
A locomotive is a
rail vehicle that provides the motive power for a
train
A train (from Old French , from Latin">-4; we might wonder whether there's a point at which it's appropriate to talk of the beginnings of French, that is, when it wa ... , from Latin , "to pull, to draw") is a series of connected vehicles th ...
. Traditionally, locomotives pulled trains from the front. However,
push–pull operation has become common, and in the pursuit for longer and heavier freight trains, companies are increasingly using
distributed power: single or multiple locomotives placed at the front and rear and at intermediate points throughout the train under the control of the leading locomotive.
Etymology
The word ''locomotive'' originates from the
Latin
Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...
'from a place',
ablative of 'place', and the
Medieval Latin
Medieval Latin was the form of Literary Latin used in Roman Catholic Church, Roman Catholic Western Europe during the Middle Ages. It was also the administrative language in the former Western Roman Empire, Roman Provinces of Mauretania, Numidi ...
'causing motion', and is a shortened form of the term ''locomotive engine'', which was first used in 1814 to distinguish between self-propelled and
stationary steam engines.
Classifications
Prior to locomotives, the motive force for railways had been generated by various lower-technology methods such as human power, horse power,
gravity
In physics, gravity (), also known as gravitation or a gravitational interaction, is a fundamental interaction, a mutual attraction between all massive particles. On Earth, gravity takes a slightly different meaning: the observed force b ...
or stationary engines that drove cable systems. Few such systems are still in existence today. Locomotives may generate their power from fuel (wood, coal, petroleum or natural gas), or they may take
power from an outside source of electricity. It is common to classify locomotives by their source of energy. The common ones include:
Steam
A steam locomotive is a locomotive whose primary power source is a
steam engine
A steam engine is a heat engine that performs Work (physics), mechanical work using steam as its working fluid. The steam engine uses the force produced by steam pressure to push a piston back and forth inside a Cylinder (locomotive), cyl ...
. The most common form of steam locomotive also contains a
boiler
A boiler is a closed vessel in which fluid (generally water) is heated. The fluid does not necessarily boil. The heated or vaporized fluid exits the boiler for use in various processes or heating applications, including water heating, centra ...
to generate the steam used by the engine. The water in the boiler is heated by burning combustible material – usually coal, wood, or oil – to produce steam. The steam moves reciprocating
piston
A piston is a component of reciprocating engines, reciprocating pumps, gas compressors, hydraulic cylinders and pneumatic cylinders, among other similar mechanisms. It is the moving component that is contained by a cylinder (engine), cylinder a ...
s which are connected to the locomotive's main wheels, known as the "
driving wheel
On a steam locomotive, a driving wheel is a powered wheel which is driven by the locomotive's pistons (or turbine, in the case of a steam turbine locomotive). On a conventional, non-articulated locomotive, the driving wheels are all coupled t ...
s". Both fuel and water supplies are carried with the locomotive, either on the locomotive itself, in
bunkers and
tanks, (this arrangement is known as a "
tank locomotive") or pulled behind the locomotive, in
tenders, (this arrangement is known as a "
tender locomotive
A tender is a special railroad car, rail vehicle hauled by a steam locomotive containing its fuel (wood fuel, wood, coal, fuel oil, oil or torrefaction, torrefied biomass) and water. Steam locomotives consume large quantities of water compared ...
").
The first full-scale working railway steam locomotive was built by
Richard Trevithick in 1802. It was constructed for the
Coalbrookdale
Coalbrookdale is a town in the Ironbridge Gorge and the Telford and Wrekin borough of Shropshire, England, containing a settlement of great significance in the history of iron ore smelting. It lies within the civil parish called The Gorge, Shro ...
ironworks in
Shropshire
Shropshire (; abbreviated SalopAlso used officially as the name of the county from 1974–1980. The demonym for inhabitants of the county "Salopian" derives from this name.) is a Ceremonial counties of England, ceremonial county in the West M ...
in England though no record of it working there has survived. On 21 February 1804, the first recorded steam-hauled railway journey took place as another of Trevithick's locomotives hauled a train from the
Penydarren
: ''For Trevithick's Pen-y-darren locomotive, see Richard Trevithick#"Pen-y-Darren" locomotive, Richard Trevithick.''
Penydarren is a Community (Wales), community and electoral ward in Merthyr Tydfil County Borough in Wales.
