Locomotives of India

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The Indian Railways primarily operates electric and diesel locomotives. Steam locomotives are operated on a few World Heritage sites and also run occasionally as heritage trains. A locomotive is also known as a loco or engine. The country's first steam locomotive ran on the Red Hill Railway (built by Arthur Cotton to transport granite for road-building) from Red Hills to the Chintadripet bridge in Madras in 1837.[1]


Locomotives were classified by track gauge, motive power, function and power (or model number) in a four- or five-letter code. The first letter denotes the track gauge. The second letter denotes motive power (diesel or electric), and the third letter denotes use (goods, passenger, mixed or shunting). The fourth letter denotes a locomotive's chronological model number.

In 2002, a new classification system was adopted. For newer diesel locomotives, the fourth letter denotes their horsepower range. Not all diesel locomotives were reclassified, and the fourth letter continues to denotes their model number.

A locomotive may have a fifth letter, generally denoting a technical variant, subclass or subtype: a variation in the basic model or series, or a different motor or manufacturer. Under the new system, the fifth letter further refines horsepower in 100-hp increments: A for 100 hp, B for 200 hp, C for 300 hp and so on. A WDP-3A is a 3,100 hp (2,300 kW) locomotive, and a WDM-3F is 3,600 hp (2,700 kW).

The system does not apply to steam locomotives, which are no longer used on main lines. They retain their original class names, such as M- or WP-class.


  • First letter (gauge):
    • W – Broad gauge (wide) – 5 ft 6 in (1,676 mm)
    • Y – Metre gauge (yard) – 3 ft 3 38 in (1,000 mm)
    • Z – 2 ft 6 in (762 mm) narrow gauge
    • N – 2 ft (610 mm) narrow (toy) gauge
  • Second letter (motive power):
    • D – Diesel
    • C – DC electric (DC overhead line)
    • A – AC electric (AC overhead line)
    • CA – DC and AC (AC or DC overhead line); CA is considered one letter
    • B – Battery (rare)
  • Third letter (job type):

In WDM 3A, W denotes broad gauge; D denotes diesel power; M denotes mixed use (goods and passenger service), and 3A denotes 3,100 hp (3,000 + 100). In WAP 5, W is broad gauge; A is AC electric; P is passenger service, and 5 indicates that the locomotive is the fifth model used.

Broad-gauge (5 ft 6 in) locomotives[edit]


Steam engine at outdoor museum
More-modern steam locomotive
Old red-and-black steam locomotive
Large steam locomotive
Indian Railways locomotives: (clockwise from upper left) Preserved HPS, NRM WP 7200, B-26 and preserved YP-class

Nineteenth-century railway companies ordered custom-built locomotives, usually from British manufacturers. The multiplicity of similar-but-not-identical designs increased manufacturing cost and slowed production. During the 1890s, British manufacturers were busy and Indian railway companies looked to Germany and the United States for locomotives.[2] Engines used were:

  • Bengal Nagpur Railway:
  • Bombay, Baroda and Central India Railway:
    • BB&CI class P: 4-6-2
    • Class A: 2-4-0T, probably 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 (probably modified)
  • East Indian Railway Company:
  • 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 Madras.
  • Nizam's Guaranteed State Railway:
    • NSR class A: 2-6-0T (No. 48, probably an Atlantic) preserved at the National Rail Museum, Delhi.
  • North Western State Railway:
    • Class EM: 4-4-2 (probably modified); 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 train from VT to Thana in 1853.


Steam locomotive in a museum
Vulcan Foundry class SPS, 1911

After acrimonious words in The Times and Parliament, 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).

Manufacturer's photo
Similar to first photo, without manufacturer documentation
Indian Railways locomotives: 1935 XP class (left) and 1927 XB class

After World War I, larger and more-powerful locomotives were designed by British consulting engineers for the Indian government. They began to appear in 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.[3]

Steam engine in transit
Steam engine at an outdoor museum
Black locomotive under cover
Locomotive on above-ground display
(clockwise from upper left) WL- and YG-class locomotives; an M2-162, and a display engine in Guntur Division

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:

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


Broad-gauge diesel classification codes are:

  • WDM – Wide diesel mixed
  • WDP – Wide diesel passenger
  • WDG – Wide diesel goods
  • WDS – Wide diesel shunter
  • WCDS – Wide converted diesel shunter

Mixed locomotives are:

