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A locomotive or engine is a
rail transport Rail transport (also known as train transport) is a means of transport that transfers passengers and goods on wheeled vehicles running on rails, which are incorporated in tracks. In contrast to road transport, where the vehicles run on a p ...
vehicle that provides the
motive power ''Motive Power'' is a bi-monthly railway related magazine that focuses on diesel locomotives in Australia. The first issue was published on 23 August 1998. Its headquarters is in Sydney. The content includes photographs of locomotives & trains, ...
for a
train In rail transport, a train (from Old French , from Latin , "to pull, to draw") is a series of connected vehicles that run along a railway track and Passenger train, transport people or Rail freight transport, freight. Trains are typically pul ...
. If a locomotive is capable of carrying a payload, it is usually rather referred to as a
multiple unit A multiple-unit train or simply multiple unit (MU) is a self-propelled train composed of one or more carriages joined together, which when coupled to another multiple unit can be controlled by a single driver, with multiple-unit train contr ...
, motor coach,
railcar A railcar (not to be confused with a railway car) is a self-propelled railway vehicle designed to transport passengers. The term "railcar" is usually used in reference to a train consisting of a single coach (carriage, car), with a drive ...
or
power car In rail transport, the expression power car may refer to either of two distinct types of rail vehicle: *a vehicle that propels, and commonly also controls, a passenger train, multiple unit or tram, often as the lead vehicle; *a vehicle equipped ...
; the use of these self-propelled vehicles is increasingly common for
passenger train A passenger train is a train used to transport people along a railroad line. These trains may consist of unpowered passenger railroad cars (also known as coaches or carriages) hauled by one or more locomotives, or may be self-propelled; self pr ...
s, but rare for
freight Cargo consists of bulk goods conveyed by water, air, or land. In economics, freight is cargo that is transported at a freight rate for commercial gain. ''Cargo'' was originally a shipload but now covers all types of freight, including transp ...
(see
CargoSprinter The CargoSprinter is a freight multiple unit designed to transport freight or equipment. The CargoSprinter was designed by Windhoff GmbH (Germany) in the mid-1990s. Initially seven vehicles were built for Deutsche Bahn. Four were built by Win ...
). Traditionally, locomotives pulled trains from the front. However, push-pull operation has become common, where the train may have a locomotive (or locomotives) at the front, at the rear, or at each end. Most recently railroads have begun adopting DPU or distributed power. The front may have one or two locomotives followed by a mid-train locomotive that is controlled remotely from the lead unit. __TOC__


Etymology

The word ''locomotive'' originates from the
Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
'from a place',
ablative In grammar, the ablative case (pronounced ; sometimes abbreviated ) is a grammatical case for nouns, pronouns, and adjectives in the grammars of various languages; it is sometimes used to express motion away from something, among other uses. T ...
of 'place', and the
Medieval Latin Medieval Latin was the form of Literary Latin used in Roman Catholic Western Europe during the Middle Ages. In this region it served as the primary written language, though local languages were also written to varying degrees. Latin functioned ...
'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 engine Stationary steam engines are fixed steam engines used for pumping or driving mills and factories, and for power generation. They are distinct from locomotive engines used on railways, traction engines for heavy steam haulage on roads, steam cars ...
s.


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 () is a fundamental interaction which causes mutual attraction between all things with mass or energy. Gravity is, by far, the weakest of the four fundamental interactions, approximately 1038 times weaker than the stro ...
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 Power most often refers to: * Power (physics), meaning "rate of doing work" ** Engine power, the power put out by an engine ** Electric power * Power (social and political), the ability to influence people or events ** Abusive power Power may a ...
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 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. This pushing force can be trans ...
. 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, central h ...
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 and is made gas-tig ...
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 ...
s". Both fuel and water supplies are carried with the locomotive, either on the locomotive itself, in
bunkers A bunker is a defensive military fortification designed to protect people and valued materials from falling bombs, artillery, or other attacks. Bunkers are almost always underground, in contrast to blockhouses which are mostly above ground. T ...
and
tanks A tank is an armoured fighting vehicle intended as a primary offensive weapon in front-line ground combat. Tank designs are a balance of heavy firepower, strong armour, and good battlefield mobility provided by tracks and a powerful engine ...
, (this arrangement is known as a "
tank locomotive A tank locomotive or tank engine is a steam locomotive that carries its water in one or more on-board water tanks, instead of a more traditional tender. Most tank engines also have bunkers (or fuel tanks) to hold fuel; in a tender-tank locom ...
") or pulled behind the locomotive, in tenders, (this arrangement is known as a "
tender locomotive A tender or coal-car (US only) is a special rail vehicle hauled by a steam locomotive containing its fuel (wood, coal, oil or torrefied biomass) and water. Steam locomotives consume large quantities of water compared to the quantity of fuel, so ...
"). The first full-scale working railway steam locomotive was built by
Richard Trevithick Richard Trevithick (13 April 1771 – 22 April 1833) was a British inventor and mining engineer. The son of a mining captain, and born in the mining heartland of Cornwall, Trevithick was immersed in mining and engineering from an early age. He w ...
in 1802. It was constructed for the
Coalbrookdale Coalbrookdale is a village in the Ironbridge Gorge in Shropshire, England, containing a settlement of great significance in the history of iron ore smelting. It lies within the civil parish called the Gorge. This is where iron ore was first s ...
ironworks in
Shropshire Shropshire (; alternatively Salop; abbreviated in print only as Shrops; demonym Salopian ) is a landlocked historic county in the West Midlands region of England. It is bordered by Wales to the west and the English counties of Cheshire to th ...
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 (; cy, Merthyr Tudful ) 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 Tydf ...
, to
Abercynon Abercynon (), is both a village and a 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 the south, ...
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 en ...
, 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 Matthew Murray (1765 – 20 February 1826) was an English steam engine and machine tool manufacturer, who designed and built the first commercially viable steam locomotive, the twin cylinder ''Salamanca'' in 1812. He was an innovative design ...
's twin-cylinder rack locomotive ''
Salamanca Salamanca () is a city in western Spain and is the capital of the Province of Salamanca in the autonomous community of Castile and León. The city lies on several rolling hills by the Tormes River. Its Old City was declared a UNESCO World Heritag ...
'' first ran on the edge-railed
rack-and-pinion A rack and pinion is a type of linear actuator that comprises a circular gear (the ''pinion'') engaging a linear gear (the ''rack''). Together, they convert rotational motion into linear motion. Rotating the pinion causes the rack to be driven i ...
Middleton Railway The Middleton Railway is the world's oldest continuously working railway, situated in the English city of Leeds. It was founded in 1758 and is now a heritage railway, run by volunteers from The Middleton Railway Trust Ltd. since 1960. The rail ...
; 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 William Hedley (13 July 1779 – 9 January 1843) was born in Newburn, near Newcastle upon Tyne. He was one of the leading industrial engineers of the early 19th century, and was instrumental in several major innovations in early rail transpor ...
for the Wylam Colliery near
Newcastle upon Tyne Newcastle upon Tyne ( RP: , ), or simply Newcastle, is a city and metropolitan borough in Tyne and Wear, England. The city is located on the River Tyne's northern bank and forms the largest part of the Tyneside built-up area. Newcastle is ...
. 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 a British civil engineer and mechanical engineer. Renowned as the "Father of Railways", Stephenson was considered by the Victorians a great example of diligent application and thirst for ...
built ''
Locomotion No. 1 ''Locomotion'' No. 1 (originally named ''Active'') is an early steam locomotive that was built in 1825 by the pioneering railway engineers George and Robert Stephenson at their manufacturing firm, Robert Stephenson and Company. It became the ...
'' 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 Shildo ...
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 The Liverpool and Manchester Railway (L&MR) was the first inter-city railway in the world. It opened on 15 September 1830 between the Lancashire towns of Liverpool and Manchester in England. It was also the first railway to rely exclusively ...
, built by Stephenson, opened a year later making exclusive use of steam power for passenger and
goods trains Rail freight transport is the use of railroads and trains to transport cargo as opposed to human passengers. A freight train, cargo train, or goods train is a group of freight cars (US) or goods wagons (International Union of Railways) hauled ...
. 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, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...
. 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 British Railways (BR), which from 1965 traded as British Rail, was a state-owned company that operated most of the overground rail transport in Great Britain from 1948 to 1997. It was formed from the nationalisation of the Big Four British rai ...
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 (US 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) i ...
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 combus ...
, 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 ...
s by a transmission. Typically they 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.


