Friday 2 November 2007

Railway operation in Japan

My recent visit to Japan gave me the opportunity to see how they run the railways in Japan. The answer appears to be 'very well', compared with the United Kingdom.

The English introduced railways to Japan, in the late 19th century. In view of the difficult terrain, a gauge of 3'6" (1067mm) was chosen, but with a generous loading gauge allowing quite large railway vehicles. At that time, speed was not seen as an issue and speeds did not exceed 100 k.p.h. A very extensive network of railways based on this formula still exists. All the major routes have been electrified at 1500 volts d.c. Japan Railways (JR) runs the majority of the routes, but there are also a number of private railways.

I was surprised to find that a lot of the infrastructure is fairly old, but it appears well-maintained and 'housekeeping' is excellent. In general, the private railways appear to have received more investment but all the trains I travelled on were punctual, clean and well-patronised.

Operational staff appear well-trained and diligent and I've commented elsewhere on the high standards of driving and the apparent discipline.

Signalling is mainly automatic block using a.c. track circuits and colour light signals. On normal routes, 3-aspect colour light signals are employed (GREEN - clear, YELLOW - caution, RED - stop). On high-density routes, 5-aspect signals are used (GREEN - clear, YELLOW OVER GREEN - reduced speed, YELLOW - caution, YELLOW OVER YELLOW - restricted speed, RED - stop). At junctions, route signalling is provided, usually with a separate signal head for each route.

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.