As railroads around the world needed to haul larger quantities of freight efficiently, the title of world's largest locomotive has often been passed to new generations of rolling stock.

Standard

It is very hard to determine what factor makes the locomotive largest: It could be the heaviest, longest, most cylinders, most horse power, or most wheels. It is often defined as the longest in absolute length, however there is even a debate on whether or not to include the tender in the measurement. To establish the "largest" category, several base factors simply take precedence: overall weight, which gives traction over driving axles; actual size (length & height of engine itself); and power, which may be given in terms of raw horsepower, tractive effort, available power at axles (shaft horsepower) or in the case of steam locomotives, available steam on a sustained basis.

Name	Railroad	Road number	Builder	Build date	Engine typeing	Wheel	Weight	Power	Disposition
PRR GG1	Pennsylvania Rail Road (PRR) & PennCentral & Amtrak Amtrak The National Railroad Passenger Corporation, doing business as Amtrak , is a government-owned corporation that was organized on May 1, 1971, to provide intercity passenger train service in the United States. "Amtrak" is a portmanteau of the words "America" and "track". It is headquartered at Union...  & NJ Transit	4800-4938, 900-929	Altoona Works Altoona Works Altoona Works is a large railroad industrial complex in Altoona, Pennsylvania. It was built by the Pennsylvania Railroad to supply the railroad with locomotives, railroad cars and related equipment. For many years it was the largest railroad shop complex in the world.-History:In 1849, PRR... , General Electric General Electric General Electric Company , or GE, is an American multinational conglomerate corporation incorporated in Schenectady, New York and headquartered in Fairfield, Connecticut, United States...	1934–1943	Electric	2-C+C-2 (4-6-6-4)	208.9 to 216.4	4629 hp, Tractive Effort: 65,500 lbf Pound-force The pound force is a unit of force in some systems of measurement including English engineering units and British gravitational units.- Definitions :...	Most scrapped; 15 production locomotives and the prototype preserved in museums
Class 461	Železnice Srbije Serbian Railways Serbian Railways is the national railway carrier of Serbia. Its current network spans a distance of 4,347 km in length, with 32% electrified railways....	ŽS461-0/1, ŽS461-2	Electroputere Craiova, Romania	1965 – 1991	Electric	Co'Co'	120 t	5100 kW 7638 horsepower	In operational in Romania,Serbia, Montenegro, Bulgaria, Hungary, Macedonia.
Allegheny 2-6-6-6 The 2-6-6-6 is an articulated locomotive type with 2 leading wheels, two sets of six driving wheels and six trailing wheels. Only two classes of the 2-6-6-6 type were built. One was the "Allegheny" class, built by the Lima Locomotive Works. The name comes from the locomotive's first service with...	Chesapeake and Ohio Railway Chesapeake and Ohio Railway The Chesapeake and Ohio Railway was a Class I railroad formed in 1869 in Virginia from several smaller Virginia railroads begun in the 19th century. Led by industrialist Collis P...  (C&O) & Virginian Railway Virginian Railway The Virginian Railway was a Class I railroad located in Virginia and West Virginia in the United States. The VGN was created to transport high quality "smokeless" bituminous coal from southern West Virginia to port at Hampton Roads....  (VGN)	1600 to 1659 (C&O) 900 to 907 (VGN)	Lima Locomotive Works Lima Locomotive Works Lima Locomotive Works was an American firm that manufactured railroad locomotives from the 1870s through the 1950s. The company took the most distinctive part of its name from its main shops location in Lima, Ohio. The shops were located between the Baltimore & Ohio's Cincinnati-Toledo main line...	1941 – 1948	Steam	2-6-6-6 2-6-6-6 The 2-6-6-6 is an articulated locomotive type with 2 leading wheels, two sets of six driving wheels and six trailing wheels. Only two classes of the 2-6-6-6 type were built. One was the "Allegheny" class, built by the Lima Locomotive Works. The name comes from the locomotive's first service with...	544 t	7500 hp	two in static display
