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List of railway electrification systems
List of railway electrification systems
List of railway electrification systems
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This is a list of the power supply systems that are, or have been, used for railway electrification.

Note that the voltages are nominal and vary depending on load and distance from the substation.

As of 2023, many trams and trains use on-board solid-state electronics to convert these supplies to run three-phase AC traction motors.

Tram electrification systems are listed here.

Key to the tables below

[edit]
  • Volts: voltage or volt
  • Current:
  • Conductors:
    • overhead line or
    • conductor rail, usually a third rail to one side of the running rails. Conductor rail can be:
      • top contact: oldest, least safe, most affected by ice, snow, rain and leaves. Protection boards are installed on most top contact systems, which increases safety and reduces these affections.
      • side contact: newer, safer, less affected by ice, snow, rain and leaves
      • bottom contact: newest, safest, least affected by ice, snow, rain and leaves
  • Red background indicates voltages no longer in use on the indicated location

Systems using standard voltages

[edit]
See also: Railway electrification system § Voltage, and List of tram systems by gauge and electrification

Voltages are defined by two standards: BS EN 50163[1] and IEC 60850.[2]

Overhead systems

[edit]

600 V DC

[edit]
Country Location Name of system Notes
Worldwide
 Many tram systems This voltage is mostly used by older tram systems worldwide but by a few modern ones as well. See List of tram systems by gauge and electrification.
Germany Trossingen Trossingen Railway
Hungary Budapest Budapest Metro Line M1
Japan Chōshi, Chiba Chōshi Electric Railway
Kyoto, Kyoto Eizan Electric Railway
Kanagawa Enoshima Electric Railway
Matsuyama, Ehime Iyotetsu Takahama Line
Shizuoka, Shizuoka Shizuoka Railway
Romania Sibiu county Sibiu-Rășinari Narrow Gauge Railway Part of the former Sibiu tram line
Spain Madrid Madrid Metro Lines 1, 4, 5, 6 and 9. In process to be converted to 1500 V
United Kingdom Crich, England National Tramway Museum
United States Boston MBTA subway Green and Mattapan Lines, the at-grade section of Blue Line northeast of Airport station
Cleveland RTA Rapid Transit Red Line
San Diego San Diego Trolley
Iowa Iowa Traction Railway
San Francisco San Francisco Municipal Railway

750 V DC

[edit]
Country Location Name of system Notes
Worldwide
 Many tram systems This voltage is used for most modern tram and light rail systems. See List of tram systems by gauge and electrification
Austria Upper Austria Local lines of Stern & Hafferl Also listed as having 1500 V and 600 V lines
Austria
Switzerland 		Rhine / Lake Constance Internationale Rheinregulierungsbahn Construction railway for the regulation works of the river Rhine near its outfall into Lake Constance, now preserved. The river forms the border between Austria and Switzerland, and the railway operated in both countries.
Germany Karlsruhe to Bad Herrenalb with a branch to Ittersbach Albtalbahn Railway of the Upper Rhine
Hong Kong Hong Kong MTR MTR Light Rail
India Bengaluru Namma Metro
Pune Pune Metro Line 3
Kolkata Kolkata Metro
Ahmedabad Ahmedabad Metro
Japan Hamamatsu, Shizuoka Enshū Railway
Hakone, Kanagawa Hakone Tozan Railway Line Between Hakone-Yumoto and Gōra
Ehime Iyotetsu Yokogawara Line and Gunchū Line
Yokkaichi, Mie Yokkaichi Asunarou Railway Utsube Line, Hachiōji Line
Mie Sangi Railway Hokusei Line
Mexico Mexico City STC Line A
Netherlands The Hague, Zoetermeer, Rotterdam and adjacent cities Randstadrail
Rotterdam Rotterdam Metro North of Capelsebrug station overhead wires
Philippines Metro Manila Manila LRT Line 1 (Manila Light Rail Transit System) Between Dr. Santos and Fernando Poe Jr.
Manila MRT Line 3 (Manila Metro Rail Transit System) Between North Avenue and Taft Avenue
Switzerland Canton of Aargau Menziken–Aarau–Schöftland railway line
Republic of China (Taiwan) New Taipei New Taipei Metro: all Light Rail lines
Turkey Adana Adana Metro
Eskişehir EsTram
Istanbul Istanbul Metro Line M1 and M5
United Kingdom Manchester Manchester Metrolink All lines

1,200 V DC

[edit]
Country Location Name of system Notes
Cuba Havana – Matanzas and branches Ferrocarriles Nacionales de Cuba Originally (and still known as) the Hershey Electric Railway
Germany Lusatia 900 mm (2 ft 11+7⁄16 in) gauge mining railways in the lignite district
Spain Barcelona, Catalonia Barcelona Metro Uses an overhead conductor rail/beam system
Palma – Sóller, Majorca Sóller Railway [3]
Switzerland Canton of Bern / canton of Solothurn Aare Seeland mobil (ASm) [4][5]
Dietikon, canton of Zürich – Wohlen, canton of Aargau Bremgarten-Dietikon-Bahn
Zürich – Esslingen, canton of Zürich Forchbahn Forchbahn proper only; Forchbahn trains access their Zürich terminus via the Zürich tram network, which is electrified at 600 V DC. The rolling stock is equipped to run off both voltages.
Frauenfeld, canton of Thurgau – Wil, canton of St. Gallen Frauenfeld-Wil-Bahn
Meiringen – Innertkirchen, canton of Bern Meiringen–Innertkirchen Bahn
United States Baltimore–Annapolis, Maryland Baltimore and Annapolis Railroad 1914–1950
Los Angeles – Inland Empire, California Pacific Electric Upland–San Bernardino Operated 1914–1950. 600 V in city limits
California Sacramento Northern Railway Operated 1910–1936. Converted to 1,500 V. The southern division was built by the Oakland, Antioch and Eastern Railway.
East Bay, California East Bay Electric Lines 1911–1941
Oregon Oregon Electric Railway 1912–1945

1,500 V DC

[edit]
Country Location Name of system Notes
Argentina Buenos Aires Buenos Aires Metro Lines A, C, D, E and H
Tren de la Costa Suburban line
Australia Melbourne Melbourne Suburban Railways
Regional New South Wales NSW TrainLink Intercity Newcastle and Central Coast, Blue Mountains to Lithgow and South Coast to Kiama
Sydney Sydney Trains
Sydney Metro Lines partially converted from Sydney Trains and North West Eppng to Tallawong only, completely new lines will use 25 kV 50 Hz AC[6]
Bangladesh Dhaka Dhaka Metro Rail MRT Line 6 (Dhaka Metro)
Brazil São Paulo São Paulo Metro Lines 4 and 5
Bulgaria Sofia Sofia Metro Line 3 Gorna Banya – Hadzhi Dimitar
Canada Montreal Réseau express métropolitain Incl. Deux-Montagnes line that was built by CNoR in 1918 as 2400 V DC, converted to 3000 V DC in the 1980s, converted to 25 kV 60 Hz in 1995 by the MTQ, being converted to light-metro standard and 1500 V DC
Ottawa O-Train Line 1 only; Line 2 is diesel LRT.
China Beijing Beijing Subway Lines 6, 14 and 16
Changchun Changchun Rail Transit Lines 1 and 2
Changsha Changsha Metro
Changzhou Changzhou Metro
Chengdu Chengdu Metro Except lines 17, 18 and 19
Chongqing Chongqing Rail Transit Lines 1, 4, 5, 6, 10 and Loop Line
Dalian Dalian Metro
Dongguan Dongguan Rail Transit
Fushun Fushun Electric Railway
Fuzhou Fuzhou Metro
Guangzhou Guangzhou Metro Except Lines 4, 5, 6, 14 and 21, but overhead wires installed in depots.
Guiyang Guiyang Metro
Haining Hangzhou-Haining Intercity Rail
Hangzhou Hangzhou Metro
Harbin Harbin Metro
Hefei Hefei Metro
Hohhot Hohhot Metro
Jinan Jinan Metro
Lanzhou Lanzhou Metro
Nanchang Nanchang Metro
Nanjing Nanjing Metro
Nanning Nanning Metro
Ningbo Ningbo Rail Transit Line 4 uses third rail for returning current
Shanghai Shanghai Metro Except Lines 16 and 17, but overhead wires installed in the depot for line 16.
Shaoxing Shaoxing Metro
Shenyang Shenyang Metro
Shenzhen Shenzhen Metro Except Lines 3 and 6, but overhead wires installed in the depot for line 6.
Shijiazhuang Shijiazhuang Metro
Suzhou Suzhou Metro
Tianjin Tianjin Metro Lines 5, 6 and 9 only
Ürümqi Ürümqi Metro
Wuhan Wuhan Metro Line 6 only
Xi’an Xi'an Metro
Xiamen Xiamen Metro
Xuzhou Xuzhou Metro
Zhengzhou Zhengzhou Metro
Colombia Medellín Medellín Metro Lines A and B
Peru Lima Lima Metro
Czech Republic Tábor – Bechyně Správa železnic Tábor – Bechyně line only (24 km, built in 1903)
Dominican Republic Santo Domingo Santo Domingo Metro
Egypt Cairo Cairo Metro Line 1[7][8]
France Société Nationale des Chemins de fer (SNCF) 25 kV AC used on new high speed lines (TGV) and in the north (see below)
Hong Kong Hong Kong Mass Transit Railway Except East Rail line and Tuen Ma line which use 25 kV 50 Hz AC (see below) and the light rail which uses 750 V DC
Hungary Budapest Budapest Cog-wheel Railway Converted from 550 V DC (city trams nominal voltage at that time) during the 1973 reconstruction.
Indonesia Jakarta KRL Jabodetabek
Jakarta MRT
Yogyakarta-Solo KRL Commuterline Yogyakarta–Solo
Ireland Dublin Dublin Area Rapid Transit
Israel Tel Aviv Tel Aviv Light Rail Red Line runs partially as a premetro
Italy Rome Rome Metro Line A, Line B, Line Roma-Ostia Lido
Japan Japan Railways (JR) lines Most electrified lines in Kantō, Chūbu, Kansai, Chūgoku, and Shikoku (except Shinkansen and Hokuriku region)
Most private railway lines See Railway electrification in Japan for more details including exceptions
Most subway lines
South Korea Seoul National Capital Area Seoul Subway Except Korail Subway Line (except Line 3)
(see below)
Busan Busan Subway
Daegu Daegu Subway
Daejeon Daejeon Subway
Gwangju Gwangju Subway
Incheon Incheon Subway Line 1
Mexico Guadalajara SITEUR Line 3
Mexico City STC Line 12
Monterrey Sistema de Transporte Colectivo Metrorrey
Netherlands Nederlandse Spoorwegen – Dutch Railways (NS) 25 kV AC used on high speed lines and freight line Betuweroute (see below); The existing 1500V DC lines might be converted to 3kV DC.
New Zealand Wellington Wellington suburban Except Wairarapa Line beyond Upper Hutt. Since 2011, the nominal voltage was 1600 V but with the same tolerances as 1500 V (i.e. 1300–1800 V), making it backwards-compatible with 1500 V rolling stock. Since May 2016 the operating voltage was increased to 1700 V DC following the full introduction of the Matangi EMUs.
Philippines Metro Manila Manila MRT Makati Intra-city Subway (Line 5) and Metro Manila Subway (Line 9) only. Line 7 uses 750 V DC third rail.
Metro Manila
Rizal 		Manila LRT Line 2 only. Line 1 uses 750 V DC.
Metro Manila
Central Luzon
Laguna 		Philippine National Railways North–South Commuter Railway
Portugal Lisbon, Oeiras and Cascais Linha de Cascais To be converted to 25kV AC.[9]
Singapore Singapore Mass Rapid Transit North East Line, operated by SBS Transit
Slovakia Tatra Mountains in the area of Poprad Tatra Electric Railway
Spain Catalonia Ferrocarrils de la Generalitat de Catalunya
Madrid ADIF Only Cercedilla-Cotos line
Mallorca Serveis Ferroviaris de Mallorca
North coast (Asturias-Leon-Cantabria-Basque Country) FEVE
Basque Country Euskotren Trena
Valencian Community Ferrocarrils de la Generalitat Valenciana
Sweden Stockholm Roslagsbanan
Switzerland Aigle – Leysin, canton of Vaud Chemin de fer Aigle–Leysin (AL)
Aigle, Vaud – Champéry, canton of Valais Chemin de fer Aigle–Ollon–Monthey–Champéry (AOMC)
Aigle – Les Diablerets, canton of Vaud Chemin de fer Aigle–Sépey–Diablerets (ASD)
Interlaken – Lauterbrunnen / Grindelwald, canton of Bern Berner Oberland Bahn (BOB)
Canton of Jura Chemins de fer du Jura (CJ) Metre gauge lines only
Lausanne – Bercher, canton of Vaud Chemin de fer Lausanne–Échallens–Bercher (LEB)
Nyon – La Cure, canton of Vaud Chemin de fer Nyon-St-Cergue-Morez (NStCNM) Converted in the 1980s from 2200 V DC
Vitznau / Goldau – Rigi Rigi Bahnen (VRB/ARB)
Wilderswil – Schynige Platte, canton of Bern Schynige Platte Bahn (SPB)
Liestal – Waldenburg, canton of Basel-Country Waldenburgerbahn (WB)
Lauterbrunnen – Grindelwald, canton of Bern Wengernalpbahn (WAB)
Turkey Bursa Bursaray
Istanbul Istanbul Metro Line M3, M4, M7, M8, M9 and M11
United Kingdom Newcastle, Sunderland, Gateshead and Tyneside Tyne & Wear Metro Light rail
United States Chicago Metra Electric District
California Sacramento Northern Railway operated 1936–c. 1960s
Maryland Purple Line Light rail under construction
Northern Indiana & Chicago South Shore Line
Oregon Southern Pacific Red Electric Lines 1914–1929
Seattle Link light rail 1 and 2 lines only

