Locomotives of India explained

Indian Railways operates India's railway system and comes under the purview of the Ministry of Railways of Government of India., it maintains over 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.

History

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) 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 was rolled out from ICF.^{[14] [15]}, Indian Railways maintains over 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], Indian Railways had 10,238 electric and 4,543 diesel locomotives amongst others.^{[19] [20]}

Classification

Locomotives are classified by track gauge, motive power, function, power rating and model in a four- or five-letter code. 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.

Locomotive classification^[21] !Letter position!Denotes!Classification

1	Track gauge
2	Motive power	D Diesel C DC Electric A AC Electric CA DC + AC Dual Electric B Battery
3	Use/ Load/ Traction	G Goods P Passenger M Mixed (Goods and Passenger) S Shunter U Multiple unit R Railcar
4	Model/ Horsepower	Version Number Model Number Number X 1000 HP
5	Sub-class/ Sub-type/ Power rating	Increments of 100 HP (For Diesel) A 100 HP B 200 HP C 300 HP and so on

Electric

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

Broad-gauge Electric Locomotives

Traction	Usage	Name	Image	Manufacturer	Axles	Number built	Production	Power (HP)	Status
WCP series
DC	Passenger	WCP-1		SLM	2-Bo-A1	22	1928-30	2160	Retired
		WCP-2		SLM	2-Bo-A1	1	1938	2160	Retired
		WCP-3		Hawthorn Leslie	2-Co-2	1	1928	2250	Retired
		WCP-4		Hawthorn Leslie, BBC	2-Co-2	1	1928	2390	Retired
WCM series
DC	Mixed	WCM-1		English Electric	Co-Co	7	1954-55	3170	Retired
		WCM-2		English Electric	Co-Co	12	1956-57	2810	Retired
		WCM-3		Hitachi	Co-Co	3	1958	2460	Retired
		WCM-4		Hitachi	Co-Co	7	1960	3290	Retired
		WCM-5		CLW	Co-Co	21	1961-63	3700	Retired
		WCM-6		CLW	Co-Co	2	1995	5000	Retired
WCG series
DC	Goods	WCG-1		SLM		41	1925-29	2400	Retired
		WCG-2		CLW	Co-Co	57	1970-76	1640	Retired
WAM series
AC	Mixed	WAM-1		50 cycles group	B-B	100	1959-60	2870	Retired
		WAM-2		Mitsubishi	Bo-Bo	36	1960-64	2790	Retired
		WAM-3		Mitsubishi	Bo-Bo	2	1964	2790	Retired
		WAM-4		CLW	Co-Co	500	1970-83	3640	Retired
WAP series
AC	Passenger	WAP-1		CLW	Co-Co	65	1980-96	3760	In service
		WAP-3		CLW	Co-Co	9	1987-88	3760	Retired
		WAP-4		CLW	Co-Co	778	1994-2015	5000	In service
				ABB, CLW	Bo-Bo	239	1995-	6000	In service
		WAP-6		CLW	Co-Co	17	1995-98	5000	Retired
		WAP-7		CLW, BLW,PLW	Co-Co	1503	2000-	6350	In service
WAG series
AC	Goods	WAG-1		SNCF, CLW	B-B	112	1963-66	2900	Retired
		WAG-2		Hitachi,Mitsubishi	B-B	45	1964-65	3180	Retired
		WAG-3		Henschel, CLW	B-B	10	1965	3150	Retired
		WAG-4		CLW	B-B	186	1966-69	3150	Retired
		WAG-5		CLW,BHEL	Co-Co	1196	1984-98	3900	In service
		WAG-6A		ASEA	Bo-Bo-Bo	6	1987-89	6000	Retired
		WAG-6B/C		Hitachi	Bo-Bo-Bo	12	1988	6110	Retired
		WAG-7		CLW	Co-Co	1994	1992-2015	5000	In service
		WAG-8		BHEL	Co-Co	1	1990	5000	Retired
		WAG-9		ABB, CLW	Co-Co	84	1996-present	6000	In service
		WAG-9H			Co-Co	4611	2006-present	6000	In service
		WAG-9I		CLW	Co-Co	43	2010-present	6000	In service
		EF-9K		CLW	Co-Co		2020-present	9000	In service
		EF-12K		CLW	Co-Co+Co-Co		2023-present	12000	In service
		WAG-10		BLW	Co-Co-Co-Co	1	2018-present	10000	In service
		WAG-11		BLW	Co-Co-Co-Co	4	2018-present	12000	In service
		WAG-12		Alstom	Bo-Bo-Bo-Bo	360	2017-present	12000	In service
WCAM series
Dual (DC/AC)	Mixed	WCAM-1		CLW	Co-Co	54	1975-79	2930 (DC) 3640 (AC)	Retired
		WCAM-2		CLW	Co-Co	20	1995-96	3780 (DC) 4720 (AC)	In service
		WCAM-3		BHEL	Co-Co	53	1997-98	4600 (DC) 5000 (AC)	In service
WCAG series
Dual (DC/AC)	Goods	WCAG-1		BHEL	Co-Co	12	1999-2000	4600 (DC) 5000 (AC)	In service

