A Space-Time Interval Based Protection Method for Virtual Coupling

As a recent hot topic in railways, Virtual Coupling (VC) is aimed at providing more frequent rail services by operating trains closer. Given that current protection methods cannot fulfill the requirements of VC in terms of safety and efficiency, the implementation of VC urgently calls for an advanced protection method that allows successive trains to drive closer on the premise of safety. Therefore, to improve efficiency, after the force analysis of the train, a train emergency braking model that can describe the real process of emergency braking is proposed. The train emergency braking distance calculated from this model is smaller compared with the traditional train emergency braking model. Then, to ensure train safety, the deficiencies of the existing relative braking distance(RBD) based protection methods are analyzed. After adding constraints of time and space to the train emergency braking process and using the train emergency braking model proposed in this paper, a space-time interval based protection method is proposed. Compared with the RBD protection method, this method can ensure that the trains can track closer under the premise of safety, which can fulfill the requirements of VC. Finally, experiments are conducted to verify the safety and efficiency of the proposed methods. When the braking performance of the preceding train is worse than that of the following train, the space-time interval based protection method avoids the train colliding during the braking process, while RBD based protection method cannot avoid train collision. Experimental results numerically show that the minimum safe distance can be reduced by 29%, compared with the RBD based protection method.