3 kV DC

[edit]
Country Location Name of system Note
Belgium Belgium National Railways (SNCB) National standard. 25 kV AC used on high speed lines and some lines in the south (see below).
Brazil Rio de Janeiro SuperVia Trens Urbanos
São Paulo São Paulo Metropolitan Trains
Chile Empresa de los Ferrocarriles del Estado
Czech Republic Správa železnic Northern part of network only (approx. the Děčín – Praha – Ostrava route). The system change stations are Kadaň-Prunéřov, Beroun, Benešov u Prahy, Kutná Hora hl.n., Svitavy, Nezamyslice, Říkovice. The southern part uses 25 kV 50 Hz (see below).
The 3 kV system is to be phased out in favour of 25 kV AC.[10]
Estonia Tallinn Elron Commuter rail only
Georgia Georgian Railways In fact 3,300 V
Italy Rete Ferroviaria Italiana 25 kV AC used on new high speed lines (see below)
North Korea Korean State Railway National standard
Latvia Latvian Railways Commuter rail only.
Morocco ONCF National standard
Netherlands ProRail Planned
Poland Polish State Railways National standard. Planned high speed lines in Poland will use 25 kV AC[11]
Warsaw and suburbs Warszawska Kolej Dojazdowa 600 V DC until 27 May 2016
Russia Russian Railways New electrification use only 25 kV AC (see below), except Moscow Central Circle and other interconnection lines in Moscow, and 2 interconnection lines (Veymarn line and Kamennogorsk line) in St. Petersburg. Sverdlovsk railway and West Siberian railway to be converted to 25 kV AC.
Slovakia Slovak Republic Railways (ŽSR) Northern main line (connected to Czech Republic and Poland) and eastern lines (around Košice and Prešov), conversion to 25 kV AC planned,[10] and the broad gauge line between Košice and the Ukraine border (it will remain 3 kV until new broad gauge line construction, then convert to 25 kV AC), planned new broad gauge line is supposed to use 25 kV AC. Currently, the part north and east of the station Púchov uses 3 kV DC, the rest uses 25 kV 50 Hz (see below).
Slovenia Slovenian Railways National standard
South Africa Transnet Freight Rail; Metrorail National standard; also 25 kV AC (see below) and 50 kV AC used
Spain Administrador de Infraestructuras Ferroviarias 25 kV AC used on high speed lines (AVE) (see below)
Ukraine Ukrainian Railways In east (Donetsk industrial zone), in west (west from L'viv – connecting to Slovakia and Poland), to be converted to 25 kV AC[12] (see below)

15 kV AC, 16+2⁄3 Hz / 16.7 Hz

[edit]
Main article: 15 kV AC railway electrification
Country Location Name of system Notes
Austria ÖBB National standard. Planned new high speed lines will near the border use 25 kV AC: Innsbruck-Italy and broad gauge to Ukraine. Austrian National Railways also operate in the small country of Liechtenstein, which also uses 15 kV AC.
Czech Republic Znojmo - Retz Správa železnic Isolated section near border with Austria
Germany Deutsche Bahn - German National Railways (DB) National standard
Norway Norwegian National Rail Administration
Sweden Swedish Transport Administration
Switzerland Canton of Bern BLS
Central Switzerland and Bernese Highlands Zentralbahn
Canton of Vaud Chemin de fer Bière-Apples-Morges (BAM)
Canton of Zürich Sihltal Zürich Uetliberg Bahn
Swiss Federal Railways (SBB CFF FFS)

25 kV AC, 50 Hz

[edit]
Main article: 25 kV AC railway electrification
Country Location Name of system Notes
Argentina Buenos Aires Roca Line Constitución – Ezeiza
Constitución – Alejandro Korn
Constitución – Bosques
Constitución – La Plata
Australia Brisbane, North Coast line, Blackwater and Goonyella coal railways Queensland Rail
Perth Transperth
Adelaide Adelaide Metro Seaford/Flinders and Gawler lines electrified
Sydney Sydney Metro Completely new lines (Western Sydney Airport and Sydney Metro West) converted lines use 1500V DC[6]
Belarus National standard
Belgium Belgium National Railways (NMBS/SNCB) High-speed lines and some other lines. The rest of the network is 3 kV DC (see above)
Bosnia and Herzegovina
Botswana Proposed line to Namibia
Bulgaria Bulgarian State Railways
China China Railway National standard
Beijing Beijing Subway Daxing Airport Line only
Chengdu Chengdu Metro Lines 17, 18 and 19 only
Wenzhou Wenzhou Rail Transit
Croatia Croatian Railways Lines Zagreb-Rijeka and Rijeka-Šapjane formerly used 3kv DC traction
Czech Republic Správa železnic Southern lines only (linking Karlovy Vary – Cheb – Plzeň – České Budějovice – Tábor – Jihlava – Brno – Břeclav – Slovakia), northern lines use 3 kV DC (see above)
Denmark Banedanmark National standard, excluding Copenhagen S-train
Djibouti Addis Ababa–Djibouti Railway Ethiopian Railway Corporation
Ethiopia Addis Ababa–Djibouti Railway Ethiopian Railway Corporation
Finland National standard
France North and new lines SNCF A number of lines also electrified with 1.5 kV (see above)
Germany Harz Rübelandbahn
Greece Hellenic Railways Organisation National standard
Hong Kong Kowloon, New Territories MTR East Rail and Tuen Ma lines
Hungary Hungarian State Railways and Raaberbahn
India Indian Railways Entire IR network uses the current system since 2016.
Mumbai Mumbai Suburban Railway Conversion from 1.5 kV DC to the current system was completed in 2012 (for Western line[13]) and 2016 (for Central line[14][15][16]) respectively
Mumbai Mumbai Metro (Line 1)
Chennai (Madras) Chennai Metro
Delhi Delhi Metro
Hyderabad Hyderabad Metro
Pune Pune Metro
Nagpur Nagpur Metro
Jaipur Jaipur Metro
Lucknow Lucknow Metro
Iran Planned
Israel Israel Railways Construction contract awarded in December 2015.[17] Initial test runs began December 2017.
Italy Rete Ferroviaria Italiana (Italian Railways Network) New high-speed lines only, other lines use 3 kV DC (see above)
Japan Kantō (northeast of Tokyo), Tōhoku, and Hokkaido regions JR East Tohoku Shinkansen, Joetsu Shinkansen, and Hokuriku Shinkansen (sections between Tokyo – Karuizawa, and between Jōetsumyōkō – Itoigawa)
JR Hokkaido Hokkaido Shinkansen 		25 kV AC 60 Hz in some areas (see below).
Kazakhstan
Laos Boten–Vientiane railway
Latvia Latvian Railways Eastern lines only (planned)
Lithuania Kena — Kaunas and Lentvaris — Trakai Lithuanian Railways (LG) Electrification of Naujoji Vilnia – Kena —

Gudogai (BCh) route for Vilnius – Minsk (Belarus) services is established on 2017. Further Kaunas – Klaipeda and Kaunas – Kybartai corridors electrification will follow projects.

Luxembourg Chemins de fer luxembourgeois (CFL) National standard
Malaysia Padang Besar – KL Sentral – Segamat KTM ETS (run through West Coast railway line), Keretapi Tanah Melayu Berhad Under construction: Segamat – Johor Bahru
Bukit Mertajam – Padang Regas and Butterworth – Padang Besar KTM Komuter Northern Sector, Keretapi Tanah Melayu Berhad
Batu Caves – Pulau Sebang/Tampin, Tanjung Malim – Port Klang and KL Sentral – Terminal Skypark KTM Komuter Central Sector (Seremban Line, Port Klang Line and Skypark Link), Keretapi Tanah Melayu Berhad
KL Sentral – KLIA2 Express Rail Link (KLIA Ekspres and KLIA Transit)
Montenegro Belgrade–Bar railway and Nikšić–Podgorica railway Railways of Montenegro
Morocco Kenitra–Tangier high-speed rail line ONCF Casablanca–Kenitra conventional line onto which high-speed trains continue remains at 3 kV DC[18]
Namibia Proposed line to Botswana
Netherlands HSL-Zuid high speed line and Betuweroute freight line Nederlandse Spoorwegen 1.5 kV DC used on the rest of the network (see above)
New Zealand Auckland Auckland suburban 77 km between Swanson and Papakura; first service 28 April 2014
Central North Island North Island Main Trunk 411 km between Palmerston North and Hamilton
North Macedonia Makedonski Železnici
Poland Hrubieszów Broad Gauge Metallurgy Line (LHS) A section from the border to Hrubieszów will be electrified in conjunction with the electrification of the connecting border – Izov – Kovel line in Ukraine.[19] The reminder sections will follow.
Portugal Portuguese Railways (CP) Except the Linha de Cascais (1500 V DC)
Romania Caile Ferate Romane
Russia Russian Railways National standard used for new electrification; some areas still use 3 kV DC (see above)
Serbia Serbian Railways
Slovakia Slovak Republic Railways (ŽSR) South-western lines only (around Bratislava, Kuty, Trencin, Trnava, Nove Zamky, Zvolen) and the rest of the network (except narrow gauge lines), currently 3 kV DC, to follow (see above)
South Africa Transnet Freight Rail, Gautrain Also 3 kV DC (see above) and 50 kV 50 Hz used.
Spain ADIF Alta Velocidad High-speed lines only, other lines use 3 kV DC (see above)
Sweden Malmö Öresund Line On the Öresund Bridge and short part of land.
Haparanda Haparanda Line broad gauge track Only at the station near the border to Finland (with 1524mm gauge)
Thailand Bangkok Suvarnabhumi Airport Link and SRT Red Lines
Tunisia [20]
Turkey Turkish State Railways (TCDD) National standard
United Kingdom Network Rail Except Southern region and Merseyrail and Northern Ireland
Ukraine Ukrainian Railways National standard, in most of the west; also 3 kV DC in the east (see above)
Uzbekistan
Zimbabwe Gweru – Harare National Railways of Zimbabwe (NRZ) De-energised in 2008. May be renewed in the future.[21]


25 kV AC, 60 Hz

[edit]
Main article: 25 kV AC railway electrification
Country Location Name of system Notes
Japan Kantō (west of Tokyo), Chūbu, Kansai, Chūgoku, and Kyushu regions Tōkaidō-Sanyō Shinkansen
Hokuriku Shinkansen (sections between Karuizawa – Jōetsumyōkō, and between Itoigawa – Tsuruga)
Kyushu Shinkansen
Nishi Kyushu Shinkansen 		25 kV AC 50 Hz in eastern Japan (see above)
South Korea Korail All Korail freight/passenger lines except Seoul subway Line 3 which is 1.5 kV DC (see above)
Seoul Shinbundang line
Incheon, Seoul A'REX
Mexico Greater Mexico City Ferrocarril Suburbano de la Zona Metropolitana del Valle de México [22]
Mexico Valley, Toluca Valley El Insurgente First section operating on 2023. Rest expected mid of 2024
Yucatán Peninsula Tren Maya Under construction. About 40% of the route to be electrified [23]
Saudi Arabia Hejaz region Haramain High-Speed Railway
Republic of China (Taiwan) Taiwan Railways Administration National standard
Western Taiwan Taiwan High Speed Rail
United States New Jersey Morris & Essex Lines, New Jersey Transit Converted from 3,000 V DC to 25 kV 60 Hz in 1984.
Aberdeen-Matawan to Long Branch, New Jersey North Jersey Coast Line, New Jersey Transit Converted in 1978 from Pennsylvania Railroad 11 kV 25 Hz system to the 12.5 kV 25 Hz on the Rahway-Matawan ROW and 12.5 kV 60 Hz electrification extended to Long Branch in 1988. The Matawan-Long Branch voltage converted from 12.5 kV 60 Hz system to the 25 kV 60 Hz in 2002.
New Haven to Boston Northeast Corridor (NEC), Amtrak Electrified in 2000; see Amtrak's 60 Hz traction power system
Denver Denver RTD Opened in 2016; separate 750 V DC system for light rail
Rancho Cucamonga to Las Vegas Brightline West Under construction, expected to be operational by 2027–28.
California California High-Speed Rail Under construction between Merced and Bakersfield, set to begin operation in 2029–30.
San Francisco Peninsula Caltrain Completed in 2024; see Caltrain Modernization Program
New Mexico Navajo Mine Railroad
Texas Monticello & Martin Lake lines, Texas Utilities De-electrified[24] around 2011

Conductor rail systems

[edit]

600 V DC conductor

[edit]

All systems are third rail unless stated otherwise. Used by some older metros.