Benzene

Benzene locomotives have an internal combustion engines that use
benzene Benzene is an organic chemical compound with the molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar ring with one hydrogen atom attached to each. Because it contains only carbon and hydrogen atoms, ...
as fuel. Between the late 1890's and 1900's, a number of commercial manufacturers for Benzene Locomotives had been operating. This began with Deutz, that produced an operating system based upon a design prototype for a manganese mine in Giessen. Following, in the early 1900's, they had been sold for multiple mining and Tunnelling operations. Post the 1900's, no wide spread use was necessary or required, their inadequacy had increased with the existence of petrol and diesel locomotives.


Kerosene

Kerosene locomotives use
kerosene Kerosene, paraffin, or lamp oil is a combustible hydrocarbon liquid which is derived from petroleum. It is widely used as a fuel in aviation as well as households. Its name derives from el, κηρός (''keros'') meaning "wax", and was regi ...
as the fuel. They were the world's first internal combustion locomotives, preceding diesel and other oil locomotives by some years. The first known kerosene rail vehicle was a
draisine A draisine () is a light auxiliary rail vehicle, driven by service personnel, equipped to transport crew and material necessary for the maintenance of railway infrastructure. The eponymous term is derived from the German inventor Baron Karl Dr ...
built by
Gottlieb Daimler Gottlieb Wilhelm Daimler (; 17 March 1834 – 6 March 1900) was a German engineer, industrial designer and industrialist born in Schorndorf (Kingdom of Württemberg, a federal state of the German Confederation), in what is now Germany. He was a ...
in 1887, but this was not technically a locomotive as it carried a payload. A kerosene locomotive was built in 1894 by the
Priestman Brothers Priestman Brothers was an engineering company based in Kingston upon Hull, England that manufactured diggers, dredgers, cranes and other industrial machinery. In the later 1800s the company also produced the Priestman Oil Engine, an early desig ...
of
Kingston upon Hull Kingston upon Hull, usually abbreviated to Hull, is a port city and unitary authority in the East Riding of Yorkshire, England. It lies upon the River Hull at its confluence with the Humber Estuary, inland from the North Sea and south-east ...
for use on
Hull docks The Port of Hull is a port at the confluence of the River Hull and the Humber Estuary in Kingston upon Hull, in the East Riding of Yorkshire, England. Seaborne trade at the port can be traced to at least the 13th century, originally cond ...
. This locomotive was built using a 12 hp double-acting marine type engine, running at 300 rpm, mounted on a 4-wheel wagon chassis. It was only able to haul one loaded wagon at a time, due to its low power output, and was not a great success. The first successful kerosene locomotive was "Lachesis" built by
Richard Hornsby & Sons Richard Hornsby & Sons was an engine and machinery manufacturer in Grantham, Lincolnshire, England from 1828 until 1918. The company was a pioneer in the manufacture of the oil engine developed by Herbert Akroyd Stuart, which was marketed un ...
and delivered to Woolwich Arsenal railway in 1896. The company built four kerosene locomotives between 1896 and 1903, for use at the Arsenal.


Petrol

Petrol locomotives use petrol (
gasoline Gasoline (; ) or petrol (; ) (see ) is a transparent, petroleum-derived flammable liquid that is used primarily as a fuel in most spark-ignited internal combustion engines (also known as petrol engines). It consists mostly of organic co ...
) as their fuel. The first commercially successful petrol locomotive was a petrol-mechanical locomotive built by the
Maudslay Motor Company The Maudslay Motor Company was a British vehicle maker based in Coventry. It was founded in 1902 and continued until 1948 when it was taken over by the Associated Equipment Company (AEC) and along with Crossley Motors the new group was rename ...
in 1902, for the Deptford Cattle Market in
London London is the capital and largest city of England and the United Kingdom, with a population of just under 9 million. It stands on the River Thames in south-east England at the head of a estuary down to the North Sea, and has been a majo ...
. It was an 80 hp locomotive using a 3-cylinder vertical petrol engine, with a two speed mechanical gearbox.


