Automatic Train Control.html

Automatic Train Control (ATC) is a train protection 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.

1 GWR ATC
2 Digital ATC
- 2.1 D-ATC
- 2.2 DS-ATC
3 ATC around the world
- 3.1 ATC in the United States
- 3.2 ATC in Scandinavia
4 References
5 See also

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.

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.

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.

D-ATC is used with the Shinkansen 700T custom built for the Taiwan High Speed Rail which opened in early January 2007.

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.

ATC around the world

ATC in the United States

ATC systems in the United States are almost always integrated with existing continuous Cab Signaling systems. The ATC comes from electronics in the locomotive that implement some form of speed control based on the inputs of the cab signaling system. If the train speed exceeds the maximum speed allowed by the cab signals an overspeed alarm sounds in the cab. If the driver fails to reduce speed and/or make a brake application to reduce speed a penalty brake application is made automatically. Due to the more sensitive train control issues with freight trains, ATC is almost exclusively applied to passenger locomotives in both inter-city and commuter service with freight trains making use of cab signals without speed control. Some high-volume passenger railroads such as Amtrak, Metro North and the Long Island Rail Road do require the use of speed control on those few freight trains that run on all or part of their systems.

While cab signaling and speed control technology has existed since the 1920s, adoption of ATC only became an issue after a number of serious accidents several decades later. The Long Island Rail Road implemented its Automatic Speed Control system within its cab signaled territory in the 1950s after a pair of deadly accidents caused by ignored signals. After the Newark Bay Lift Bridge Disaster the state of New Jersey legislated use of speed control on all major passenger train operators within the State. While speed control is currently used on many passenger lines in the United States, in most cases it has been adopted voluntarily by the train operating company.

ATC in Scandinavia

In Sweden the introduction of ATC started in the 1980s ^[1] together with high speed rail and points. As of 2003, 9410 km out of the 11697 km of track maintained by Banverket had ATC-2 installed^[2]. The Norwegian railroad, JBV utilize the same system as well.