Big Boy Union Pacific Big Boy Big Boy was the name of the Union Pacific Railroad's 4000-class 4-8-8-4 articulated steam locomotives, built between 1941 and 1944 by American Locomotive Company...	Union Pacific Union Pacific Railroad The Union Pacific Railroad , headquartered in Omaha, Nebraska, is the largest railroad network in the United States. James R. Young is president, CEO and Chairman....	X4000 to X4024	ALCO American Locomotive Company The American Locomotive Company, often shortened to ALCO or Alco , was a builder of railroad locomotives in the United States.-Early history:...	1941 – 1944	Steam	4-8-8-4 4-8-8-4 In the Whyte notation for the classification of steam locomotives by wheel arrangement, a 4-8-8-4 is a locomotive with a four-wheel leading truck, two sets of eight driving wheels, and a four-wheel trailing truck.Other equivalent classifications are:...	548 t	6290 hp	several in static display
XA Triplex 2-8-8-8-4 Under the Whyte notation for the classification of steam locomotives, a 2-8-8-8-4 has two leading wheels, three sets of eight driving wheels, and a four trailing wheels.Other equivalent classifications are:...	Virginian Railway Virginian Railway The Virginian Railway was a Class I railroad located in Virginia and West Virginia in the United States. The VGN was created to transport high quality "smokeless" bituminous coal from southern West Virginia to port at Hampton Roads....	700	Baldwin Baldwin - United States of America :* Baldwin, Florida* Baldwin, Georgia* Baldwin, Illinois* Baldwin, Iowa* Baldwin, Louisiana* Baldwin, Maine* Baldwin, Maryland* Baldwin, Michigan* Baldwin, Chemung County, New York* Baldwin, Nassau County, New York...	1916	Steam	2-8-8-8-4 2-8-8-8-4 Under the Whyte notation for the classification of steam locomotives, a 2-8-8-8-4 has two leading wheels, three sets of eight driving wheels, and a four trailing wheels.Other equivalent classifications are:...	383 t	Unknown, Tractive Effort: 199,560 lb simple; 166,600 lb compound	Rebuilt into separate locomotives
Challenger Union Pacific 3985 Union Pacific 3985 or UP 3985 is a four-cylinder simple articulated 4-6-6-4 Challenger-type steam locomotive owned by Union Pacific Railroad. The UP 3985 locomotive was built in 1943 by the American Locomotive Company of Schenectady, New York...	Union Pacific	3985 Union Pacific 3985 Union Pacific 3985 or UP 3985 is a four-cylinder simple articulated 4-6-6-4 Challenger-type steam locomotive owned by Union Pacific Railroad. The UP 3985 locomotive was built in 1943 by the American Locomotive Company of Schenectady, New York...	ALCOhale American Locomotive Company The American Locomotive Company, often shortened to ALCO or Alco , was a builder of railroad locomotives in the United States.-Early history:...	1936 – 1943	Steam	4-6-6-4 4-6-6-4 In Whyte notation, a 4-6-6-4 is a railroad steam locomotive that has four leading wheels followed by six coupled driving wheels, a second set of six driving wheels and four trailing wheels.Other equivalent classifications are:...	485 t	6200 hp	Operates in excursion service; largest operational steam locomotive as of 2007
GTEL 8500 'Big Blow' Union Pacific GTELs Union Pacific operated the largest fleet of gas turbine-electric locomotives of any railroad in the world. The prototype, UP 50 was the first in a series built by General Electric for Union Pacific's long-haul cargo services. The prototype was introduced in 1948 and was followed by three series...	Union Pacific	1-30 (control cab), 1B-30B (turbine unit)	General Electric GE Transportation Systems GE Transportation, formerly known as GE Rail, is a division of General Electric. The organization manufactures equipment for the railroad, marine, mining, drilling and energy generation industries. It is based in Erie, Pennsylvania. Locomotives are assembled at the Erie plant, while engine...	1958 – 1961	Gas turbine-electric	C-C+C-C		8469 hp	Two preserved in museums
EMD DDA40X EMD DDA40X The EMD DDA40X was a D-D diesel-electric locomotive built by the General Motors EMD division of La Grange, Illinois for the Union Pacific Railroad...	Union Pacific	6936 Union Pacific 6936 Union Pacific 6936 is an EMD DDA40X locomotive owned by Union Pacific Railroad . It is the sole example of the "Centennial" type that is still in operation, and thus is the largest operational diesel-electric locomotive in the world...	Electro-Motive Division of General Motors	1969 – 1971	Diesel-electric	D-D	244 t	6600 hp	One operational Union Pacific 6936 Union Pacific 6936 is an EMD DDA40X locomotive owned by Union Pacific Railroad . It is the sole example of the "Centennial" type that is still in operation, and thus is the largest operational diesel-electric locomotive in the world... , several in museums; largest operational single-unit diesel locomotive and the most powerful