=Petrol-mechanical

= The most common type of petrol locomotive are petrol-mechanical locomotives, which use
mechanical Mechanical may refer to: Machine * Machine (mechanical), a system of mechanisms that shape the actuator input to achieve a specific application of output forces and movement * Mechanical calculator, a device used to perform the basic operations of ...
transmission Transmission may refer to: Medicine, science and technology * Power transmission ** Electric power transmission ** Propulsion transmission, technology allowing controlled application of power *** Automatic transmission *** Manual transmission *** ...
in the form of
gearboxes Propulsion transmission is the mode of transmitting and controlling propulsion power of a machine. The term ''transmission'' properly refers to the whole drivetrain, including clutch, gearbox, prop shaft (for rear-wheel drive vehicles), differe ...
(sometimes in conjunction with
chain drive Chain drive is a way of transmitting mechanical power from one place to another. It is often used to convey power to the wheels of a vehicle, particularly bicycles and motorcycles. It is also used in a wide variety of machines besides vehicles. ...
s) to deliver the power output of the engine to the driving wheels, in the same way as a
car A car or automobile is a motor vehicle with wheels. Most definitions of ''cars'' say that they run primarily on roads, seat one to eight people, have four wheels, and mainly transport people instead of goods. The year 1886 is regarded as ...
. The second petrol-mechanical locomotive was built by F.C. Blake of
Kew Kew () is a district in the London Borough of Richmond upon Thames. Its population at the 2011 census was 11,436. Kew is the location of the Royal Botanic Gardens ("Kew Gardens"), now a World Heritage Site, which includes Kew Palace. Kew is a ...
in January 1903 for the Richmond Main Sewerage Board.


=Petrol-electric

= Petrol-electric locomotives are petrol locomotives which use
electric transmission Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described ...
to deliver the power output of the engine to the driving wheels. This avoids the need for
gearboxes Propulsion transmission is the mode of transmitting and controlling propulsion power of a machine. The term ''transmission'' properly refers to the whole drivetrain, including clutch, gearbox, prop shaft (for rear-wheel drive vehicles), differe ...
by converting the rotary
mechanical force In physical sciences, mechanical energy is the sum of potential energy and kinetic energy. The principle of conservation of mechanical energy states that if an isolated system is subject only to conservative forces, then the mechanical energy is ...
of the engine into
electrical energy Electrical energy is energy related to forces on electrically charged particles and the movement of electrically charged particles (often electrons in wires, but not always). This energy is supplied by the combination of electric current and electr ...
by a
dynamo file:DynamoElectricMachinesEndViewPartlySection USP284110.png, "Dynamo Electric Machine" (end view, partly section, ) A dynamo is an electrical generator that creates direct current using a commutator (electric), commutator. Dynamos were the f ...
, and then powering the wheels by multi-speed electric
traction motor A traction motor is an electric motor used for propulsion of a vehicle, such as locomotives, electric vehicle, electric or hydrogen vehicles, elevators or electric multiple unit. Traction motors are used in electrically powered rail vehicles (ele ...
s. This allows for smoother acceleration, as it avoids the need for gear changes, however, it is more expensive, heavier, and sometimes bulkier than mechanical transmission. A notable early petrol-electric locomotive was built in 1913 for the Minneapolis, St. Paul, Rochester and Dubuque Electric Traction Company. It weighed 60 tons, generated 350 hp and drove through a pair of
bogie A bogie ( ) (in some senses called a truck in North American English) is a chassis or framework that carries a wheelset, attached to a vehicle—a modular subassembly of wheels and axles. Bogies take various forms in various modes of transp ...
s in a
Bo-Bo B-B and Bo-Bo are the Association of American Railroads (AAR) and British classifications of wheel arrangement for railway locomotives with four axles in two individual bogies. They are equivalent to the B′B′ and Bo′Bo′ classifications in ...
arrangement.


Diesel

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 ...
s are powered by
diesel engine The diesel engine, named after Rudolf Diesel, is an internal combustion engine in which ignition of the fuel is caused by the elevated temperature of the air in the cylinder due to mechanical compression; thus, the diesel engine is a so-call ...
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.


=Diesel-mechanical

= A diesel–mechanical locomotive uses
mechanical transmission Propulsion transmission is the mode of transmitting and controlling propulsion power of a machine. The term ''transmission'' properly refers to the whole drivetrain, including clutch, gearbox, prop shaft (for rear-wheel drive vehicles), differ ...
to transfer power to the wheels. This type of transmission is generally limited to low-powered, low speed shunting (switching) locomotives, lightweight
multiple unit A multiple-unit train or simply multiple unit (MU) is a self-propelled train composed of one or more carriages joined together, which when coupled to another multiple unit can be controlled by a single driver, with multiple-unit train contr ...
s and self-propelled
railcar A railcar (not to be confused with a railway car) is a self-propelled railway vehicle designed to transport passengers. The term "railcar" is usually used in reference to a train consisting of a single coach (carriage, car), with a drive ...
s. The earliest diesel locomotives were diesel-mechanical. In 1906,
Rudolf Diesel Rudolf Christian Karl Diesel (, ; 18 March 1858 – 29 September 1913) was a German inventor and Mechanical engineering, mechanical engineer who is famous for having invented the diesel engine, which burns diesel fuel; both are named after him. ...
,
Adolf Klose Adolf Klose (21 May 1844 – 2 September 1923) was the chief engineer of the Royal Württemberg State Railways in southern Germany from June 1885 to 1896. Klose was born in Bernstadt auf dem Eigen, in Saxony. Before his taking up his post in Stu ...
and the steam and diesel engine manufacturer Gebrüder Sulzer founded Diesel-Sulzer-Klose GmbH to manufacture diesel-powered locomotives. The Prussian State Railways ordered a diesel locomotive from the company in 1909. The world's first diesel-powered locomotive (a diesel-mechanical locomotive) was operated in the summer of 1912 on the
Winterthur–Romanshorn railway The Winterthur–Romanshorn railway, also known in German as the ''Thurtallinie'' ("Thur valley line"), is a Swiss railway line and was built as part of the railway between Zürich and Lake Constance (Bodensee). It connects Winterthur with Romansh ...
in Switzerland, but was not a commercial success. Small numbers of prototype diesel locomotives were produced in a number of countries through the mid-1920s.