Metre-gauge

Metre-gauge Electric Locomotives^[23]

Traction	Usage	Name	Image	Manufacturer	Axles	Number built	Production	Power (	HP)	Status
DC	Goods	YCG-1		English Electric	Bo-Bo	4	1930	640	Retired
AC	Mixed	YAM-1		Mitsubishi	B-B	20	1964-66	1740	Retired

Electric multiple unitsIn 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]

Diesel

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

Broad-gauge Diesel Locomotives^[27]

Usage	Name	Numbers	Image	Manufacturer	Axles	Number built	Production	Power (HP)	Status
WDM series
Mixed	WDM-1	17000-17099		ALCO	Co-Co	100	1957-59	1950	Retired
	WDM-2	16000-16887, 17100-17999, 18040-18079, 18112-18514, 18523-18900, 18903-18999		ALCO, BLW	Co-Co	2700	1962-98	2600	Retired
	WDM-2G	80000,80001		BLW	Co-Co	2	2013	2400	Retired
	WDM-3	18515-18522		Henschel	Bo-Bo	8	1970	2500	Retired
	WDM-3A	13xxx, 14001-14057, 14058-14143, 16000-		BLW	Co-Co	1431	1994-98	3100	In service
	WDM-3D	11101 - 11590		BLW	Co-Co	500	2003-13	3300	In service
	WDM-4	18000-039, 18080-18111		GM	Co-Co	72	1962	2600	Retired
	WDM-6	18901,18902		BLW	Bo-Bo	2	1981-82	1350	Retired
	WDM-7	11001-11015		BLW	Co-Co	15	1987-89	2000	Retired
WDP series
Passenger	WDP-1	15001-15069		BLW, ALCO	Bo-Bo	69	1995-99	2300	In service
	WDP-3A	15501-15544		BLW, ALCO	Co-Co	44	1998-2002	3100	In service
	WDP-4	20000-20103, 40001-40608		EMD, BLW	Bo1-1Bo	711	2002-18	4000	In service
WDG series
Goods	WDG-2/3A	14501-14999, 13000-13665		BLW	Co-Co	2004	1995-2010	3100	In service
	WDG-4	12001-12999, 70001-70190		EMD, BLW	Co-Co	1188	1999-2018	4500	In service
	WDG-4D	70301-70882, 12681		BLW	Co-Co	583	2012-2018	4500	In service
	WDG-4G	49001-49700		GE	Co-Co	468	2017-present	4500	In service
	WDG-5	50001-50007		BLW	Co-Co	7	2012-17	5500	Withdrawn^[28]
	WDG-6G	69001-69300		GE	Co-Co	92	2018-present	6000	In service
WDS series
Shunter	WDS-1	19000-19014		GE	Bo-Bo	15	1944-45	386	Retired
	WDS-2	19016-19045		Krauss-Maffei	C	30	1954-55	440	Retired
	WDS-3	19046-19052		Maschinenbau Kiel	C	7	1961	618	Retired
	WDS-4	19057-19732		CLW	C	662	1968-97	600-700	Retired
	WDS-5	19087-19107		ALCO, BLW	Co-Co	21	1967	1065	Retired
	WDS-6			BLW	Co-Co	270	1975–	1400	In service
	WDS-8			CLW	Bo-Bo	5	1979-82	800	Retired

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

Metre-gauge Diesel Locomotives

Usage	Name	Image	Manufacturer	Axles	Number built	Production	Power (HP)	Status
YDM series
Mixed	YDM-1		NBL	B-B	20	1955-56	700	Retired
	YDM-2		CLW	B-B	41	1986-90	700	Retired
	YDM-3		EMD	B-B	30	1961-62	1390	Retired
	YDM-4		ALCO, BLW		541	1961–93	1400	In service
	YDM-5		GM		25	1964	1390	Retired

gauge

gauge Diesel Locomotives

Usage	Name	Image	Manufacturer	Axles	Number built	Production	Power (HP)	Status
ZDM series
Mixed	ZDM-1		Arnold Jung	B-B	5	1955	290	Retired
	ZDM-2		Maschinenbau Kiel	B-B	25	1964-65	700	Retired
	ZDM-3		CLW	B-B	40	1970-82	700	In service
	ZDM-4		CLW	1-B-B-1	49	1975-90	700	In service
	ZDM-5		CLW	B-B	41	1989	450	In service

gauge

gauge Diesel Locomotives

Usage	Name	Image	Manufacturer	Axles	Number built	Production	Power (HP)	Status
NDM series
Mixed	NDM-1		Arnold Jung	B-B	7	1955	290	In service
	NDM-5		CLW		11	1987-89	450	In service
	NDM-6		SAN	B	6	1997	335	In service

Diesel multiple unitsIn 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]

Steam

Broad-gaugeIn 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. List of locomotives used below:

• Bengal Nagpur Railway

• • Class F:
  • Class GM: (probably modified)
  • BNR class HSG

Garratt locomotive, first Garratt locomotive

• • Class M: 4-6-2 (probably modified)
  • BNR class N

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

Garratt, four were built by Beyer, Peacock & Company in 1939; withdrawn in the early 1970s

