The class YDM-4 is

Indian Railways Indian Railways (IR) is a statutory body under the ownership of Ministry of Railways, Government of India that operates India's national railway system. It manages the fourth largest national railway system in the world by size, with a tot ...

' workhorse

diesel locomotive A diesel locomotive is a type of railway locomotive in which the prime mover is a diesel engine. Several types of diesel locomotives have been developed, differing mainly in the means by which mechanical power is conveyed to the driving whee ...

. The first units were imported fully built from the

American Locomotive Company The American Locomotive Company (often shortened to ALCO, ALCo or Alco) was an American manufacturer of locomotives, diesel generators, steel, and tanks that operated from 1901 to 1969. The company was formed by the merger of seven smaller locomo ...

(Alco) in 1961. Since 1968, it has been manufactured in India by the

Banaras Locomotive Works The Banaras Locomotive Works (BLW) (formerly Diesel Locomotive Works (DLW)) in Varanasi, India, is a production unit of Indian Railways. DLW stopped manufacturing diesel locomotives in March 2019 and was renamed BLW in Oct 2020. History Founde ...

(BLW), Varanasi. The model name stands for

metre gauge Metre-gauge railways are narrow-gauge railways with track gauge of or 1 metre. The metre gauge is used in around of tracks around the world. It was used by European colonial powers, such as the French, British and German Empires. In Europe, la ...

(Y), diesel (D), mixed traffic (M) engine. The YDM-4 has been the most successful diesel locomotive in the metre gauge operation of Indian Railways. The YDM-4A is a variant of the YDM-4 supplied by MLW . Originally equipped with

vacuum brake The vacuum brake is a braking system employed on trains and introduced in the mid-1860s. A variant, the automatic vacuum brake system, became almost universal in British train equipment and in countries influenced by British practice. Vacuum bra ...

s. Some were later equipped with dual brakes, particularly those working in the Northeast Frontier Railway were retrofitted with dual brake system by Lumding shed. The YDM-4 locos have a maximum speed of , restricted to .

History

In the mid 1950s

began introducing diesel locomotives to its metre gauge system. Metre gauge, though rare gauge today, used to be a dominant gauge that time. After the introduction of YDM-1 locomotives by North British, Indian Railway thought for more powerful ones and hence

General Motors Electro-Motive Division Progress Rail Locomotives, doing business as Electro-Motive Diesel (EMD), is an American manufacturer of diesel-electric locomotives, locomotive products and diesel engines for the rail industry. The company is owned by Caterpillar through its sub ...

(EMD) and the

(ALCO) submitted designs of YDM-3/ YDM-5 ( 12-567C) and YDM-4 respectively for new diesel locomotives. Each company supplied 30 locomotives in 1961. While YDM-3 was 13 ton lighter than the YDM-4, Indian Railways opted for the

ALCo The American Locomotive Company (often shortened to ALCO, ALCo or Alco) was an American manufacturer of locomotives, diesel generators, steel, and tanks that operated from 1901 to 1969. The company was formed by the merger of seven smaller locomo ...

design because of the heavier axle load and technology agreement that would allow these locomotives to be manufactured in India. After

(BLW) completed construction of its factory in Varanasi, production of the locomotives began in India. Initial 30 YDM-4 locomotives supplied by American Locomotive Company (ALCo) in 1961 had the road numbers in #6020 to #6049 range. Another batch of 8 locomotives followed the route to India soon which had the road numbers in #6105-6112 range. YDM-4 #6113-6129 were built perhaps in 1964. Siliguri Diesel Locoshed was the first DLS to home YDM-4 locomotives in 1962. The very first YDM4 numbered as #6020 was allotted to New Guwahati Diesel Loco Shed which was an outbase of Siliguri DLS on 30/10/1962. The loco, however is assumed to be scrapped due to overage. YDM4 numbered in #6130 to #6198 range were built by

Montreal Locomotive Works Montreal Locomotive Works (MLW) was a Canadian railway locomotive manufacturer which existed under several names from 1883 to 1985, producing both steam and diesel locomotives. For a number of years it was a subsidiary of the American Locomotive ...

(MLW) in 1964 under the license of ALCo and were classified as YDM-4A. All the YDM-4 delivered till then were presumably based at three premier DLS across India namely Siliguri (SGUJ), Golden Rock (GOC) and Sabarmati (SBI). The First YDM-4 built by Banaras Locomotive Works (BLW) Varanasi was #6199 christened as Hubli. This loco rolled out from DLW in 1968 and was dedicated to the nation by the then Deputy Prime Minister of India, Morarji Desai. DLW built at first locos in the range #6199 to #6258. Another batch of YDM-4A were dispatched from MLW in 1969 in the range #6259 to #6288. From 1969 till 1993 DLW produced YDM-4 locomotives for Indian Railways in the number range #6289 to #6769. Last YDM-4 was based at Rangapara North outbase of Siliguri DLS but later on transferred to Myanmar (Burma) Railways and possibly renumbered as DF1332.

Locomotive sheds

Technical specifications

References

External links

YDM-4 Diesel Locomotive Internals
{{Metre gauge locomotives of India, state=expanded M, Y-4 Co-Co locomotives ALCO locomotives Railway locomotives introduced in 1961 Metre gauge locomotives