Research on the scheduling in sea-rail intermodal trains based on full-length and full-occupied strategy

In 2023, Total Freight Volume of Sea-Rail Intermodal train in China reached 11.7 million TEUs, setting a historical record. However, this volume only accounts for 3 % of the total throughput at China's coastal ports, compared to 20 %–40 % in other developed countries. This indicates that there is still significant potential for development in China's sea-rail intermodal transport. This paper identifies two main reasons hindering its development. On the one hand, the conflict between railway operators and shippers leads to wasted train capacity, preventing an increase in transportation volume. On the other hand, the high cost of empty container repositioning has resulted in a shortage of empty container resources, leaving many regions without sufficient empty containers to meet transportation demand. This paper aims to integrate the transport demand for loaded and empty containers throughout the entire train journey, maximizing the effective utilization of train capacity and achieving a “Full-length and Full-occupied” strategy for the entire route. This paper optimizes train scheduling under random demand, minimizing the conflicts above while alleviating the shortage of empty containers. The study first uses Monte Carlo simulation to generate data on random demand. Then, it establishes a collaborative optimization model for loaded and empty containers to maximize the railway operators' transportation profits. Finally, Ningbo-Zhoushan Port and its hinterland are used as an empirical case to demonstrate the feasibility of this strategy. The results show that while capacity utilization increased by 10 %, profit margins also increased by 27 %, indicating that train capacity waste was controlled and more transportation demand was met.