Optimization of the loading plan for a railway wagon from the perspectives of running safety and energy conservation

The improvement in running safety and energy efficiency of railway freight transportation brings about great social and environmental benefits. This paper proposes a novel strategy for promoting the curving performance and reducing driving energy consumption by optimizing the position of the wagon's combined center of gravity (CCOG) when loading the cargo. The dynamics analysis of the vehicle model is conducted to reveal the effect of CCOG position. Based on the simulation results of the established and verified multibody dynamics model, the critical role that CCOG plays in driving energy consumption is investigated, which is proved to be different from the relationship between CCOG and the wheel unloading ratio. Furthermore, the optimal velocity of the specified loaded wagon is inferred to be about 26 m/s, and the small radius curve is demonstrated to be the worse working condition in most cases. Finally, the Pareto-optimal solutions of the CCOG position are derived, and their superiorities in running safety and energy conservation are validated. The proposed methodology which realizes the multi-objective optimization of the CCOG position can be applied to set other parameters of the railway wagon.