Country Location Name of system Notes
Argentina Buenos Aires Urquiza Line Federico Lacroze-General Lemos
Canada Toronto Toronto subway Only on subway lines
Greece Athens EIS/ISAP used between 1904 and 1985
Italy Turin Superga Rack Railway
Japan Tokyo Tokyo Metro Ginza Line and Marunouchi Line
Nagoya, Aichi Nagoya Municipal Subway Higashiyama Line and Meijō Line
Sweden Stockholm Stockholm Metro 650 V, Green and Red Lines
United Kingdom Glasgow Glasgow Subway
United States Anaheim, California Disneyland Monorail
Boston Massachusetts Bay Transportation Authority Red and Orange Lines, the subway part of the Blue Line southwest of Airport station
Chicago Chicago "L" elevated and subway lines
Staten Island Staten Island Railway
New York City metro area PATH
Philadelphia SEPTA Metro - B
Bay Lake, Florida Walt Disney World Monorail System
California Sacramento Northern Railway Used 1906–c. 1960s. The Northern subdivision was built by the Northern Electric Railway and operated with overhead wires in towns.

750 V DC conductor

[edit]

Conductor rail systems have been separated into tables based on whether they are top, side or bottom contact. Used by most metros outside Asia and the former Eastern bloc.

Bottom contact
[edit]
Country Location Name of system Notes
Algeria Algiers Algiers Metro
Austria Vienna Vienna U-Bahn
Brazil São Paulo São Paulo Metro Except Lines 4 and 5
China Beijing Beijing Subway Capital Airport Line only
Kunming Kunming Metro Except Line 4
Tianjin Tianjin Metro Lines 2 and 3 only
Wuhan Wuhan Metro Lines 1, 2, 3 and 4 only
Czech Republic Prague Prague Metro
Denmark Copenhagen Copenhagen Metro
Egypt Cairo Cairo Metro Line 2 and Line 3
Finland Helsinki Helsinki Metro
Germany Berlin Berlin U-Bahn and Berlin S-Bahn Lines from U5 to U9 (large profile). Negative polarity.
Hamburg Hamburg U-Bahn
Munich Munich U-Bahn
Nuremberg Nuremberg U-Bahn
India Bangalore Namma Metro
Kochi Kochi Metro
Ahmedabad Ahmedabad Metro
Kanpur Kanpur Metro
Gurgaon Rapid Metro Gurgaon
Kolkata Kolkata Metro
South Korea Busan Busan-Gimhae Light Rail Transit
Malaysia Klang Valley Klang Valley Integrated Transit System LRT Ampang and Sri Petaling lines, MRT Kajang and Putrajaya lines, and KL Monorail to be used on LRT Shah Alam Line
Netherlands Amsterdam Amsterdam Metro including line 51 north of Station Zuid
Rotterdam Rotterdam Metro North of Capelsebrug station overhead wires
Norway Oslo Oslo T-bane
Poland Warsaw Warsaw Metro
Romania Bucharest Bucharest Metro
Singapore Singapore Mass Rapid Transit North–South, East–West, Circle and Thomson-East Coast lines operated by SMRT Trains
Downtown line operated by SBS Transit
Republic of China (Taiwan) Kaohsiung Kaohsiung Metro
Taipei Taipei Metro
Taoyuan–Taipei Taoyuan Metro
Turkey Ankara Ankara Metro
Istanbul Istanbul Metro Lines M2 and M6 only
İzmir İzmir Metro
United Kingdom London Docklands Light Railway
United States New York City Metro-North Railroad
Side contact
[edit]
Country Location Name of system Notes
Canada Montreal Montreal Metro (guide bars, see DC, four-rail below)
China Shanghai Shanghai Metro – Pujiang line Central guide rail for rubber-tyred Bombardier Innovia APM 300
Chile Santiago Santiago Metro
France Paris Paris Métro (Rubber tired) Positive (and sometimes negative) polarity on guide bars. See DC, four-rail below.
Lyon Lyon Métro
Marseille Marseille Métro
Lille Lille Métro
Rennes Rennes Métro
Toulouse Toulouse Métro
Hong Kong Hong Kong Hong Kong International Airport
Automated People Mover (APM) 		Mitsubishi "Crystal Mover" system using two power rails (positive and negative) with side collection.
Indonesia Palembang Palembang Light Rail Transit Palembang Light Rail Transit and Greater Jakarta Light Rail Transit are operated by Kereta Api Indonesia. Jakarta Light Rail Transit is operated by Jakarta Propertindo (Jakpro).
Jakarta Jakarta Light Rail Transit
Greater Jakarta Light Rail Transit
Japan Sapporo, Hokkaido Sapporo Municipal Subway Namboku Line
Singapore Singapore Light Rail Transit Sengkang and Punggol lines operated by SBS Transit
Singapore Sentosa Express Sentosa Express operated by SDC
Malaysia Klang Valley Klang Valley Integrated Transit System LRT Kelana Jaya line Innovia Metro system using two power rails (positive and negative) with side collection.
United States Las Vegas Las Vegas Monorail
Top contact
[edit]
Country Location Name of system Notes
Canada Vancouver Vancouver SkyTrain Canada Line only
China Beijing Beijing Subway Capital Airport Line use bottom contact
Tianjin Tianjin Metro Line 1 only
France Paris Paris Métro (Conventional metro)
Germany Berlin Berlin U-Bahn Lines from U1 to U4 (small profile)
Greece Athens Athens Metro Line 1 was 600 V before 1985.
Hungary Budapest Budapest Metro Except line M1, which is 600 V DC with overhead lines.
India Kolkata Kolkata Metro
Japan Osaka, Osaka Osaka Metro Except the Sakaisuji Line, Nagahori Tsurumi-ryokuchi Line, and the Imazatosuji Line, which are 1,500 V DC with overhead lines.
Suita, Osaka
Toyonaka, Osaka 		Kita-Osaka Kyuko Railway
Higashiosaka, Osaka
Ikoma, Nara
Nara, Nara 		Kintetsu Keihanna Line
Yokohama, Kanagawa Yokohama Municipal Subway Blue Line (Line 1 and Line 3) only
North Korea Pyongyang Pyongyang Metro based on fleet of cars from Beijing and Germany
South Korea Yongin Everline
Portugal Lisbon Lisbon Metro
Sweden Stockholm Stockholm Metro Nominal voltage 650 V, subway 3 (blue line) 750 V. Subway 1 and 2 will change in the long term to 750 V.
United Kingdom Liverpool Merseyrail
London Northern City Line access to City (Moorgate)
London Suburban electrification of the LNWR Suburban Network formerly four-rail out of Euston and Broad Street, curtailed, upgraded and standardised
Southern England Southern Region of British Railways and successors 660 V system upgraded and expanded
London Waterloo and City line Upgraded by British Rail to 750V prior to sale to London Underground
United States Atlanta MARTA
Los Angeles Los Angeles Metro Rail B and D Lines
Miami Metrorail
New York City and Long Island
East River Tunnels shared with Amtrak 		Long Island Rail Road Central, Greenport, and Oyster Bay branches not electrified; Montauk Branch not electrified east of Babylon; Port Jefferson Branch not electrified east of Huntington
Philadelphia PATCO Speedline
Puerto Rico Tren Urbano
Washington, D.C. Washington Metro
within the Hudson and East River Tunnels as well as under Manhattan
Northeast Corridor 		Amtrak
within the Hudson Tunnel into Manhattan New Jersey Transit
Mixed
[edit]
Type Country Location Name of system Notes
See note China Tianjin Tianjin Metro Top contact in Line 1, bottom contact in Lines 2 and 3

1,200 V DC conductor

[edit]

All systems are third rail and side contact unless stated otherwise.

Country Location Name of system Notes
Germany Hamburg Hamburg S-Bahn 15 kV  16.7 Hz AC with overhead line in part of network.
United Kingdom Greater Manchester Bury Line Converted to 750 V DC overhead in 1991 for operation by the Manchester Metrolink light rail system
United States California Central California Traction Company 1908–1946, bottom contact[25]

1,500 V DC conductor

[edit]

All systems are third rail unless stated otherwise.

Type Country Location Name of system Notes
Bottom contact France Paris Paris Métro Line 18 Currently under construction
Toulouse Line C (Toulouse Metro) [fr] Currently under construction
Side contact Chambéry – Modane Culoz–Modane railway used between 1925 and 1976, today overhead wire
Bottom contact China Beijing Beijing Subway Line 7 only
Guangzhou Guangzhou Metro Lines 4, 5, 6, 14 and 21 only. Overhead wires in depots; all trains are equipped with pantographs
Kunming Kunming Metro Line 4 only
Qingdao Qingdao Metro
Shanghai Shanghai Metro Lines 16 and 17 only. Overhead wires in depot of Line 16, all trains on Line 16 have pantographs for depot use.
Shenzhen Shenzhen Metro Lines 3 and 6 only. Overhead wires in depot of Line 6, all trains on Line 6 have pantographs for depot use.
Wuhan Wuhan Metro Lines 7, 8, 11 and Yangluo Line only
Wuxi Wuxi Metro

Systems using non-standard voltages

[edit]

Overhead systems

[edit]

