Integrated optimisation of train schedule and rolling stock circulation for Y-type metro lines using an online flexible train composition mode

This research introduces a flexible train composition mode for metro systems using an online coupling and decoupling strategy to match transportation capacity with dynamic passenger demand efficiently. An integrated optimisation model is developed for train schedules and rolling stock circulation. Linearisation techniques are applied to convert the model into a linear form, facilitating solutions using commercial solvers. Validation through a Y-type metro line case study shows a significant reduction in both the number of rolling stock utilised and train operation costs. Specifically, train operating costs decrease by 24.31% compared to the trunk/branch mixed operation mode and by 16.23% compared to the branch-independent operation mode. The model's effectiveness is further demonstrated across various passenger demand scenarios, indicating its suitability for low-demand situations. The flexible train composition operation mode, using an online coupling/decoupling strategy, showcases its adaptability and potential for enhancing metro operational efficiency and resource utilisation.