Description
The area ...
ironworks, in
Merthyr Tydfil
Merthyr Tydfil () is the main town in Merthyr Tydfil County Borough, Wales, administered by Merthyr Tydfil County Borough Council. It is about north of Cardiff. Often called just Merthyr, it is said to be named after Tydfil, daughter of K ...
, to
Abercynon
Abercynon () is a village and community (Wales), community (and electoral ward) in the Cynon Valley within the unitary authority of Rhondda Cynon Taf, Wales. The community comprises the village and the districts of Carnetown and Grovers Field to ...
in South Wales. Accompanied by
Andrew Vivian
Andrew Vivian (1759–1842) was a British mechanical engineer, inventor, and mine captain of the Dolcoath mine in Cornwall, England.
In partnership with his cousin Richard Trevithick, the inventor of the "high pressure" steam engine, and the ...
, it ran with mixed success.
The design incorporated a number of important innovations including the use of high-pressure steam which reduced the weight of the engine and increased its efficiency.
In 1812,
Matthew Murray's twin-cylinder
rack locomotive ''
Salamanca
Salamanca () is a Municipality of Spain, municipality and city in Spain, capital of the Province of Salamanca, province of the same name, located in the autonomous community of Castile and León. It is located in the Campo Charro comarca, in the ...
'' first ran on the
edge-railed rack-and-pinion Middleton Railway;
this is generally regarded as the first commercially successful locomotive. Another well-known early locomotive was ''
Puffing Billy'', built 1813–14 by engineer
William Hedley for the Wylam Colliery near
Newcastle upon Tyne
Newcastle upon Tyne, or simply Newcastle ( , Received Pronunciation, RP: ), is a City status in the United Kingdom, cathedral city and metropolitan borough in Tyne and Wear, England. It is England's northernmost metropolitan borough, located o ...
. This locomotive is the oldest preserved, and is on static display in the Science Museum, London.
George Stephenson
George Stephenson (9 June 1781 – 12 August 1848) was an English civil engineer and Mechanical engineering, mechanical engineer during the Industrial Revolution. Renowned as the "Father of Railways", Stephenson was considered by the Victoria ...
built ''
Locomotion No. 1'' for the
Stockton & Darlington Railway
The Stockton and Darlington Railway (S&DR) was a railway company that operated in north-east England from 1825 to 1863. The world's first public railway to use steam locomotives, its first line connected coal mining, collieries near with ...
in the north-east of England, which was the first public steam railway in the world. In 1829, his son Robert built ''
The Rocket'' in Newcastle upon Tyne. Rocket was entered into, and won, the
Rainhill Trials. This success led to the company emerging as the pre-eminent early builder of steam locomotives used on railways in the UK, US and much of Europe.
The
Liverpool & Manchester Railway, built by Stephenson, opened a year later making exclusive use of steam power for passenger and
goods trains.
The steam locomotive remained by far the most common type of locomotive until after
World War II
World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...
. Steam locomotives are less efficient than modern diesel and electric locomotives, and a significantly larger workforce is required to operate and service them.
British Rail figures showed that the cost of crewing and fuelling a steam locomotive was about two and a half times larger than the cost of supporting an equivalent diesel locomotive, and the daily mileage they could run was lower. Between about 1950 and 1970, the majority of steam locomotives were retired from commercial service and replaced with electric and diesel–electric locomotives.
While North America transitioned from steam during the 1950s, and continental Europe by the 1970s, in other parts of the world, the transition happened later. Steam was a familiar technology that used widely-available fuels and in low-wage economies did not suffer as wide a cost disparity. It continued to be used in many countries until the end of the 20th century. By the end of the 20th century, almost the only steam power remaining in regular use around the world was on
heritage railway
A heritage railway or heritage railroad (U.S. usage) is a railway operated as living history to re-create or preserve railway scenes of the past. Heritage railways are often old railway lines preserved in a state depicting a period (or periods) ...
s.
Internal combustion

Internal combustion locomotives use an
internal combustion engine
An internal combustion engine (ICE or IC engine) is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal comb ...