SJ Dm3 SJ Dm3 Dm and Dm3 is a series of locomotives used by Statens Järnvägar and later Malmtafik i Kiruna for pulling iron ore trains on Malmbanan in Sweden and Ofotbanen in Norway. A total of 39 double-locomotives were delivered between 1953 and 1971, built by ASEA. A further 19 center locomotives were...	Malmbanan Malmbanan The Iron Ore Line is a long railway line between Riksgränsen and Boden in Norrbotten County, Sweden. The line contains two branches, from Kiruna to Svappavaara and from Gällivare to Koskullskulle. The term is often colloquially used to also include the Ofoten Line, from Riksgränsen to Narvik in...		ASEA ASEA Allmänna Svenska Elektriska Aktiebolaget was a Swedish industry company. It merged with the Swiss Brown, Boveri & Cie in 1988 to form Asea Brown Boveri...	1953 – 1971	Electric	1'D+D+D1'	273 t	9655 hp	Highest continuous tractive effort in the world when built, most powerful locomotive using jackshafts
DB Class 103 DB Class 103 The Baureihe 103 is a class of electric locomotives in Germany, originally operated by Deutsche Bundesbahn. For a long period, they were perceived as flagships of the DB rolling stock.- Development :...				1970 – 1973	Electric	Co'Co'	114 t	9977 hp
SBB-CFF-FFS Re 620 SBB-CFF-FFS Re 620 The Re 620, Re 6/6 in the old numbering scheme, are six-axle, electric locomotives of the SBB-CFF-FFS, which were acquired as a replacement for the Ae 6/6 for heavy services on the Gotthardbahn...	Gotthardbahn Gotthardbahn Gotthardbahn was the name of a private Swiss railway company which operated the railway line from Immensee to Chiasso . Nowadays this term usually does not refer to that company, but to the railway line itself...		BBC Brown, Boveri & Cie Brown, Boveri & Cie was a Swiss group of electrical engineering companies.It was founded in Baden, Switzerland, in 1891 by Charles Eugene Lancelot Brown and Walter Boveri who worked at the Maschinenfabrik Oerlikon. In 1970 BBC took over the Maschinenfabrik Oerlikon...	1972 – 1980	Electric	Bo'Bo'Bo'	120 t	10527 hp	Most powerful undividable locomotive in series production when built
JR Freight Class EF200 JR Freight Class EF200 The EF200 class of electric locomotives are Bo-Bo-Bo wheel arrangement DC freight locomotives operated by JR Freight in Japan.Between 2006 and 2009, the entire fleet was repainted into a new livery similar to that used for the later EF210 locomotives....	JR Freight		Hitachi Ltd.	1990 –	Electric	Bo'Bo'Bo'	100.8 t	8046 hp	Most powerful undividable narrow-gauge locomotive in series production
EMD SD90MAC EMD SD90MAC The EMD SD90MAC is a C-C diesel-electric hood unit locomotive produced by General Motors Electro-Motive Division. It is, with the SD80MAC, one of the largest single-engined locomotives produced by that company, surpassed only by the dual-engined DD series...	Union Pacific	8500-8561	Electro-Motive Diesel	1996 – 2002	Diesel-Electric	C-C	210 t	6300 hp	Retired from service, some on lease with EMLX
GE AC6000CW GE AC6000CW The AC6000CW is a diesel electric locomotive that is built by GE Transportation Systems. They are all used by major railroads in the United States, except for 8 units exported to BHP Billiton Iron Ore in Australia...	Union Pacific; CSX Transportation CSX Transportation CSX Transportation operates a Class I railroad in the United States known as the CSX Railroad. It is the main subsidiary of the CSX Corporation. The company is headquartered in Jacksonville, Florida, and owns approximately 21,000 route miles... ; BHP Billiton BHP Billiton BHP Billiton is a global mining, oil and gas company headquartered in Melbourne, Australia and with a major management office in London, United Kingdom...	7500-7579 (being overhauled and renumbered to 69xx); 600-699, 5000-5016; 6070-6077	General Electric	1996 – 2001	Diesel-Electric	Co'Co'	210 t	6250 hp	Actual HP output is 4350; due to problems with engine.
