Automatic train control (ATC) is a general class of

train protection system A train protection system is a railway technical installation to ensure safe operation in the event of human error. Development Train stops The earliest systems were train stops, as still used by the New York City Subway, the Toronto subway, ...

s for

railway Rail transport (also known as train transport) is a means of transport that transfers passengers and goods on wheeled vehicles running on rails, which are incorporated in tracks. In contrast to road transport, where the vehicles run on a pre ...

s that involves a speed control mechanism in response to external inputs. For example, a system could effect an emergency brake application if the driver does not react to a signal at danger. ATC systems tend to integrate various

cab signalling Cab signaling is a railway safety system that communicates track status and condition information to the cab, crew compartment or driver's compartment of a locomotive, railcar or multiple unit. The information is continually updated giving an e ...

technologies and they use more granular deceleration patterns in lieu of the rigid stops encountered with the older

automatic train stop Automatic train stop or ATS is a system on a train that automatically stops a train if certain situations occur (unresponsive train operator, earthquake, disconnected rail, train running over a stop signal, etc.) to prevent accidents. In some scena ...

(ATS) technology. ATC can also be used with automatic train operation (ATO) and is usually considered to be the

safety-critical A safety-critical system (SCS) or life-critical system is a system whose failure or malfunction may result in one (or more) of the following outcomes: * death or serious injury to people * loss or severe damage to equipment/property * environme ...

part of a railway system. Over time, there have been many different safety systems labelled as "automatic train control". The first experimental apparatus was installed on the

Henley branch line The Henley branch line is a branch railway line between Twyford in Berkshire and Henley-on-Thames in Oxfordshire. It was built by the Great Western Railway in 1857. Train services are provided by the present day Great Western Railway tra ...

in January 1906 by the Great Western Railway, although it would now be referred to as an automatic warning system (AWS) because the driver retained full command of braking. The term is especially common in Japan, where ATC is used on all

Shinkansen The , colloquially known in English as the bullet train, is a network of high-speed railway lines in Japan. Initially, it was built to connect distant Japanese regions with Tokyo, the capital, to aid economic growth and development. Beyond l ...

(bullet train) lines, and on some conventional rail lines, as a replacement for ATS.

Africa

Egypt

The accident report for the 2006 Qalyoub accident mentions an ATC system.

South Africa

In 2017,

Huawei Huawei Technologies Co., Ltd. ( ; ) is a Chinese multinational technology corporation headquartered in Shenzhen, Guangdong, China. It designs, develops, produces and sells telecommunications equipment, consumer electronics and various smar ...

was contracted to install

GSM-R GSM-R, Global System for Mobile Communications – Railway or GSM-Railway is an international wireless communications standard for railway communication and applications. A sub-system of European Rail Traffic Management System (ERTMS), it is us ...

partly to provide communication services to automatic train protection systems.

Asia

Japan

In Japan, the Automatic Train Control (ATC) system was developed for high-speed trains like the

, which travel so fast that the driver has almost no time to acknowledge trackside signals. Although the ATC system sends AF signals carrying information about the speed limit for the specific track section along the

track circuit A track circuit is an electrical device used to prove the absence of a train on rail tracks to signallers and control relevant signals. An alternative to track circuits are axle counters. Principles and operation The basic principle behind t ...

. When these signals are received on board, the train's current speed is compared with the speed limit and the brakes are applied automatically if the train is travelling too fast. The brakes are released as soon as the train slows below the speed limit. This system offers a higher degree of safety, preventing collisions that might be caused by driver error, so it has also been installed in heavily used lines, such as Tokyo's

Yamanote Line The Yamanote Line ( ja, 山手線, Yamanote-sen) is a loop service in Tokyo, Japan, operated by the East Japan Railway Company (JR East). It is one of Tokyo's busiest and most important lines, connecting most of Tokyo's major stations and urban c ...

and some subway lines. Although the ATC applies the brakes automatically when the train speed exceeds the speed limit, it cannot control the motor power or train stop position when pulling into stations. However, the automatic train operation (ATO) system can automatically control departure from stations, the speed between stations, and the stop position in stations. It has been installed in some subways. However, ATC has three disadvantages. First, the headway cannot be increased due to the idle running time between releasing the brakes at one speed limit and applying the brakes at the next slower speed limit. Second, the brakes are applied when the train achieves maximum speed, meaning reduced ride comfort. Third, if the operator wants to run faster trains on the line, all the related relevant wayside and on-board equipment must be changed first.