  • WDM 1: India's first mainline diesel electric locomotives, imported in 1957 from ALCO as part of ALCO FA 'world Locomotive' .It was rated at 1,950-horsepower (1,450 kW) with a top speed of 110 km/h (68 mph). The very first WDM1 #17000 is on display in the National Rail Museum, New Delhi.Rest are scrapped
  • WDM-2: The country's most widely-used and first homemade mainline diesel-electric locomotives, the prototypes were made by ALCO. Introduced in 1962, over 2,700 have been manufactured and they are rated at 2,600 hp (1,900 kW).
    Kundan, the first WDM-2 locomotive assembled at DLW, Varanasi
  • WDM-2A, WDM-2B: WDM-2 variants; the WDM-2A has dual brakes, and the 2B usually has air brakes.
  • WDM-2G: Indian Railways' first Multi-Gen-set[clarify] locomotive, manufactured by DLMW[clarification needed] Patiala in 2013. In February 2014, two locos were in service: #80000 and #80001.[4] They have been approved for a maximum speed of 105 km/h (65 mph).[5]
  • WDM-3: Eight were imported in 1970 from Henschel & Son. With a hydraulic transmission, the 2,500 hp (1,900 kW) engines have a maximum speed of 120 km/h (75 mph).Scrapped in late 1990s
  • WDM-3A: Formerly known as the WDM-2C, it is a WDM-2 variant unrelated to the WDM-3. With a maximum speed of 120 km/h (75 mph), it has 30,450 kgf of tractive effort. Manufactured since 1994, it is one of India's most heavily-used diesel locomotives.
  • WDM-3A R: Formerly the WDM-2, it is rebuilt with DBR[clarification needed] on a short hood and is unrelated to the WDM-3.
  • WDM-3B: Co-Co bogies with a top speed of 120 km/h (75 mph), they operate out of the Uttar Pradesh sheds. Twenty-three were built by DLW. Similar to the WDM-3D, they are rated at 3,100 hp (2,300 kW).[6]
  • WDM-3C: Higher-powered versions of the WDM-3A, rated at 3,300 hp (2,500 kW). The WDM-3C is rebuilt from the WDM-2. The WDM-3C have maximum speeds of 120 km/h (75 mph)
  • WDM-3D: A class formed by incorporating the best features of the WDP-4 and WDG-4 to the ALCO platform.These locomotives can be easily distinguished from other ALCOs by narrower body shell with platform space for the crew to move around it, EMD-style railings,solid cowcatcher and on the roof of the short hood.They are Microproccessor controlled with improved Fabricated (welded) Alco High-Adhesion Co-Co bogies.Over 590 Locos have been manufactured by DLW.
  • WDM-3E: Reclassified as WDM-3D, it is restricted to freight at 105 km/h (65 mph). Eight 3,500 hp (2,600 kW) units were known to have been manufactured by DLW.
  • WDM-3F: Manufactured by DLW, the 3,600 hp (2,700 kW) HAHS[jargon] bogies have conventional DBR and air brakes.
    WDM7 BioDiesel
  • WDM-4: Entering service with the WDM-2, its 2,600 hp (1,900 kW) prototypes were designed by General Motors. Although it was considered superior to the WDM-2, General Motors did not agree to a technology transfer agreement.
  • WDM-6: Two were made, and exported to Sri Lanka. Rated at 1,350 hp (1,010 kW), their maximum speed was 75 km/h (47 mph) and they had 19,200 kgf of tractive effort and Bo-Bo bogies.
  • WDM-7: Fifteen 2,000 hp (1,500 kW) locos were built from June 1987 through 1989. Designed for branch-line duty, they are used primarily for shunting. They can be spotted performing shunting duties at Chennai Central or Chennai Egmore.

Passenger locomotives are:

  • WDP-1: With Bo-Bo bogies and weighing 80 tons, their top speed is 120 km/h (75 mph). The 12-cylinder, 2,300 hp (1,700 kW) engines were built by DLW in 1970 and operate out of the Vijayawada and Tughlakabad sheds.
  • WDP-2 (new class name WDP-3A: Entering service in 1998, the DLW loco has a maximum speed of 140 km/h (87 mph), 29.25 tons of tractive effort and is rated at 3,100 hp (2,300 kW).[7][8]
  • WDP-3: WDP-1 prototypes, they were designed in 1996 by DLW. The 2,300 hp (1,700 kW) locos have Co-Co bogies.
  • WDP-4: A 4,000 hp (3,000 kW) EMD (former GM-EMD) GT46PAC passenger version of the WDG-4 (GT46MAC)
  • WDP-4B: Improved WDP-4 with 4,500 hp (3,400 kW), six traction motors (like the WDG-4), a wider cabin to aid visibility and minor exterior design changes. Production of the single-cab locomotives has ended.
  • WDP 4D: A WDP-4 with twin cabs, the 4,500 hp (3,400 kW) locomotive with an LCD instrument display and driver toilet has entered serial production and regular service.

