Impact of Longitudinal Train Dynamics on Train Operations: A Simulation-Based Study

Abstract

The paper is an attempt to evaluate the impact of coupler forces in the train produced during braking. The braking signal generated from a locomotive control valve takes a few milliseconds to reach the adjoining car in coupled passenger trains. The brake comes into effect in the last car of the train after a few seconds due to the time lag. This delayed application of brakes results in pushing off the rear cars into the front cars, producing large compressive forces in the coupler. These compressive forces, mainly longitudinal in nature cause passenger discomfort and poor ride quality. Non-linear dynamic analysis has been conducted to represent the characteristic of coupling forces between the coaches in longitudinal train dynamics. The analysis involved the mathematical model of coupler force and braking force through experimental results. In addition, effects of various braking phases, i.e., auxiliary, service and emergency braking on the in-train forces, were also investigated using ‘universal mechanism—software of dynamics of mechanical systems’. The train response due to different braking phases on the train longitudinal dynamics is thoroughly studied using multibody dynamics analysis. The results establish that the in-train forces were well within the limits prescribed by Research Design and Standard Organisation. The maximum compression force increased when the forward velocity of the train is reduced during the braking phase. And, this maximum compression occurs at the third quarter of the train.