Indian locomotive class WAG-9 Indian locomotive class WAG-9 WAG-9 is the name of a type of electric locomotive used in India. Homed mainly at Gomoh, Ajni,Lallaguda,Tughlakabad and Bhilai, it is currently the most powerful locomotive in Indian Railways' fleet. It is very similar to the class WAP-7; The only difference being the gear ratio which makes it...	Indian Railways Indian Railways Indian Railways , abbreviated as IR , is a departmental undertaking of Government of India, which owns and operates most of India's rail transport. It is overseen by the Ministry of Railways of the Government of India....		Chittaranjan Locomotive Works India	1998	Electric	Co'Co'	123 t	6350 hp	Most powerful electric locomotive in India as of 2010.
China Railways HXN3 EMD JT56ACe The China Railways HXN3 is a 6000 horsepower diesel-electric locomotive produced by Electro-Motive Diesels designed for export to China. All JT56ACe locomotives use AC traction motor technology and utilize the EMD H-Engine as their prime mover...	China Railways China Railways China Railways is the national railway operator of the People's Republic of China, under the Chinese Ministry of Railways.China Railways operates rail commuter and freight transport via several smaller companies....	HXN30001-HXN30300	Dalian Locomotive, EMD	2008 –	Diesel-Electric	Co'Co'	150 t	6300 hp	Most powerful Diesel-Electric locomotive in active production.
China Railways HXN5 China Railways HXN5 The GE ES59ACi, also known as the HXN5 or China Mainline Locomotive, is a type of diesel locomotive built by GE Transportation Systems and Qishuyan Locomotive and Rolling Stock Works for use on freight trains from Harbin to Qiqihar and Mudanjiang in the People's Republic of China.In October 2005,...	China Railways China Railways China Railways is the national railway operator of the People's Republic of China, under the Chinese Ministry of Railways.China Railways operates rail commuter and freight transport via several smaller companies....	HXN50001-HXN50300	GE, CSR Qishuyan Locomotive	2008 –	Diesel-Electric	Co'Co'	150 t	6250 hp	Most powerful Diesel-Electric locomotive in active production.