, connected to the
driving wheel
On a steam locomotive, a driving wheel is a powered wheel which is driven by the locomotive's pistons (or turbine, in the case of a steam turbine locomotive). On a conventional, non-articulated locomotive, the driving wheels are all coupled t ...
s by a transmission. They typically keep the engine running at a near-constant speed whether the locomotive is stationary or moving. Internal combustion locomotives are categorised by their fuel type and sub-categorised by their transmission type.
The first internal combustion rail vehicle was a
kerosene
Kerosene, or paraffin, is a combustibility, combustible hydrocarbon liquid which is derived from petroleum. It is widely used as a fuel in Aviation fuel, aviation as well as households. Its name derives from the Greek (''kērós'') meaning " ...
-powered
draisine built by
Gottlieb Daimler
Gottlieb Wilhelm Daimler (; 17 March 1834 – 6 March 1900) was a German engineer, industrial designer and industrialist. He was a pioneer of internal-combustion engines and automobile development. He invented the high-speed liquid petroleum-fue ...
in 1887, but this was not technically a locomotive as it carried a payload.
The earliest
gasoline
Gasoline ( North American English) or petrol ( Commonwealth English) is a petrochemical product characterized as a transparent, yellowish, and flammable liquid normally used as a fuel for spark-ignited internal combustion engines. When for ...
locomotive in the western United States was built by the
Best Manufacturing Company in 1891 for
San Jose and Alum Rock Railroad. It was only a limited success and was returned to Best in 1892.
The first commercially successful
petrol
Gasoline (North American English) or petrol ( Commonwealth English) is a petrochemical product characterized as a transparent, yellowish, and flammable liquid normally used as a fuel for spark-ignited internal combustion engines. When formul ...
locomotive in the United Kingdom was a
petrol–mechanical locomotive built by the
Maudslay Motor Company in 1902, for the Deptford Cattle Market in
London
London is the Capital city, capital and List of urban areas in the United Kingdom, largest city of both England and the United Kingdom, with a population of in . London metropolitan area, Its wider metropolitan area is the largest in Wester ...
. It was an 80 hp locomotive using a three-cylinder vertical petrol engine, with a two speed mechanical gearbox.
In 1903, the Hungarian
Weitzer railmotor was the world's first
petrol electric locomotive.
Diesel
Diesel locomotives are powered by
diesel engine
The diesel engine, named after the German engineer Rudolf Diesel, is an internal combustion engine in which Combustion, ignition of diesel fuel is caused by the elevated temperature of the air in the cylinder due to Mechanics, mechanical Compr ...
s. In the early days of diesel propulsion development, various transmission systems were employed with varying degrees of success, with electric transmission proving to be the most popular. In 1914,
Hermann Lemp, a
General Electric
General Electric Company (GE) was an American Multinational corporation, multinational Conglomerate (company), conglomerate founded in 1892, incorporated in the New York (state), state of New York and headquartered in Boston.
Over the year ...
electrical engineer, developed and patented a reliable
direct current
Direct current (DC) is one-directional electric current, flow of electric charge. An electrochemical cell is a prime example of DC power. Direct current may flow through a conductor (material), conductor such as a wire, but can also flow throug ...
electrical control system (subsequent improvements were also patented by Lemp). Lemp's design used a single lever to control both engine and generator in a coordinated fashion, and was the
prototype
A prototype is an early sample, model, or release of a product built to test a concept or process. It is a term used in a variety of contexts, including semantics, design, electronics, and Software prototyping, software programming. A prototype ...
for all
diesel–electric locomotive control. In 1917–18, GE produced three experimental diesel–electric locomotives using Lemp's control design.
In 1924, a diesel–electric locomotive (
Eel2 original number Юэ 001/Yu-e 001) started operations. It had been designed by a team led by
Yury Lomonosov and built 1923–1924 by
Maschinenfabrik Esslingen
Maschinenfabrik Esslingen (ME) was a German engineering firm that manufactured locomotives, tramways, railway wagons, roll-blocks, technical equipment for the railways, (turntable (rail), turntables and traverser (railway), traversers), bridges, s ...
in Germany. It had five driving axles (1'E1'). After several test rides, it hauled trains for almost three decades from 1925 to 1954.