Analogue ATC

The following analogue systems have been used: *ATC-1: ATC-1 is used on the Tōkaidō and

Sanyō Shinkansen , stylized as SANYO, is a Japanese electronics company and formerly a member of the ''Fortune'' Global 500 whose headquarters was located in Moriguchi, Osaka prefecture, Japan. Sanyo had over 230 subsidiaries and affiliates, and was founded by ...

since 1964. The system used on the Tōkaido Shinkansen is classified as ATC-1A and ATC-1B on the Sanyō Shinkansen. Originally utilizing trackside speed limits of 0, 30, 70, 110, 160 and 210 km/h, it was upgraded to utilize speed limits of 0, 30, 70, 120, 170, 220, 230, 255, 270, 275, 285 and 300 km/h with the introduction of new rolling stock on both lines. Variants include ATC-1D and ATC-1W, the latter being used exclusively on the Sanyō Shinkansen. Since 2006, the Tōkaidō Shinkansen's ATC-1A system has been superseded by ATC-NS. *ATC-2: Used on the Tōhoku, Jōetsu and

Nagano Shinkansen The is a high-speed Shinkansen railway line jointly operated by East Japan Railway Company (JR East) and West Japan Railway Company (JR West), connecting Tokyo with in the Hokuriku region of Japan. The first section, between and in Nagano ...

routes, it utilized 0, 30, 70, 110, 160, 210 and 240 km/h trackside speed limits. In recent years, ATC-2 has been superseded by the digital DS-ATC. The Japanese ATC-2 system is not to be confused with the Ansaldo L10000 ATC system (also more often known as ATC-2) used in Sweden and Norway, which is similar to the

EBICAB EBICAB is a trademark registered by Bombardier (later Alstom) for the equipment on board a train used as a part of an Automatic Train Control system. EBICAB was originally derived from Ericsson's SLR system in Sweden. Most trains in Sweden and Norw ...

700 and 900 ATC systems used in some other parts of Europe. *ATC-3 (WS-ATC): Actually the first implementation of ATC in Japan, it was first used on

Tokyo Metro Hibiya Line The is a subway line in Tokyo, Japan, owned and operated by Tokyo Metro. The line was named after the Hibiya area in Chiyoda's Yurakucho district, under which it passes. On maps, diagrams and signboards, the line is shown using the color sil ...

(together with ATO) in 1961 and later on the

Tokyo Metro Tōzai Line The is a rapid transit line in Tokyo and Chiba Prefecture, Japan, owned and operated by Tokyo Metro. Its name translates to "''East-West Line"''. The line runs between Nakano in Nakano-ku, Tokyo and Nishi-Funabashi in Funabashi, Chiba Pr ...

. Stands for Wayside-ATC. Both lines converted to New CS-ATC (ATC-10) in 2003 and 2007 respectively. WS-ATC is also used on 5 Osaka Metro lines (the Midosuji Line, the

Tanimachi Line The is a rapid transit line of Osaka Metro, running from Dainichi Station in Moriguchi to Yaominami Station in Yao through Osaka. Its official name is , while the Osaka Municipal Transportation Bureau refers to it as , and in MLIT publicat ...

, the

Yotsubashi Line The is an underground rapid transit line in Osaka, Japan, operated by Osaka Metro. The line connects Umeda, Hommachi, Yotsubashi, Namba, Daikokuchō and Suminoe, and runs parallel to the Midōsuji Line from Daikokuchō to Nishi-Umeda. Its offic ...

, the Chuo Line and the Sakaisuji Line). *ATC-4 (CS-ATC): First used on the

Tokyo Metro Chiyoda Line The is a subway line owned and operated by Tokyo Metro in Tokyo, Japan. On average, the line carries 1,447,730 passengers daily (2017), the second highest of the Tokyo Metro network, behind the Tozai Line (1,642,378).JR East

Jōban Line The Jōban Line ( ja, 常磐線, ) is a railway line in Japan operated by the East Japan Railway Company (JR East). The line officially begins at Nippori Station in Arakawa, Tokyo before the line officially ends at Iwanuma Station in Iwanuma, ...

) in 1971, CS-ATC (which stands for Cab Signalling-ATC), is an analogue ATC technology using ground-based control, and, like all ATC systems, used cab signalling. CS-ATC uses trackside speed limits of 0, 25, 40, 55, 75 and 90 km/h. Its use has extended to include the

Tokyo Metro Ginza Line The is a subway line in Tokyo, Japan, operated by Tokyo Metro. The official name is . It is 14.3 km long and serves the wards of Shibuya, Minato, Chūō, Chiyoda, and Taitō. It is the oldest subway line in Asia. The line was named aft ...

(CS-ATC introduced in 1993, changed to New CS-ATC),

Tokyo Metro Marunouchi Line The is a subway line in Tokyo, Japan, operated by Tokyo Metro. The line runs in a U-shape between Ogikubo Station in Suginami and Ikebukuro Station in Toshima, with a branch line between Nakano-Sakaue Station and Hōnanchō Station. The offici ...

(CS-ATC introduced in 1998), and most recently, the

Tokyo Metro Yurakucho Line Tokyo (; ja, 東京, , ), officially the Tokyo Metropolis ( ja, 東京都, label=none, ), is the capital and largest city of Japan. Formerly known as Edo, its metropolitan area () is the most populous in the world, with an estimated 37.468 ...

(CS-ATC enabled in 2008). It is also used on all

Nagoya Municipal Subway The is a rapid transit system serving Nagoya, the capital of Aichi Prefecture in Japan. It consists of six lines that cover of route and serve 87 stations. Approximately 90% of the subway's total track length is underground. The subway system ...

lines and 3 Osaka Metro lines (the

Sennichimae Line is an underground rapid transit line in Osaka, Japan. It is one of the lines of Osaka Metro. It links the northwestern district of Fukushima-ku and the southeastern district of Ikuno-ku with the central commercial and entertainment district ...

, the Nagahori Tsurumi-ryokuchi Line and the

Imazatosuji Line The is a rapid transit line of Osaka Metro, running from Itakano Station in Higashiyodogawa-ku to Imazato Station in Higashinari-ku, all within Osaka city. Its official name is , and in MLIT publications, it is written as . Station number ...

). *ATC-5: Introduced on the

Sōbu Line (Rapid) The Sōbu Line (Rapid) ( ja, 総武快速線, ) is a railway service on the Sōbu Main Line in Tokyo and Chiba Prefecture, Japan, operated by East Japan Railway Company (JR East). It connects Tokyo Station in Chūō, Tokyo with Chiba Station ...

and the

Yokosuka Line The is a railway line in Japan operated by the East Japan Railway Company (JR East). The Yokosuka Line connects Tokyo Station with in Yokosuka, Kanagawa. Officially, the name Yokosuka Line is assigned to the 23.9 km segment between an ...

from 1972 to 1976, it utilized trackside speed limits of 0, 25, 45, 65, 75 and 90 km/h. ATC-5 was deactivated on both lines in 2004 in favour of

ATS-P Automatic train stop or ATS is a system on a train that automatically stops a train if certain situations occur (unresponsive train operator, earthquake, disconnected rail, train running over a stop signal, etc.) to prevent accidents. In some scena ...

. *ATC-6: Introduced in 1972, used on the

Saikyō Line The Saikyō Line ( ja, 埼京線, ) is a Japanese railway line operated by the East Japan Railway Company (JR East). It connects Ōsaki Station in Shinagawa, Tokyo, and Ōmiya Station in Saitama Prefecture. The line's name is an abbreviation o ...

and (formerly) Keihin-Tōhoku Line (through service with

Negishi Line The Negishi Line ( ja, 根岸線, ) is a Japanese railway line which connects Yokohama and Ōfuna stations. It is operated by East Japan Railway Company (JR East). Freight trains also operate on this line, and it is essential for the southern ...

, introduced 1984) and

(introduced 1981). Some

freight train Rail freight transport is the use of railroads and trains to transport cargo as opposed to human passengers. A freight train, cargo train, or goods train is a group of freight cars (US) or goods wagons (International Union of Railways) haul ...

s were fitted with ATC-6 as well. In 2003 and 2006, the Keihin-Tōhoku and Yamanote Lines replaced their ATC-6 systems with D-ATC. *ATC-9: Used on the Chikuhi Line (through service with

Fukuoka City Subway The serves Fukuoka, Japan. It consists of three subway lines, the Kūkō, or Airport Line, the Hakozaki Line and the Nanakuma Line). The lines are operated by the Fukuoka City Transportation Bureau. Unlike most other public operators in Japa ...

Kūkō Line) in Kyushu. *ATC-10 (New CS-ATC): Developed from ATC-4 (CS-ATC), ATC-10 can be partially compatible with D-ATC and completely compatible with the older CS-ATC (ATC-4) technology. ATC-10 can be seen as a hybrid of analogue and digital technology, although ATC-10 is not recommended for use with D-ATC because of poor performance of the full-service brake during trial tests. It is used on all

Tokyo Metro The is a major rapid transit system in Tokyo, Japan, operated by the Tokyo Metro Co. With an average daily ridership of 6.84 million passengers, the Tokyo Metro is the larger of the two subway operators in the city; the other being the Toe ...

lines, the

Tōkyū Den-en-toshi Line The is a major commuter line operated by the private railway operator Tokyu Corporation and connecting south-western suburbs of Tokyo and neighbouring Kanagawa Prefecture, with its western terminus of , to a major railway junction of western d ...

