Indian Railways operates India's railway system and comes under the purview of the Ministry of Railways of Government of India. As of 2023^[update], it maintains over 108,706 km (67,547 mi) of tracks and operates over 13,000 trains daily with a fleet of 14,800 locomotives. The railways primarily operates a fleet of electric and diesel locomotives along with a few compressed natural gas (CNG) locomotives. Steam locomotives are operated on mountain railways and on heritage trains.

The history of the Indian Railway began in 1832 with the proposal to construct the first railway line in India at Madras. In 1837, the first train ran on Red Hill railway line between Red Hills and Chintadripet in Madras and was hauled by a rotary steam engine imported from England.^[1][2] In 1852, a steam locomotive imported from England was tried at Byculla.^[3] In 1853, the first passenger train ran between Bombay and Thane which had 14-carriages hauled by three steam locomotives: the Sahib, Sindh and Sultan.^[4] In 1877, an Ajmer built F-1/734 Steam Locomotive became the first indigenously built locomotive in India.^[5] In 1925, the first electric train ran between Bombay and Kurla, hauled by a Swiss Locomotive and Machine Works (SLM) 2,400 hp (1,800 kW) electric locomotive on 1500 V DC traction.^[1][6] The first diesel locomotive used in India was fabricated by North British Locomotive Company in 1954.^[7]

Chittaranjan Locomotive Works, commissioned in 1950, was the first locomotive manufacturing unit in India.^[8] Banaras Locomotive Works, commissioned in 1961, is the second locomotive manufacturing unit operated by Indian Railways.^[9] In the 1960s, Integral Coach Factory-Chennai (ICF) started developing self-propelled Electric multiple units for short-haul and local routes.^[10][11] BHEL and Patiala Locomotive Works, established in 1981, also manufacture locomotives in India.^[12] In 2015, the first compressed natural gas (CNG) powered trains were rolled out by ICF.^[13] In 2018, a semi-high speed self-propelled train-set capable of reaching speeds of over 160 km/h (99 mph) was rolled out from ICF.^[14][15] As of 2023^[update], Indian Railways maintains over 108,706 km (67,547 mi) of tracks and operates over 13,000 trains daily with a fleet of over 14,800 locomotives.^[16][17] 37% of the trains are operated by diesel locomotives and rest mostly by electric locomotives.^[18] As of December 2023^[update], Indian Railways had 10,238 electric and 4,543 diesel locomotives amongst others.^[19][20]

Locomotives are classified by track gauge, motive power, function, power rating and model in a four- or five-letter code.^[21] The locomotives may be Longer Hood Front (LHF), where the driver cabin is behind the hood of the engine or Short Hood Front (SHF), where the cabin is located towards the front.^[21]

In 1925, the first electric train ran between Bombay and Kurla, hauled by a imported SLM locomotive on a DC traction.^[22] In 1927, the first electric locomotive hauled passenger train was pulled by an imported WCP-1.^[6] In 1957, Indian Railways adopted 25 kV 50 Hz AC traction with the first runs beginning in December 1959 with the WAM-1 locomotives.^[22]

Broad-gauge

Metre-gauge

EMU

In 1925, the Electric Multiple Units (EMU) introduced in Bombay were 1.5KV DC units imported were from Cammell Laird and Uerdingenwagonfabrik.^[22] In the 1960s, EMUs were developed by Intergral Coach Factory (ICF) in Chennai. Indian Railways uses multiple DC units in operation in several suburban sections which are classified from WCU-1 through WCU-15. BHEL developed AC-DC dual use EMUs which can run on 25kV AC and 1.5kV DC traction lines.^[22] In the late 1990s, MEMUs were developed which ran on 25KV AC power. AC Electric multiple units are designated WAU-1 to WAU-4.^[24] In 2019, ICF rolled out three-phase AC units to replace conventional DC units.^[25]

In 1954, the first diesel locomotive was used in India, which was manufactured by North British Locomotive Company.^[7] In 1958, WDM-1, the first locomotive used for mainline traffic was imported from ALCO.^[26] In 1964, the first broad-gauge WDM-2 diesel locomotive was rolled out by Banaras Locomotive Works.^[9]

Broad-gauge

In 2009, a YDM-4 locomotive was converted to a broad gauge shunter by Golden Rock Railway Workshop, codenamed WCDS-6, with C for "Converted" and delivered to RITES.^[29]

Metre-gauge

Narrow-gauge

Narrower-gauge

Diesel multiple units

In 1993-94, Diesel multiple units (DMU) were introduced into service. Depending on their transmission system, they are classified as DEMU (diesel-electric transmission) or DHMU (diesel-hydraulic transmission).^[24] With increase in electrifiction, DEMUS have been replaced by MEMUs in stages.^[24]

Broad-gauge

In the 19th century, the railway companies ordered custom-built steam locomotives, usually from British manufacturers. With non-standardized and multiple designs, manufacturing cost was high and production was slow. During the 1890s, Indian railway companies imported locomotives from Germany and the United States when British manufacturers were suffering from work outages.^[32] List of locomotives used below:

