Train Automatic Stopping Controller

A Train automatic stopping controller (定位置停止装置^?) (TASC), is a train protection system currently used only in Japan. It allows trains equipped with TASC to stop automatically at stations without the need for the train operator to operate the brakes manually.

TASC was originally developed in the 1950s and 1960s as a way of ensuring that trains stop properly at stations, especially if the driver has made a minor driving lapse and stopped with a slight overrun/underrun, which can prove to be an inconvenience for passengers, particularly if the first or last door is partially (or, in rare cases, completely) outside the station. It has also been useful at preventing SPADs. TASC is also compatible with automatic train operation (ATO) and automatic train control (ATC).

The TASC system is used on the following lines.

In addition, the JR East Yamanote Line is expected to be TASC-ready by 2017.

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Wikipedia