Assurance evaluation technology for an autonomous decentralized ATC system

High transport capacity, high safety, and high reliability are required of train control systems in the high-density operational sections. The conventional systems operate as follows. The presence of a train is detected at each fixed section. Based on a decision as to whether or not the train should progress into the section, the velocity of the train is calculated by a centralized control system on the ground, and the result is communicated to the automatic train control device (ATC) of the train. It is difficult to realize high-density transport by this mechanism. This paper proposes an autonomous decentralized ATC system (D-ATC), which works as follows. Each train detects its own position. Only the position at which to stop is communicated from the ground to the train, and the velocity of the train is determined and controlled autonomously on the basis of this instruction. Then, an assurance technology is proposed in which trains with D-ATC are introduced stepwise without disturbing the operation of the whole system, and their testing in on-line operation is assured while they coexist with trains with the existing ATC. The on-train integration and the on-train separation technologies are presented as two methods of stepwise introduction and are evaluated from the viewpoint of assurance. Based on the results obtained in this study, a practical application was performed in the train control system of the JR East Yamanote/Keihin Tohoku line.