Tōkyū Tōyoko Line The is a major railway line connecting Tokyo (Shibuya) to Yokohama. The line is owned and operated by the private railway operator Tokyu Corporation. The name of the line, ''Tōyoko'' (東横), is a combination of the first characters of ''Tōky ...

and

Tsukuba Express The , or TX, is a Japanese railway line operated by the third-sector company Metropolitan Intercity Railway Company, which links Akihabara Station in Chiyoda, Tokyo and Tsukuba Station in Tsukuba, Ibaraki. The route was inaugurated on 24 Aug ...

. *ATC-L: Used on the

Kaikyō Line The is an 87.8-kilometer long railway line operated mainly by the Hokkaido Railway Company (JR Hokkaido). The line connects Naka-Oguni Station in Sotogahama, Aomori, through the Seikan Tunnel between Honshu and Hokkaido, to Kikonai Station in K ...

(inclusive of the

Seikan Tunnel The Seikan Tunnel ( ja, 青函トンネル, or , ), is a dual-gauge railway tunnel in Japan, with a portion under the seabed of the Tsugaru Strait, which separates Aomori Prefecture on the main Japanese island of Honshu from the northern isl ...

section) along with

Automatic Train Stop Automatic train stop or ATS is a system on a train that automatically stops a train if certain situations occur (unresponsive train operator, earthquake, disconnected rail, train running over a stop signal, etc.) to prevent accidents. In some scena ...

from 1988–2016. Replaced by DS-ATC following opening of the Hokkaido Shinkansen.

Digital ATC

The digital ATC system uses the track circuits to detect the presence of a train in the section and then transmits digital data from wayside equipment to the train on the track circuit numbers, the number of clear sections (track circuits) to the next train ahead, and the platform that the train will arrive at. The received data is compared with data about track circuit numbers saved in the train on-board memory and the distance to the next train ahead is computed. The on-board memory also saves data on track gradients, and speed limits over curves and points. All this data forms the basis for ATC decisions when controlling the service brakes and stopping the train. In a digital ATC system, the running pattern creates determines the braking curve to stop the train before it enters the next track section ahead occupied by another train. An alarm sounds when the train approaches the braking pattern and the brakes are applied when the braking pattern is exceeded. The brakes are applied lightly first to ensure better ride comfort, and then more strongly until the optimum deceleration is attained. The brakes are applied more lightly when the train speed drops to a set speed below the speed limit. Regulating the braking force in this way permits the train to decelerate in accordance with the braking pattern, while ensuring ride comfort. There is also an emergency braking pattern outside the normal braking pattern and the ATC system applies the emergency brakes if the train speed exceeds this emergency braking pattern. The digital ATC system has a number of advantages: *Use of one-step brake control permits high-density operations because there is no idle running time due to operation delay between brake release at the intermediate speed limit stage. *Trains can run at the optimum speed with no need to start early deceleration because braking patterns can be created for any type of rolling stock based on data from wayside equipment indicating the distance to the next train ahead. This makes mixed operation of express, local, and freight trains on the same track possible at the optimum speed. *There is no need to change the wayside ATC equipment when running faster trains in the future. To date, the following digital ATC systems are used: *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. The first D-ATC was enabled on the section of track from

Tsurumi Station is a railway station in Tsurumi-ku, Yokohama, Kanagawa Prefecture, Japan, operated by East Japan Railway Company (JR East). Lines Tsurumi Station is an interchange between the Keihin-Tōhoku Line and the Tsurumi Line (of which it is a terminus ...