Goods locomotives are:

  • WDG-2 (new class name WDG-3A): Upgraded WDM-2 built by DLW, with a maximum speed of 100 km/h (62 mph)
Indian Diesel locomotive WDG 3A
  • WDG-3B, -3C and -3D: Upgraded WDG-2 or -3As. The WDG-3B and WDG-3C are rebuilt WDG-3As, and the WDG-3C is rated at 3,330 hp (2,480 kW).[9]
  • WDG-4: General Motors 4,000–4,500 hp (3,000–3,400 kW) GT46MAC models, first imported in 1999 and numbered from #12000 to #12999 and upward from #70000.[10] Local production began in 2002.
  • WDG-4D: A WDG-4 with dual air-conditioned cabs and a maximum speed of 100 km/h (62 mph), India's first dual-cab diesel freight engine[11]
  • WDG-4G and WDG-6: Evolution Series GE ES43ACmi 4,500 hp (3,400 kW) and 6,000 hp (4,500 kW) diesel locomotives which GE Transportation is building for Indian Railways[citation needed]
  • WDG-5: Developed by Diesel Locomotive Works and supported by Electro Motive Diesels, the first unit left DLW on 25 February 2012. Numbered upwards from #50001, two were produced by 29 April 2015. Rated at 5,500 hp (4,100 kW), it has a fire control system, a TFT display and driver's toilet. The locomotive has entered serial production, and is assigned to the Sabarmati Diesel Loco Shed.
Orange-and-tan locomotive
Red locomotive
Two Indian Railways shunting locomotives: a WDS-4D (left) and a WDS-4

Shunting locomotives are:

  • WDS-1: India's first widely-deployed diesel locomotive (imported in 1944–45), the 386 hp (288 kW) engine is out of service.
  • WDS-2: With o-C-o[jargon] bogies and an eight-cylinder engine, it is based at Central Railway. Built by Kraus Maffei in 1954–55, the 440 hp (330 kW) engine has 15,420 kgf of tractive effort and a maximum speed of 54 km/h (34 mph).
  • WDS-3: The 618 hp (461 kW) locomotives of this class were rebuilt and reclassified as WDS-4C from 1976 to 1978. With 17,100 kgf of tractive effort, they were built in 1961.
  • WDS-4, -4A, -4B and -4D: Designed by Chittaranjan Locomotive Works (CLW), the 600–700 hp (450–520 kW) locos have C bogies and were built from 1968 to 1997.
  • WDS-4C: Rebuilt by CLW and reclassified from WDS-3, the 700 hp (520 kW) locomotive has 18,000 kgf of tractive effort and C bogies. Out of service, its maximum speed is 65 km/h (40 mph).
  • WDS-5: Some are used for industrial shunting, and a few are used on Indian Railways. It is rated at 1,065 hp (794 kW).
  • WDS-6: Heavy-haul shunters made in large numbers for industry and Indian Railways, it is rated at 1,200–1,350 hp (890–1,010 kW).
    WDS-6R 36217
  • WDS-6R, -6SL and -6AD: Variants of the WDS-6, the -6SL is exported to Sri Lanka. The -6AD has a maximum speed of 50 km/h (31 mph) and a six-cylinder engine.[12]
  • WDS-8: Five 800 hp (600 kW) locos, with a maximum speed of 35 km/h (22 mph) and 22,000 kgf of tractive effort, were made by CLW and transferred to steelworks.[13]
Tan-and-green train
Newer red train
Indian Railways DHMU (left) and DEMU

Several 250 hp (190 kW) hydraulic diesel shunters were in use at Integral Coach Factory, Diesel Locomotive Works and Chittaranjan Locomotive Works.[14] The WDS-1 to WDS-4D classes have a hydraulic transmission, and the WDS-4, -4B, -4C and -4D are the only extant broad-gauge diesel-hydraulic locomotives.

The WCDS6, a YDM4 locomotive, was converted to broad gauge by the Golden Rock Railway Workshop for large industrial companies; the first one was delivered to RITES. New water and air lines were added, the control stand was modified, and it has a dual brake system.

A few routes have DMU service. Depending on their transmission system, they are classified as DEMU (diesel-electric transmission) or DHMU (diesel-hydraulic transmission). There is diesel railcar service (known as railbus) in several areas.

DC electric[edit]

These locomotives, no longer in use, were used only in and around Mumbai with 1,500 V DC power. All sections of Central Railway, including Thane to Mumbai CST (Main Line), Nerul to Thane (Trans-Harbour Line), Vadala Road to Mahim (Harbour Line, connecting Central and Western Railway) and Panvel to Mumbai CST (Harbour Line) have been converted to 25 kV AC.

Mixed locomotives were:

  • WCM 1: India's first electric Co-Co locomotives. Seven 3,350 hp (2,500 kW) engines were built by English Electric at Vulcan Foundry in 1954–55.
  • WCM 2: Twelve 3,120 hp (2,330 kW) locomotives with Co-Co bogies and a maximum speed of 120 km/h (75 mph) were built by Vulcan Foundry in 1956–57 and modified by the Research Design and Standards Organisation (RDSO).
  • WCM 3: Three 3,400 hp (2,500 kW) Co-Co locomotives with a maximum speed of 120 km/h (75 mph) were built by Hitachi in 1958, used in Kolkata and transferred to Mumbai.
  • WCM 4: Seven 4,000 hp (3,000 kW) Co-Co locomotives, rated at 120 km/h (75 mph) and intended for freight with 31,300 kgf of tractive effort, were built by Hitachi in 1960.
  • WCM 5: Built in 1962 by the Chittaranjan locomotive works to RDSO specifications, with auxiliaries by Westinghouse and North Boyce, the 3,700 hp (2,800 kW) Co-Co engines were India's first indigenously-designed DC electric locomotives.
  • WCM 6: Two 4,700 hp (3,500 kW) locomotives were built in 1995 by CLW and converted to AC power. Initially rated at 105 km/h (65 mph), they are restricted to 65 km/h (40 mph).
Preserved black electric locomotive
Preserved 1930 WCP1

