamical model, the characteristics of the coupler force and its variation law are analyzed; and the calculated coupler force is taken as a boundary condition in the 3D dynamic coupling model to analyze how the coupler force and eccentric distance affect the safety indexes in the course of the train running on a small-radius curve track. The results show that for the 10 000 t train, the maximum coupler pressure decreases with the train sequence. When the eccentric load is outward, the coupler pressure greatly affects the train safety, but the coupler tension has little influence. When the coupler pressure reaches 800 kN and the eccentric distance 500 mm, the wheel weight reduction rate rises to 1.00. Therefore, with eccentric loads, derailment accidents are more likely to occur in braking conditions. With the same eccentric load amplitude, the wheel weight reduction rate under the outward eccentric load is higher than that under the inward eccentric load. When the coupler pressure increases from 0 to 800 kN, according to the wheel weight reduction rate the limit of the lateral eccentric distance decreases from −421 mm to −215 mm. This demonstrates that the longitudinal impulse and braking acceleration should be considered when designing the safety limit of the heavy-haul the train.