Minami-Urawa Station is a junction passenger railway station located in Minami-ku, Saitama, Saitama Prefecture, Japan, operated by East Japan Railway Company (JR East). Lines Minami-Urawa Station is served by the Keihin-Tōhoku Line linking Saitama Prefecture w ...

on the Keihin-Tohoku Line on 21 December 2003 following the conversion of the

209 series The is an electric multiple unit (EMU) commuter train type operated by East Japan Railway Company (JR East) in the Tokyo area of Japan since 1993. The series was introduced in 1992 for experimental operations (as the 901 series) and in 1993 fo ...

trains there to support D-ATC. The

was also D-ATC enabled in April 2005, following the replacement of all old

205 series 5 (five) is a number, numeral and digit. It is the natural number, and cardinal number, following 4 and preceding 6, and is a prime number. It has attained significance throughout history in part because typical humans have five digits on eac ...

rolling stock to the new, D-ATC enabled

E231 series The is an electric multiple unit (EMU) train type used for commuter and outer-suburban services operated by East Japan Railway Company (JR East) in Japan since 2000. Design Trains were manufactured by Tokyu Car Corporation, Kawasaki Heavy In ...

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 The is a rapid transit line in Tokyo and Chiba Prefecture, Japan, operated by Tokyo Metropolitan Bureau of Transportation (Toei). The line runs between Motoyawata Station in Ichikawa, Chiba in the east and Shinjuku Station in the west. At Shin ...

in use from 14 May 2005 is very similar to D-ATC. Since 18 March 2006, Digital ATC has also been enabled for

Tōkaidō Shinkansen The is a Japanese high-speed rail line that is part of the nationwide Shinkansen network. Along with the Sanyo Shinkansen, it forms a continuous high-speed railway through the Taiheiyō Belt, also known as the Tokaido corridor. Opened in 1964, ...

, the original

owned by Central Japan Railway Company, replacing the old analog ATC system. D-ATC is used with the

THSR 700T The THSR 700T ( zh, t=台灣高鐵700T型電聯車) is the high-speed electric multiple unit trainset derived from the Japanese Shinkansen family for Taiwan High Speed Rail (THSR), Taiwan's high-speed rail line. The THSR 700T is based primarily ...

built for the

Taiwan High Speed Rail Taiwan High Speed Rail (THSR) is the high-speed railway of Taiwan consisting of one line that runs approximately along the west coast, from the capital Taipei to the southern city of Kaohsiung. With construction and operations managed by a pri ...

, which opened in early January 2007. *DS-ATC: Implemented on

lines operated by JR East. Stands for Digital communication & control for Shinkansen-ATC. It is used on the

Tōhoku Shinkansen The is a Japanese high-speed Shinkansen rail line, connecting Tokyo with Aomori in Aomori Prefecture in a route length of , making it Japan's longest Shinkansen line. It runs through the more sparsely populated Tōhoku region of Japan's main ...

Hokkaido Shinkansen The is a Japanese high-speed Shinkansen rail line that links up with the Tōhoku Shinkansen in northern Aomori Prefecture in Honshu and continues on into the interior of Hokkaido through the undersea Seikan Tunnel. Construction started in May ...

, Joetsu Shinkansen and the

Hokuriku Shinkansen The is a high-speed Shinkansen railway line jointly operated by East Japan Railway Company (JR East) and West Japan Railway Company (JR West), connecting Tokyo with in the Hokuriku region of Japan. The first section, between and in Nagano Pr ...

. *RS-ATC: Used on the Tōhoku, Hokkaido, Hokuriku and Jōetsu Shinkansen at a fallback level from DS-ATC. RS-ATC is similar to

in that radio signals are used to control the speed limit on trains, as compared to trackside beacons on other types of ATC. *ATC-NS: First used on the Tōkaidō Shinkansen since 2006, ATC-NS (which stands for ATC-New System), is a digital ATC system based on DS-ATC. Also used on the

Taiwan High Speed Railway Taiwan High Speed Rail (THSR) is the high-speed railway of Taiwan consisting of one line that runs approximately along the west coast, from the capital Taipei to the southern city of Kaohsiung. With construction and operations managed by a pri ...

and the

San'yō Shinkansen The is a line of the Japanese Shinkansen high-speed rail network, connecting Shin-Osaka in Osaka with Hakata Station in Fukuoka, the two largest cities in western Japan. Operated by the West Japan Railway Company (JR West), it is a westward cont ...

. *KS-ATC: Used on the

Kyushu Shinkansen The is a Japanese Shinkansen high-speed railway network. It is an extension of the San'yō Shinkansen from Honshu connecting the city of Fukuoka (Hakata Station) in the north of Japan's Kyushu Island to the city of Kagoshima ( Kagoshima-Chuo St ...

since 2004. Stands for Kyushu Shinkansen-ATC.

South Korea

Several subway lines in South Korea use ATC, in some cases enhanced with ATO.

Busan

All lines use ATC. All lines are enhanced with ATO.

Seoul

Other than on Lines 1 and 2 (MELCO cars only), all lines use ATC. Line 2 (VVVF cars), Line 5 cars, Line 6 cars, Line 7 cars, and Line 8 cars have their ATC systems enhanced with ATO.

Europe

Denmark

Denmark's system of ATC (officially designated

ZUB 123 The ZUB 1xx system is a family of train protection systems produced by Siemens. Its ZUB balises were deployed in the ZUB 121 train protection system in the Swiss railway network, in the ZUB 122 tilting control system in the German railway networ ...

) is different from that of its neighbours. From 1978 until 1987, the Swedish ATC system was trialled in Denmark, and a new Siemens-designed ATC system was implemented between 1986 and 1988. In consequence of the Sorø railway accident, which occurred in April 1988, the new system was progressively installed on all Danish main lines from the early 1990s onwards. Some trains (such as those employed on the

Øresundståg Øresundståg (, ) is a passenger train network operated by Skånetrafiken and Transdev in the transnational Øresund Region of Denmark and Sweden. The name is a hybrid of the Danish ''Øresundstog'' and the Swedish ''Öresundståg'', both meani ...

service and some

X 2000 X 2000, also called SJ X2 or simply as X2, is an electric tilting train operated by SJ in Sweden. It was constructed by Kalmar Verkstad in Kalmar, Sweden (prior to the company being bought by Adtranz in 1996) and launched in 1990 as a ...

trains) have both the Danish and the Swedish systems, while others (e.g. ten of the ICE-TD trains) are fitted with both the Danish and the German systems. The ZUB 123 system is now considered by

Banedanmark Banedanmark (; previously Banestyrelsen) is a Danish company that is responsible for the maintenance and traffic control on all of the state owned Danish railway network. History In 1997, Banedanmark came into existence, having been branched o ...

, the Danish railway infrastructure company, to be obsolete and the entire Danish rail network is expected to be converted to ETCS Level 2 by 2030. The ZUB 123 system is however not used on the

Copenhagen S-train The Copenhagen S-train ( da, S-tog), the S-train of Copenhagen, Denmark is a key part of public transport in the city. It is a hybrid urban-suburban rail serving most of the Copenhagen urban area, and is analogous to S-Bahn systems of Berlin, Vi ...

network, where another, incompatible safety system called HKT ( da:Hastighedskontrol og togstop) has been in use since 1975, as well as on the

Hornbæk Line The Hornbæk Line ( da, Hornbækbanen) is a long standard gauge single track local passenger railway line north of Copenhagen, Denmark. It runs along the coast of Øresund between Helsingør and Gilleleje, through an area with many holiday hom ...

, which uses a much more simplified ATP system introduced in 2000. This system is gradually being replaced by the modern and worldwide

CBTC Communications-based train control (CBTC) is a railway signaling system that uses telecommunications between the train and track equipment for traffic management and infrastructure control. CBTC allows a train's position to be known more accurat ...

signalling standard as of 2022.

Norway

Bane NOR Bane NOR SF, formerly Jernbaneinfrastrukturforetaket (English: ''Railway Infrastructure Company''), is the Norwegian government agency responsible for owning, maintaining, operating and developing the Norwegian railway network, including the tra ...

—the Norwegian government's agency for railway infrastructure—uses the Swedish system of ATC. Trains can therefore generally cross the border without being specially modified. However, unlike in Sweden, the ATC system used in Norway differentiates between partial ATC (''delvis ATC'', DATC), which ensures that a train stops whenever a red signal is passed, and full ATC (FATC), which, in addition to preventing overshooting red signals, also ensures that a train does not exceed its maximum allowed speed limit. A railway line in Norway can have either DATC or FATC installed, but not both at the same time. ATC was first trialled in Norway in 1979, after the

Tretten train disaster The Tretten train disaster occurred on 22 February 1975 when a northbound train (no. 351) from Oslo and a southbound express train (no. 404) from Trondheim, both loaded with vacationing skiers, collided head-on north of Tretten station. With 27 kil ...

, caused by a

signal passed at danger A signal passed at danger (SPAD), known in the United States as a stop signal overrun and in Canada as passing a stop signal, is an event on a railway where a train passes a stop signal without authority. In the United States and Canada, this ...