Passenger locomotives were:

Another preserved black locomotive
Preserved 1928 WCG1

Goods locomotives were:

  • WCG 1: GIPR EF/1, 2,600–2,950 hp (1,940–2,200 kW) Swiss crocodile locomotives imported in 1928 (10 from SLM and 30 from Vulcan Foundry). They were among India's earliest electric locomotives. The first, the Sir Leslie Wilson, is preserved at the National Rail Museum.
  • WCG 2: Fifty-seven 4,200 hp (3,100 kW) locomotives with a maximum speed of 90 km/h (56 mph) and 35600 kgf of tractive effort were designed by the Chittaranjan locomotive works in 1970 and built until 1977.[15] They were used extensively around 2000 in Mumbai.[16])

WCU 1 to WCU 15 electric multiple units (EMU) were used in the Mumbai region.

AC electric[edit]

A 25 kV AC system with overhead lines is used throughout the country. Mixed locomotives are:

  • WAM-1: Among the first AC locomotives used in India, the 3,010 hp (2,240 kW) engines with a maximum speed of 112 km/h (70 mph) were introduced in 1959. A Hundred locos of this type have been supplied by European Group and put into service in 1960. The locomotives are designed for mixed traffic operation.The locomotive is powered by four fully suspended, forced ventilation pulsating current type traction motors. The motors are coupled to the axles through 'Jaquemin' drive with the Superstructure is connected to the bogies through pendulum suspension and low traction bars.The motors are permanently connected in parallel and speed control is obtained throuh HT tap changer and traction motor field weakening.These constructional features help to give better adhesion.Compressed air brake for the locomotives and vacuum brake for the train has been provided. They are now out of service and scrapped. one unit has been preserved

  • WAM-2/WAM-3: Built by Mitsubishi between 1960 and 1964, the 2,910 hp (2,170 kW) locomotives with Bo-Bo bogies, 25,240 kgf of tractive effort and a maximum speed of 112 km/h (70 mph). WAM-3 are similar to the WAM-2 except for reverse pantographs. Ten locomotives of WAM2 type have been supplied by Mitsubishi (Japan) and put into service in 1961. Repeat order for 28 locomotives was placed on the firm for meeting the requirement of push-pull operation for sub-urban trains. These are provided with air brakes only, two locomotives of this order designated as WAM3 are provided with silicon rectifiers.A few WAM2 locomotives fitted with flexicoil fabricated bogie have been designated as WAP2.The locomotive is powered by four fully suspended forced ventilated pulsating current type traction motors. The motor is coupled to the axle through a flexible WN gear drive. The motors are permanently connected in parallel and the speed control is obtained by means of HT 3 changer and field weakening. The rectifiers are water-cooled and ignition type in WAM2 locomotives.For initially procured, 10 locomotives, compressed air brake for locomotives and vacuum brake for the trains are provided.

  • WAM4 in Itarsi
    WAM-4: Designed by Chittaranjan Locomotive Works (CLW) in 1970, the 4,850 hp (3,620 kW) locomotive is one of India's most successful locomotives. Variants are the WAM-4B, -4P, -4PD, -4PR, -4PDBHS, -46PD, -4PDB3P, -42S3P, -46PDBHS, -46PE, -4G, -4H and -4E.

Passenger locomotives are:

  • WAP-1: Designed by CLW in 1980 for the Kolkata-Delhi Rajdhani Express, the locomotive is rated 3,900 hp (2,900 kW) continuous and has a maximum speed of 130 km/h (81 mph).
  • WAP-2: Four units, decommissioned in the late 1980s,WAM-2 and 3 with Flexicoil Mark-II bogies and {{convert|2910|hp|kW|[17]
  • WAP-3: Five WAP-1s have been rebuilt since 1987, with a maximum speed of 140 km/h (87 mph).
  • WAP4
    WAP-4: Upgraded from the WAP-1 for heavier loads by CLW in 1994, the locomotive is rated 5,060 hp (3,770 kW) continuous and has a speed limit of 140 km/h (87 mph).
  • WAP5 in Vadodara
    WAP-5: Imported in 1995 from Switzerland and used on express trains, the 6,000 hp (4,500 kW) maximum, 5,450 hp (4,060 kW) continuous locomotive with Bo-Bo bogies and a speed limit of 160 km/h (99 mph) has been built by CLW since 2000.
  • WAP-6: Primarily rebuilt WAP-4s, 16 5,000 hp (3,700 kW) locomotives were built by CLW in 1997.
  • WAP7
    WAP-7: Same design as the WAG-9, with a modified gear ratio. The 6,350 hp (4,740 kW) maximum, 6,000 hp (4,500 kW) continuous locomotives with a speed limit of 140 km/h (87 mph) have been built by CLW since 2000.
  • WAP-7 HS (High Speed): Upgraded version of current WAP-7 locomotives. Currently only one locomotive is manufactured by CLW.

