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.
Etymology
The word locomotive originates from the Latinloco 'from a place', ablative of locus 'place', and the Medieval Latinmotivus 'causing motion', and is a shortened form of the term locomotive engine,[1] which was first used in 1814[2] to distinguish between self-propelled and stationary steam engines.
Prior to locomotives, the motive force for railways had been generated by various lower-technology methods such as human power, horse power, gravity 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:
A steam locomotive is a locomotive whose primary power source is a steam engine. The most common form of steam locomotive also contains a boiler 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 pistons which are connected to the locomotive's main wheels, known as the "driving wheels". 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").
The first full-scale working railway steam locomotive was built by Richard Trevithick in 1802. It was constructed for the Coalbrookdale ironworks in Shropshire in England though no record of it working there has survived.[3] 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 ironworks, in Merthyr Tydfil, to Abercynon in South Wales.[4][5] Accompanied by Andrew Vivian, it ran with mixed success.[6] 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.
The steam locomotive remained by far the most common type of locomotive until after World War II.[11] Steam locomotives are less efficient than modern diesel and electric locomotives, and a significantly larger workforce is required to operate and service them.[12]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.[citation needed] Between about 1950 and 1970, the majority of steam locomotives were retired from commercial service and replaced with electric and diesel–electric locomotives.[13][14] 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 railways.
Internal combustion locomotives use an internal combustion engine, connected to the driving wheels 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-powered draisine built by Gottlieb Daimler in 1887,[15] but this was not technically a locomotive as it carried a payload.
The first commercially successful petrol 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. It was an 80hp locomotive using a three-cylinder vertical petrol engine, with a two speed mechanical gearbox.
Diesel
Diesel locomotives are powered by diesel engines. 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 electrical engineer, developed and patented a reliable direct current electrical control system (subsequent improvements were also patented by Lemp).[17] Lemp's design used a single lever to control both engine and generator in a coordinated fashion, and was the prototype for all diesel–electric locomotive control. In 1917–18, GE produced three experimental diesel–electric locomotives using Lemp's control design.[18] 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 in Germany. It had 5 driving axles (1'E1'). After several test rides, it hauled trains for almost three decades from 1925 to 1954.[19]
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 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 (DC) or alternating current (AC).
Various collection methods exist: a trolley pole, 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, which is a hinged frame that holds the collecting shoes against the wire in a fixed geometry; or a contact shoe, 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. The railway usually provides its own distribution lines, switches and transformers.
Electric locomotives usually cost 20% less than diesel locomotives, their maintenance costs are 25–35% lower, and cost up to 50% less to run.[20]
Direct current
Werner von Siemens experimental DC electric train, 1879Baltimore & Ohio electric engine, 1895
The earliest systems were DC systems. The first electric passenger train was presented by Werner von Siemens at Berlin in 1879. The locomotive was driven by a 2.2kW, series-wound motor, and the train, consisting of the locomotive and three cars, reached a speed of 13km/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 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.[21]
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.[22] 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.[23]
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
A prototype of a Ganz AC electric locomotive in Valtellina, Italy, 1901
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 am Main West, a distance of 280km. 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, were simpler to manufacture and maintain.[a] However, they were much larger than the DC motors of the time and could not be mounted in underfloor bogies: they could only be carried within locomotive bodies.[25]
In 1894, Hungarian engineer Kálmán Kandó 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.[26][27][28][29][30] In 1918,[31] 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 (50Hz) single phase AC of the high voltage national networks.[32]
In 1896, Oerlikon installed the first commercial example of the system on the Lugano Tramway. Each 30-tonne locomotive had two 110kW (150hp) motors run by three-phase 750V 40Hz 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 40km 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 15kV, 50Hz 345kW (460hp), 48tonne locomotives used transformers and rotary converters to power DC traction motors.[33]
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 106km Valtellina line was opened on 4 September 1902, designed by Kandó and a team from the Ganz works.[34][32] The electrical system was three-phase at 3kV 15Hz. The voltage was significantly higher than used earlier and it required new designs for electric motors and switching devices.[35][36] 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.[35]
Battery–electric
A London Underground battery–electric locomotive at West Ham station used for hauling engineers' trainsA narrow-gauge battery–electric locomotive used for mining
A battery–electric locomotive (or battery locomotive) is an electric locomotive powered by onboard batteries; a kind of battery electric vehicle.
