A Virtually Coupled Train Control Model Under Allowable Safe Distance Range Based on Vehicle-Following Approach With Operational Hazard Analysis and the Labelled Transition System

The virtual coupling system has been developed for controlling trains operating as a convoy. To achieve this, an effective approach to virtually merge trains into the same convoy, operating safely in normal situations and in emergencies, is essential. This paper proposes a new virtually coupled train control model based on the vehicle-following approach and operational hazard analysis that can ensure safe operation. Unlike existing models in previous works, the proposed model is generalised and flexible for real operations, allowing for the coupling of different train types with varying acceleration and deceleration capabilities and variable safe separation distance. The comprehensive set of operational states is created by adopting the labelled transition system to determine all interconnected state movements which can control the following train based on the preceding train operation. Suitable acceleration and deceleration equations for initial, virtual coupling, and emergency states are introduced to improve coupling capability and ensure safety in all operational states. Moreover, the minimum safe distance equation is modified to ensure safety and provide riding comfort by preventing fluctuating movement of trains in the convoy. The proposed model was simulated by using MATLAB and applied to a 250 km high-speed train line linking Thailand and Laos. The simulation includes normal train operations, varying acceleration and deceleration capabilities, communication time delays, and emergency scenarios such as unintentional stops, communication loss, and temporary speed restrictions. The simulation results demonstrate that the proposed model can accommodate virtual coupling of any train type, various braking capabilities, and a safe distance range, whereas it enhances capacity and guarantees operational safety. The following trains smoothly operate in coordination with the preceding train to maintain a safe separation distance, thereby preventing collisions between trains.