WAG Series[edit]

Goods locomotives are:

  • WAG 1
    WAG1 20710 Bidhaan at NRM
    Forty-two locomotives of this type were ordered from European Group. Five of these were completely assembled in Europe and the remaining were built at CLW. A repeat order was placed on for 20 locomotives in 1963. Further these locomotives were manufactured at CLW.The typical feature of these locomotive is the Monomotor bogies. This construction results in substantial saving in weight in traction equipment and gives better adhesion.The traction motors are force ventilated and are fully suspended type. These motors are permanently grouped in parallel and are controlled by tap changer and field weakening.This can be used for a multiple unit operation to a maximum of four locomotives.Compressed air brake for the loco and vacuum brake for the train are provided, in addition, these locomotives have been provided with regenerative braking. Few locomotives have been converted to dual brake system.They were in service until 2000 when all were scrapped.The first indigenously produced WAG-1 Bidhaan is preserved at the National Rail Museum, New Delhi.

  • WAG 2

Forty-five of these locos were ordered on Hitachi (Japan) and the First of these has been put into service in 1964. The locos are built for Goods traffic operation.The locomotive is powered by two bogie mounted forced ventilated Type dc traction motors permanently grouped in parallel. The speed control is achieved by a HT tap changer provided on the transformer primary. Field weakening is also provided.These locomotives utilise silicon rectifiers for conversion of ac lower into dc.Compressed air brake for the loco and vacuum brake for the train re provided. In addition these locomotive are provided with rheostatic raking also.

The locomotives can be used for multiple operation.All were withdrawn before 2000.None have been preserved

  • WAG 3

Ten locomotives of this type were ordered from European Group. All these locomotives have been assembled in Europe. First locomotive was put in service in July, 1965.The typical feature of these locomotives is a Monomotor bogie. This construction results in substantial saving in weight in traction equipment and gives better adhesion.These locomotives utilise silicon rectifiers for conversion of ac power into dc.The traction motors are force ventilated and are fully suspended type. These motors are permanently grouped in parallel and controlled by tap changer and field weakening. The traction motors for the WAG3 were two units of Alstom MG1580A1 which output 23% more top power than the WAG1.This can be used for a multiple unit operation to a maximum of four locomotives.Compressed air brake for the loco and vacuum brake for the train are provided. In addition, these locomotives have been provided with rheostatic braking.WAG4 is based on this class

  • WAG 4

Modified version of the WAG-3..Major equipments for first fifty-six locomotives of this type were procured from European Group. Auxiliary machines and some control equipments have been procured from indigenous sources. All these locomotives were built by CLW. The typical feature of these locomotives is Monomotor Bogie. This construction results in substantial saving in weight in traction equipment and gives better adhesion. These locomotives utilise silicon rectifiers for conversion of ac power into dc. The traction motors are force ventilated and are fully suspended type. These motors are permanently grouped in parallel and speed control is obtained through HT tap changer and TM field weakening. These locomotives can be used for a multiple unit operation to a maximum of four locomotives.They also have Compressed air brake for the loco and vacuum brake for the train are provided. In addition, these locomotives are also provided with rheostatic braking. Few locomotives have been converted to dual brake system later on by Railways.All are withdrawn and scrapped

Manufacturer:Chittaranjan Locomotive Works ( CLW )


  • WAG 5

Manufacturer:All of the series except WAG 5HB: CLW, WAG 5HB: Bharat Heavy Electricals Ltd ( BHEL )