Electric

An electric locomotive is a locomotive powered only by electricity. Electricity is supplied to moving trains with a (nearly) continuous
conductor running along the track that usually takes one of three forms: an
overhead line, suspended from poles or towers along the track or from structure or tunnel ceilings; a
third rail
A third rail, also known as a live rail, electric rail or conductor rail, is a method of providing electric power to a railway locomotive or train, through a semi-continuous rigid conductor placed alongside or between the rails of a track (r ...
mounted at track level; or an onboard
battery. Both overhead wire and third-rail systems usually use the running rails as the return conductor but some systems use a separate fourth rail for this purpose. The type of electrical power used is either
direct current
Direct current (DC) is one-directional electric current, flow of electric charge. An electrochemical cell is a prime example of DC power. Direct current may flow through a conductor (material), conductor such as a wire, but can also flow throug ...
(DC) or
alternating current
Alternating current (AC) is an electric current that periodically reverses direction and changes its magnitude continuously with time, in contrast to direct current (DC), which flows only in one direction. Alternating current is the form in w ...
(AC).

Various collection methods exist: a
trolley pole
A trolley pole is a tapered cylindrical pole of wood or metal, used to transfer electricity from a "live" (electrified) overhead line, overhead wire to the control and the electric traction motors of a tram or trolley bus. It is a type of current ...
, which is a long flexible pole that engages the line with a wheel or shoe; a
bow collector, which is a frame that holds a long collecting rod against the wire; a
pantograph
A pantograph (, from their original use for copying writing) is a Linkage (mechanical), mechanical linkage connected in a manner based on parallelograms so that the movement of one pen, in tracing an image, produces identical movements in a se ...
, which is a hinged frame that holds the collecting shoes against the wire in a fixed geometry; or a
contact shoe
A current collector (often called a "pickup") is a device used in trolleybuses, trams, electric locomotives and Electric multiple unit, EMUs to carry electric power (Electric current, current) from overhead lines, electric third rails, or ground ...
, which is a shoe in contact with the third rail. Of the three, the pantograph method is best suited for high-speed operation.
Electric locomotives almost universally use axle-hung traction motors, with one motor for each powered axle. In this arrangement, one side of the motor housing is supported by plain bearings riding on a ground and polished journal that is integral to the axle. The other side of the housing has a tongue-shaped protuberance that engages a matching slot in the truck (bogie) bolster, its purpose being to act as a torque reaction device, as well as a support. Power transfer from motor to axle is effected by
spur gearing, in which a
pinion on the motor shaft engages a
bull gear on the axle. Both gears are enclosed in a liquid-tight housing containing lubricating oil. The type of service in which the locomotive is used dictates the gear ratio employed. Numerically high ratios are commonly found on freight units, whereas numerically low ratios are typical of passenger engines.
Electricity is typically generated in large and relatively efficient
generating stations, transmitted to the railway network and distributed to the trains. Some electric railways have their own dedicated generating stations and
transmission lines but most purchase power from an
electric utility
An electric utility, or a power company, is a company in the electric power industry (often a public utility) that engages in electricity generation and distribution of electricity for sale generally in a regulated market. Electric utilities are ...
. The railway usually provides its own distribution lines, switches and
transformer
In electrical engineering, a transformer is a passive component that transfers electrical energy from one electrical circuit to another circuit, or multiple Electrical network, circuits. A varying current in any coil of the transformer produces ...
s.
Electric locomotives usually cost 20% less than diesel locomotives, their maintenance costs are 25–35% lower, and cost up to 50% less to run.
Direct current
The earliest systems were
DC systems. The first electric passenger train was presented by
Werner von Siemens
Ernst Werner Siemens ( von Siemens from 1888; ; ; 13 December 1816 – 6 December 1892) was a German electrical engineer, inventor and industrialist. Siemens's name has been adopted as the SI unit of electrical conductance, the siemens. He ...
at
Berlin
Berlin ( ; ) is the Capital of Germany, capital and largest city of Germany, by both area and List of cities in Germany by population, population. With 3.7 million inhabitants, it has the List of cities in the European Union by population withi ...
in 1879. The locomotive was driven by a 2.2 kW, series-wound motor, and the train, consisting of the locomotive and three cars, reached a speed of 13 km/h. During four months, the train carried 90,000 passengers on a circular track. The electricity (150 V DC) was supplied through a third insulated rail between the tracks. A contact roller was used to collect the electricity. The world's first electric tram line opened in Lichterfelde near Berlin, Germany, in 1881. It was built by Werner von Siemens (see
Gross-Lichterfelde Tramway and
Berlin Straßenbahn). The
Volk's Electric Railway opened in 1883 in Brighton, and is the oldest surviving electric railway. Also in 1883,
Mödling and Hinterbrühl Tram opened near Vienna in Austria. It was the first in the world in regular service powered from an overhead line. Five years later, in the U.S. electric
trolleys were pioneered in 1888 on the
Richmond Union Passenger Railway, using equipment designed by
Frank J. Sprague.