DC voltage

[edit]
Voltage Country Location Name of system Notes
120 United Kingdom Seaton, Devon Seaton Tramway Half scale trams. Operated 1969-now. Substations have battery banks for back up.
250 United States Chicago Chicago Tunnel Company operated 1906–1959
370 United States Connecticut Norwich and Westerly Railway operated 1906–1922[26]
525 Switzerland Lauterbrunnen Bergbahn Lauterbrunnen-Mürren
550 Hong Kong Hong Kong Island Hong Kong Tramways
Isle of Man Isle of Man Manx Electric Railway
Snaefell Mountain Railway The third rail is for the Fell Brake and doesn't carry any power
India Kolkata Trams in Kolkata
United States Bakersfield, California Bakersfield and Kern Electric Railway operated 1888–1942
Fresno, California Fresno Traction Company operated 1903–1939
Monterey, California Monterey and Pacific Grove Railway operated 1905–1923
Phoenix, Arizona Phoenix Street Railway operated 1888–1948[27]
Reno, Nevada Reno Traction Company operated 1904–1927, see Streetcars in Reno
575 United States Birmingham, Alabama Birmingham Railway, Light and Power Company [28]
650 United States Buffalo, New York Buffalo Metro Rail
El Paso, Texas El Paso Streetcar
Pittsburgh Pittsburgh Light Rail
Switzerland Basel Basel Trams (BVB/BLT)
660 Poland Metropolis GZM Silesian Interurbans
700 Switzerland Bex – Col de Bretaye, Vaud Chemin de fer Bex-Villars-Bretaye
730 United States Pennsylvania Philadelphia Suburban Transportation Company purchased by Philadelphia and Western Railroad in 1953 and converted to 600 VDC[29]
800 Poland Tricity Szybka Kolej Miejska (Tricity) Operated 1951–1976. Converted to 3,000 V DC in 1976.
825 United States Portland, Oregon MAX, TriMet Light rail sections west of NE 9th Avenue & Holladay Street utilize a 750 V system
850 Switzerland Capolago – Monte Generoso, Ticino Ferrovia Monte Generoso (MG)
900 Fribourg Gruyere – Fribourg – Morat
Vaud Montreux–Lenk im Simmental line
Vevey–Les Pléiades
1,000 Italy
Switzerland 		St Moritz, canton of Graubünden – Tirano, Lombardy Rhätische Bahn (RhB) Bernina line only; remainder of system electrified at 11 kV AC, 16 2⁄3 Hz. The Bernina line is an international line linking Switzerland (St. Moritz) with Italy (Tirano)
Hungary Budapest Budapest Commuter Rail and Rapid Transit (BHÉV) [30]
1,100 Argentina Buenos Aires Buenos Aires Metro (Subterráneos de Buenos Aires) Only Line A (converted to 1,500 V DC with La Brugeoise trains replaced by new rolling stock in 2013)
1,250 Switzerland Canton of Bern Regionalverkehr Bern-Solothurn (RBS) All lines except tram line 6 between Bern and Worb, which is electrified at 600 V DC[31]
1,350 Italy
Switzerland 		Domodossola, Piedmont – Locarno, canton of Ticino Domodossola–Locarno railway line (FART / SSIF [de]) International railway between Italy (Domodossola) and Switzerland (Locarno)
Switzerland Lugano – Ponte Tresa, canton of Ticino Ferrovia Lugano–Ponte Tresa (FLP)
1,650 Denmark Copenhagen Copenhagen S-train Suburban rail network in Copenhagen
Italy Rome Rome–Giardinetti railway Isolated Italian metre gauge line.
2,400 Germany Lausitzer work line of the Lausitzer Braunkohle coal company
Poland Konin Konin Coal Mine[32]
Turek PAK KWB ADAMÓW[32] mine closed in February 2021, the railway will be dismantled[33]
France Grenoble Chemin de fer de La Mure −1,200 V, +1,200 V two wire system from 1903 to 1950. 2,400 V since 1950.[34]
United States Montana Butte, Anaconda and Pacific Railway electrified 1913–1967, dismantled in favor of diesel power
3,500 United Kingdom Manchester Bury – Holcombe Brook operated 1913–1918
6,000 Russia experiments in the late 1970s (3,000 V DC lines)

AC voltage

[edit]
Voltage Frequency Country Location Name of system Notes
3,300 15 Hz United States Tulare County, California Visalia Electric Railroad 1904–1992
25 Hz United States Napa and Solano Counties, California San Francisco, Napa and Calistoga Railway 1905–1937
Indiana Indianapolis and Cincinnati Traction Company[35] 1905–1924
5,500 16+2⁄3 Hz Germany Murnau Ammergau Railway 1905–1955, after 1955 15 kV, 16.7 Hz
6,250 50 Hz United Kingdom London, Essex, Herts Great Eastern suburban lines Great Eastern suburban lines from Liverpool Street London, 1950s–c1980 (converted to 25 kV)
United Kingdom Glasgow Glasgow suburban lines Sections of the North Clyde Line and Cathcart Circle Line from 1960-1970s
6,300 25 Hz Germany Hamburg Hamburg S-Bahn Operated with AC 1907–1955. Used both AC and DC (1,200 V 3rd rail) 1940–1955.
6,500 25 Hz Austria Sankt Pölten Mariazellerbahn
6,600 Norway Orkland Thamshavnbanen
United Kingdom Lancaster to Heysham Morecambe branch line 1908–1951
Converted for testing of 50 Hz electrification in 1952
6,600 50 Hz 1952-1966
Germany Cologne Lowland Hambachbahn and Nord-Süd-Bahn transports lignite from open-pit mines to powerplants. Owned by RWE.
6,600 United States Northern Indiana Chicago, Lake Shore and South Bend Railway 1908–1925
Converted to 1,500 V DC
6,700 25 Hz United Kingdom London Victoria to London Bridge South London line 1909–1928
Converted to 660 V (later 750 V) DC third-rail supply
8 kV 25 Hz Germany Karlsruhe Alb Valley Railway 1911–1966, today using 750 V DC
10 kV Netherlands The Hague – Rotterdam Hofpleinlijn from 1908, in 1926 converted to 1,500 DC, In 2006 replaced by 750 V DC light rail
10 kV 50 Hz Russia industrial railways at quarries Russian Railways operated from 1950s at coal and ore quarries
Ukraine Ukrainian Railways
Kazakhstan some private industrial railways in Kazakhstan
11 kV 16+2⁄3 Hz Switzerland Graubünden Rhätische Bahn (RhB) Except the Bernina line, which is electrified at 1,000 V DC
Matterhorn-Gotthard-Bahn (MGB) formerly Furka Oberalp Bahn (FO) and BVZ Zermatt-Bahn
50 Hz France Saint-Gervais-les-Bains Mont Blanc Tramway
11 kV 25 Hz United States Pennsylvania Railroad
Etc., 		All lines now 12 kV 25 Hz or 12.5 kV 60 Hz
See Railroad electrification in the United States
United States Washington Cascade Tunnel Converted from three-phase 6600 V 25 Hz in 1927, dismantled 1956
United States Colorado Denver and Intermountain Railroad dismantled c. 1953[36]
12 kV 16+2⁄3 Hz France lines in Pyrenees Chemin de fer du Midi most converted to 1,500 V 1922–23; Villefranche-Perpignan diesel 1971, then 1,500 V 1984
12 kV 25 Hz United States Washington, DC – New York City Northeast Corridor (NEC), Amtrak 11 kV until 1978
Harrisburg, Pennsylvania to Philadelphia Keystone Corridor, Amtrak 11 kV until 1978
Philadelphia SEPTA Regional Rail system only; 11 kV until 1978
12 kV 25 Hz United States Rahway to Aberdeen-Matawan, New Jersey North Jersey Coast Line, New Jersey Transit 1978–2002 (11 kV until 1978). Converted to 25 kV 60 Hz
12.5 kV 60 Hz United States Pelham, NY-New Haven, CT New Haven Line, Metro-North Railroad, Amtrak 11 kV until 1985
16 kV 50 Hz Hungary Budapest–Hegyeshalom railway Budapest to Hegyeshalom Kandó system 1931–1972, converted to 25 kV 50 Hz
20 kV Germany Freiburg Höllentalbahn Operated 1933–1960. Converted to 15 kV 16+2⁄3 Hz.
France Aix-les-Bains – La Roche-sur-Foron Société Nationale des Chemins de fer (SNCF) Operated 1950–1953. Converted to 25 kV 50 Hz.
20 kV 50 Hz Japan most electrified JR/the third sector lines in Hokkaidō and Tōhoku JR East, JR Hokkaidō, and others
60 Hz most electrified JR/the third sector lines in Kyūshū and Hokuriku region JR Kyūshū and others
50 kV 50 Hz South Africa Northern Cape, Western Cape Sishen–Saldanha railway line opened in 1976 and hauls iron ore
60 Hz Canada British Columbia Tumbler Ridge Subdivision of BC Rail (Now Canadian National Railway) Opened in 1983 to serve a coal mine in the northern Rocky Mountains. No longer in use.
United States Arizona Black Mesa and Lake Powell Railroad First line to use 50 kV electrification when it opened in 1973. This was an isolated coal-hauling short line; no longer in use.
60 Hz United States Utah Deseret Power Railroad Formerly Deseret Western Railway. This is an isolated coal-hauling short line.

Three-phase AC voltage

[edit]
Main article: Three-phase AC railway electrification
Two wires
[edit]
Voltage Frequency
& phases 		Country Location Name of system Notes
725 50 Hz, 3φ Switzerland Zermatt – Gornergrat, canton of Valais Gornergratbahn
750 40 Hz, 3φ Burgdorf – Thun Burgdorf-Thun Bahn Operated 1899–1933
Converted to 15 kV 16+2⁄3 Hz in 1933
900 60 Hz, 3φ Brazil Rio de Janeiro Corcovado Rack Railway
1125 50 Hz, 3φ Switzerland Interlaken Jungfraubahn
3600 15 Hz, 3φ Italy Northern Italy Valtellina Electrification 1902–1917
50 Hz, 3φ France Saint-Jean-de-Luz to Larrun Chemin de Fer de la Rhune
3600 16 Hz, 3φ Italy
Switzerland 		Simplon Tunnel 1906–1930
3600 16+2⁄3 Hz, 3φ Italy Operated 1912–1976 in Upper Italy (more info needed)
Porrettana railway FS 1927–1935
3600 16+2⁄3 Hz, 3φ Italy Trento/Trient – Brenner Brenner Railway 1929–1965
5200 25 Hz, 3φ Spain Gérgal – Santa Fe C.de H. Sur de España 1911–1966?
6600 25 Hz, 3φ United States Cascade Tunnel, Washington state Great Northern Railway 1909–1929
10 kV 45 Hz, 3φ Italy Roma – Sulmona FS 1929–1944[37]
Three wires
[edit]
Voltage Frequency Country Location Name of system Notes
3 kV 50 Hz Germany Kierberg Zahnradbahn Tagebau Gruhlwerk Rack railway (0.7 km)
Operated 1927–1949
10 kV Berlin-Lichterfelde (de) Test track (1.8 km)
Variable voltage and frequency
Trial runs 1898–1901
14 kV
(See notes) 		38 Hz – 48 Hz
(See notes) 		Zossen – Marienfelde Test track (23.4 km)
Trial runs 1901–1904
Variable voltage between 10 and 14 kV
Frequency between 38 and 48 Hz
50 Hz Russia Ship elevator of Krasnoyarsk Reservoir Length 1.5 km, gauge 9000 mm

Conductor rail systems (DC voltage)

[edit]

Conductor rail systems have been separated into tables based on whether they are top, side or bottom contact.

Top contact systems

[edit]
Voltage Type Country Location Name of system Notes
50 See notes United Kingdom Brighton Volk's Electric Railway Volk's Railway prior to 1884
(current fed through running rails)
110 third rail Claims to be the world's oldest operational electric railway
160 Volk's Railway between 1884 and 1980s
100 fourth rail Beaulieu Beaulieu Monorail (National Motor Museum – Beaulieu Palace House) current fed by 2 contact wires
180 See notes Germany Berlin-Lichterfelde Siemens streetcar Current fed through the running rails
Operated 1881–1891
200 third rail United Kingdom Southend Southend Pier Railway Until 1902[38]
250 Hythe, Hampshire Hythe Pier Railway
United States Chicago, Illinois Chicago Tunnel Company Morgan Rack
1904, revenue service 1906–1908
300 Georgia New Athos Cave Railway
400 Germany Berchtesgaden Berchtesgaden Salt Mine Railway
440 United Kingdom London Post Office Railway Disused by post office since 2003[39] Now small section near Mount Pleasant operated as tourist attraction with battery powered stock[40]
150 V was used in station areas to limit train speed
550 Argentina Buenos Aires Buenos Aires Metro (Subterráneos de Buenos Aires) Only Line B
625 United States New York City New York City Subway
630 Philadelphia SEPTA Metro - M
fourth rail United Kingdom London London Underground Supplied at +420 V and −210 V (630 V total).
750 See notes Euston to Watford DC Line, London underground

Sub surface lines, metropolitan lines, district and circle lines

Third rail with fourth rail bonded to running rail
To enable London Underground trains to operate between Queen's Park and Harrow & Wealdstone. Similar bonding arrangements are used on the North London Line between Richmond and Gunnersbury and on the District Line between Putney Bridge and Wimbledon.
660 third rail Southern Railway & London & South Western Railway some areas up to 1939, original standard, mostly upgraded to 750 V (except for sections that operate with LUL stock).
700 United States Baltimore, Maryland Baltimore Metro SubwayLink
800 Germany Berlin Berlin S-Bahn discontinued, today 750 V
825 North Korea Pyongyang Pyongyang Metro uses old 750 V Berlin U-Bahn rolling stock
1000 United States San Francisco Bay Area Rapid Transit [41]

Side contact systems

[edit]

All third rail unless otherwise stated.