  • WAG 5 - 5A,5H, 5HA, 5HB, 5HG, 5HR, 5RH, 5D, 5P, 5HE, 5E, 5B
  • Build dates:
    • WAG 5, 1988–98
    • WAG 5A, 1983–88
    • WAG 5B, 1978–83
  • Wheel arrangement: Co-Co
  • Traction Motors: Alstom TAO 659 (575 kW, 750 V, 1070 rpm) or TAO 656; or Hitachi HS 15250A (See description under WAP-4.) Axle-hung, nose-suspended. Six motors.
  • Gear Ratio: 62:16 or 62:15 with Alstom motors, some 64:18 (Hitachi motors), many now 58:21 for mixed use.
  • Transformer: BHEL, type HETT-3900. 3900 kVA, 22.5 kV, 182 A. 32 taps.
  • Rectifiers: Silicon rectifiers (two) using 64 S-18FN-350 diodes each from Hind Rectifier. 2700 A / 1050 V per cubicle.
  • Bogies: Co-Co cast bogies (Alco asymmetric trimount—shared with WDM-2, WAM-4).
  • Axle load: 20 t
  • Max. Haulage: 2375 t
  • Pantographs: Two Faiveley AM-12
  • Current Ratings: 1100 A / 10 min, 750 A continuous
  • WAG 6
  • Manufacturer: ASEA ( WAG 6A ),Hitachi ( WAG 6B,WAG 6C )
  • Build dates:
    • WAG 6A, 1988–89
    • WAG 6B, 1988
    • WAG 6C, 1988
  • Wheel arrangement:
  • Traction Motors: ASEA make (WAG-6A), L3 M 450-2. Six motors, fully suspended, force-ventilated, separately excited, 3100 kg ; (WAG-6B) Hitachi HS 15556-OIR, bogie mounted, force-ventilated, compound-wound, 3200 kg ; (WAG-6C) Hitachi HS 15256-UIR, axle-hung nose-suspended, force-ventilated, compound-wound, 3650 kg.
  • Transformer: (WAG-6A) ASEA: TMZ 21, 7533 kVA; (WAG-6B/C) Hitachi AFIC-MS, 6325 kVA.
  • Thyristor controller: (WAG-6A) 24 YST 45-26P24C thyristors each with 24 YSD35-OIP26 diodes, 2 x 511 V, 2 x 4500 A; (WAG-6B/C) 32 CGOIDA thyristors each with 24 DSP2500A diodes. 2x720 A, 850 V.
  • Pantographs: (WAG-6A) Two Stemman BS 95; (WAG-6B/C) Two Faiveley LV2600
  • WAG 6 - 6A, 6B, 6C
  • WAG 6A

These 6-axle locomotives have been ordered from ASEA by IR for working under arduous climatic conditions with ambient temperature reaching 50 °C.Multiple connection of the locomotive is possible and they are pared for a future increase of the speed up to maximum 160 km/h. by have a micro-computer based control and indication system which assist the driver and the maintenance staff. Micro-processor control has been used not only for switching the thrusters but also for continuous monitoring of vulnerable equipment, thereby also providing diagnostic system and fault indication system (FIS) with facilities for automatic isolation of faulty equipment & answer back display on cut off operation to check whether emergency counter measures were correctly taken. FIS has facility for storage of the last 100 faults which can be printed along with details of conditions which existed when fault occurred. The creep control system using Doppler radar sensors, comparing wheel speed with true ground speed gives instant feed back & regulates the power to each individual axle, permitting maximum utilization of the available adhesion. Thruster-switched power factor correction is incorporated. ASEA hollow-shaft traction motor drive tern has been adopted for transmission of power. Air and dynamic brake system exists on the locomotive while it can haul air brake stock only.

  • WAG 6B/6C
VSKP based WAG-6C locos at Koraput

A total of 12 thruster controlled electric locomotives built by M/s Hitachi/Japan were procured by lR in 1988. Out of these, 6 are having Bo-Bo-Bo bogie arrangement and are designated as WAG-6B class and 6 having Co -Co bogie arrangement have been designated as WAG-6C class.Special design features like fully suspended traction motor with WN coupling drive in WAG-6B class and unidirectional axle-hung, nose-suspended traction motor in WAG-6C have been incorporated to achieve higher adhesion.Speed control is through phase angle control of thruster bridges combined with a separate control for field current. Automatic control is realised through a microprocessor based control system. Freon cooling for thyristor converters has been provided.The design provides for a future increase in speed up to a maximum of 160 km/h.The locomotives have air and dynamic brake system and are designed to haul air brake stock only. A maximum of four locomotives can be used in a multiple operation.

  • WAG 7
Indian locomotive class WAG-7 (old variant)
Indian locomotive class WAG-7 built by BHEL
  • WAG 7 - 7H
  • Build dates: 1992-2015
  • Wheel arrangement: Co-Co
  • Traction Motors: Hitachi HS15250-G (a variant of the standard HS15250 with higher current rating (thicker wire gauge, better insulation); see description under WAP-4.) Motors built by CLW and BHEL.
  • Gear Ratio: 65:18 (65:16?)
  • Transformer: CCL India, type CGTT-5400, 5400 kVA, 32 taps.
  • Rectifiers: Two silicon rectifiers, cell type S18FN350 (from Hind Rectifier), 64 per bridge, 2700 A / 1050 V per cubicle.
  • Axle load: 20.5 t
  • Bogies: Alco High-Adhesion bogies, fabricated bogie frame assembly, with unidirectional mounting of traction motors, primary and secondary suspension.
  • Hauling Capacity: 3010 t
  • Pantographs: Two Stone India (Calcutta) type AM-12.
  • Current Ratings: 1350 A / 2 min, 1200 A / 10 min, 960 A / hr, 900 A continuous
  • Last WAG-7 was manufactured on 24 September 2015. Its loco number is 28770 & its serial number is HH-1770
  • WAG 8
  • Build date: 1996
  • Wheel arrangement: Co-Co

This is an experimental class of which only one or two were built by BHEL in 1996. They are similar in appearance to the WCAM-2 locos. Power output is similar to the WAG-7 at 5000 hp. There is thyristor chopper control of the DC motors. The class probably shared some components with the WCAM-3 which BHEL was building at the time. They are thought to have Flexicoil Mark IV hi-adhesion bogies. This class was abandonded because of the success of WAG-7 and Arrival of 3-Phaser locos like WAG9. The shell was left at BHEL, jhansi in Rusted condition https://indiarailinfo.com/blog/post/2906557