• Bengal Nagpur Railway:
  • Class F: 0-6-0
  • Class GM: 2-6-0 (probably modified)
  • BNR class HSG: 2-8-0+0-8-2 Garratt locomotive, first Garratt locomotive
  • Class M: 4-6-2 (probably modified)
  • BNR class N: 4-8-0+0-8-4 Garratt, India's largest locomotive; One is preserved at the National Rail Museum, New Delhi
  • BNR class NM: Ten were built in 1931 by Beyer, Peacock & Company; withdrawn in the late 1960s
  • BNR class P: 4-8-2+2-8-4 Garratt, four were built by Beyer, Peacock & Company in 1939; withdrawn in the early 1970s
• Bombay, Baroda & Central India Railway:
  • BB&CI class P: 4-6-2
  • Class A: 2-4-0T, an Atlantic; was at the Palej shed
  • Class U36: 0-4-2, used on hauling suburban trains in Bombay
  • Class D1: 4-4-0, one was named Princess May
  • Class M: 4-6-2
• East Indian Railway Company:
  • Class CT: 0-6-4T, converted to a superheater
  • EIR class G: 2-2-2T, first two named Express and Fairy Queen; Built in 1855, the latter is the world's oldest locomotive to be in working order and was rebuilt by ICF; Housed at East Indian Railway (EIR)
  • EIR class P: 4-6-0
• Great Indian Peninsula Railway:
  • GIPR classes Y1, Y2, Y3, and Y4: 0-8-4T, Used on Thal Ghat as bankers for pushing trains up the Western Ghats.
  • GIPR Class F and F3: 2-6-0
  • GIPR class J1: 0-6-0
  • Class D4: 4-6-0, one is named Hero
  • Class D5: 4-6-0 passenger locomotive
  • Class E1: 4-4-2, Atlantic built by the North British Locomotive Company in 1907–8; Rebuilt with a superheater between 1925 and 1928.
  • Class T: Tank locomotive used for hauling Mumbai suburban trains
  • Class Y: 2-8-4T
  • Crane tank: 0-6-0T, one is preserved at the National Rail Museum in New Delhi
• Madras and Southern Mahratta Railway:
  • M&SM class V: 4-4-0, one is preserved.
  • Class BTC: 2-6-4T, based on BESA specifications
  • Class T: 0-4-2; one is preserved in Chennai
• Nizam's Guaranteed State Railway:
  • NSR class A: 2-6-0T, No. 48, an Atlantic preserved at the National Rail Museum, Delhi
• North Western State Railway:
  • Class EM: 4-4-2, one is preserved at the National Rail Museum
  • NWR class GAS: 2-6-2+2-6-2 Garratt, one built in 1925 and retired in 1937
  • NWR class P: 2-4-0
  • Class E1: 4-4-2
  • Class N1: 4-8-0
• Oudh and Rohilkhand Railway:
  • Class B26: 0-6-0, one is preserved at the National Rail Museum
• Others:
  • Class B: 2-6-0
  • Class E: 2-4-0
  • Class F: 2-8-2, built between 1926 and 1950 by Nasmyth Wilson for service on Central Railway (CR)
  • Class G: 2-6-0, probably intended for freight
  • Class NA2
  • Class PTC: 2-6-4T, owned by Northern Railway (NR); probably a converted passenger locomotive
  • Class Y2: 2-8-2T, reclassified L2
  • Phoenix: 0-4-0T, one is at the National Rail Museum
  • Ramgotty: 2-2-0T, the National Rail Museum's oldest locomotive, it was converted to broad gauge
  • Sultan, Sahib and Sindh, Hauled the first passenger train in 1853

In the early 1900s, the British Engineering Standards Committee (later the British Engineering Standards Association) began designing a series of locomotives for use by Indian railways. The first two designs emerged in 1903: a 4-4-0 passenger and 0-6-0 goods. They were revised in 1905 and 1906 with additional heavier, more-powerful locomotives:

• Class SP: Standard passenger (4-4-0)
• Class SG: Standard goods (0-6-0)
• Class PT: Passenger tank (2-6-4T)
• Class HP: Heavy passenger (4-6-0)
• Class AP: Atlantic passenger (4-4-2)
• Class HG: Heavy goods (2-8-0)
• Class HT: Heavy tank (2-8-2T)

These advisory BESA designs were customized by the railway companies, which used different classification systems; only the state-operated railways used the class designations SP, SG, PT, HP, AP, HG and HT. When superheating was accepted, superheated versions were classified SPS, SGS and so on (if built with superheaters) and SPC, SGC and so on (if converted from saturated to superheated).