The first electrically worked
underground line was the
City & South London Railway, prompted by a clause in its enabling act prohibiting use of steam power. It opened in 1890, using electric locomotives built by
Mather & Platt. Electricity quickly became the power supply of choice for subways, abetted by the Sprague's invention of
multiple-unit train control in 1897.
The first use of electrification on a main line was on a four-mile stretch of the
Baltimore Belt Line of the
Baltimore & Ohio (B&O) in 1895 connecting the main portion of the B&O to the new line to New York through a series of tunnels around the edges of Baltimore's downtown. Three
Bo+Bo units were initially used, at the south end of the electrified section; they coupled onto the locomotive and train and pulled it through the tunnels.
DC was used on earlier systems. These systems were gradually replaced by AC. Today, almost all main-line railways use AC systems. DC systems are confined mostly to urban transit such as metro systems, light rail and trams, where power requirement is less.
Alternating current

The first practical
AC electric locomotive was designed by
Charles Brown, then working for
Oerlikon, Zürich. In 1891, Brown had demonstrated long-distance power transmission, using
three-phase AC, between a
hydro-electric plant at
Lauffen am Neckar and
Frankfurt
Frankfurt am Main () is the most populous city in the States of Germany, German state of Hesse. Its 773,068 inhabitants as of 2022 make it the List of cities in Germany by population, fifth-most populous city in Germany. Located in the forela ...
am Main West, a distance of 280 km. Using experience he had gained while working for
Jean Heilmann on steam–electric locomotive designs, Brown observed that
three-phase motors had a higher power-to-weight ratio than
DC motors and, because of the absence of a
commutator
In mathematics, the commutator gives an indication of the extent to which a certain binary operation fails to be commutative. There are different definitions used in group theory and ring theory.
Group theory
The commutator of two elements, ...
, were simpler to manufacture and maintain. However, they were much larger than the DC motors of the time and could not be mounted in underfloor
bogie
A bogie ( ) (or truck in North American English) comprises two or more Wheelset (rail transport), wheelsets (two Railroad wheel, wheels on an axle), in a frame, attached under a vehicle by a pivot. Bogies take various forms in various modes ...
s: they could only be carried within locomotive bodies.
In 1894, Hungarian engineer
Kálmán Kandó
Kálmán Kandó de Egerfarmos et Sztregova (''egerfarmosi és sztregovai Kandó Kálmán''; July 10, 1869 – January 13, 1931) was a Hungary, Hungarian engineer, the inventor of phase converter and a pioneer in the development of AC electric rai ...
developed a new type 3-phase asynchronous electric drive motors and generators for electric locomotives. The new 3-phase asynchronous electric drive motors were more effective than the synchronous electric motors of earlier locomotive designs.
Kandó's early 1894 designs were first applied in a short three-phase AC tramway in Evian-les-Bains (France), which was constructed between 1896 and 1898. In 1918, Kandó invented and developed the
rotary phase converter, enabling electric locomotives to use three-phase motors whilst supplied via a single overhead wire, carrying the simple industrial frequency (50 Hz) single phase AC of the high voltage national networks.
In 1896, Oerlikon installed the first commercial example of the system on the
Lugano Tramway. Each 30-tonne locomotive had two motors run by three-phase 750 V 40 Hz fed from double overhead lines. Three-phase motors run at constant speed and provide
regenerative braking, and are well suited to steeply graded routes, and the first main-line three-phase locomotives were supplied by Brown (by then in partnership with
Walter Boveri) in 1899 on the 40 km
Burgdorf—Thun line, Switzerland. The first implementation of industrial frequency single-phase AC supply for locomotives came from Oerlikon in 1901, using the designs of
Hans Behn-Eschenburg and
Emil Huber-Stockar; installation on the Seebach-Wettingen line of the Swiss Federal Railways was completed in 1904. The 15 kV, 50 Hz , 48 tonne locomotives used transformers and rotary converters to power DC traction motors.
Italian railways were the first in the world to introduce electric traction for the entire length of a main line rather than just a short stretch. The 106 km Valtellina line was opened on 4 September 1902, designed by Kandó and a team from the Ganz works.
The electrical system was three-phase at 3 kV 15 Hz. The voltage was significantly higher than used earlier and it required new designs for electric motors and switching devices.
The three-phase two-wire system was used on several railways in Northern Italy and became known as "the Italian system". Kandó was invited in 1905 to undertake the management of Società Italiana Westinghouse and led the development of several Italian electric locomotives.
Battery–electric

A battery–electric locomotive (or battery locomotive) is an electric locomotive powered by onboard
batteries; a kind of
battery electric vehicle
A battery electric vehicle (BEV), pure electric vehicle, only-electric vehicle, fully electric vehicle or all-electric vehicle is a type of electric vehicle (EV) that uses electrical energy exclusively from an electric vehicle battery, on-boa ...
.
Such locomotives are used where a conventional diesel or electric locomotive would be unsuitable. An example is maintenance trains on electrified lines when the electricity supply is turned off. Another use is in industrial facilities where a combustion-powered locomotive (i.e.,
steam- or
diesel-powered) could cause a safety issue due to the risks of fire, explosion or fumes in a confined space. Battery locomotives are preferred for mines where gas could be ignited by
trolley-powered units
arcing at the collection shoes, or where
electrical resistance
The electrical resistance of an object is a measure of its opposition to the flow of electric current. Its reciprocal quantity is , measuring the ease with which an electric current passes. Electrical resistance shares some conceptual paral ...
could develop in the supply or return circuits, especially at rail joints, and allow dangerous current leakage into the ground. Battery locomotives in over-the-road service can recharge while absorbing dynamic-braking energy.
The first known electric locomotive was built in 1837 by chemist
Robert Davidson of
Aberdeen
Aberdeen ( ; ; ) is a port city in North East Scotland, and is the List of towns and cities in Scotland by population, third most populous Cities of Scotland, Scottish city. Historically, Aberdeen was within the historic county of Aberdeensh ...
, and it was powered by
galvanic cells (batteries). Davidson later built a larger locomotive named ''Galvani'', exhibited at the
Royal Scottish Society of Arts Exhibition in 1841. The seven-ton vehicle had two
direct-drive reluctance motors, with fixed electromagnets acting on iron bars attached to a wooden cylinder on each axle, and simple
commutators. It hauled a load of six tons at four miles per hour (6 kilometers per hour) for a distance of . It was tested on the
Edinburgh and Glasgow Railway in September of the following year, but the limited power from batteries prevented its general use.
[Renzo Pocaterra, ''Treni'', De Agostini, 2003]
Another example was at the
Kennecott Copper Mine,
Latouche, Alaska, where in 1917 the underground haulage ways were widened to enable working by two battery locomotives of tons. In 1928, Kennecott Copper ordered four 700-series electric locomotives with on-board batteries. These locomotives weighed 85 tons and operated on 750-volt overhead trolley wire with considerable further range whilst running on batteries. The locomotives provided several decades of service using
Nickel–iron battery (Edison) technology. The batteries were replaced with
lead-acid batteries, and the locomotives were retired shortly afterward. All four locomotives were donated to museums, but one was scrapped. The others can be seen at the
Boone and Scenic Valley Railroad, Iowa, and at the
Western Railway Museum
The Western Railway Museum, in Solano County, California is located on California State Route 12, Highway 12 between Rio Vista, California, Rio Vista and Suisun, California, Suisun. The museum is built along the former mainline of the
Sacrament ...
in Rio Vista, California. The
Toronto Transit Commission previously operated a battery electric locomotive built by
Nippon Sharyo
, formed in 1896, is a major rolling stock, Heavy equipment, heavy equipment, Diesel generator, generator, Special-purpose entity, special purpose vehicle and bridge manufacturer based in Nagoya, Japan. In 1996, it abbreviated its ...
in 1968 and retired in 2009.
London Underground regularly operates
battery–electric locomotives for general maintenance work.