  • WAG 9
Indian locomotive class WAG-9
  • WAG 9 - 9H,9h(H=HEAVY),9HH( The first H stands for higher axle load and the second H stands for the higher power rating)[18]
  • Build dates: 1996+
  • Wheel arrangement: Co-Co
  • Manufacturers: ABB, CLW, BHEL
  • Traction Motors: ABB 6FRA 6068 (850 kW, 2180 V, 1283/2484 rpm, 270 / 310 A. Weight 2100 kg) Axle-hung, nose-suspended.
  • Gear Ratio: 77:15 / 64:18
  • Transformer: ABB LOT 6500, 4 x 1450 kVA.
  • Power Drive: Power converter from ABB, type UW-2423-2810 with SG 3000G X H24 Gate turn-off thyristors (D 921S45 T diodes), 14 thyristors per unit (two units). Line converter rated at 2 x 1269 V @ 50 Hz, with DC link voltage of 2800 V. Motor/drive converter rated at 2180 V phase to phase, 971 A output current per phase, motor frequency from 0 to 132 Hz.
  • Hauling capacity: 4250 t
  • Bogies: Co-Co, ABB bogies; bogie wheelbase 1850 mm + 1850 mm
  • Wheelbase: 15700 mm
  • Axle load: 20.5 t
  • Unsprung mass per axle: 3.984 t
  • Length over buffers: 20562 mm
  • Length over headstocks: 19280 mm
  • Body width: 3152 mm
  • Cab length: 2434 mm
  • Pantographs: Two Secheron ES10 1Q3-2500.
  • Pantograph locked down height: 4525 mm
  • WAG-11: In November 2018, Diesel Locomotive Works , Research Design and Standards Organisation made twin section 12,000HP (8,950 kW) locomotive.
  • WAG-12 Prima: India's most powerful class, rated at 12,000HP (8,950 kW), locomotives built by Alstom at the Madhepura locomotive factory in Bihar

Electric multiple units are designated WAU-1 to WAU-4.

Dual (AC and DC)[edit]

These locomotives are used only in the Mumbai. Their main purpose is to prevent the need to change engines. Mixed locomotives are:

  • WCAM 1: Designed by Chittaranjan Locomotive Works, total 53 were built between 1975 and 1979. Decommissioned by Western Railway, it is the only locomotive with reverse pantographs.
  • WCAM 2/2P: Designed by BHEL, 20 were built in 1995–96 and tested at 135 km/h (84 mph) on AC.
  • WCAM 3:53 were designed by Bharat Heavy Electricals, rated at 4,600 hp (3,400 kW) on DC traction and 5,000 hp (3,700 kW) on AC. Owned by Central Railway, they are the most widely-used locomotive on the Mumbai-Pune section.

In the Mumbai area, some EMUs can operate on dual traction.


In 1927, English Electric and WBC built two shunters for yard use in Bombay with Bo-Bo bogies. Rated at 240 hp (180 kW), they weighed 58 tons. These are now preserved in National Rail Museum in Delhi. They were charged using the 1500 V DC OHE which was available there. [19]


Metre-gauge (3 ft 3⅜ in) locomotives[edit]


  • Nilgiri Mountain Railway X class
  • BESA designs:
    • Passenger (4-6-0)
    • Mixed (4-6-0)
    • Goods (4-8-0)
    • Tank (2-6-2T)
  • Wartime designs:
  • Indian Railway Standards designs
    • Class YA: 4-6-2 with 9-ton axle load (none built)
    • Class YB: 4-6-2 with 10-ton axle load
    • Class YC: 4-6-2 with 12-ton axle load
    • Class YD: 2-8-2 with 10-ton axle load
    • Class YE: 2-8-2 with 12-ton axle load (none built)
    • Class YF: 0-6-2; later examples were 2-6-2
    • Class YK: 2-6-0 version of the 2-6-2 YF
    • Class YL: 2-6-2
    • Class YT: light 0-4-2T
    • Class YG: 2-8-2 goods locomotive
    • Class YP: 4-6-2 passenger locomotive


Faded red locomotive
Orange-and-white loco
Indian Railways YDM-1 (left) and YDM-4 locomotives


Maroon-and-gold locomotive
YAM 1 metre-gauge electric locomotive
  • Locomotives:
    • YCG 1: Among India's earliest electric locomotives, the class was imported to serve the Chennai area in the early 1930s.
    • YAM-1: Twenty 1,740 hp (1,300 kW) locomotives, imported from Japan, were in service until 2002 in the Chennai area.
  • Electric multiple units:
    • YAU class: India's first EMU service was introduced around 1920 in the Chennai area.

Narrow-gauge (2 ft 6 in and 2 ft) locomotives[edit]


2 ft 6 in[edit]

  • 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

2 ft[edit]

Black locomotive
DHR B class locomotive in Darjeeling shed (1979)


2 ft 6 in[edit]

Blue-and-white locomotive
NDM-1 diesel loco on the Matheran Hill Railway.

2 ft[edit]


  • NBM-1: Designed by BHEL in 1987

Research and development[edit]

Indian Railways' diesel locomotives are fitted with auxiliary power units, which save nearly 88 percent on fuel when the trains are not running.[29]

The APUs are smaller 25 HP diesel engines that run the air brake compressors of the locomotive, which are normally operated by the main diesel engine when the locomotive is running. This allows the bigger engine to be switched off, and yet maintain the air brake pressure in a parked locomotive. The APU is fitted in the short hood of all ALCo based locomotives such as WDM 3D.

See also[edit]



  1. ^ "[IRFCA] India's First Railways". www.irfca.org.
  2. ^ Hughes 1979, p. 17
  3. ^ Baldwin Locomotive Works drawing index and bill of materials for special order 43306, locomotive design 2-8-0 19S, numbers 666 to 845 for the U.S. Government, War Department.
  4. ^ http://www.irfca.org/apps/locos/show/12721
  5. ^ http://www.rdso.indianrailways.gov.in/works/uploads/File/Speed%20Certificate%20of%20%20WDM2G%20loco.pdf
  6. ^ "Vadakkus".
  7. ^ http://www.irfca.org/faq/faq-loco2d.html
  8. ^ "24coaches".
  9. ^ http://forum.irfca.org/showthread.php/31486-Ready-to-capture-WDG-4-70000?highlight=70000[permanent dead link]
  10. ^ "IR Gazette".
  11. ^ "DLW".
  12. ^ https://www.irfca.org/gallery/Heritage/WDS-8.jpg.html
  13. ^ "IRFCA diesel".
  14. ^ "IRFCA2".
  15. ^ "IRFCA Loco Database".
  16. ^ http://www.indianrailways.gov.in/railwayboard/uploads/codesmanual/ACTraction-I/AcTractionI_ADDITIONAL_Data.htm
  17. ^ https://indiarailinfo.com/blog/post/4283482
  18. ^ "IRFCA".
  19. ^ "Indian Railways creates history! Converts diesel loco to 'Make in India' electric locomotive; watch video". The Financial Express. 3 March 2018. Retrieved 1 October 2018.
  20. ^ Meter Gauge Diesel Locomotives
  21. ^ YDM-1
  22. ^ a b c d e [IRFCA] Indian Railways FAQ: Locomotives – Specific classes : Meter Gauge & Narrow Gauge Diesel
  23. ^ [IRFCA] Indian Railways FAQ: Diesel and Electric Locomotive Specifications
  24. ^ [IRFCA] Indian Railways FAQ: Diesel and Electric Locomotive Specifications
  25. ^ [IRFCA] Indian Railways FAQ: Diesel and Electric Locomotive Specifications
  26. ^ [IRFCA] Indian Railways FAQ: Diesel and Electric Locomotive Specifications
  27. ^ [IRFCA] Indian Railways FAQ: Diesel and Electric Locomotive Specifications
  28. ^ "New Technology allows Railways to save Rs 20 Lakhs Diesel per Engine". Retrieved 6 September 2013.


  • Hughes, Hugh (1976). Steam in India. Truro, Cornwall: D. Bradford Barton Ltd. ISBN 0851532586.
  • Hughes, Hugh (1979). Steam locomotives in India, Part 3 – Broad Gauge. Harrow, Middlesex: The Continental Railway Circle. ISBN 0-9503469-4-2.
  • Hughes, Hugh (1990). Indian Locomotives: Part 1 – Broad Gauge 1851–1940. Harrow, Middlesex: The Continental Railway Circle. ISBN 0-9503469-8-5.
  • Hughes, Hugh (1992). Indian Locomotives: Part 2 – Metre Gauge 1872–1940. Harrow, Middlesex: The Continental Railway Circle. ISBN 0-9503469-9-3.
  • Hughes, Hugh (1994). Indian Locomotives: Part 3 – Narrow Gauge 1863–1940. Harrow, Middlesex: The Continental Railway Circle. ISBN 0-9521655-0-3.
  • Hughes, Hugh (1996). Indian Locomotives: Part 4 – 1941–1990. Harrow, Middlesex: The Continental Railway Circle. ISBN 0-9521655-1-1.
  • Marshall, Lawrence G (2001). Indian Narrow Gauge Steam Remembered. East Harling, Norfolk: Plateway Press. ISBN 1871980488.
  • Marshall, Lawrence G (2005). Indian Metre Gauge Steam Remembered. East Harling, Norfolk: Plateway Press. ISBN 1871980542.
  • Marshall, Lawrence G (2009). Indian Broad Gauge Steam Remembered. East Harling, Norfolk: Taverner Publications. ISBN 9781901470154.
  • Woods, George (2017). Indian Steam in the 1970s. Stroud, Glos: Amberley Publishing. ISBN 9781445666785.

External links[edit]