After World War I, larger and more-powerful locomotives were designed by British consulting engineers for the Indian government. They began to operate from 1927:

• Class XA: branch passenger 4-6-2 design, 12.5-ton axle load
• Class XB: light passenger 4-6-2 design, 17-ton axle load
• Class XC: heavy passenger 4-6-2 design, 19.5-ton axle load
• Class XD: Light goods 2-8-2 design, 17-ton axle load
• Class XE: heavy goods 2-8-2 design, 22.5-ton axle load

• Class XF: light shunting 0-8-0 design, 18-ton axle load
• Class XG: heavy shunting 0-8-0 design, 23-ton axle load
• Class XH: 4-cylinder 2-8-2, 28-ton axle load; none were built
• Class XP: experimental passenger 4-6-2, 18.5-ton axle load
• Class XS: experimental 4-cylinder 4-6-2, 21.5-ton axle load
• Class XT: light tank 0-4-2T, 15-ton axle load

During World War II, large numbers of 2-8-2 locomotives were acquired from the United States and Canada and classified AWD and CWD. The Baldwin Locomotive Works adapted the USATC S160 Class locomotive design for India, and it became class AWC. Sixty broad-gauge locomotives were built in 1944 as part of an order of 180 S160 engines. In addition to modified frame spreaders, axles, cylinders, and cab, the Indian locomotives had a turbo generator and electric lighting (not included in the standard European design). Many parts (including boilers) were identical to those in standard-gauge locomotives.^[33]

Although new classes were designed shortly before the war, many did not enter service until the post-war period. The new classes were indicated by the change of broad-gauge prefix from X to W, and plans were implemented to begin manufacturing locomotives in India. The new classes were:

• Class WP: passenger 4-6-2, 18.50-ton axle load
• Class WG: goods 2-8-2, 18.50-ton axle load
• Class WL (1st): light 4-6-2, 16.00-ton axle load (four for North Western Railway in 1939; all to Pakistan during partition of India)
• Class WL (2nd): light 4-6-2, 16.75-ton axle load
• Class WM: 2-6-4T, 16.25-ton axle load
• Class WT: 2-8-4T, 18.00-ton axle load
• Class WU: 2-4-2T, 16.50-ton axle load
• Class WV: 2-6-2T, 16.25-ton axle load
• Class WW: 0-6-2T, 16.50-ton axle load

All broad-gauge steam locomotives in India have been withdrawn from normal service, with only occasional steam specials continuing to operate.

Metre-gauge

• Nilgiri Mountain Railway X class
• BESA designs:
  • Passenger (4-6-0)
  • Mixed (4-6-0)
  • Goods (4-8-0)
  • Tank (2-6-2T)
• Indian Railway Standards designs of the late 1920s
  • Class YA: 4-6-2 with 9-ton axle load (none built)
  • Class YB: 4-6-2 with 10-ton axle load (161 built for India and 50 for Burma)
  • Class YC: 4-6-2 with 12-ton axle load (15 built for India and 13 for Burma)
  • Class YD: 2-8-2 with 10-ton axle load (171 built for India, 61 for Burma, and 25 for East Pakistan)
  • Class YE: 2-8-2 with 12-ton axle load (none built)
  • Class YF: 0-6-2 with 8-ton axle load; later examples were 2-6-2 (111 built for India)
  • Class YK: 2-6-0 version of the 2-6-2 YF, 8-ton axle load (25 built for India)
  • Class YT: 0-4-2T with 8-ton axle load (2 built for India)
• Wartime designs:
  • Class MAWD: 2-8-2 USATC S118 Class
  • Class MWGX: 4-6-2+2-6-4 Garratt
• Indian Railway Standards post war designs
  • Class YL: 2-6-2 mixed traffic locomotive with 8-ton axle load (264 built 1953–1957)
  • Class YG: 2-8-2 goods locomotive with 101⁄2-ton axle load (1074 built 1949–1972)
  • Class YP: 4-6-2 passenger locomotive with 101⁄2-ton axle load (871 built 1949–1970)
  • Class YM 2-6-4T with 9-ton axle load (12 built 1956)

Narrow-gauge

• Barsi Light Railway:
  • Class A: 0-8-4T
  • Class B: 4-8-4T
  • Class C: 0-6-0ST
  • Class D: 0-4-0
  • Class E: Sentinel railcars
  • Class F: 2-8-2
  • Class G: 4-6-4
• Indian Railway Standards:
  • Class ZA: 2-6-2 with 4.5-ton axle load (none built)
  • Class ZB: 2-6-2 with 6-ton axle load
  • Class ZC: 2-8-2 with 6-ton axle load (none built)
  • Class ZD: 4-6-2 with 8-ton axle load (none built)
  • Class ZE: 2-8-2 with 8-ton axle load
  • Class ZF: 2-6-2T with 8-ton axle load

Narrower-gauge

• Darjeeling Himalayan Railway:
  • DHR A Class: 0-4-0WT;
  • DHR B Class: 0-4-0ST; #777 and #778 preserved
  • DHR C Class: 4-6-2
  • DHR D Class: 0-4-0+0-4-0 Garratt
• Indian Railway Standards (none built):
  • QA: 2-6-2 with 4.5-ton axle load
  • QB: 2-6-2 with 6-ton axle load
  • QC: 2-8-2 with 6-ton axle load

In 2015, the first compressed natural gas (CNG) powered Multiple unites were rolled out by ICF.^[13] In 2020, Southern Railway zone introduced the first battery/AC dual shunter termed as WAG5HA with "H" for hybrid.^[34]

• Rail transport in India
• List of locomotive builders