=Diesel-electric

= Diesel–electric locomotives are diesel locomotives using
electric transmission Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described ...
. The diesel engine drives either an electrical
DC generator In electricity generation, a generator is a device that converts motive power (mechanical energy) or fuel-based power (chemical energy) into electric power for use in an external circuit. Sources of mechanical energy include steam turbines, gas ...
(generally, less than net for traction), or an electrical AC alternator-rectifier (generally net or more for traction), the output of which provides power to the
traction motor A traction motor is an electric motor used for propulsion of a vehicle, such as locomotives, electric vehicle, electric or hydrogen vehicles, elevators or electric multiple unit. Traction motors are used in electrically powered rail vehicles (ele ...
s that drive the locomotive. There is no mechanical connection between the diesel engine and the wheels. The vast majority of diesel locomotives today are diesel-electric. In 1914, Hermann Lemp, a
General Electric General Electric Company (GE) is an American multinational conglomerate founded in 1892, and incorporated in New York state and headquartered in Boston. The company operated in sectors including healthcare, aviation, power, renewable energ ...
electrical engineer, developed and patented a reliable
direct current Direct current (DC) is one-directional flow of electric charge. An electrochemical cell is a prime example of DC power. Direct current may flow through a conductor such as a wire, but can also flow through semiconductors, insulators, or even ...
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 prototyp ...
for all
diesel–electric 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 wheels ...
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 Yury Vladimirovich Lomonosov (russian: Юрий Владимирович Ломоносов; 24 April 1876 – 19 November 1952) was a Russian railway engineer and a leading figure in the development of Russian Railways in the early 20th century ...
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, (turntables and traversers), bridges, steel structures, pumps and boilers. ...
in Germany. It had 5 driving axles (1'E1'). After several test rides, it hauled trains for almost three decades from 1925 to 1954.


=Diesel-hydraulic

= Diesel–hydraulic locomotives are diesel locomotives using hydraulic transmission. In this arrangement, they use one or more
torque converter A torque converter is a type of fluid coupling that transfers rotating power from a prime mover, like an internal combustion engine, to a rotating driven load. In a vehicle with an automatic transmission, the torque converter connects the power ...
s, in combination with gears, with a mechanical final drive to convey the power from the diesel engine to the wheels. The main worldwide user of main-line hydraulic transmissions was the Federal Republic of
Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...
, with designs including the 1950s
DB Class V 200 DB Class V 200 (also known as Class 220) was the first series production diesel-hydraulic express locomotive of the German Deutsche Bundesbahn and – as Am 4/4 – of the SBB-CFF-FFS in Switzerland. History DB Service Five prototypes of ...
, and the 1960 and 1970s
DB V 160 family The ''DB V 160 locomotive family'' comprises several classes of closely related 4-axle diesel-hydraulic locomotives built in the 1960s and 1970s for the Deutsche Bundesbahn which take the family name from the earliest built model: the 'DB Class V 1 ...
.
British Rail British Railways (BR), which from 1965 traded as British Rail, was a state-owned company that operated most of the overground rail transport in Great Britain from 1948 to 1997. It was formed from the nationalisation of the Big Four British rai ...
introduced a number of diesel hydraulic designs during it
1955 Modernisation Plan Events January * January 3 – José Ramón Guizado becomes president of Panama. * January 17 – , the first nuclear-powered submarine, puts to sea for the first time, from Groton, Connecticut. * January 18– 20 – Battle of Yijian ...
, initially license built versions of German designs. In Spain Renfe used high power to weight ratio twin engined German designs to haul high speed trains from the 1960s to 1990s. (see Renfe Classes 340,
350 __NOTOC__ Year 350 (Roman numerals, CCCL) was a common year starting on Monday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Sergius and Nigrinianus (or, less frequentl ...
,
352 Year 352 (Roman numerals, CCCLII) was a leap year starting on Wednesday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Decentius and Paulus (or, less frequently, year 110 ...
,
353 __NOTOC__ Year 353 ( CCCLIII) was a common year starting on Friday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Magnentius and Decentius (or, less frequently, year 110 ...
,
354 __NOTOC__ Year 354 ( CCCLIV) was a common year starting on Saturday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Constantius and Constantius (or, less frequently, yea ...
). Hydrostatic drive systems have also been applied to rail use, for example shunting locomotives by CMI Group (Belgium). Hydrostatic drives are also used in railway maintenance machines such as tampers and rail grinders.


