The Indian Railways primarily operates a fleet of electric and diesel locomotives, along with several compressed natural gas (CNG) 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 more popularly as an 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.
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.
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 (2,300 kW) (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 AC electric classification codes are:
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Many are being converted to WAP-4
Arrangement
Built
CLW
These locomotives, no longer in use, were used only in and around Mumbai with 1.5 kV 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.
Broad-gauge DC electric classification codes are:
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MetroVick
MetroVick
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MetroVick
/Vulcan Foundry
MetroVick
WCU 1 to WCU 15 electric multiple units (EMU) were used in the Mumbai region.
Broad-gauge DC and AC electric classification codes are:
These locomotives are used only in the Mumbai area. They were built to prevent the need to change locos. Mixed locomotives are:
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Broad-gauge battery classification code is:
In 1927, English Electric and WBC built two shunters for yard use in Bombay with Bo-Bo bogies. They were of the WBCS class. 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.
The locomotives are classified as WCAS. Where W means Wide Gauge, C means DC(Battery), A means AC power, S means Shunting.
Broad-gauge diesel and electric classification code is:
These locomotives are used on routes that can run on both electrified and non-electrified tracks. Their main purpose is to prevent the need of engine change in electrified routes. Passenger locomotives are:
Number used: 71000
Broad-gauge diesel classification codes are:
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& BLW
& BLW
& BLW
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Maffei
nenbau Kiel
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.
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, many British manufacturers were recovering from work outages, thus Indian railway companies looked to Germany and the United States for locomotives. Engines used were:
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:
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 appear in 1927:
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.
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.
Metre-gauge electric classification codes are:
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In the Chennai area.
Metre-gauge diesel classification code is:
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Built
Narrow-gauge diesel classification codes are:
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Built
Narrow-gauge battery classification code is: