Digital ATC support for the RAMS standard

A RAMS (Reliability, Availability, Maintainability and Safety) document concerned with a brand new digital ATC (Automatic Train Control) system has been developed in proportion to IEC 62278. The ATC system is going to be applied for the most important commuter lines in the Tokyo Metropolitan Area in place of the present analog ATC system. East Japan Railway has taken a leading role in the safety and reliability field from the system development phase. Thorough documentation activities had been kept from the principle examination stage in 1996 prior to the establishment of the IEC standard. The digital ATC realizes shorter train headway, and improves riding comfort. Its train control functions are as follows. (1) An ATC logic controller generates stop point information based on areas such as the position of the preceding train, and transmits it to the following train through the rails as a digital ATC signal. (2) An on-board ATC device monitors the position of the train, retrieves the parabolic train deceleration profiles and applies the brakes if necessary. The design, manufacture, and installation have been underway since 2000, with operation on the Keihin Tohoku Line scheduled to commence in 2003. System requirements were developed further into a set of system fundamentals in such a way that the basic content was already organized in accordance with the RAMS concept and system definition and application conditions stages. In 2003, East Japan Railway and Hitachi began to align the process of achieving safety and reliability of the digital ATC system with IEC 62278. This is possibly the first attempt anywhere to actually adjust such a large scale system as a whole to comply with the RAMS standard. As the result, we confirmed that our conventional development process of safety related railway equipment is one which sufficiently fulfills the RAMS standard.