• Bombay, Baroda & Central India Railway

• • BB&CI class P:
  • Class A:, an Atlantic; was at the Palej shed
  • Class U36:, used on hauling suburban trains in Bombay
  • Class D1:, one was named Princess May
  • Class M:
• East Indian Railway Company

• • Class CT:, converted to a superheater
  • EIR class G:, 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:
• Great Indian Peninsula Railway

• • Sultan, Sahib and Sindh

Hauled the first passenger train in 1853

• • Lord Falkland

0-6-0

• • GIPR classes Y1, Y2, Y3, and Y4:, 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

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.^[32]

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 10-ton axle load (1074 built 1949–1972)
  • Class YP: 4-6-2 passenger locomotive with 10-ton axle load (871 built 1949–1970)
  • Class YM 2-6-4T with 9-ton axle load (12 built 1956)

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

gauge

• Darjeeling Himalayan Railway

• • DHR A Class: 0-4-0WT;
  • DHR B Class: 0-4-0ST; #777 and
    1. 778
    preserved
  • DHR C Class: 4-6-2
  • DHR D Class: 0-4-0+0-4-0 Garratt
• Matheran Light Railway

• • MLR 1-4:
• 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

Others

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.^[33]

See also

• Rail transport in India
• List of locomotive builders

Notes

Bibliography

• • Book: Hughes, Hugh . 1979 . Steam locomotives in India, Part 3 – Broad Gauge . Harrow, Middlesex . The Continental Railway Circle . 0-9503469-4-2 .
    • • • • Book: Marshall, Lawrence G. Indian Metre Gauge Steam Remembered. 2005. Plateway Press. East Harling, Norfolk. 1871980542.
  • Book: Woods . George . Indian Steam in the 1970s . 2017 . Amberley Publishing. Stroud, Glos . 9781445666785.

Notes and References

1. Understanding Indian Railway Heritage. Indian Railways. 6. 1 December 2023.
2. News: Chennai: The track record. 16 April 2018. New Indian Express. 9 August 2023.
3. First running of a railway locomotive in India. Indian Railways. 6. 1 December 2023.
4. News: When India's first train blew steam. 25 April 2013. The Times of India. 1 December 2023.
5. News: Oldest locomotive: Built in Ajmer, pride of Delhi. 3 August 2017. The Times of India. 1 December 2023.
6. Evolution of Electric Locomotives. Indian Railways. 1 December 2023.
7. Gandhidham shed details. Indian Railways. 1 December 2023.
8. Chittaranjan Locomotive works. Indian Railways. 1 December 2023.
9. Banaras Locomotive works. Indian Railways. 1 December 2023.
10. 15 October 1999. Electrical Multiple Units. Indian Rail Info. 1 December 2023.
11. Web site: Historical Background of Railway Electrification. 19 May 2023. Indian Railways.
12. Web site: Indian railway facilities. Indian Railways. 1 April 2023.
13. News: India's first CNG train for the Rewari-Rohtak section. 15 January 2015. The Economic Times. 1 December 2023.
14. News: 20 February 2017. Indian Railways to roll out 'Make in India' 160 kmph self-propelled 'world-class' train sets at half the cost of import!. 20 May 2023. The Financial Express.
15. News: 29 October 2018. Train 18: Country's first engine-less train rolled out; Train 20 next. The Economic Times. 20 May 2023. 0013-0389.
16. Web site: About Indian Railways. Indian Railways. 1 January 2024.
17. Trains at a glance. Indian Railways. 1 January 2024.
18. News: 37% of trains in India being hauled by diesel locomotives, rest by electric engines. 10 December 2021. 1 December 2023. The Hindu.
19. Electric locomotive holding. Indian Railways. 1 January 2024.
20. Diesel locomotive holding. Indian Railways. 1 January 2024.
21. Locomotive classification. Indian Railways. 1 January 2024.
22. Electrification history. Indian Railways. 1 December 2023. 9 June 2017. https://web.archive.org/web/20170609072045/http://elocos.railnet.gov.in/Analysis/Elect_Tr_history.htm. dead.
23. Heritage list of locomotives. Indian Railways. 1 December 2023.
24. Web site: Multiple Units. IRFCA. 1 December 2023.
25. News: 3-phase MEMU to replace conventional DC rakes soon. The Hindu. 3 October 2019. 1 December 2023.
26. Book: The Complete Encyclopedia of Locomotives. Mirco. De Cet. Alan. Kent. 2006. 286. 978-9-0366-1505-1. Rebo International.
27. Web site: Loco classes. IRFCA. 1 December 2023.
28. Loco availability April 2024. 1 April 2024. Indian Railways.
29. Web site: Locomotive FAQ. IRFCA. 1 December 2023.
30. Web site: Achievements of 2021. RDSO. 1 December 2023.
31. News: 17 January 2016 . Railways to manufacture dual-mode locomotives that run on diesel, electricity. 20 May 2020. The Times of India.
32. 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.
33. News: Indian Railways goes green with eco-friendly loco! Adds battery-operated shunting locomotive to its fleet. 12 October 2020. Financial Express. 1 December 2023.