Other types
Fireless
Atomic–electric
In the early 1950s, Lyle Borst of the
University of Utah
The University of Utah (the U, U of U, or simply Utah) is a public university, public research university in Salt Lake City, Utah, United States. It was established in 1850 as the University of Deseret (Book of Mormon), Deseret by the General A ...
was given funding by various US railroad line and manufacturers to study the feasibility of an electric-drive locomotive, in which an onboard atomic reactor produced the steam to generate the electricity. At that time, atomic power was not fully understood; Borst believed the major stumbling block was the price of uranium. With the Borst atomic locomotive, the center section would have a 200-ton reactor chamber and steel walls 5 feet thick to prevent releases of radioactivity in case of accidents. He estimated a cost to manufacture atomic locomotives with 7000 h.p. engines at approximately $1,200,000 each.
"Atomic Locomotive Produces 7000 h.p."
''Popular Mechanics'', April 1954, p. 86. Consequently, trains with onboard nuclear generators were generally deemed unfeasible due to prohibitive costs.
Fuel cell–electric
In 2002, the first 3.6 tonne, 17 kW hydrogen
Hydrogen is a chemical element; it has chemical symbol, symbol H and atomic number 1. It is the lightest and abundance of the chemical elements, most abundant chemical element in the universe, constituting about 75% of all baryon, normal matter ...
-(fuel-cell)–powered mining locomotive was demonstrated in Val-d'Or, Quebec
Quebec is Canada's List of Canadian provinces and territories by area, largest province by area. Located in Central Canada, the province shares borders with the provinces of Ontario to the west, Newfoundland and Labrador to the northeast, ...
. In 2007 the educational mini-hydrail in Kaohsiung
Kaohsiung, officially Kaohsiung City, is a special municipality located in southern Taiwan. It ranges from the coastal urban center to the rural Yushan Range with an area of . Kaohsiung City has a population of approximately 2.73 million p ...
, Taiwan
Taiwan, officially the Republic of China (ROC), is a country in East Asia. The main geography of Taiwan, island of Taiwan, also known as ''Formosa'', lies between the East China Sea, East and South China Seas in the northwestern Pacific Ocea ...
went into service. The Railpower GG20B finally is another example of a fuel cell–electric locomotive.
Hybrid locomotives
There are many different types of hybrid or dual-mode locomotives using two or more types of motive power. The most common hybrids are electro-diesel locomotives powered either from an electricity supply or else by an onboard diesel engine
The diesel engine, named after the German engineer Rudolf Diesel, is an internal combustion engine in which Combustion, ignition of diesel fuel is caused by the elevated temperature of the air in the cylinder due to Mechanics, mechanical Compr ...
. These are used to provide continuous journeys along routes that are only partly electrified. Examples include the EMD FL9 and Bombardier ALP-45DP
Use
There are three main uses of locomotives in rail transport operations
Rail transport operations are the day-to-day operations of a railway. A railway has two major components: the infrastructure (the permanent way, tracks, stations, freight facilities, viaducts, tunnels, etc.) and the rolling stock (the passenger ...
: hauling passenger trains, freight
In transportation, cargo refers to goods transported by land, water or air, while freight refers to its conveyance. In economics, freight refers to goods transported at a freight rate for commercial gain. The term cargo is also used in ...
trains, and switching (UK English: shunting).
Freight locomotives are normally designed to deliver high starting tractive effort and high sustained power. This allows them to start and move long, heavy trains, but usually comes at the cost of relatively low maximum speeds. Passenger locomotives usually develop lower starting tractive effort but are able to operate at the high speeds required to maintain passenger schedules. Mixed-traffic locomotives (US English: general purpose or road switcher locomotives) meant for both passenger and freight trains do not develop as much starting tractive effort as a freight locomotive but are able to haul heavier trains than a passenger locomotive.
Most steam locomotives have reciprocating engines, with pistons coupled to the driving wheels by means of connecting rods, with no intervening gearbox. This means the combination of starting tractive effort and maximum speed is greatly influenced by the diameter of the driving wheels. Steam locomotives intended for freight service generally have smaller diameter driving wheels than passenger locomotives.
In diesel-electric and electric locomotives the control system between the traction motors and axle
An axle or axletree is a central shaft for a rotation, rotating wheel and axle, wheel or gear. On wheeled vehicles, the axle may be fixed to the wheels, rotating with them, or fixed to the vehicle, with the wheels rotating around the axle. In ...
s adapts the power output to the rails for freight or passenger service. Passenger locomotives may include other features, such as head-end power (also referred to as hotel power or electric train supply) or a steam generator.