(SPAD), occurred four years earlier. DATC was first implemented on the section Oslo S - Dombås - Trondheim - Grong between 1983 and 1994, and FATC was first implemented on the

Ofoten Line The Ofoten Line ( no, Ofotbanen) is a railway line in Narvik, Norway. It runs from the Port of Narvik to Riksgränsen on the Norway–Sweden border, where the line continues as the Ore Line via Kiruna and Gällivare to Luleå. The Ofoten Lin ...

in 1993. The high-speed

Gardermoen Line The Gardermoen Line ( no, Gardermobanen) is a high-speed railway line between Oslo and Eidsvoll, Norway, running past Lillestrøm and Oslo Airport, Gardermoen. The line is long and replaced the older Hoved Line as the main line north-east of O ...

has had FATC since its opening in 1998. After the

Åsta accident The Åsta accident was a railway accident that occurred at 13:12:25 on 4 January 2000 at Åsta in Åmot, south of Rena in Østerdalen, Norway. A train from Trondheim collided with a local train from Hamar on the Røros Line, resulting in an exp ...

occurred in 2000, the implementation of DATC on the Røros Line was accelerated, and it became operational in 2001.

Sweden

In Sweden the development of ATC started in the 1960s (ATC-1), and was formally introduced in the early-1980s together with high-speed trains (ATC-2/Ansaldo L10000). As of 2008, 9,831 km out of the 11,904 km of track maintained by

Swedish Transport Administration The Swedish Transport Administration ( sv, Trafikverket) is a government agency in Sweden, controlled by the Riksdag and the Government of Sweden. It is responsible for long-term infrastructure planning for transport: road, rail, shipping and avi ...

—the Swedish agency responsible for railway infrastructure—had ATC-2 installed. However, since ATC-2 is generally incompatible with

ERTMS The European Rail Traffic Management System (ERTMS) is the system of standards for management and interoperation of signalling for railways by the European Union (EU). It is conducted by the European Union Agency for Railways (ERA) and is the ...

ETCS The European Train Control System (ETCS) is the signalling and control component of the European Rail Traffic Management System (ERTMS). It is a replacement for legacy train protection systems and designed to replace the many incompatible s ...

(as in the case of the

Bothnia Line The Bothnia Line ( sv, Botniabanan) is a high-speed railway line in northern Sweden. The long route, from Höga Kusten Airport, where it connects to the Ådalen Line, via Örnsköldsvik to Umeå, was opened in 2010 and trains are allowed to t ...

which is the first railway line in Sweden to exclusively use ERTMS/ETCS), and with the aim of Trafikverket to eventually replace ATC-2 with ERTMS/ETCS over the next few decades, a Special Transmission Module (STM) has been developed to automatically switch between ATC-2 and ERTMS/ETCS.

United Kingdom

In 1906, the Great Western Railway in the UK developed a system known as "automatic train control". In modern terminology, GWR ATC is classified as an automatic warning system (AWS). This was an intermittent train protection 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. The ramps were provided at distant signals. A development of the design, intended for use at stop signals, was never implemented. If the signal associated with the ramp was at caution, 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. In testing, the GWR demonstrated the effectiveness of this system by sending an express train at full speed past a distant signal at caution. The train was brought safely to a stand before reaching the home signal. If the signal associated with the ramp was clear, the ramp was energised. The energized ramp would lift the shoe on the passing locomotive and cause a bell to sound on the footplate. If the system were to fail then the shoe would remain unenergised, the caution state; it therefore failed safe, a fundamental requirement of all safety equipment. The system had been implemented on all GWR main lines, including Paddington to Reading, by 1908. The system remained in use until the 1970s, when it was superseded by the British Rail

Automatic Warning System The Automatic Warning System (AWS) was introduced in the 1950s in the United Kingdom to provide a train driver with an audible warning and visual reminder that they were approaching a distant signal at caution. Its operation was later extended t ...

(AWS).

North America

Canada

Starting in 2017, the

Toronto Transit Commission The Toronto Transit Commission (TTC) is the public transport agency that operates bus, subway, streetcar, and paratransit services in Toronto, Ontario, Canada, some of which run into the Peel Region and York Region. It is the oldest and larges ...

began the implementation of ATC on to

Line 1 Yonge–University Line 1 Yonge–University is a rapid transit line on the Toronto subway. It serves Toronto and the neighbouring city of Vaughan in Ontario, Canada. It is operated by the Toronto Transit Commission, has 38 stations and is in length, making it th ...