Voltage Country Location Name of system Notes
650 Canada Vancouver SkyTrain Expo Line (1985) and Millennium Line (2006). Linear induction.
850 France Martigny Saint-Gervais–Vallorcine railway
1200 Germany Hamburg Hamburg S-Bahn Since 1940. Used both third rail DC (1200 V) and overhead line AC (6.3 kV 25 Hz) until 1955. Also uses German standard 15 kV AC 16 2/3 Hz overhead electrification on the section between Neugraben and Stade on line S3, opened in December 2007.

Bottom contact systems

[edit]

All third rail unless otherwise stated.

Voltage Country Location Name of system Notes
550 United States California Central California Traction Company 1907–1908, raised to 1,200 V[25]
700 United States New York Metro-North Railroad Hudson and Harlem Lines, southern part of New Haven Line. Original New York Central Railroad electrification scheme to Grand Central Terminal.
Philadelphia SEPTA Metro – L Originally 600 V, raised to 700 V
825 Belarus Minsk Minsk Metro FSU underground system standard,[42] 825V substation output, 750V in rail on average
Bulgaria Sofia Sofia Metro Lines 1 and 2
Russia Moscow Moscow Metro Nominal voltage: 825 V; allowed range: 550 V – 975 V[43]
Saint Petersburg Saint Petersburg Metro
Kazan Kazan Metro
Nizhny Novgorod Nizhny Novgorod Metro
Novosibirsk Novosibirsk Metro
Samara Samara Metro
Yekaterinburg Yekaterinburg Metro
Ukraine Kyiv Kyiv Metro FSU underground systems share the same standard[42]
Dnipro Dnipro Metro
Kharkiv Kharkiv Metro
830 Argentina Buenos Aires Mitre Line Retiro – José León Suárez
Retiro – Bartolomé Mitre
Retiro – Tigre
Once – Moreno Sarmiento Line
850 France Villefranche Ligne de Cerdagne Often referred to as the "Yellow Train"
Austria Vienna Wiener Lokalbahn
900 Belgium Brussels Brussels Metro

Conductor rail systems (AC voltage)

[edit]

All systems are 3-phase unless otherwise noted.

Voltage Current Contact Country Location Name of system Notes
500 50 Hz top/bottom[44] Australia Gold Coast, Queensland Sea World Monorail Operated 1986–2021
Oasis Shopping Centre Operated 1989–2017
Sydney, New South Wales Sydney Monorail Operated 1988–2013[45]
600 50 Hz side China Guangzhou Guangzhou Metro – APM Line
Singapore LRT – Bukit Panjang line [46]
Japan Saitama New Shuttle
Tokyo Nippori-Toneri Liner
Yurikamome
60 Hz Kobe, Hyōgo Kobe New Transit
Osaka Osaka Metro – Nankō Port Town Line
Kansai International Airport – Wing Shuttle
Taiwan Taoyuan Taoyuan International Airport – Skytrain

Special or unusual types

[edit]

DC, plough collection from conductors in conduit below track

[edit]
Main article: Conduit current collection

DC, one ground-level conductor

[edit]

DC, two-wire

[edit]

DC, power from running rails

[edit]

DC, four-rail

[edit]
Voltage Type Contact system Name of system Location Country Notes
750 Guide bars Lateral to both guide bars (one guide connected to running rail) Paris Metro Paris France Rubber-tyred lines only
Lateral (positive) and top of running rails (negative) contact Montreal Metro Montreal Canada Rubber-tyred lines
Mexico City Metro Mexico City Mexico Rubber-tyred lines
Third and fourth rail Lateral (positive) and top (negative) contact Milan Transportation System Milan Italy Metro (only line 1)
630 Third and fourth rail Top contact London Underground London United Kingdom Transport for London[47]

See also

[edit]

Footnotes

[edit]

References

[edit]
[edit]
Revisions and contributorsEdit on WikipediaRead on Wikipedia

List of railway electrification systems

View on Grokipedia
from Grokipedia
Railway electrification systems encompass the standardized and variant configurations of electrical used to propel on rail networks, replacing traditional diesel or with electric drawing power from fixed . These systems deliver primarily through two methods: overhead wires, which use pantographs on the to collect power, or a third rail positioned alongside the track for direct contact via shoes on the vehicle. They operate using either (DC) for shorter distances and urban applications or (AC) for efficient long-haul and high-speed services, with voltages and frequencies tailored to operational needs and regional standards. The core of such lists compiles the nominal supply voltages and permissible ranges defined by international standards like IEC 60850, which outlines DC systems at 750 V (range: 500–1,000 V), 1,500 V (1,000–1,950 V), and 3,000 V (2,000–3,900 V), alongside AC systems including 15 kV at 16.7 Hz (11,000–18,000 V) and 25 kV at 50 Hz or 60 Hz (17,500–29,000 V). These standards ensure compatibility, safety, and reliability across traction fixed installations, , and auxiliary devices, accounting for temporary voltage fluctuations during normal and abnormal conditions. Non-standard systems, such as older 1,200 V DC or 6.6 kV AC setups, persist in legacy networks, while historical variants like battery-powered or experimental third-rail configurations highlight evolving technologies. Globally, adoption varies by region, with overhead AC systems dominating high-speed and freight corridors in many European and Asian countries due to their efficiency for heavy loads over long distances. In contrast, third-rail DC systems prevail in urban metros and commuter lines, such as those in the UK and , where electrification rates remain low at under 1% for freight (as of ) but support dense passenger operations with lower infrastructure costs. As of 2024, recent progress includes electrifying over 93% of its broad-gauge network. This diversity reflects economic, geographical, and regulatory factors, driving ongoing investments in upgrades and expansions to enhance sustainability and interoperability.

Key to the Tables

Column Explanations

The tables in this article present a structured overview of railway electrification systems, categorizing them by key parameters to enable comparison of technical specifications, geographical prevalence, and operational contexts. This format draws from international standards that emphasize and safety in , allowing engineers, policymakers, and researchers to assess system compatibility across networks. The inclusion of these columns historically stems from efforts to document the evolution of since the early , when diverse proprietary systems proliferated, prompting organizations like the (IEC) to standardize data presentation for global adoption tracking and regulatory compliance. The Voltage column specifies the nominal operating voltage of the system, denoted as direct current (DC) or alternating current (AC) with its frequency in hertz (Hz), such as 1,500 V or 25 kV 50 Hz . This value represents the rated supply level under normal conditions, with associated tolerance ranges defined by international norms to ensure operates reliably despite fluctuations; for instance, permanent voltage limits (Umin1 and Umax1) maintain stability for continuous service, while non-permanent extremes (Umin2 and Umax2) account for short-term deviations not exceeding specified durations like 2 or 5 minutes. These ranges, with permanent tolerances varying from approximately -30% to +20% depending on the system, are critical for preventing overloads or undervoltage shutdowns in traction . The Contact Method column describes the means of delivering electrical power to the , primarily distinguishing between overhead systems—where a on the collects current from suspended wires—and third-rail systems, which use a powered rail positioned alongside or below the running rails for contact via a . Overhead methods dominate high-speed and long-distance applications due to their capacity for higher voltages, while third rails are common in urban and metro settings for their lower profile and weather resilience, though they require insulated enclosures for safety. This distinction is tracked to highlight compatibility and implications, as hybrid systems occasionally combine both for transitional zones. The Regions column identifies the primary countries, continents, or geographical areas where the system is most prevalent, reflecting historical development patterns such as early DC adoption in urban networks in and . This geographic data aids in understanding market dominance and cross-border interoperability challenges, with notations for multi-system countries to indicate overlapping usage. Standardization bodies include such details to monitor adoption rates and support harmonization initiatives, like the European Union's Technical Specifications for Interoperability (TSI). The Example Railways column provides representative instances of rail networks employing the system, selected to illustrate practical implementation without exhaustive listing. These entries underscore real-world applications, such as urban metros or lines, and are chosen based on prominence and influence in shaping subsequent standards. Additional symbols appear in the tables to convey status or limitations: an (*) denotes systems restricted to specific applications, like high-speed lines; a (^) indicates partial network coverage rather than nationwide use; and other markers, such as daggers (†), may signal phased-out or transitional systems under modernization. These notations evolved from early 20th-century surveys to address the fragmentation of practices, enabling concise communication of dynamic industry shifts toward unified standards like those in IEC 60850.

Voltage and Frequency Notations

Railway electrification systems employ two primary types of electrical power: (DC) and (AC). DC systems deliver power without , thus requiring no specification, and are commonly used for urban and metro networks due to their simplicity in control and compatibility with series motors. In contrast, AC systems involve oscillating current, necessitating a notation in hertz (Hz), which indicates cycles per second, and are favored for mainline railways to enable efficient voltage transformation and long-distance transmission. Nominal voltages represent the designated standard values for system design, such as 25 kV for many AC overhead lines, but actual operating voltages fluctuate within defined tolerance bands to account for load variations, drops along feeders, and safety margins. For instance, a nominal 25 kV AC system may operate between 17.5 kV and 27.5 kV under permanent conditions, with the lower limit ensuring minimum performance and the upper preventing equipment overload. These ranges are standardized to maintain and reliability, with DC systems tolerating asymmetric variations, such as -33% to +20% for 1,500 V systems, around nominal values. Common AC frequencies include 16.7 Hz, often denoted as 16+2/3 Hz for precision, which is prevalent in Central European networks for its compatibility with historical traction equipment and reduced inductive reactance in long feeders. The 50 Hz aligns with the European public grid standard, facilitating direct connections without conversion, while 60 Hz matches North American and some Asian grids for similar efficiency. These frequencies are selected to minimize transmission losses over extended distances by balancing in conductors and efficiency, as lower frequencies reduce losses in AC traction motors. Power supply in railway systems is typically single-phase for the overhead contact line or to the train, simplifying the or rail infrastructure by requiring only two conductors (positive and return via rails). Three-phase power, common in grids, is converted to single-phase at substations to match this setup, avoiding the complexity of distributing three wires along the track. Units are expressed in kilovolts (kV, where 1 kV = 1,000 volts) for voltage and hertz (Hz) for , with tolerance bands governed by IEC standards allowing permanent tolerances varying from approximately -30% to +20% depending on the system to accommodate dynamic loads without de-energizing lines.

Standard Overhead Systems

600 V DC

The 600 V DC overhead system is primarily used in older tram and light rail networks worldwide for urban transit, where low voltage suits short distances and frequent stops in confined environments. This direct current setup powers vehicles via overhead catenary wires, collected by trolley poles or pantographs, offering simpler installation than higher-voltage systems in historic city centers. It is less common on heavy rail due to higher current requirements leading to greater energy losses over longer routes. Early 20th-century implementations include many European tram systems, such as the in , operating over 100 km of tracks since the 1870s with upgrades to maintain 600 V DC overhead for efficient local services. Safety features involve insulated wire supports and automatic tensioning to ensure reliable contact during vehicle acceleration. While some networks have upgraded to 750 V for increased capacity, 600 V persists in legacy urban operations due to cost barriers for . Modern extensions occasionally retain this voltage for compatibility with existing infrastructure.

750 V DC

The 750 V DC overhead system supplies electricity to and metro vehicles via wires, enabling efficient power delivery for urban and suburban operations where is impractical due to tunneling or weather constraints. This voltage provides a balance between power capacity and safety, supporting acceleration for short inter-station runs without excessive infrastructure complexity. It aligns with IEC 60850 standards for DC systems in the 500–1,000 V range. In the , the network employs 750 V DC overhead electrification across approximately 103 km of track, serving since 1992 with high-frequency services. The system uses single-wire with return via running rails, featuring auto-tensioning devices to maintain contact at speeds up to 80 km/h. Rolling stock like trams is designed for this voltage, with some dual-capable for future expansions. Internationally, systems like the in use similar 750 V DC overhead for integrated urban transit. Technically, the is positioned 4.5–5.5 m above rails, using or wires to handle currents up to 1,500 A during . Substations are spaced every 2–3 km to manage voltage drops under 5%, with grounding and phase breaks for fault isolation. protocols include visual indicators and to prevent access to live wires. As of 2025, the system supports sustainable urban mobility, with ongoing extensions emphasizing for energy efficiency.