Some locomotives are designed specifically to work steep grade railways, and feature extensive additional braking mechanisms and sometimes rack and pinion. Steam locomotives built for steep rack and pinion railways frequently have the boiler tilted relative to the locomotive frame, so that the boiler remains roughly level on steep grades.
Locomotives are also used on some high-speed trains. Some of them are operated in push-pull formation with trailer control cars at another end of a train, which often have a cabin with the same design as a cabin of locomotive; examples of such trains with conventional locomotives are Railjet and Intercity 225.
Also many high-speed trains, including all TGV, many Talgo (250 / 350 / Avril / XXI), some Korea Train Express, ICE 1/ ICE 2 and Intercity 125
The InterCity 125 (originally Inter-City 125) or High Speed Train (HST) is a diesel-powered High-speed rail, high-speed passenger train built by British Rail Engineering Limited between 1975 and 1982. A total of 95 sets were produced, each com ...
, use dedicated power cars, which do not have places for passengers and technically are special single-ended locomotives. The difference from conventional locomotives is that these power cars are integral part of a train and are not adapted for operation with any other types of passenger coaches. On the other hand, many high-speed trains such as the Shinkansen
The , colloquially known in English as the bullet train, is a network of high-speed railway lines in Japan. It was initially built to connect distant Japanese regions with Tokyo, the capital, to aid economic growth and development. Beyond lon ...
network never use locomotives. Instead of locomotive-like power-cars, they use electric multiple unit
An electric multiple unit or EMU is a multiple-unit train consisting of self-propelled carriages using electricity as the motive power. An EMU requires no separate locomotive, as electric traction motors are incorporated within one or a number o ...
s (EMUs) or diesel multiple units (DMUs) – passenger cars that also have traction motors and power equipment. Using dedicated locomotive-like power cars allows for a high ride quality and less electrical equipment;
but EMUs have less axle weight, which reduces maintenance costs, and EMUs also have higher acceleration and higher seating capacity.
Also some trains, including TGV PSE, TGV TMST and TGV V150, use both non-passenger power cars and additional passenger motor cars.
Operational role
Locomotives occasionally work in a specific role, such as:
* Train engine is the technical name for a locomotive attached to the front of a railway train
A train (from Old French , from Latin">-4; we might wonder whether there's a point at which it's appropriate to talk of the beginnings of French, that is, when it wa ... , from Latin , "to pull, to draw") is a series of connected vehicles th ...
to haul that train. Alternatively, where facilities exist for push-pull operation, the train engine might be attached to the rear of the train;
* Pilot engine – a locomotive attached in front of the train engine, to enable double-heading;
* Banking engine – a locomotive temporarily assisting a train from the rear, due to a difficult start or a sharp incline gradient;
* Light engine – a locomotive operating without a train behind it, for relocation or operational reasons. Occasionally, a light engine is referred to as a train in and of itself.
* Station pilot – a locomotive used to shunt passenger trains at a railway station
Rail transport (also known as train transport) is a means of transport using wheeled vehicles running in railway track, tracks, which usually consist of two parallel steel railway track, rails. Rail transport is one of the two primary means of ...
.
Wheel arrangement
The wheel arrangement of a locomotive describes how many wheels it has; common methods include the AAR wheel arrangement, UIC classification, and Whyte notation systems.
Remote control locomotives
In the second half of the twentieth century remote control locomotives started to enter service in switching operations, being remotely controlled by an operator outside of the locomotive cab.
The main benefit is one operator can control the loading of grain, coal, gravel, etc. into the cars. In addition, the same operator can move the train as needed. Thus, the locomotive is loaded or unloaded in about a third of the time.
See also
Notes
References
Bibliography
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External links
An engineer's guide from 1891
Locomotive cutaways and historical locomotives of several countries ordered by dates
* Pickzone Locomotiv
Model
International Steam Locomotives
* ''Turning a Locomotive into a Stationary Engine'', Popular Science
Popular science (also called pop-science or popsci) is an interpretation of science intended for a general audience. While science journalism focuses on recent scientific developments, popular science is more broad ranging. It may be written ...
monthly, February 1919, page 72, Scanned by Google Books
Popular Science
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19th-century inventions