Editing Locomotive (section)

===Steam===
{{Main|Steam locomotive}}
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 (power generation)|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 [[piston]]s which are connected to the locomotive's main wheels, known as the "[[driving wheel]]s". Both fuel and water supplies are carried with the locomotive, either on the locomotive itself, in [[Fuel bunker|bunkers]] and [[Water tank|tanks]], (this arrangement is known as a "[[tank locomotive]]") or pulled behind the locomotive, in [[Tender (rail)|tenders]], (this arrangement is known as a "[[Tender (rail)|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.<ref>{{cite book |title=Life of Richard Trevithick: With an Account of His Inventions, Volume 1 |author=Francis Trevithick |publisher=E.&F.N.Spon |date=1872}}</ref> 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.<ref>{{cite web |url=http://www.museumwales.ac.uk/en/rhagor/article/trevithic_loco/ |title=Richard Trevithick's steam locomotive &#124; Rhagor |publisher=Museumwales.ac.uk |access-date=3 November 2009 |url-status=dead |archive-url=https://web.archive.org/web/20110415125004/http://www.museumwales.ac.uk/en/rhagor/article/trevithic_loco |archive-date=15 April 2011}}</ref><ref>{{cite news | title = Steam train anniversary begins | url = http://news.bbc.co.uk/1/hi/wales/3509961.stm | publisher = [[BBC News]] | access-date = 13 June 2009 | quote = 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 | date = 21 February 2004 | archive-date = 3 June 2020 | archive-url = https://web.archive.org/web/20200603021117/http://news.bbc.co.uk/2/hi/uk_news/wales/3509961.stm | url-status = live }}</ref> Accompanied by [[Andrew Vivian]], it ran with mixed success.<ref name="ODNBTrevithick">{{cite book |last = Payton | first=Philip|year=2004 |title=Oxford Dictionary of National Biography | publisher=[[Oxford University Press]]}}</ref> The design incorporated a number of important innovations including the use of high-pressure steam which reduced the weight of the engine and increased its efficiency.

In 1812, [[Matthew Murray]]'s twin-cylinder [[Rack railway#Rolling stock|rack locomotive]] ''[[Salamanca (locomotive)|Salamanca]]'' first ran on the [[Wagonway|edge-railed]] [[Rack and pinion|rack-and-pinion]] [[Middleton Railway]];<ref name="Young,1923">{{cite book |last=Young |first=Robert |title=Timothy Hackworth and the Locomotive |publisher= The Book Guild |location= Lewes, UK |year= 2000 |edition= reprint | orig-year = 1923}}</ref> this is generally regarded as the first commercially successful locomotive.<ref>{{cite book |title=Developments and Changes in Science Based Technologies |author1=P. Mathur |author2=K. Mathur |author3=S. Mathur |publisher=Partridge Publishing |date=2014 |page=139}}</ref><ref>{{cite book |title=Encyclopedia of Railroads |first=Oswald |last=Nock |author-link=Oswald Nock |publisher=Galahad Books |date=1977}}</ref> Another well-known early locomotive was ''[[Puffing Billy (locomotive)|Puffing Billy]]'', built 1813–14 by engineer [[William Hedley]] for the Wylam Colliery near [[Newcastle upon Tyne]]. This locomotive is the oldest preserved, and is on static display in the Science Museum, London. [[George Stephenson]] built ''[[Locomotion No. 1]]'' for the [[Stockton & Darlington Railway]] in the north-east of England, which was the first public steam railway in the world. In 1829, his son Robert built ''[[Stephenson's Rocket|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.<ref name="Ellis,1968" >{{cite book |title=The Pictorial Encyclopedia of Railways |author=Hamilton Ellis |publisher=[[Hamlyn (publisher)|Hamlyn Publishing Group]]|year=1968 |pages=24–30}}</ref> The [[Liverpool & Manchester Railway]], built by Stephenson, opened a year later making exclusive use of steam power for passenger and [[Rail freight transport|goods trains]].

The steam locomotive remained by far the most common type of locomotive until after [[World War II]].<ref>Ellis, p. 355</ref> Steam locomotives are less efficient than modern diesel and electric locomotives, and a significantly larger workforce is required to operate and service them.<ref>{{cite web |url=http://mikes.railhistory.railfan.net/r085.html |title=Diesel Locomotives. The Construction of and Performance Obtained from the Oil Engine |year=1935 |access-date=4 October 2007 |archive-date=3 October 2020 |archive-url=https://web.archive.org/web/20201003122924/http://mikes.railhistory.railfan.net/r085.html |url-status=live }}</ref> [[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 |date=September 2018}} Between about 1950 and 1970, the majority of steam locomotives were retired from commercial service and replaced with electric and diesel–electric locomotives.<ref>{{cite journal |last=Meiklejohn |first=Bernard |date=January 1906 |title=New Motors on Railroads: Electric and Gasoline Cars Replacing the Steam Locomotive |journal=The World's Work: A History of Our Time |volume=XIII |pages=8437–54 |url= https://books.google.com/books?id=3IfNAAAAMAAJ&pg=PA8446|access-date=10 July 2009 }}</ref><ref name="Diesel,1935" >{{Cite web|url=http://mikes.railhistory.railfan.net/r085.html|title=Diesel locomotives |website=mikes.railhistory.railfan.net|access-date=4 October 2007|archive-date=3 October 2020|archive-url=https://web.archive.org/web/20201003122924/http://mikes.railhistory.railfan.net/r085.html|url-status=live}}</ref> 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]]s.
{{gallery
|File:Locomotive trevithick.svg|Trevithick's 1802 locomotive
|File:Locomotion No. 1..jpg|The ''[[Locomotion No. 1]]'' at Darlington Railway Centre and Museum}}
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