System dynamics of distributed-power train under failed brake communication

This paper studied the system dynamics of a distributed-power (DP) train under failed brake communication. The DP train with the configuration of 1 locomotive + 105 wagons + 1 locomotive + 105 wagons was modeled with advanced air brake and draft gear models. The air brake model is based on fluid dynamics, which considers a wide range of details of the brake systems such as brake pipe characteristics (pipe wall friction, connection resistance, diameter, etc.) and brake valve structural parameters. The draft gear model considers all components and their geometries of the draft gear. A simulation was conducted to simulate the remote locomotive not responding to the brake signal during a minimum service brake. The simulation case is based on real cases reported in operational service. The simulation results of the failed case are compared with that of a normal case. This comparison shows that the communication failure decreases the braking capability of the train and increases time delay for brake release. The failed case has evidently larger tensile coupler forces than the normal case in the rake from Coupler 45 to Coupler 107. The implications of the communication failure have not reached a level to threaten the train operational safety due to the small brake forces during the minimums service brake.