Optimized Train-Set Rostering Plan for Taiwan High-Speed Rail

Railway rolling stock is one of the most expensive assets of railway operators. Efficient utilization of rolling stock is one of the most important objectives pursued in practice. This research focuses on the improvement in rolling stock rostering efficiency for high-speed rail system. According to the circulation schedule and long-term maintenance plan, the rostering planner decides the assignment between rolling stock and duties subject to a set of practical constraints. Owing to its complexity, this task remains a manual process at the Taiwan High Speed Rail Corporation. Experienced railway practitioners can generally create a good and feasible plan, but they cannot guarantee optimality of the solution considering only short-term process. In this research, we developed an exact optimization model and a heuristic method to automate this process and improve the efficiency of rolling stock utilization. Results from the case studies demonstrate that the efficiency of the rolling stock usage can be increased by 3% similar to 4%, and that the process time can be significantly reduced from hours to seconds. Note to Practitioners-This paper was motivated by the problem of rolling stock rostering in Taiwan High Speed Rail System. The rolling stock rostering needs to take several practical factors into consideration such as maintenance requirements, depot maintenance capacity, connections among duties for successive days, and daily train-set availability. The manual process for rolling stock rostering is time-consuming and tedious, and the quality of the results can be improved. In this study, we proposed a heuristic method which consists of five phases to allot train-sets to duties automatically. The idea of assigning train-sets to duties is to keep the cumulative mileage of each train-set close to a corresponding ideal cumulative mileage. The cumulative mileages of all train-sets can evenly approach to the upper limitation of maintenance mileage so that the utilization of train-sets can be raised. The automation process can also provide prompt response to incidents during daily operation. Using this decision support tool will help railways with similar characteristics maximize their return from rolling stock investment and provide reliable service to their customers.