Gas turbine

A
gas turbine locomotive A gas turbine locomotive is a type of railway locomotive in which the prime mover is a gas turbine. Several types of gas turbine locomotive have been developed, differing mainly in the means by which mechanical power is conveyed to the driving w ...
is 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 combus ...
locomotive consisting of a
gas turbine A gas turbine, also called a combustion turbine, is a type of continuous flow internal combustion engine. The main parts common to all gas turbine engines form the power-producing part (known as the gas generator or core) and are, in the directi ...
. ICE engines require a transmission to power the wheels. The engine must be allowed to continue to run when the locomotive is stopped. Gas turbine-mechanical locomotives use a
mechanical transmission Propulsion transmission is the mode of transmitting and controlling propulsion power of a machine. The term ''transmission'' properly refers to the whole drivetrain, including clutch, gearbox, prop shaft (for rear-wheel drive vehicles), differ ...
to deliver the power output of gas turbines to the wheels. A gas turbine locomotive was patented in 1861 by Marc Antoine Francois Mennons (British patent no. 1633). There is no evidence that the locomotive was actually built but the design includes the essential features of gas turbine locomotives, including compressor, combustion chamber, turbine and air pre-heater. In 1952, Renault delivered a prototype four-axle 1150 hp gas-turbine-mechanical locomotive fitted with the Pescara "free turbine" gas- and compressed-air producing system, rather than a co-axial multi-stage compressor integral to the turbine. This model was succeeded by a pair of six-axle 2400 hp locomotives with two turbines and Pescara feeds in 1959. Several similar locomotives were built in USSR by
Kharkov Locomotive Works The Malyshev Factory ( uk , Завод імені В.О. Малишева, translit=Zavod imeni V.O. Malysheva; abbreviated ), formerly the Kharkov Locomotive Factory (, ), is a state-owned manufacturer of heavy equipment in Kharkiv, Ukraine. It ...
. Gas turbine-electric locomotives, use a
gas turbine A gas turbine, also called a combustion turbine, is a type of continuous flow internal combustion engine. The main parts common to all gas turbine engines form the power-producing part (known as the gas generator or core) and are, in the directi ...
to drive an
electrical generator In electricity generation, a generator is a device that converts motive power (mechanical energy) or fuel-based power (chemical energy) into electric power for use in an external circuit. Sources of mechanical energy include steam turbines, gas ...
or
alternator An alternator is an electrical generator that converts mechanical energy to electrical energy in the form of alternating current. For reasons of cost and simplicity, most alternators use a rotating magnetic field with a stationary armature.Go ...
which produced electric current powers the
traction motor A traction motor is an electric motor used for propulsion of a vehicle, such as locomotives, electric vehicle, electric or hydrogen vehicles, elevators or electric multiple unit. Traction motors are used in electrically powered rail vehicles (ele ...
which drive the wheels. In 1939 the
Swiss Federal Railways Swiss Federal Railways (german: link=no, Schweizerische Bundesbahnen, ''SBB''; french: link=no, Chemins de fer fédéraux suisses, ''CFF''; it, Ferrovie federali svizzere, ''FFS'') is the national railway company of Switzerland. It is usuall ...
ordered Am 4/6, a GTEL with a of maximum engine power from
Brown Boveri Brown, Boveri & Cie. (Brown, Boveri & Company; BBC) was a Swiss group of electrical engineering companies. It was founded in Zürich, in 1891 by Charles Eugene Lancelot Brown and Walter Boveri who worked at the Maschinenfabrik Oerlikon. In 1970 ...
. It was completed in 1941, and then underwent testing before entering regular service. The Am 4/6 was the first gas turbine – electric locomotive. British Rail 18000 was built by Brown Boveri and delivered in 1949.
British Rail 18100 British Rail 18100 was a prototype main line gas turbine-electric locomotive built for British Railways in 1951 by Metropolitan-Vickers, Manchester. It had, however, been ordered by the Great Western Railway in the 1940s, but construction was de ...
was built by
Metropolitan-Vickers Metropolitan-Vickers, Metrovick, or Metrovicks, was a British heavy electrical engineering company of the early-to-mid 20th century formerly known as British Westinghouse. Highly diversified, it was particularly well known for its industrial el ...
and delivered in 1951. A third locomotive, the British Rail GT3, was constructed in 1961.
Union Pacific The Union Pacific Railroad , legally Union Pacific Railroad Company and often called simply Union Pacific, is a freight-hauling railroad that operates 8,300 locomotives over routes in 23 U.S. states west of Chicago and New Orleans. Union Paci ...
ran a large fleet of turbine-powered freight locomotives starting in the 1950s. These were widely used on long-haul routes, and were cost-effective despite their poor fuel economy due to their use of "leftover" fuels from the petroleum industry. At their height the railroad estimated that they powered about 10% of Union Pacific's freight trains, a much wider use than any other example of this class. A gas turbine offers some advantages over a
piston engine A reciprocating engine, also often known as a piston engine, is typically a heat engine that uses one or more reciprocating pistons to convert high temperature and high pressure into a rotating motion. This article describes the common featu ...
. There are few moving parts, decreasing the need for
lubrication Lubrication is the process or technique of using a lubricant to reduce friction and wear and tear in a contact between two surfaces. The study of lubrication is a discipline in the field of tribology. Lubrication mechanisms such as fluid-lubric ...
and potentially reducing maintenance costs, and the
power-to-weight ratio Power-to-weight ratio (PWR, also called specific power, or power-to-mass ratio) is a calculation commonly applied to engines and mobile power sources to enable the comparison of one unit or design to another. Power-to-weight ratio is a measuremen ...
is much higher. A turbine of a given power output is also physically smaller than an equally powerful piston engine, allowing a locomotive to be very powerful without being inordinately large. However, a turbine's power output and efficiency both drop dramatically with
rotational speed Rotational frequency (also known as rotational speed or rate of rotation) of an object Rotation around a fixed axis, rotating around an axis is the frequency of rotation of the object. Its unit is revolution per minute (rpm), cycle per second ...
, unlike a piston engine, which has a comparatively flat power curve. This makes GTEL systems useful primarily for long-distance high-speed runs. Additional problems with gas turbine-electric locomotives included that they were very noisy.