1,200 V DC

The 1,200 V DC overhead electrification system is a niche standard used in select regional and commuter railways, allowing moderate power distribution over urban-adjacent routes with reduced substation needs compared to 600–750 V systems. This voltage minimizes I²R losses while remaining compatible with legacy DC equipment, though global adoption is limited to under 200 km due to standardization preferences for 1,500 V. A key example is the Uetliberg railway (S10 line) in , operating 1,200 V DC overhead since 1936 over 13 km from to Uetliberg, serving commuter and tourist traffic with rack-assisted gradients up to 7%. The system uses asymmetric pantographs to collect from a lower-positioned contact wire for clearance in mountainous terrain. It integrates with 's 15 kV AC S-Bahn network via voltage changers at Hauptbahnhof. Another instance is the Forchbahn in , electrified at 1,200 V DC overhead since 1912, spanning 14 km with low-floor trams for efficient local service. Historically, early 20th-century Swiss networks adopted 1,200 V to bridge low- and high-voltage eras, with insulated and weatherproofing to handle alpine conditions. As of 2025, these systems endure for regional , though upgrades to 1,500 V are considered for capacity enhancements without full replacement.

1,500 V DC

The 1,500 V DC overhead system is a standard method for mainline and commuter railways, ideal for routes with moderate distances and high power demands, such as in and . This voltage halves current needs compared to 750 V for the same power, reducing conductor sizes and losses while supporting speeds up to 160 km/h. It typically uses wires with pantographs, complying with IEC 60850 ranges of 1,000–1,950 V. Widespread in the , the Dutch railway network operates over 3,000 km at 1,500 V DC overhead since the 1920s, powering NS intercity and regional services like to . designs include copper contact wires with auto-tensioning for reliable collection at 140 km/h averages. In , conventional lines such as the Tokaido Main Line use 1,500 V DC overhead for dense commuter operations, spanning thousands of km with dual-voltage compatibility. The system excels on undulating terrain, with substations every 15–20 km to limit drops. As of 2025, 1,500 V DC overhead remains operational globally, including in Ireland's DART network (about 100 km) and parts of Australia's , emphasizing for efficiency. Modernizations focus on digital signaling integration rather than conversion, supporting via multi-voltage locomotives.

3 kV DC

The 3 kV DC overhead electrification system is a standard primarily employed for mainline railways requiring substantial power delivery, particularly in southern and . Adopted in , it became the dominant system for Italy's national network, where it was selected for its ability to support heavier locomotives and longer distances compared to lower-voltage DC alternatives. In , the system was introduced in 1936 and now powers nearly all electrified lines, spanning over 12,000 km and enabling efficient operations for both passenger and freight services. Similarly, former Soviet states implemented 3 kV DC starting in the early , with initial applications in challenging terrains like Georgia's Surami Pass, and it remains in use across regions such as the northern , , and parts of western for legacy mainline infrastructure. Prominent examples include Italy's high-speed services on conventional lines, such as routes from to and to , where multi-voltage ETR 1000 trainsets operate under 3 kV DC alongside dedicated high-speed segments. In , utilizes the system for intercity routes like to , with locomotives such as the Newag Dragon 2 designed for 3 kV DC to handle speeds up to 200 km/h and heavy freight loads. These networks, totaling around 12,000 km in alone for conventional lines, demonstrate the system's scalability for mixed-traffic corridors. Technically, 3 kV DC systems feature robust overhead constructed from copper-silver alloys or high-strength CuNiSi materials, providing enhanced thermal stability and wear resistance under high current loads up to 200 A per . , often single-arm designs like the MoComp, are engineered for dynamic stability at speeds approaching 300 km/h on upgraded lines, maintaining consistent to minimize arcing and support power demands for heavy freight trains exceeding 10 MW. This configuration excels in delivering direct power without frequency conversion, though it requires more frequent substations than AC systems for efficient long-distance transmission. The 3 kV DC standard has remained stable since its widespread adoption, with modernization focusing on increasing capacity for faster trains rather than wholesale replacement. Dual-voltage locomotives, capable of switching between 3 kV DC and 25 kV AC, facilitate cross-border operations, such as those between and or and , enhancing without extensive infrastructure changes.

15 kV AC, 16.7 Hz

The 15 kV AC, 16.7 Hz railway electrification system originated in in , when the German railway authorities standardized single-phase AC at this voltage and frequency following extensive research into efficient traction power for mainline operations. This , approximately one-third of the standard 50 Hz grid, was selected to minimize inductive reactance in early transformers and motors, allowing higher voltages without excessive rotational speeds in synchronous generators and traction equipment. and adopted the same standard shortly thereafter in the 1910s and 1920s, respectively, to enable interoperable cross-border services and leverage shared power generation infrastructure centered on dedicated rotary converters. This system powers extensive networks in , including Germany's (DB) infrastructure, which supports the (ICE) high-speed services across over 20,000 km of electrified track as of 2023. In , the (SBB) operates a fully electrified standard-gauge network at 15 kV, 16.7 Hz, covering approximately 3,200 km and enabling seamless integration with neighboring systems in the Alpine region. Key features include locomotives equipped with step-down transformers to convert the high-voltage supply for traction motors, ensuring compatibility with the single-phase overhead . designs incorporate every 10–20 km to prevent short-circuit faults between adjacent track sections fed from different substations, while the system tolerates variations of ±1 Hz to maintain stability during load fluctuations. As of 2025, ongoing initiatives promote harmonization toward a unified 25 kV, 50 Hz standard for new high-speed lines to enhance cross-border interoperability, but the 15 kV, 16.7 Hz system remains dominant in the due to prohibitive conversion costs estimated at billions of euros.

25 kV AC, 50 Hz

The 25 kV AC, 50 Hz system represents the predominant international standard for overhead on mainlines, enabling efficient for high-speed and heavy-haul operations with minimal energy losses compared to lower-voltage DC alternatives. This single-phase alternating current configuration was first adopted as a national standard by British Railways in 1956, following successful trials in the early 1950s, and has since been implemented across , , and beyond for its compatibility with public utility grids operating at 50 Hz. In , the system was standardized in 1957 based on French technology, supporting the electrification of the vast broad-gauge network. China's extensive infrastructure, exceeding 40,000 km by the early , relies heavily on this voltage and frequency for trunk lines, marking a shift from earlier DC systems. Prominent examples include the high-speed service, which operates under 25 kV 50 Hz on the UK's line and connecting international routes, delivering up to 16 MW of power to multi-voltage trainsets. In , premier trains like the now run entirely on electric traction via this system, following the completion of key route electrification in 2025, which eliminated diesel dependencies on long-distance corridors. The system's adoption has accelerated post-2020 in to meet goals, with achieving nearly 100% broad-gauge electrification at approximately 68,701 route kilometers by March 2025—well ahead of its 2030 net-zero target—and enabling annual savings of over $2 billion in fuel costs. Key design elements include overhead wiring supported by auto-transformers, which boost effective voltage to 50 kV between feeder and rail while maintaining 25 kV to the , reducing current and allowing substation spacing of 40-60 km with low transmission losses. This configuration supports operational speeds up to 350 km/h, as demonstrated on lines like France's network, where reinforced ensures stable contact at high velocities. The system complies with IEC 60850, which defines nominal supply voltages, permissible ranges (19-27.5 kV), and fixed installation requirements to ensure and safety across global networks. A 60 Hz variant exists in the to align with regional grids, but the 50 Hz version dominates internationally due to its alignment with European and Asian power standards.

25 kV AC, 60 Hz

The 25 kV AC, 60 Hz electrification system is an overhead power supply standard primarily adopted in regions with a 60 Hz , such as parts of and the , enabling efficient synchronization with local utility power for high-speed and operations. This system delivers at 25 kilovolts and 60 hertz, facilitating higher power transmission over longer distances compared to lower-voltage DC systems, while minimizing substation requirements through direct grid integration. It supports train speeds exceeding 200 km/h and is particularly suited for dense, urban corridors due to its compatibility with modern and variable-frequency drives in locomotives. In , the system was first implemented on the , which opened on October 1, 1964, marking the world's inaugural line with 25 kV AC, 60 Hz overhead electrification spanning approximately 515 km from to Shin-Osaka. This adoption aligned with Japan's western grid frequency, allowing seamless power draw from existing infrastructure, and the line's design incorporates advanced safety features like cab signaling and to handle grades up to 1:50 and curves of 2,500 m radius. The 's success led to its extension via the Sanyo Shinkansen to Hakata, maintaining the same 25 kV, 60 Hz parameters for over 500 km of electrified track in seismically active terrain, where resilient supports ensure operational continuity. All Shinkansen lines now utilize 25 kV AC, with 60 Hz predominant in the west to match regional power grids. In the United States, partial adoption occurred on Amtrak's North End, from , to , —a 373 km segment electrified at 25/50 kV, 60 Hz using an configuration, completed in the late 1990s to extend high-speed service northward. More recently, 's Peninsula Corridor between and San Jose (82 km) launched full electric operations in September 2024 under this system, replacing diesel locomotives with Plus EMUs capable of 160 km/h, reducing emissions and enabling more frequent service. Proposed high-speed projects, including California's statewide network, incorporate 25 kV, 60 Hz to align with the national grid and Amtrak's , though implementation faces challenges from high upfront costs exceeding $50 million per km for installation and land acquisition. As of 2025, the system remains stable and integral to Japan's network, carrying over 300 million passengers annually, while U.S. expansion is limited to commuter upgrades like , with broader high-speed ambitions stalled by funding constraints. The 25 kV AC, 50 Hz variant is more globally widespread, but the 60 Hz version offers advantages in North American contexts through native grid harmony.

Standard Third Rail Systems

600 V DC

The 600 V DC third rail system is widely employed in urban subway networks for its suitability in confined tunnel environments, where overhead wiring would be challenging to install and maintain. This low-voltage direct current setup powers trains via a conductor rail positioned alongside the running rails, insulated on ceramic or composite supports to prevent unintended grounding. Primarily featuring top-contact configurations, the system uses spring-loaded shoegear on train undercarriages to maintain electrical connection while navigating curves and gradients common in dense city infrastructure. Pioneered in early 20th-century urban rail projects, the Subway's original Interborough Rapid Transit (IRT) lines adopted 600 V DC upon opening in 1904, with a nominal operating voltage of 625 V to account for distribution losses. The network encompasses over 600 km of electrified track, demanding robust safety interlocks—such as electrical detection relays and mechanical train stops—to prevent collisions and unauthorized access to live rails in high-traffic tunnels. management is critical in these enclosed spaces, achieved through substations spaced approximately every 3 km to limit reductions to under 2% in feeder circuits, ensuring consistent power delivery for frequent services. Similar implementations appear in other major metros, such as Tokyo's subway lines operating at 600 V DC third for efficient urban transit. While some legacy networks have converted to 750 V DC for improved energy efficiency and capacity, the 600 V configuration endures in established high-density systems due to the prohibitive costs of extensive underground infrastructure. Surface extensions in certain cities occasionally employ overhead 600 V DC wiring to bridge gaps, but third remains dominant in core subway operations.

750 V DC

The 750 V DC third rail system supplies electricity to trains via a conductor rail mounted parallel to the running rails, enabling efficient power delivery for metro and commuter operations in urban settings. This voltage standard emerged as an upgrade over earlier 600 V DC configurations, providing greater power capacity for sustained acceleration and longer inter-station distances without excessive current draw. It is particularly suited to environments where overhead wiring is impractical due to clearance constraints or aesthetic considerations. In the , the 750 V DC is the dominant electrification method on the southeastern network, encompassing commuter and regional services around and extending over approximately 2,300 km of track, which accounts for more than 30% of the nation's electrified routes. Notable examples include the Southern and Southeastern franchises, where the system supports high-frequency operations with protective coverboards—typically or wooden barriers—installed along exposed sections to mitigate weather exposure and accidental contact. Some , such as Class 375 and Class 377 electric multiple units, features dual-voltage capability, allowing seamless transitions to 25 kV AC overhead systems on mixed-electrification lines. Outside the UK, the in employs 750 V DC for its urban lines, demonstrating the system's adaptability in dense Asian transit corridors. Technically, the conductor rail is positioned with its top surface 0.076 to 0.1 m above the running rails to facilitate reliable contact by train-mounted shoes, which currents up to 2,000 A during for multi-car formations. The rail itself, often made of steel-aluminum composites, is segmented into insulated sections to manage fault isolation and prevent widespread disruptions. features include grounded to the running rails for return current and periodic coverboard reinforcements to shield against debris or flooding. Post-2010 incidents involving contact prompted enhanced safety protocols across networks, including mandatory insulator inspections, upgraded coverboard installations, and staff training programs to reduce trespasser risks, resulting in a decline in electrification-related accidents. As of 2025, no large-scale phase-outs have occurred, with the system remaining integral to ongoing operations and future expansions limited by regulatory preferences for overhead alternatives.

1,200 V DC

The 1,200 V DC third rail electrification system represents a niche application in railway networks, primarily employed in urban and commuter settings where higher voltage enables efficient power distribution over moderate distances while utilizing ground-level conduction. This voltage level, higher than the more common 600 V or 750 V DC systems, allows for fewer substations due to reduced current requirements and associated I²R losses, making it suitable for legacy infrastructure in dense areas. However, its adoption has been limited globally, with total electrified length estimated at under 200 km across active and historical installations, reflecting challenges in and safety. A prominent example is the in , which has operated on 1,200 V DC side-contact since 1939, covering approximately 147 km of mostly dedicated tracks serving the metropolitan region. The side-contact design, where collector shoes engage the vertical face of the rail rather than the top, enhances safety by minimizing exposure to the live conductor, particularly important at this voltage to prevent accidental contact in urban environments. This system integrates with a small portion of 15 kV 16.7 Hz AC overhead lines for extended routes, demonstrating hybrid compatibility in a constrained network. Historically, the in the utilized a similar 1,200 V DC side-contact system from 1916 until its conversion in 1991, spanning about 15 km as part of the Lancashire and Yorkshire Railway's commuter service. Introduced to support frequent urban operations with steel-bodied electric multiple units like the British Rail Class 504, the higher voltage reduced the need for intermediate power feeds compared to lower-voltage contemporaries. Insulation challenges were notable in wet climates, requiring robust weatherproofing of the rail and shoes to mitigate arcing and corrosion risks inherent to exposed at elevated potentials. As of 2025, most 1,200 V DC third rail systems have been phased out or converted for , with remaining a key operational holdout for legacy compatibility, though some networks have transitioned to 1,500 V DC for enhanced capacity.

1,500 V DC

The 1,500 V DC third rail system is a high-voltage direct current method designed for railway traction in demanding environments, such as steep gradients and high-load routes, where it provides greater power capacity than lower-voltage third rail systems like 750 V DC. This voltage reduces the current required for equivalent power output, minimizing conductor size and energy losses while supporting more powerful locomotives for express and freight services. The system typically employs a side or bottom-contact third rail to enhance by limiting exposure to the live conductor, particularly in areas with snow or ice accumulation. Gap-bridging devices, such as spring-loaded contacts on the train's shoegear, ensure continuous across interruptions in the rail at switches or stations. A prominent historical application was on France's Maurienne line (part of the Culoz–Modane route), where the 94 km section from to was electrified with 1,500 V DC third rail between 1925 and 1930 to handle the alpine terrain's 30‰ gradients and heavy traffic. This setup powered mixed passenger and freight operations, including international trains to via the Tunnel, using side-mounted third rail for reliable contact in mountainous conditions. The system operated successfully for over 50 years, demonstrating the voltage's suitability for high-power needs, until its conversion to 1,500 V DC overhead catenary in 1976 to boost capacity and reduce maintenance. Locomotives like the SNCF BB 1-80 class were specifically adapted for this line, often running in permanently coupled pairs to manage steep hauls. As of 2025, no operational 1,500 V DC third rail systems exist globally, with the technology phased out in favor of overhead configurations for similar voltages in legacy networks. The historical example underscores its role in early 20th-century mainline for challenging routes, though modern DC systems emphasize integration for — a feature absent in the original Maurienne setup but compatible with high-voltage third rail designs. Lower-voltage DC third rails remain common for inner-city urban networks.

Non-Standard Overhead Systems

DC Voltages

Non-standard DC overhead systems employ voltages deviating from the predominant ranges of 600–3,000 , often arising from early 20th-century experiments or adaptations to local power grids and infrastructure constraints. These systems were adopted primarily to balance power delivery with the technological limitations of the era, such as the availability of DC generators and the need for simpler designs without onboard rectification. For instance, higher voltages like 4,000 aimed to reduce current and transmission losses over longer distances in secondary or industrial lines, while lower voltages around 1,000 facilitated integration with urban or legacy grids. However, such choices frequently led to compatibility issues with evolving standards, prompting widespread conversions to AC or standardized DC by the mid-20th century. In legacy applications, 2,400 V DC overhead electrification appeared in industrial and port settings, such as the Harbour Commissioners' system in , electrified in the 1920s to handle heavy freight with reduced conductor sizes compared to lower-voltage DC. This voltage allowed for efficient in confined areas but required custom designs. The system persisted until the 1950s, after which it was converted to diesel and later integrated into broader AC networks, reflecting the global shift away from intermediate DC voltages. The rare 4,000 V DC overhead system exemplifies extreme non-standard adoption, implemented on Italy's Torino-Ceres secondary line in 1920 to achieve high for mountainous terrain using direct DC supply from hydroelectric sources. This voltage minimized line losses but demanded specialized insulators and transformers. Operations continued until the 1980s, when the line was converted to 3 kV DC amid national unification; today, it serves as a regional commuter route with no active 4,000 V remnants. Industrial applications, such as short-haul factory sidings in , occasionally retained this voltage into the 1990s for compatibility with legacy equipment, though all known instances were decommissioned by the 2020s due to and costs. Technical challenges in these systems included the need for custom pantographs with enhanced insulation and contact strips to withstand higher , as standard designs risked at elevated voltages. At extremes like 4,000 V, arcing risks intensified during pantograph-catenary separation, potentially causing waveform distortion, , and accelerated wear on overhead wires—issues mitigated in modern systems via but problematic in historical DC setups without advanced controls. By contrast, standard DC voltages (e.g., 1,500–3,000 V) offer better balance, reducing such hazards through proven components. In , the Cascais suburban line uses a 1,500 V DC third rail system, originally adopted in the to align with Lisbon's early grid; as of November 2025, modernization works are ongoing to convert it to 25 kV AC overhead contact line, with completion expected in 2026.

AC Single-Phase Voltages

AC single-phase overhead electrification systems operating at voltages other than the widespread 25 kV standard have been employed historically in various regions to address specific constraints or legacy power supplies. These systems typically utilize frequencies of 25 Hz, 50 Hz, or 60 Hz, offering advantages in over longer distances compared to DC equivalents, though they often require specialized transformers and locomotives. In the , a 6.25 kV AC 50 Hz was adopted in the and 1960s for sections with limited overhead clearance, such as urban tunnels and bridges, covering approximately 200 route kilometers by 1977. This voltage was part of a hybrid approach integrated with 25 kV sections, using booster transformers to step down voltage where needed while maintaining overall compatibility. By the 1980s and 1990s, most 6.25 kV segments had been converted to full 25 kV operation to simplify maintenance and enhance capacity, with completions on lines like the by the early 2000s. The featured prominent legacy applications of 11-12 kV AC 25 Hz systems during the early 20th-century electrification boom, particularly on the Pennsylvania Railroad's lines electrified starting in 1915, spanning over 1,200 route kilometers by the 1930s. These systems powered high-traffic corridors like the , leveraging industrial 25 Hz generation common at the time for efficient single-phase distribution. Progressive phase-outs began in the 1970s, with conversions to 25 kV 60 Hz on portions of the completed by 1981 to align with national grid standards, though remnants of 12 kV 25 Hz persist on Amtrak's southern NEC segments as of November 2025 for operational continuity. Interoperability challenges in these non-standard systems often necessitate frequency converters or multi-voltage locomotives, as seen in transitions between 25 Hz legacy lines and 50/60 Hz grids; for instance, static frequency converters enable seamless from networks to railway-specific frequencies without dedicated generators. As of November 2025, revivals of non-standard AC single-phase configurations remain rare but are emerging in isolated railway microgrids, where hybrid AC-DC setups allow flexible voltages like 12-15 kV for off-grid or renewable-integrated traction in remote areas, enhancing resilience without full-scale conversions.

Three-Phase AC Voltages

Three-phase AC electrification systems for supply power through two overhead contact wires carrying the two live phases, with the running rail serving as the return for the third phase, allowing direct operation of three-phase induction motors without commutators. This configuration provided efficient and capabilities, making it particularly suitable for steep gradients and heavy freight services where high torque at low speeds was essential. Early systems operated at relatively low voltages and frequencies to match the capabilities of contemporary motors and transformers, prioritizing reliability over . The pioneering implementation occurred in , where engineer Kálmán Kandó developed the technology for the railway, electrified in 1902 as the world's first high-voltage AC mainline at 3 kV, 15 Hz three-phase. Subsequent expansions adopted 3.6 kV at 15 Hz, with on-board phase converters enabling variable effective frequencies up to 45 Hz for precise speed control of asynchronous motors, achieving outputs up to 2,000 kW and speeds of 100 km/h. This "Italian system" proliferated across from the early 1900s through the 1950s, covering over 2,000 km of challenging alpine routes like the Giovi and Simplon lines, before gradual replacement with DC systems due to needs. These systems offered superior power factors close to unity and reduced weight in locomotives compared to DC alternatives, enhancing performance on gradients exceeding 25‰, but suffered from intricate designs requiring dual pantographs and specialized substations, which increased installation and maintenance complexity. By the late , economic pressures and the dominance of simpler single-phase AC networks led to widespread decommissioning; Italy's final three-phase line converted to 3 kV DC in 1976. As of November 2025, three-phase AC remains virtually obsolete for revenue operations, confined to a handful of preserved Swiss mountain tourist lines like the , with no active mainline use and post-2000 abandonments of minor installations largely unrecorded in public sources.

Non-Standard Third Rail Systems

Top Contact DC Systems

Top contact DC third rail systems utilize a conductor rail positioned alongside the running rails, where power is collected from the upper surface via a sliding shoe on the . These systems are distinct from standard voltages (600 V, 750 V, 1,200 V, and 1,500 V DC) and are typically employed in legacy urban networks or specialized industrial applications due to their in low-speed environments but to environmental factors. One notable example is the 630 V DC system used in parts of inner London for inter-running with the London Underground's fourth-rail configuration, where the positive third rail operates at +420 V relative to the running rails and a central fourth rail at -210 V, though top contact remains the primary interface. Historical implementations include the former French Culoz–Modane line, electrified at 1,500 V DC third rail from 1925 until its conversion to overhead lines in 1976, serving alpine routes with steep gradients. Designs for top contact third rails often feature an exposed aluminum or conductor supported by insulators spaced approximately 3 meters apart, with protective hoods or covers to shield against debris while allowing shoe contact. The contact shoe applies a of 50–100 N to maintain reliable current collection, typically up to 3,000 A, but the open-top configuration makes these systems susceptible to , , and accumulation, necessitating frequent or de-icing measures. Safety standards for these systems are governed by EN 50122-1, which outlines protective provisions against electrical hazards, including earthing, insulation coordination, and barriers to prevent accidental contact with the live rail. EN 50123 series addresses DC switchgear and controlgear, ensuring fault protection and stray current mitigation in traction power supplies. These requirements emphasize shielding and , as the exposed top rail poses higher shock risks compared to side- or bottom-contact variants, limiting deployment to fenced or enclosed rights-of-way. Primarily found in legacy urban metros and industrial facilities, top contact DC third rail systems beyond standard voltages account for less than 500 km of electrified track globally as of 2025, with ongoing conversions to overhead AC reducing their footprint.

Side Contact DC Systems

Side contact DC systems feature a conductor rail mounted laterally adjacent to the running rails, with the train's collector shoe making contact along the side of the rail rather than the top or bottom. This configuration enhances safety by allowing the live rail to be more easily enclosed or shielded, thereby reducing the risk of accidental human contact or interference from debris compared to exposed top contact designs. The lateral positioning also facilitates better integration in constrained urban environments, such as tunnels, where space is limited. Historical development of side contact systems drew from early 20th-century innovations in protected designs, including U.S. US921508A granted in 1909, which described a system with laterally projecting supports for secure installation and insulation. By the 1910s, publications like the Electric Railway Journal documented advancements in contact mechanisms suitable for side approaches, emphasizing economical and safe power delivery for lines. These early patents and engineering efforts laid the groundwork for non-standard DC applications focused on reliability and reduced exposure risks. Historical implementations include the former French Culoz–Modane line, electrified at 1,500 V DC side-contact from 1925 until its conversion to overhead lines in 1976, serving alpine routes with steep gradients. A prominent example is the in , which has operated with a side contact at 1,200 V DC since 1940, supplying power to its extensive suburban network. Another historical instance was the Manchester-Bury line in , which used 1,200 V DC side contact from 1916 until its conversion to in 1991, marking one of the few such systems in Britain. These European metro and suburban applications highlight the system's suitability for dense urban operations at voltages around 1,000–1,200 V DC. Technically, side contact rails support high current capacities—often exceeding 5,000 A per section—due to their robust cross-sections, enabling efficient power delivery for multiple-unit trains in mass transit settings. Insulation from the is achieved through specialized covers and support insulators, preventing electrical leakage and ensuring ground isolation, with materials like graphite-based shoes providing low and high conductivity during collection. Grounding shoes align voltages at transitions, minimizing arcing risks. By 2025, side contact DC systems have been phased out in many historical locations due to conversions to overhead electrification or modern standards, though operational remnants persist in key networks like the Hamburg S-Bahn, where upgrades such as ETCS signaling continue to support their viability. This contrasts with more widespread top contact systems, which remain simpler but expose greater safety challenges in open areas.