, at a cost of $562.3million. Awarding the contract to Alstom in 2009, the TTC will be able to reduce the headway between trains on Line 1 during rush hours, and allow an increase in the number of trains operating on Line 1. Work would however not begin until the delivery of brand new trains with ATC compatibility and the retirement of older rolling stock that was not compatible with the new system. ATC was introduced in phases, beginning with a test on November 4, 2017 during regular service between Dupont and Yorkdale stations. It was first introduced in a permanent manner with the opening of the Toronto–York Spadina subway extension in December 17, 2017, between and stations.Implementation of the system on to the remainder of the line was carried out during weekend closures and night time work when the subway would close. There were delays on the project, with deadlines for the complete conversion of Line 1 pushed back multiple times until 2022. ATC conversion was completed to Finch station on September 24, 2022.Converting all of Line 1 to ATC required the installation of 2,000 beacons, 256 signals, and more than one million feet of cable. ATC is also planned to be used on the soon to open

Line 5 Eglinton Line 5 Eglinton (also known as the Eglinton Crosstown or the Crosstown) is a light rail line that is under construction in Toronto, Ontario, Canada. Owned by Metrolinx and operated by the Toronto Transit Commission (TTC), the line will be part of ...

line, however, Unlike on Line 1, the system on Line 5 will be supplied by Bombardier Transportation using its Cityflo 650 technology.The TTC plans to convert

Line 2 Bloor-Danforth Line most often refers to: * Line (geometry), object with zero thickness and curvature that stretches to infinity * Telephone line, a single-user circuit on a telephone communication system Line, lines, The Line, or LINE may also refer to: Arts ...

and

Line 4 Sheppard Line 4 Sheppard is the newest and shortest subway line of the Toronto subway system, operated by the Toronto Transit Commission (TTC). It opened on November 22, 2002, and has five stations along of track, which is built without any open section ...

to ATC in the future, subject to funding availability and being able to replace the current non-ATC compatible fleet on Line 2 with trains that are, with an estimated date of completion by 2030.

United States

ATC systems in the United States are almost always integrated with existing continuous

systems. The ATC comes from electronics in the locomotive that implement some form of speed control based on the inputs of the cab signalling system.Amtrak Employee Timetable #3, Northeast Region, Jan, 18th, 2010, Section 550 If the train speed exceeds the maximum speed allowed for that portion of track, an overspeed alarm sounds in the cab. If the engineer 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 handling and control issues with North American 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 The National Railroad Passenger Corporation, doing business as Amtrak () , is the national passenger railroad company of the United States. It operates inter-city rail service in 46 of the 48 contiguous U.S. States and nine cities in Canada ...

, Metro North and the Long Island Rail Road require the use of speed control on freight trains that run on all or part of their systems. While cab signalling 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 signalled 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 New Jersey is a state in the Mid-Atlantic and Northeastern regions of the United States. It is bordered on the north and east by the state of New York; on the east, southeast, and south by the Atlantic Ocean; on the west by the Delaware ...

legislated use of speed control on all major passenger train operators within the State. While speed control is used on many passenger lines in the United States, in most cases it has been adopted voluntarily by the railroads that own the lines. Only three freight railroads,

Union Pacific The Union Pacific Railroad , legally Union Pacific Railroad Company and often called simply Union Pacific, is a freight-hauling railroad that operates 8,300 locomotives over routes in 23 U.S. states west of Chicago and New Orleans. Union Pac ...

Florida East Coast The Florida East Coast Railway is a Class II railroad operating in the U.S. state of Florida, currently owned by Grupo México. Built primarily in the last quarter of the 19th century and the first decade of the 20th century, the FEC was a pro ...

and CSX Transportation, have adopted any form of ATC on their own networks. The systems on both FEC and CSX work in conjunction with pulse code cab signals, which in the case of CSX was inherited from the Richmond, Fredericksburg and Potomac railroad on its single main line. Union Pacific's was inherited on portions of the Chicago and Northwestern east–west main line and works in conjunction with an early two aspect cab signaling system designed for use with ATC. On CSX and FEC more restrictive cab signal changes require the engineer to initiate a minimum brake application or face a more severe penalty application that will bring the train to a stop. Neither system requires explicit speed control or adherence to a

braking curve A brake is a mechanical device that inhibits motion by absorbing energy from a moving system. It is used for slowing or stopping a moving vehicle, wheel, axle, or to prevent its motion, most often accomplished by means of friction. Background ...

.CSX Baltimore Division Timetable - RF&P Sub Section The Union Pacific system requires an immediate brake application that cannot be released until the train's speed has been reduced to (for any train traveling above that speed). Then, the train's speed must be further reduced to no more than within 70 seconds of the initial cab signal drop. Failure to apply the brakes for these speed reductions will result in a penalty application. All three freight ATC systems provide the engineer with a degree of latitude in applying brakes in a safe and proper manner, since improper braking can result in a derailment or a runaway. None of the systems are in effect in difficult or mountainous terrain.

References

{{Authority control Train protection systems