Two bad accidents in the 1960s led to the installation of an Automatic Train Stop (ATS) system throughout Japan. There are various enhancements to the basic ATS system.
ATS-S uses a series of track inductors. An alarm sounds in the cab when approaching a red signal and failure to initiate braking within 5 seconds causes an automatic brake application. 'Absolute Stop' track inductors do not rely on driver acknowledgement and are used in stations and at starting signals.
ATS-P is a later system which does not rely on driver acknowledgement but which monitors train speed, based on a sequence of track inductors located 30m, 180m and 650m before the signal, all wired to a 'Code Processor' at the signal. Two passive track inductors are provided even further back from the signal. There is a 'continuous' version of ATS where information is fed along track circuits.
The Automatic Train Control System (ATC) also feeds information along track circuits. It was developed for use on the 'Shinkansen' lines and indicates maximum speed for each section.
Automatic Train Operation (ATO) is used on some subways to control departure, line speed and stopping point in stations.More pictures of Japan's railways today.