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 An overhead line or overhead wire is an electrical cable that is used to transmit electrical energy to electric locomotives, trolleybuses or trams. It is known variously as: * Overhead catenary * Overhead contact system (OCS) * Overhead equipmen ...
, 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 railway t ...
mounted at track level; or an onboard
battery Battery most often refers to: * Electric battery, a device that provides electrical power * Battery (crime), a crime involving unlawful physical contact Battery may also refer to: Energy source *Automotive battery, a device to provide power t ...
. 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 flow of electric charge. An electrochemical cell is a prime example of DC power. Direct current may flow through a conductor such as a wire, but can also flow through semiconductors, insulators, or even ...
(DC) or
alternating current Alternating current (AC) is an electric current which 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 whic ...
(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 wire to the control and the electric traction motors of a tram or trolley bus. It is a type of current collector. Th ...
, which is a long flexible pole that engages the line with a wheel or shoe; a
bow collector A bow collector is one of the three main devices used on tramcars to transfer electric current from the wires above to the tram below. While once very common in continental Europe, it was replaced by the pantograph or the trolley pole, itself of ...
, 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 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 second pen. If a line dr ...
, which is a hinged frame that holds the collecting shoes against the wire in a fixed geometry; or a
contact shoe Electric current collectors are used by trolleybuses, trams, electric locomotives or EMUs to carry electrical power from overhead lines, electrical third rails, or ground-level power supplies to the electrical equipment of the vehicles. Those for ...
, 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 A pinion is a round gear—usually the smaller of two meshed gears—used in several applications, including drivetrain and rack and pinion systems. Applications Drivetrain Drivetrains usually feature a gear known as the pinion, which may ...
on the motor shaft engages a
bull gear This page lists the standard US nomenclature used in the description of mechanical gear construction and function, together with definitions of the terms. The terminology was established by the American Gear Manufacturers Association (AGMA), under ...
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 In electrical engineering, a transmission line is a specialized cable or other structure designed to conduct electromagnetic waves in a contained manner. The term applies when the conductors are long enough that the wave nature of the transmis ...
but most purchase power from an
electric utility An electric utility 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. The electrical utility industry is a major pr ...
. The railway usually provides its own distribution lines, switches and
transformer A transformer is a passive component that transfers electrical energy from one electrical circuit to another circuit, or multiple circuits. A varying current in any coil of the transformer produces a varying magnetic flux in the transformer' ...
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 foun ...
at
Berlin Berlin ( , ) is the capital and largest city of Germany by both area and population. Its 3.7 million inhabitants make it the European Union's most populous city, according to population within city limits. One of Germany's sixteen constitue ...
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 300-metre-long (984 feet) 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 The Gross Lichterfelde Tramway was one of the world's first electric tramways ( Miller's line was electrified in 1875). It was built by the Siemens & Halske company in Lichterfelde, a suburb of Berlin, and went in service on 16 May 1881. Over ...
and
Berlin Straßenbahn The Berlin tramway (german: Straßenbahn Berlin) is the main tram system in Berlin, Germany. It is one of the oldest tram networks in the world having its origins in 1865 and is operated by (BVG), which was founded in 1929. It is notable ...
). The
Volk's Electric Railway Volk's Electric Railway (VER) is a narrow gauge railway, narrow gauge heritage railway that runs along a length of the seafront of the English seaside resort of Brighton. It was built by Magnus Volk, the first section being completed in August ...
opened in 1883 in Brighton, and is the oldest surviving electric railway. Also in 1883,
Mödling and Hinterbrühl Tram Mödling and Hinterbrühl Tram or ''Mödling and Hinterbrühl Local Railway'' (German: ''Lokalbahn Mödling–Hinterbrühl'') was an electric tramway in Austria, running 4.5 km (2.8 mi) from Mödling to Hinterbrühl, in the southwest ...
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 The Richmond Union Passenger Railway, in Richmond, Virginia, was the first practical electric Tram, trolley (tram) system, and set the pattern for most subsequent electric trolley systems around the world. It is an Institute of Electrical and E ...
, using equipment designed by
Frank J. Sprague Frank Julian Sprague (July 25, 1857 in Milford, Connecticut – October 25, 1934) was an American inventor who contributed to the development of the electric motor, electric railways, and electric elevators. His contributions were especially ...
. The first electrically worked
underground Underground most commonly refers to: * Subterranea (geography), the regions beneath the surface of the Earth Underground may also refer to: Places * The Underground (Boston), a music club in the Allston neighborhood of Boston * The Underground (S ...
line was the
City & South London Railway The City and South London Railway (C&SLR) was the first successful deep-level underground "tube" railway in the world, and the first major railway to use electric traction. The railway was originally intended for cable-hauled trains, but owing ...
, prompted by a clause in its enabling act prohibiting use of steam power. It opened in 1890, using electric locomotives built by
Mather & Platt Mather & Platt is the name of several large engineering firms in Europe, South Africa and Asia that are subsidiaries of Wilo SE, Germany or were founded by former employees. The original company was founded in the Newton Heath area of Manchester, ...
. Electricity quickly became the power supply of choice for subways, abetted by the Sprague's invention of
multiple-unit train control Multiple-unit train control, sometimes abbreviated to multiple-unit or MU, is a method of simultaneously controlling all the traction equipment in a train from a single location—whether it is a multiple unit comprising a number of self-powered ...
in 1897. The first use of electrification on a main line was on a four-mile stretch of the
Baltimore Belt Line The Baltimore Belt Line was constructed by the Baltimore and Ohio Railroad (B&O) in the early 1890s to connect the railroad's newly constructed line to Philadelphia and Central Railroad of New Jersey Terminal, New York City/Jersey City with the re ...
of the
Baltimore & Ohio The Baltimore and Ohio Railroad was the first common carrier railroad and the oldest railroad in the United States, with its first section opening in 1830. Merchants from Baltimore, which had benefited to some extent from the construction of ...
(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 A Bo+Bo (UK usage) is a locomotive with two four-wheeled bogies with articulated connection between them and with all axles powered by individual traction motors.Encyclopædia Britannica, Volume 18, 1969 Edition, p1118 Table IV, SBN(GB) 85229 004 ...
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 Hydroelectricity, or hydroelectric power, is electricity generated from hydropower (water power). Hydropower supplies one sixth of the world's electricity, almost 4500 TWh in 2020, which is more than all other renewable sources combined and ...
at
Lauffen am Neckar Lauffen am Neckar () or simply Lauffen is a town in the district of Heilbronn, Baden-Württemberg, Germany. It is on the river Neckar, southwest of Heilbronn. The town is famous as the birthplace of the poet Friedrich Hölderlin and for its qu ...
and
Frankfurt Frankfurt, officially Frankfurt am Main (; Hessian: , "Frank ford on the Main"), is the most populous city in the German state of Hesse. Its 791,000 inhabitants as of 2022 make it the fifth-most populous city in Germany. Located on its na ...
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, a ...
, 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 ( ) (in some senses called a truck in North American English) is a chassis or framework that carries a wheelset, attached to a vehicle—a modular subassembly of wheels and axles. Bogies take various forms in various modes of transp ...
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''; 10 July 1869 – 13 January 1931) was a Hungarian engineer, the inventor of phase converter and a pioneer in the development of AC electric railway tract ...
developed a new type 3-phase asynchronous electric drive motors and generators for electric locomotives. 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 A rotary phase converter, abbreviated RPC, is an electrical machine that converts power from one polyphase system to another, converting through rotary motion. Typically, single-phase electric power is used to produce three-phase electric power ...
, 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 Regenerative braking is an energy recovery mechanism that slows down a moving vehicle or object by converting its kinetic energy into a form that can be either used immediately or stored until needed. In this mechanism, the electric traction mo ...
, 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 Walter Boveri (born 21 February 1865 in Bamberg, Bavaria, died 28 October 1924 in Baden, Switzerland) was a Swiss-German industrialist and co-founder of the global electrical engineering group Brown, Boveri & Cie. (BBC). Biography Boveri's ances ...
) 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 Hans Behn-Eschenburg (10 January 1864 – 18 May 1938) was born in Obertrass (now Zurich), Switzerland. His work on the AC single-phase motor was important to the electrification of railways. He studied mathematics and physics in Zurich and Be ...
and
Emil Huber-Stockar Emil Huber-Stockar (July 15, 1865 - May 9, 1939) was a Swiss entrepreneur and railway pioneer. He was an instrumental figure in the electrification of the Swiss railway network and worked as lead engineer and consultant for the Swiss Federal Rai ...
; 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 on-board
batteries Battery most often refers to: * Electric battery, a device that provides electrical power * Battery (crime), a crime involving unlawful physical contact Battery may also refer to: Energy source *Automotive battery, a device to provide power t ...
; 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 exclusively uses chemical energy stored in rechargeable battery packs, wi ...
. 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 An electric arc, or arc discharge, is an electrical breakdown of a gas that produces a prolonged electrical discharge. The electric current, current through a normally Electrical conductance, nonconductive medium such as air produces a plasma (p ...
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 parallels ...
could develop in the supply or return circuits, especially at rail joints, and allow dangerous current leakage into the ground. The first known electric locomotive was built in 1837 by chemist Robert Davidson of
Aberdeen Aberdeen (; sco, Aiberdeen ; gd, Obar Dheathain ; la, Aberdonia) is a city in North East Scotland, and is the third most populous city in the country. Aberdeen is one of Scotland's 32 local government council areas (as Aberdeen City), and ...
, and it was powered by
galvanic cell A galvanic cell or voltaic cell, named after the scientists Luigi Galvani and Alessandro Volta, respectively, is an electrochemical cell in which an electric current is generated from spontaneous Oxidation-Reduction reactions. A common apparatus ...
s (batteries). Davidson later built a larger locomotive named ''Galvani'', exhibited at the
Royal Scottish Society of Arts The Royal Scottish Society of Arts is a learned society in Scotland, dedicated to the study of science and technology. It was founded as The Society for the Encouragement of the Useful Arts in Scotland by David Brewster, Sir David Brewster in 182 ...
Exhibition in 1841. The seven-ton vehicle had two
direct-drive A direct-drive mechanism is a mechanism design where the force or torque from a prime mover is transmitted directly to the effector device (such as the drive wheels of a vehicle) without involving any intermediate couplings such as a gear train or ...
reluctance motor A reluctance motor is a type of electric motor that induces non-permanent magnetic poles on the ferromagnetic rotor. The rotor does not have any windings. It generates torque through magnetic reluctance. Reluctance motor subtypes include synchro ...
s, 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 The Edinburgh and Glasgow Railway was authorised by Act of Parliament on 4 July 1838. It was opened to passenger traffic on 21 February 1842, between its Glasgow Queen Street railway station (sometimes referred to at first as Dundas Street) and ...
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 The Bingham Canyon Mine, more commonly known as Kennecott Copper Mine among locals, is an open-pit mining operation extracting a large porphyry copper deposit southwest of Salt Lake City, Utah, in the Oquirrh Mountains. The mine is the largest m ...
, 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 The nickel–iron battery (NiFe battery) is a rechargeable battery having nickel(III) oxide-hydroxide positive plates and iron negative plates, with an electrolyte of potassium hydroxide. The active materials are held in nickel-plated steel tub ...
(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 The Boone and Scenic Valley Railroad is a heritage railroad that operates freight and passenger excursions in Boone County, Iowa. History The heritage and excursion railroad was begun in 1983 by a group of volunteers who wanted to preserve a sce ...
, Iowa, and at the
Western Railway Museum The Western Railway Museum, in Solano County, California is located on Highway 12 between Rio Vista and Suisun. The museum is built along the former mainline of the Sacramento Northern Railway. Their collection focuses on trolleys, as it is ...
in Rio Vista, California. The
Toronto Transit Commission The Toronto Transit Commission (TTC) is the public transport agency that operates bus, subway, streetcar, and paratransit services in Toronto, Ontario, Canada, some of which run into the Peel Region and York Region. It is the oldest and largest ...
previously operated a battery electric locomotive built by
Nippon Sharyo , formed in 1896, is a major rolling stock manufacturer based in Nagoya, Japan. In 1996, it abbreviated its name to "日本車両" Nippon Sharyō. Its shortest abbreviation is Nissha "日車". It was a listed company on Nikkei 225 until 2 ...
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, Dr. Lyle Borst of the
University of Utah The University of Utah (U of U, UofU, or simply The U) is a public research university in Salt Lake City, Utah. It is the flagship institution of the Utah System of Higher Education. The university was established in 1850 as the University of De ...
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 the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic, an ...
(fuel cell) -powered mining locomotive was demonstrated in
Val-d'Or Val-d'Or (, , ; "Golden Valley" or "Valley of Gold") is a city in Quebec, Canada with a population of 32,752 inhabitants according to the Canada 2021 Census. The city is located in the Abitibi-Témiscamingue region near La Vérendrye Wildlife R ...
,
Quebec Quebec ( ; )According to the Canadian government, ''Québec'' (with the acute accent) is the official name in Canadian French and ''Quebec'' (without the accent) is the province's official name in Canadian English is one of the thirtee ...
. In 2007 the educational mini-hydrail in
Kaohsiung Kaohsiung City (Mandarin Chinese: ; Wade–Giles: ''Kao¹-hsiung²;'' Pinyin: ''Gāoxióng'') is a special municipality located in southern Taiwan. It ranges from the coastal urban center to the rural Yushan Range with an area of . Kaohsi ...
,
Taiwan Taiwan, officially the Republic of China (ROC), is a country in East Asia, at the junction of the East and South China Seas in the northwestern Pacific Ocean, with the People's Republic of China (PRC) to the northwest, Japan to the nort ...
went into service. The
Railpower GG20B The Railpower GG20B ''Green Goat'' is a low-emissions diesel hybrid switcher locomotive built by Railpower Technologies Corp. It is powered by a single Caterpillar C9 six cylinder inline engine developing , which is also connected to a large bat ...
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 locomotive An electro-diesel locomotive (also referred to as a dual-mode or bi-mode locomotive) is a type of locomotive that can be powered either from an electricity supply (like an electric locomotive) or by using the onboard diesel engine (like a diese ...
s powered either from an electricity supply or else by an onboard
diesel engine The diesel engine, named after Rudolf Diesel, is an internal combustion engine in which ignition of the fuel is caused by the elevated temperature of the air in the cylinder due to mechanical compression; thus, the diesel engine is a so-call ...
. These are used to provide continuous journeys along routes that are only partly electrified. Examples include the
EMD FL9 The EMD FL9 (New Haven Class EDER-5) is a model of electro-diesel locomotive, capable of operating either as a traditional diesel-electric locomotive or as an electric locomotive powered from a third rail. Sixty units were built between October 1 ...
and
Bombardier ALP-45DP The Bombardier ALP-45DP is a type of single cab dual-mode locomotive built by Bombardier Transportation (later Alstom) and operated by New Jersey Transit and Exo. Operators New Jersey Transit New Jersey Transit (NJT) purchased 26 ALP-45DPs ...