Bottom Contact DC Systems

Bottom contact DC third rail systems position the conductor rail beneath the running rails, typically between them, where power is collected from the underside using a shoe or plough mechanism mounted on the train. This configuration requires the rail to be encased in protective covers, often made of weatherproof materials like rubber or composite insulators, to shield it from environmental elements such as moisture, debris, and ice accumulation while maintaining electrical integrity. The design originated in early 20th-century innovations, such as the Wilgus-Sprague system patented in 1905, which emphasized enclosed contact to prevent accidental exposure. Notable implementations include the Metro-North Railroad's and Hudson Lines in the United States, operating at 750 V DC with bottom contact extending approximately 115 km from , where the system was first deployed to facilitate safe underground operations. In Europe, the employs a similar 750 V DC bottom contact setup across much of its 101 km network, combining it with overhead lines in some sections for flexibility in urban environments. These systems demonstrate the approach's suitability for high-density, safety-critical settings like terminals and metros, though adoption remains sparse globally due to installation complexities. The primary advantage of bottom contact lies in its superior safety profile, as the live rail is fully enclosed and inaccessible from the surface, drastically reducing and risks compared to top or side contact variants—paralleling safety enhancements in side contact systems but achieving even lower exposure. Weatherproofing via insulated covers further mitigates disruptions from or frost, enabling reliable performance in varied climates. Worldwide, such systems total approximately 250 km of operational track as of 2025, confined to select urban and suburban routes where maximum mitigation outweighs higher costs.

AC Systems

AC systems for third rail electrification are exceptionally rare in railway history, primarily due to significant technical challenges associated with alternating current delivery through a conductor rail positioned close to the ground. Unlike DC systems, which dominate third rail applications for their simplicity and compatibility with series motors, AC third rail configurations suffer from electromagnetic induction effects that induce unwanted voltages in adjacent running rails and nearby metallic structures. These induction issues lead to electromagnetic interference (EMI) with trackside signaling and communication systems, posing safety risks and requiring complex mitigation measures such as additional grounding or shielding. Technically, AC third rail systems typically employ single-phase power, with collector shoes on the train equipped with step-down transformers to convert the supply voltage to suitable levels for traction motors, often universal series motors capable of AC operation. However, this setup incurs higher energy losses at low speeds, where the reactance of the system reduces efficiency compared to DC, and arcing at the contact interface is exacerbated by the oscillating current. Representative historical examples include legacy interurban lines in the US experimenting with 1,500 V AC at 25 Hz to leverage existing AC generation infrastructure, such as early applications in . By the mid-20th century, these systems had become obsolete, supplanted by more reliable DC third rail and overhead AC configurations that avoid ground-level induction problems. As of 2025, no active AC third rail systems remain in service worldwide, rendering them a purely historical footnote in railway electrification.

Special Electrification Systems

Conduit Plough Systems

Conduit plough systems represent an early form of direct current (DC) railway electrification designed to supply power without visible overhead wires, primarily for urban tramways and street railways. In this setup, electrical power is delivered through a conduit—a narrow underground channel running between the rails—accessed via a slot in the track surface. A plough, a metal shoe attached to the underside of the vehicle, dips into the slot to maintain contact with a live conductor rail within the conduit, enabling current collection at voltages typically ranging from 500 to 600 V DC. Historically, these systems saw significant adoption in major cities to preserve aesthetic appeal in densely built environments. In , conduit plough electrification powered street railways starting in the late 1880s, with extensive networks in operating until the 1930s, covering over 100 km of tracks that facilitated the transition from cable and horse-drawn systems to electric traction. In , the tram network employed the conduit system from 1901 onward, serving central areas until the system's full abandonment in 1952, with approximately 140 km of conduit-equipped routes at its peak. These installations demonstrated the system's viability for high-density urban operations but were limited to low-speed applications due to the mechanical challenges of plough engagement. The decline of conduit plough systems stemmed from prohibitive maintenance demands and operational vulnerabilities. The open slot was prone to accumulation of , dirt, and water, leading to frequent arcing, short circuits, and failures, while harsh weather—particularly and —exacerbated and contact interruptions, necessitating constant cleaning and repairs. Installation costs were high due to the need for deep excavation, and scalability proved difficult compared to simpler alternatives like overhead wires. By the mid-20th century, economic pressures led to widespread replacement; all such systems had been decommissioned globally by the , with none operational as of 2025. This approach briefly influenced the development of enclosed systems, though without the conduit's surface slot vulnerabilities.

Ground-Level Single Conductor Systems

Ground-level single conductor systems represent a modern approach to , particularly for urban tramways, where a single conductive rail or band is embedded at track level to supply power without overhead wires or underground conduits. These DC systems typically operate at 750 V, with the conductor divided into short segments that are energized only on demand as a approaches, enhancing by minimizing exposure to live parts. This technology evolved as a successor to earlier conduit systems, addressing historical limitations like mechanical complexity while preserving visual appeal in cityscapes. The core mechanism involves a or series of studs/bands flush with the ground between the running rails, activated via onboard vehicle signals or proximity detection to supply power precisely under the collector. For instance, in the APS (Alimentation Par le Sol) system, developed in the early 2000s, each 11-meter segment powers up automatically for the passing , delivering 750 V DC and supporting speeds up to 70 km/h without continuous . Safety features include automatic de-energization after the vehicle passes and insulation to prevent accidental contact, allowing pedestrians and vehicles to cross tracks safely. Prominent examples include the French APS, first implemented on Bordeaux's tramway Line A in 2003, where it powers trams in historic districts to avoid overhead infrastructure. By 2025, APS has been fitted across 155 km of single track in 12 cities on three continents, including expansions in (12 km), Orléans (4 km), and a recent 3.9 km debut in Barcelona's tramway network in November 2024, serving up to 24,000 daily passengers. The Italian Ansaldo TramWave system, pioneered by Ansaldo STS (now part of ), uses similar segmented ground conductors at 750 V DC and underwent trials on a 400-meter test track in , with initial operational deployment on an 8.7 km double-track line in , , starting in 2017—though it faced challenges with reliability and ridership. However, the Zhuhai line ceased operations in December 2023 and was approved for demolition in May 2024 due to ongoing issues. As of 2025, these systems remain operational on select European tram networks totaling around 10-20 km per major installation, with broader adoption in and ongoing expansions like Barcelona's integration of 18 Citadis trams. Advantages include enhanced urban aesthetics by eliminating wires, reduced in heritage areas, and compatibility with battery hybrids for full catenary-free routes, promoting climate-resilient operations up to 55°C. Despite higher initial costs, their reliability—evidenced by over 85 million kilometers traveled on APS alone—supports growing European interest in sustainable, wire-free .

Two-Wire DC Systems

Two-wire DC systems represent a specialized approach to railway electrification, employing two dedicated conductors—typically overhead wires—for both the supply and return paths of , rather than using the running rails as the return conductor. This configuration, distinct from standard single-return DC systems where the rails serve as the return, aims to limit stray currents in the ground and mitigate issues like electrolytic corrosion of nearby utilities and interference with trackside signaling. The design features a balanced return arrangement, with one wire carrying positive voltage and the other negative voltage relative to ground, resulting in zero net ground potential and reduced . Voltages in these systems typically range from 600 V to 1,500 V DC, allowing for efficient over short to medium distances without excessive . The two wires are suspended in parallel overhead, with the train's or contacting both to complete the circuit. Early adoption occurred in the United States during the railway boom of the early 1900s, where such configurations were used for longer rural runs to overcome limitations of single-wire setups. Similar applications appeared in lines, where isolated environments benefited from the reduced ground leakage; a 2014 IEEE study proposed two-wire DC distribution for mobile equipment to optimize cost per of extracted by minimizing AC-DC conversion losses. These systems offer benefits such as lower ground currents, which decrease the risk of to buried and simplify electrical isolation in sensitive areas like urban or industrial zones. However, their use has declined with the rise of higher-voltage AC systems and improved rail-return technologies, leaving rare survivors in industrial settings, including short and lines totaling less than 50 km worldwide as of 2025.

Running Rail Power Systems

Running rail power systems in DC railway electrification utilize the running rails as the return conductor for traction current, a configuration prevalent in most standard DC transit networks worldwide. This approach leverages the existing track infrastructure to complete the electrical circuit, with current flowing from the power supply through the or to the train, and returning via the wheels and axles to the running rails, which are then connected back to the substation. The system is designed to maintain the running rails at a floating potential relative to , minimizing unintended leakage and ensuring efficient power return without direct grounding. Technical implementation involves comprehensive to achieve low-impedance paths for the return current, including rail-to-rail bonds at joints and cross-bonding between parallel tracks to equalize potentials and reduce voltage gradients. Grounding is limited or avoided in these systems; instead, the rails are insulated from the ground through or sleepers to confine current flow, with periodic connections to earth only for or surge protection. Operating voltages typically range from 600 V to 3,000 V DC, allowing compatibility with urban metros at lower voltages like 750 V and higher-speed mainlines up to 3 kV. A notable example is the Southern Railway's 750 V DC third-rail network, electrified in the 1920s and 1930s, where running rails served as the return path but required high-insulation setups, including insulated rail joints and block sections, to prevent electrolysis-induced corrosion in nearby metallic structures like water pipes. These insulated blocks segmented the rails electrically, reducing stray current paths while maintaining signaling integrity through track circuits. Key challenges include stray currents arising from imperfections in rail-to-earth insulation, which can leak into the soil and cause electrolytic of buried utilities; mitigation strategies emphasize enhanced insulation materials, regular rail , and insulated joints in high-risk areas. As of 2025, these systems remain standard but incorporate modern monitoring technologies, such as real-time rail-to-earth potential sensors and centralized data analytics, to detect and localize stray currents proactively, with market growth in such solutions projected at 7.8% CAGR through 2033. For scenarios requiring greater isolation, two-wire DC systems with dedicated return conductors offer alternatives, though they increase infrastructure complexity.

Four-Rail DC Systems

Four-rail DC systems employ a configuration with two conductor rails for —one positive and one negative—and two running rails serving as the return path, operating at a nominal voltage of 630 DC. This setup positions the running rails at potential, isolating the traction current from the track to prevent stray currents that could cause electrolytic in nearby . The design originated to address interference issues in densely packed urban rail networks, where standard two-rail DC systems using running rails for return could lead to electromagnetic disruptions and safety hazards. By providing separate positive (+420 V) and negative (-210 V) conductor rails—typically the outer and inner fourth rails, respectively—the system allows for zoned power distribution, enabling independent control of electrical sections to minimize cross-talk between adjacent lines. This configuration was first implemented on the London Underground's in 1905, following electrification trials that resolved debates over AC versus DC traction. A primary example is the Underground network, which adopted the four-rail system across its sub-surface and deep-tube lines starting in 1905, with full implementation by 1961. Powered initially by stations like Lots Road (44 MW capacity) and , the system supported the transition from steam to electric multiple units, enhancing efficiency in London's congested tunnels. Advantages include reduced arcing and corrosion risks through dedicated return paths, as well as sectional zoning that isolates faults and optimizes power in high-density operations. As of 2025, the four-rail DC system remains unique to the London Underground, spanning approximately 250 km of track with no expansions or new adoptions elsewhere. Upgrades to 750 V DC were completed on sub-surface lines by 2019 to boost train performance, while the core four-rail infrastructure for deep-tube lines has seen no extensions, reflecting its specialized evolution for historical urban constraints.

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