The ATS-P system, which generates a "speed pattern" in accordance with the train's performance and the distance to the stop-aspect signal and activates the emergency brake automatically if the real speed exceeds the speed pattern, was developed and placed on trial for an extended period on the Kansai line in 1980. The system, however, was not able to provide enough ground-to-cab information to allow its application to high-density operation sections. Improvements to the ATS-P system were spurred by the accident which occurred in Nishi Akashi station in October 1984.
The first ATS-P system utilizing a "transponder", which provides more diverse information, was introduced on the Keiyo line in 1988. Since then, the new ATS-P system has been expanded on main lines up to now. Table 4 shows the outlines of various ATS and ATC systems.
