99notes at 19:37, 2 December 2025

2025-12-02T19:37:07Z

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{{Short description|Class of diesel-electric locomotives}}
{{Use Indian English|date=May 2020}}
{{Use mdy dates|date=June 2025}}
{{multiple issues|
{{more citations needed|date=August 2024}}
{{Missing information|locomotive disposition|date=June 2025}}
}}
{{Infobox locomotive
| name = WDM-4<ref name=IRFCAspecs>{{cite web |title=IRFCAspecs |url=http://www.irfca.org/faq/faq-specs.html#WDM-4}}</ref>
| powertype = Diesel
| image = WDM-4 18001 locomotive.jpg
| caption = Preserved loco at [[National Rail Museum, New Delhi]]
| builder = [[Electro-Motive Diesel]]
| buildmodel = [[EMD G16|EMD GT16]] (based on [[EMD SD24]])
| builddate = 1961–1962
| totalproduction = 72
|Britishclass=[[Co-Co locomotive|Co-Co]]
|uicclass=Co′Co′
| gauge = {{track gauge|1676mm|lk=on}}
| bogies = [[Flexicoil suspension|Flexicoil]] Mark I cast steel
| locoweight = {{convert|112800|kg|abbr=on}}
| axleload = 18.8 tonnes
| fueltype = [[Diesel fuel]]
| primemover = [[Electro-Motive Diesel|EMD]] [[EMD 567|16-567D3A]]
| enginetype = [[Two-stroke engine|two-stroke]] [[V16 engine|V16]] [[Diesel engine|diesel]]
| aspiration = [[Turbocharger|Turbo]]-[[Supercharger|Supercharged]]
| cylindercount = 16
| transmission = [[Diesel electric]]
| maxspeed = Restricted: {{convert|120|km/h|0|abbr=on}}<br />Running: {{convert|130|km/h|0|abbr=on}}<br/>Rated: {{convert|140|km/h|0|abbr=on}}<br/>Tested: {{convert|145|km/h|0|abbr=on}}
| poweroutput = {{convert|2600|HP|abbr=on}}/<br />{{convert|2430|HP|abbr=on}}
| tractiveeffort = {{convert|28200|kgf|0|abbr=on}}
| trainbrakes = [[Vacuum brake|Vacuum]]
| operator = [[Indian Railways]]
| fleetnumbers = 18000-039, 18080-18111
| locale =[[Northern Railway zone|Northern Railway]]
| withdrawndate = 2001
| disposition =
}}
The Indian locomotive class '''WDM-4''' is a class of [[diesel–electric locomotive]] that was developed in 1962 by [[Electro-Motive Diesel]] for [[Indian Railways]]. The model name stands for [[5 ft 6 in gauge railway|broad gauge (W)]], Diesel (D), Mixed traffic (M) engine, 4th generation (4). They entered service in 1962. A total of 72 WDM-4 locomotives were built between 1961 and 1962.

==Origin ==
The history of WDM-4 begins in the early 1960s with the stated aim of the [[Indian Railways]] to remove [[steam locomotive]]s from Indian Rails after recommendation of Karnail Singh Fuel Committee.<ref>{{Cite web|title=Report of the expert Committee on Coal Consumption on Railways, 1958|url=http://www.indianculture.gov.in/report-expert-committee-coal-consumption-railways-1958|website=INDIAN CULTURE|language=en|access-date=April 29, 2020}}</ref> Therefore, required building a large number of [[Co-Co locomotives|Co-Co]] diesel locomotives producing at least 2,600 hp (1,900 kW) with [[road switcher]] cabs to achieve this aim. Thus Indian Railways began looking at various [[Diesel-electric train|diesel-electric]] designs.

Initially, the Indian railways invited tenders to build locomotives to the new specification. The following responses were received:

* General Motors (EMD) submitted their [[EMD SD24|SD24]], given model number GT16 for the India export version.<ref>{{Cite web|title=wdm3_001.jpg|url=https://www.irfca.org/gallery/Locos/Diesel/wdm1_4_5_6_7/wdm3_001.jpg.html|website=www.irfca.org|access-date=April 29, 2020}}</ref> They had Co-Co bogies with 16-cylinder 2-stroke turbo-supercharged engines.<ref>{{Cite web|title=WDM-4 specs for IR|url=https://rdso.indianrailways.gov.in/works/uploads/File/WDM4.PDF}}</ref>
* [[American Locomotive Company|ALCO]] submitted their model (RSD29 / [[ALCO DL560C|DL560C]]) with 2,600 hp, 16-cylinder, 4-stroke turbo-supercharged engine with Co-Co bogies.

Each company submitted their prototypes and Indian Railways designated these prototypes as the WDM-4 class and [[Indian locomotive class WDM-2|WDM-2]] class respectively.<ref>{{Cite web|title=[IRFCA] Indian Railways FAQ: Locomotives - General Information - I|url=https://www.irfca.org/faq/faq-loco.html#class|website=www.irfca.org|access-date=April 18, 2020}}</ref> It is not known as to why Indian Railways decided to classify it as WDM-4, as no WDM-3 class existed when they were ordered. Technologically the General Motors WDM-4 was superior to ALCO WDM-2, but Indian Railways required a transfer of technology agreement that would allow these locomotives to be indigenously manufactured in India. Since General Motors did not agree to the transfer of technology agreement, the ALCO prototype was selected for production.

However, even before the arrival of WDM-4 another type of diesel locomotive was imported from ALCO in 1957. This locomotive was classified as [[Indian locomotive class WDM-1|WDM-1]].<ref>{{Cite web|title=Four decades of service: The early workhorses of India's diesel age - National Rail Museum|url=https://artsandculture.google.com/exhibit/four-decades-of-service-the-early-workhorses-of-india-s-diesel-age/-gKCw2asIUlWLg|website=Google Arts & Culture|language=en|access-date=April 29, 2020}}</ref> However, WDM-1s were not selected for mass production because of having only one forward cab at one end, necessitating turntables for the driver's field of view.<ref>{{Cite web|title=Diesel Locomotive Roster – The WDM (ALCO) Series|url=https://24coaches.com/indian-railways-wdm-series/|date=October 30, 2013|website=24 Coaches|language=en-US|access-date=April 29, 2020}}</ref>

==Service history==
The WDM-4 locomotives were capable of hauling both freight and passenger trains, however they were primarily used on passenger service. The WDM-4 was India's first [[Electro-Motive Diesel|EMD]] locomotive, and a model of GT16.<ref name="EMD GT16 Order Numbers">{{cite web|title=TrainWeb.org|url=http://www.trainweb.org/emdloco/gt16.htm}}</ref> These were the fastest locomotives in India until the arrival of WAP-3 engines.

==See also==
*[[Indian locomotive class WDM-2]]
*[[List of diesel locomotives of India]]
*[[Indian Railways]]
*[[Rail transport in India]]

==References==
{{reflist}}

{{Broad gauge locomotives of India}}
{{EMD misc}}

{{DEFAULTSORT:WDM-4}}
[[Category:Diesel–electric locomotives of India|M-4]]
[[Category:Co-Co locomotives]]
[[Category:Railway locomotives introduced in 1962]]
[[Category:5 ft 6 in gauge locomotives]]
[[Category:Electro-Motive Division locomotives]]

Indian locomotive class WDM-4 - Revision history

99notes at 19:37, 2 December 2025