Analysis of Capacity of Train Operation at Junction under the Virtual Coupling System with Speed Limit Difference and Train Sequence

A railway junction is a crucial point on a railway network where multiple routes intersect and many train services run through it. Its connectivity to different railway routes can increase demand and traffic in shared corridors, turning the junction into a bottleneck. Upgrading the signalling system is one of many solutions to manage the traffic utilization and increase the capacity at the junction. The Virtual Coupling System (VCS), as the latest signalling technology, has proven to improve the capacity of the railway. However, many junction-related factors remain inadequately addressed. In this paper, we introduce the constraint of differences in speed limits between the main route and the secondary route to design a merging process in which three trains from different routes can start merging or coupling into VCS mode as they approach the converging point at a junction under different train sequence scenarios. A Finite State Machine (FSM) model is developed to control the train motion under VCS. Secondly, simulations are performed to compare the travel time required for the following train to reach the last milepost under VCS with that under the traditional Moving Block (MB) system, as well as to compare overall capacity. The simulation results show that the second and third trains can arrive at the final milepost earlier under VCS mode than under the MB system. In addition, the theoretical operational capacity under VCS mode improves compared to MB mode when a proper train sequence design is selected.