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 locomotiv ...
: for hauling
passenger A passenger (also abbreviated as pax) is a person who travels in a vehicle, but does not bear any responsibility for the tasks required for that vehicle to arrive at its destination or otherwise operate the vehicle, and is not a steward. The ...
trains,
freight Cargo consists of bulk goods conveyed by water, air, or land. In economics, freight is cargo that is transported at a freight rate for commercial gain. ''Cargo'' was originally a shipload but now covers all types of freight, including transp ...
trains, and for switching (UK English: shunting). Freight locomotives are normally designed to deliver high starting
tractive effort As used in mechanical engineering, the term tractive force can either refer to the total traction a vehicle exerts on a surface, or the amount of the total traction that is parallel to the direction of motion. In railway engineering, the term tr ...
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 locomotive A locomotive or engine is a rail transport vehicle that provides the motive power for a train. If a locomotive is capable of carrying a payload, it is usually rather referred to as a multiple unit, motor coach, railcar or power car; the us ...
s (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 motor A traction motor is an electric motor used for propulsion of a vehicle, such as locomotives, electric vehicle, electric or hydrogen vehicles, elevators or electric multiple unit. Traction motors are used in electrically powered rail vehicles (ele ...
s and
axle An axle or axletree is a central shaft for a rotating 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 the former case, bearing ...
s adapts the power output to the rails for freight or passenger service. Passenger locomotives may include other features, such as
head-end power In rail transport, head-end power (HEP), also known as electric train supply (ETS), is the electrical power distribution system on a passenger train. The power source, usually a locomotive (or a generator car) at the front or 'head' of a train, p ...
(also referred to as hotel power or electric train supply) or a
steam generator A Steam generator is a device used to boil water to create steam. More specifically, it may refer to: *Boiler (steam generator), a closed vessel in which water is heated under pressure *Monotube steam generator *Supercritical steam generator or Ben ...
. Some locomotives are designed specifically to work
steep grade railway A steep grade railway is a railway that ascends and descends a slope that has a steep grade. Such railways can use a number of different technologies to overcome the steepness of the grade. Usage Many steep grade railways are located in mountain ...
s, 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 A locomotive frame is the structure that forms the backbone of the railway locomotive, giving it strength and supporting the superstructure elements such as a cab, boiler or bodywork. The vast majority of locomotives have had a frame structure o ...
, so that the boiler remains roughly level on steep grades. Locomotives are also used on some High-speed trains: All
TGV The TGV (french: Train à Grande Vitesse, "high-speed train"; previously french: TurboTrain à Grande Vitesse, label=none) is France's intercity high-speed rail service, operated by SNCF. SNCF worked on a high-speed rail network from 1966 to 19 ...
, many
AVE ''Alta Velocidad Española'' (''AVE'') is a service of high-speed rail in Spain operated by Renfe, the Spanish national railway company, at speeds of up to . As of December 2021, the Spanish high-speed rail network, on part of which the AVE s ...
, some
Korea Train Express Korea Train eXpress (), often known as KTX (), is South Korea's high-speed rail system, operated by Korail. Construction began on the high-speed line from Seoul to Busan in 1992. KTX services were launched on April 1, 2004. From Seoul Station th ...
and the
ICE 1 The ICE 1 is the first batch-produced German high-speed train and one of six in the Intercity Express family. Revenue service at speeds up to started in 1991. It was raised to in May 1995 and temporary reduced to again, as a result of ...
and
ICE 2 The ICE 2 is the second series of German high-speed trains and one of six in the Intercity-Express family since 1995. The ICE 2 (half-) trains are even closer to a conventional push–pull train than the ICE 1, because each train consists ...
trains all use locomotives, which may also be known as power cars. 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. Initially, it was built to connect distant Japanese regions with Tokyo, the capital, to aid economic growth and development. Beyond l ...
network never use locomotives. Instead of locomotives, 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 numbe ...
s (EMUs) -- passenger cars that also have traction motors. Using 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. The
KTX-Sancheon The KTX-Sancheon (formerly called the KTX-II) is a South Korean high-speed train built by Hyundai Rotem in the second half of the 2000s and operated by Korail since March 2009. With a top speed of , the KTX-Sancheon is the second commercial hi ...
and ICE 3/4/T use a mixture of electric multiple units and power 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 In rail transport, a train (from Old French , from Latin , "to pull, to draw") is a series of connected vehicles that run along a railway track and Passenger train, transport people or Rail freight transport, freight. Trains are typically pul ...
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 In railroad terminology, double heading indicates the use of two locomotives at the front of a train, each operated individually by its own crew. The practice of triple-heading involves the use of three locomotives. The practice of multi-headi ...
– a locomotive attached in front of the train engine, to enable
double-heading In railroad terminology, double heading indicates the use of two locomotives at the front of a train, each operated individually by its own crew. The practice of triple-heading involves the use of three locomotives. The practice of multi-headin ...
; *
Banking engine A bank engine (United Kingdom/Australia) (colloquially a banker), banking engine, helper engine or pusher engine (North America) is a railway locomotive that temporarily assists a train that requires additional power or traction to climb a grad ...
– a locomotive temporarily assisting a train from the rear, due to a difficult start or a sharp incline gradient; *
Light engine Rail terminology is a form of technical terminology. The difference between the American term ''railroad'' and the international term ''railway'' (used by the International Union of Railways and English-speaking countries outside the United St ...
– 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 switcher, shunter, yard pilot, switch engine, yard goat, or shifter is a small railroad locomotive used for manoeuvring railroad cars inside a rail yard in a process known as ''switching'' (US) or ''shunting'' (UK). Switchers are not inten ...
– a locomotive used to shunt passenger trains at a railway station.


