Joint optimization of train platforming and shunting with service scheduling at a railway hub

The rapidly developing high-speed railway system in China has posed increasing challenges to train and station scheduling. During rush hours, several switches and tracks are often congested due to the lack of synchronized train platforming and service scheduling. Therefore, we investigate a train platforming and shunting with service scheduling (TPSSS) problem of high-speed railway hub at the tactical level. This joint optimization approach can reduce conflicts, decrease the shunting work, and promote balanced resource utilization at stations and depots. By constructing a two-layer time–space network based on the hub layout, a multi-commodity flow model and a heuristic algorithm that utilizes the alternating direction method of multipliers (ADMM) are developed. Applying an iterative framework that includes inner and outer loops, as well as a pre-assignment strategy, the algorithm can produce a near-optimal (gap < 5 %) TPSSS plan within a computation time of 1 h in cases where there are no cancelled trains. Furthermore, a comparison between conservative and aggressive strategies indicates that the aggressive strategy can achieve an overall better solution.