China Railways HXD1 China Railways HXD1 The China Railways HXD1 also sometimes known as the DJ4Both the HXD1 and HXD2 double unit locomotives were designated DJ4, the HXD2 units being disambiguated DJ4-6000...	China Railways China Railways China Railways is the national railway operator of the People's Republic of China, under the Chinese Ministry of Railways.China Railways operates rail commuter and freight transport via several smaller companies....	HXD10001-HXD10220	CSR Zhuzhou Electric Locomotive, Siemens	2006 – 2008	Electric	Bo'Bo'+Bo'Bo'	200 t	12874 hp
China Railways HXD2 China Railways HXD2 The HXD2 locomotives are a series of related locomotive classes built by CNR Datong Electric Locomotive and Alstom. The locomotives designs are based on the Alstom Prima electric locomotives, and are a product of a cooperation agreement signed between the two companies in 2004...	China Railways China Railways China Railways is the national railway operator of the People's Republic of China, under the Chinese Ministry of Railways.China Railways operates rail commuter and freight transport via several smaller companies....	HXD20001-HXD20180	Datong Electric Locomotive, Alstom	2006 – 2008	Electric	Bo'Bo'+Bo'Bo'	200 t	13410 hp
China Railways HXD3 China Railways HXD3 HXD3 is an electric locomotive built in Mainland China by CNR Dalian Locomotives.The locomotive is designed for hauling 5,000t freight trains on main lines...	China Railways China Railways China Railways is the national railway operator of the People's Republic of China, under the Chinese Ministry of Railways.China Railways operates rail commuter and freight transport via several smaller companies....	HXD30001-HXD30890, HXD38001-38150	Toshiba, Dalian Locomotive	2006 – 2009	Electric	Co'Co'	150 t	9655 hp
China Railways HXD1B	China Railways China Railways China Railways is the national railway operator of the People's Republic of China, under the Chinese Ministry of Railways.China Railways operates rail commuter and freight transport via several smaller companies....	HXD1B0001-HXD1B0500	CSR Zhuzhou Electric Locomotive, Siemens	2009 –	Electric	Co'Co'	150 t	12874 hp	Most powerful undividable locomotive in series production
China Railways HXD2B	China Railways China Railways China Railways is the national railway operator of the People's Republic of China, under the Chinese Ministry of Railways.China Railways operates rail commuter and freight transport via several smaller companies....	HXD2B0001-HXD2B0500	Datong Electric Locomotive, Alstom	2009 –	Electric	Co'Co'	150 t	12874 hp	Most powerful undividable locomotive in series production
China Railways HXD3B China Railways HXD3B HXD3B is a class of electric locomotives for heavy freight service built by Bombardier Transportation and CNR Dalian Locomotives.- History :...	China Railways China Railways China Railways is the national railway operator of the People's Republic of China, under the Chinese Ministry of Railways.China Railways operates rail commuter and freight transport via several smaller companies....	HXD3B0001-HXD3B0500	Dalian, Bombardier	2009 –	Electric	Co'Co'	150 t	12874 hp	Most powerful undividable locomotive in series production
China Railways HXD1C	China Railways China Railways China Railways is the national railway operator of the People's Republic of China, under the Chinese Ministry of Railways.China Railways operates rail commuter and freight transport via several smaller companies....	HXD1C0001-HXD1C0990	CSR Zhuzhou Electric Locomotive, Siemens	2009 –	Electric	Co'Co'	150 t	9655 hp
China Railways HXD2C	China Railways China Railways China Railways is the national railway operator of the People's Republic of China, under the Chinese Ministry of Railways.China Railways operates rail commuter and freight transport via several smaller companies....	HXD2C0001-	Datong Electric Locomotive, Alstom	2010 –	Electric	Co'Co'	150 t	9655 hp
China Railways HXD3C	China Railways China Railways China Railways is the national railway operator of the People's Republic of China, under the Chinese Ministry of Railways.China Railways operates rail commuter and freight transport via several smaller companies....	HXD3C0001-	Dalian, Bombardier	2010 –	Electric	Co'Co'	150 t	9655 hp
IORE IORE Iore, often stylized IORE, is a class of 26 electric locomotives built by Adtranz and its successor Bombardier Transportation for the Swedish mining company LKAB's railway division Malmtrafik. The class is a variation of Adtranz's Octeon modular product platform, thus related to Bombardier's later...	Malmbanan Malmbanan The Iron Ore Line is a long railway line between Riksgränsen and Boden in Norrbotten County, Sweden. The line contains two branches, from Kiruna to Svappavaara and from Gällivare to Koskullskulle. The term is often colloquially used to also include the Ofoten Line, from Riksgränsen to Narvik in...	IORE 101- IORE 126	Bombardier Bombardier Transportation Bombardier Transportation is the rail equipment division of the Canadian firm, Bombardier Inc. Bombardier Transportation is one of the world's largest companies in the rail-equipment manufacturing and servicing industry. Its headquarters are in Berlin, Germany....	2000 – 2004	Electric	Co'Co'+Co'Co'	360 t	14483 hp for a pair, possible to operate halves which is not usually done	Highest continuous tractive effort in the world

External links

• Steamlocomotive.com article regarding the largest steam locomotives