Joint optimization of metro train timetable and stopping plan for the first service period: an integrated energy-efficient and time-saving model

This paper addresses the energy conservation challenge in metro systems during the first service period, characterized by large train headways and low passenger demands. A novel train timetabling method incorporating an express-local mode is proposed to maximize the overlap time between accelerating and braking trains, thereby facilitating the utilization of regenerative braking energy (RBE). Local and express trains depart alternately, with skip-stop strategies implemented for express trains. Considering the interests of operator and passengers for energy and travel time savings, a bi-objective model is proposed to jointly optimize train timetable and stopping plan. NSGA-II is applied to solve the model and obtain Pareto optimal solutions. Numerical experiments based on Ningbo Metro Line 1 data validate the effectiveness of proposed methods, showcasing significant enhancement in RBE utilization and notable reduction in passenger travel time. The proposed express-local mode establishes stable tracking relationships within train pairs, ensuring effective RBE utilization. Comparative analyses reveal that deadheading is more effective than flexible skip-stop for energy-efficient and time-saving metro operations.