Automatic Train Control
From Wikipedia, the free encyclopedia
Automatic Train Control (ATC) is a safety system for railways, ensuring the safe and smooth operation of trains on ATC-enabled lines. Its main advantages include making possible the use of cab signalling instead of track-side signals, and the use of smooth deceleration patterns in lieu of the rigid stops encountered with the older ATS technology. There are several implementations and versions of ATC, and each is different.
It is especially common in Japan, where ATC is used on all Shinkansen (bullet train) lines. In Japan, ATC has been introduced on various lines as a replacement for ATS.
Contents |
[edit] GWR ATC
In 1906, the Great Western Railway in the UK developed a system known as "Automatic Train Control" which does not conform to the modern definition of the term. This was an intermittent system that relied on an electrically energised (or unenergised) rail between, and higher than, the running rails. This rail sloped at each end and was known as an ATC ramp, and would make contact with a shoe on the underside of the passing locomotive.
If the signal associated with the ramp was displaying a cautionary aspect the ramp would not be energised. The ramp would lift the shoe on the passing locomotive and start a timer sequence at the same time sounding a horn on the footplate. If the driver failed to acknowledge this warning within a preset time the brakes of the train would be applied.
If the signal associated with the ramp was displaying a 'clear' aspect the ramp would be energised. The ramp would lift the shoe on the passing locomotive and cause a bell to sound on the footplate.
[edit] Digital ATC
Digital ATC is a digitized form of Automatic Train Control in use in a few JR lines in Japan.
The following forms of Digital ATC are in existence.
[edit] D-ATC
Used on non-high speed lines on some East Japan Railway Company (JR East) lines. Stands for Digital ATC. Its main difference from the older analog ATC technology is the shift from ground-based control to train-based control, allowing braking to reflect each train's ability, and improving comfort and safety. The fact that it can also increase speeds and provide for denser timetables is important for Japan's busy railways.
First D-ATC was enabled on the section of track from Tsurumi Station to Minami-Urawa Station on the Keihin-Tohoku Line on 21 December 2003 following the conversion of the 209 series trains there to support D-ATC.
The Yamanote Line was also D-ATC enabled in April 2005, following the replacement of all old 205 series rolling stock to the new, D-ATC enabled E231 series trains.
There are plans to D-ATC enable the rest of the Keihin-Tohoku line and the Negishi line, pending conversion of onboard and ground-based systems.
The ATC system on the Toei Shinjuku Line in use from 14 May 2005 is very similar to D-ATC.
On 18 March 2006, Digital ATC has also been enabled for Tōkaidō Shinkansen, the original Shinkansen owned by Central Japan Railway Company, replacing its old analog ATC system.
[edit] DS-ATC
Implemented on Shinkansen lines operated by JR East. Stands for Digital communication & control for Shinkansen-ATC. It is currently used on the section of track from Furukawa Station to Hachinohe Station on the Tōhoku Shinkansen. Other Shinkansen lines under the control of JR East are also due to be switched over to DS-ATC in the future. There are plans to implement the system on the remaining sections of the Tohoku Shinkansen and all sections of the Joetsu Shinkansen in the fiscal year of 2009. There are currently no plans to do so for the Nagano Shinkansen.
[edit] ATC around the world
[edit] ATC in the United States
A number of commuter railroads in the United States are installing ATC on all their lines. For example, New Jersey Transit has an active ATC conversion program with a budget of US $90 million. As of January 2006, ATC is in use on 92 percent of New Jersey Transit lines.[1] The San Francisco BART System was the first subway system to use this method of control in the United States.
[edit] ATC in Sweden
In Sweden the introduction of ATC started in the 1980s together with high speed rail and points. As of 2003, 9410 km out of the 11697 km of track maintained by Banverket had ATC installed[2].
[edit] References
Harold W. Lawson, Sivert Wallin, Berit Bryntse, Bertil Friman, "Twenty Years of Safe Train Control in Sweden," ecbs, p. 0289, Eighth Annual IEEE International Conference and Workshop on the Engineering of Computer Based Systems (ECBS '01), 2001.
