Analysis of Rail Vehicle Derailment in a Train Consist Considering the Influence of Coupler Forces

Abstract

In the context of derailment safety analysis, the influence of coupler forces from the whole train is often neglected. This paper proposes a coupled approach combining a longitudinal train dynamics model and a spatial dynamic model of a freight wagon to evaluate the influence of coupler forces under Vietnamese freight operating conditions. The coupler force is first determined from the longitudinal train dynamics model, then resolved through the coupler deflection angle and introduced into the spatial model to calculate the safety indices Y/Q and ∆Q/Q. The case study considers a covered freight wagon in a 15-car freight train hauled by a D19E locomotive, running at 50 km/h on a 450 m radius curve with a 1000 mm gauge. The results show that the maximum longitudinal coupler force occurs at the first coupler, while wagon No. 1 and wagon No. 2 are the two wagons of greater concern in terms of coupler-force distribution. However, under the investigated condition, the influence of coupler forces on derailment safety is very small: Y/Q remains unchanged at 0.3967, while ∆Q/Q decreases only from 0.3233 to 0.3231. The results indicate that, for a freight train with a relatively limited length and load such as the investigated case, the influence of coupler forces on derailment safety indices is negligible.