Wheel arrangement

The wheel arrangement of a locomotive describes how many wheels it has; common methods include the
AAR wheel arrangement The AAR wheel arrangement system is a method of classifying locomotive (or unit) wheel arrangements that was developed by the Association of American Railroads. Essentially a simplification of the European UIC classification, it is widely used in ...
,
UIC classification The UIC classification of locomotive axle arrangements, sometimes known as the German classification''The Railway Data File''. Leicester: Silverdale, 2000. p. 52. . or German system,Kalla-Bishop P.M. & Greggio, Luciano, ''Steam Locomotives'', Cre ...
, and
Whyte notation Whyte notation is a classification method for steam locomotives, and some internal combustion locomotives and electric locomotives, by wheel arrangement. It was devised by Frederick Methvan Whyte, and came into use in the early twentieth ce ...
systems.


Remote control locomotives

In the second half of the twentieth century
remote control locomotive A remote control locomotive (also called an RCL) is a railway locomotive that can be operated with a remote control. It differs from a conventional locomotive in that a remote control system has been installed in one or more locomotives within the ...
s 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

* * * *


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 known as ''PopSci'') is an American digital magazine carrying popular science content, which refers to articles for the general reader on science and technology subjects. ''Popular Science'' has won over 58 awards, incl ...
monthly, February 1919, page 72, Scanned by Google Books
Popular Science
{{Authority control 19th-century inventions