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 could develop in the supply or return circuits, especially at rail joints, and allow dangerous current leakage into the ground.[37] Battery locomotives in over-the-road service can recharge while absorbing dynamic-braking energy.[38]
The first known electric locomotive was built in 1837 by chemist Robert Davidson of Aberdeen, 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-drivereluctance 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 one and a half miles (2.4 kilometres). 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.[39][40][41]
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 4+1⁄2 tons.[42] 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.[43] 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 in Rio Vista, California. The Toronto Transit Commission previously operated a battery electric locomotive built by Nippon Sharyo in 1968 and retired in 2009.[44]
In the early 1950s, Lyle Borst of the University of Utah 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.[45] Consequently, trains with onboard nuclear generators were generally deemed unfeasible due to prohibitive costs.
In 2002, the first 3.6 tonne, 17kW hydrogen (fuel cell) -powered mining locomotive was demonstrated in Val-d'Or, Quebec. In 2007 the educational mini-hydrail in Kaohsiung, Taiwan went into service. The Railpower GG20B finally is another example of a fuel cell–electric locomotive.
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. These are used to provide continuous journeys along routes that are only partly electrified. Examples include the EMD FL9 and Bombardier ALP-45DP
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 axles 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, 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 network never use locomotives. Instead of locomotive-like power-cars, they use electric multiple units (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;[46] but EMUs have less axle weight, which reduces maintenance costs, and EMUs also have higher acceleration and higher seating capacity.[46] 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 to haul that train. Alternatively, where facilities exist for push-pull operation, the train engine might be attached to the rear of the train;
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.
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.[citation needed]
↑ Heilmann evaluated both AC and DC electric transmission for his locomotives, but eventually settled on a design based on Thomas Edison's DC system.[24]
Related Research Articles
Rail transport is a means of transport using wheeled vehicles running in tracks, which usually consist of two parallel steel rails. Rail transport is one of the two primary means of land transport, next to road transport. It is used for about 8% of passenger and freight transport globally, thanks to its energy efficiency and potentially high speed.
A multiple-unit train is a self-propelled train composed of one or more carriages joined, which if coupled to another multiple unit can be controlled by a single driver, with multiple-unit train control.
The history of rail transport began before the beginning of the common era. It can be divided into several discrete periods defined by the principal means of track material and motive power used.
A railcar 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, with a driver's cab at one or both ends. Some railway companies, such as the Great Western, termed such vehicles "railmotors".
A switcher locomotive, shunter locomotive, or shifter locomotive is a locomotive used for maneuvering railway vehicles over short distances. Switchers do not usually move trains over long distances. Instead, they typically assemble trains in order for another locomotive to take over. Switchers often operate in a railyard or make short transfer runs. They may serve as the primary motive power on short branch lines or switching and terminal railroads.
A diesel locomotive is a type of railway locomotive in which the power source 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. The most common are diesel–electric locomotives and diesel–hydraulic.
An electric locomotive is a locomotive powered by electricity from overhead lines, a third rail or on-board energy storage such as a battery or a supercapacitor. Locomotives with on-board fuelled prime movers, such as diesel engines or gas turbines, are classed as diesel–electric or gas turbine–electric and not as electric locomotives, because the electric generator/motor combination serves only as a power transmission system.
Railway electrification is the use of electric power for the propulsion of rail transport. Electric railways use either electric locomotives, electric multiple units or both. 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. The railway usually provides its own distribution lines, switches, and transformers.
Kálmán Kandó de Egerfarmos et Sztregova was a Hungarian engineer, the inventor of phase converter and a pioneer in the development of AC electric railway traction.
A traction motor is an electric motor used for propulsion of a vehicle, such as locomotives, electric or hydrogen vehicles, or electric multiple unit trains.
The Ganz Machinery Works Holding is a Hungarian holding company. Its products are related to rail transport, power generation, and water supply, among other industries.
Hungarian State Railways is the Hungarian national railway company and the MÁV Zrt. is the railway infrastructure manager, with subsidiaries "MÁV-START Zrt.", and "Utasellátó".
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 at the front or 'head' of a train, provides the electricity used for heating, lighting, electrical and other 'hotel' needs. The maritime equivalent is hotel electric power. A successful attempt by the London, Brighton and South Coast Railway in October 1881 to light the passenger cars on the London to Brighton route heralded the beginning of using electricity to light trains in the world.
An electro-diesel locomotive is a type of locomotive that can be powered either from an electricity supply or by using the onboard diesel engine. For the most part, these locomotives are built to serve regional, niche markets with a very specific purpose.
Indian Railways operates India's railway system and comes under the purview of the Ministry of Railways of Government of India. As of 2023, it maintains over 108,706 km (67,547 mi) of tracks and operates over 13,000 trains daily with a fleet of 14,800 locomotives. The railways primarily operates a fleet of electric and diesel locomotives along with a few compressed natural gas (CNG) locomotives. Steam locomotives are operated on mountain railways and on heritage trains.
A hybrid train is a locomotive, railcar or train that uses an onboard rechargeable energy storage system (RESS), placed between the power source and the traction transmission system connected to the wheels. Since most diesel locomotives are diesel-electric, they have all the components of a series hybrid transmission except the storage battery, making this a relatively simple prospect.
This page explains the numbering and classification schemes for locomotives employed by the Japanese Government Railways, the Japanese National Railways and the Japan Railways Group.
The DRG locomotive classification system was developed by the German Imperial Railway Company or Deutsche Reichsbahn-Gesellschaft (DRG), which was formed in 1924 following the merger of the German state railways (Länderbahnen) in 1920. A common classification and numbering scheme was needed in order to organise effectively the four hundred or so different steam locomotive classes taken over from the state railways, as well as new locomotives. This process lasted until 1926. Only then was the final renumbering plan fixed.
An electro-diesel multiple unit (EDMU) or bi-mode multiple unit (BMU) is a form of a multiple unit train that can be powered either by electric power picked up from the overhead lines or third rail or by using an onboard diesel engine, driving an electric generator, which produces alternating current (AC) or direct current (DC) electric power.
An internal combustion locomotive is a type of railway locomotive that produces its pulling power using an internal combustion engine. These locomotives are fuelled by burning fossil fuels, most commonly oil or gasoline, to produce rotational power which is transmitted to the locomotive's driving wheels by various direct or indirect transmission mechanisms. The fuel is carried on the locomotive.
↑ "Most Important and highly Valuable Sea-Sale Colliery, Near Newcastle-on-Tyne, to be sold by auction, by Mr. Burrell". Leeds Mercury. 12 February 1814. p.2.
↑ Francis Trevithick (1872). Life of Richard Trevithick: With an Account of His Inventions, Volume 1. E.&F.N.Spon.
↑ "Steam train anniversary begins". BBC News. 21 February 2004. Archived from the original on 3 June 2020. Retrieved 13 June 2009. A south Wales town has begun months of celebrations to mark the 200th anniversary of the invention of the steam locomotive. Merthyr Tydfil was the location where, on 21 February 1804, Richard Trevithick took the world into the railway age when he set one of his high-pressure steam engines on a local iron master's tram rails
↑ Lemp, Hermann. US Patent No. 1,154,785, filed 8 April 1914, and issued 28 September 1915. Accessed via Google Patent Search at: US Patent #1,154,785Archived 22 December 2012 at the Wayback Machine on 8 February 2007.
Churella, Albert J. (1998). From Steam To Diesel: Managerial Customs and Organizational Capabilities in the Twentieth-Century American Locomotive Industry. Princeton: Princeton University Press. ISBN978-0-691-02776-0.
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Trevithick's 1802 locomotive
The Locomotion No. 1 at Darlington Railway Centre and Museum
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