Editing Rail transport (section)

===Steam power introduced===
{{See also|Steam locomotive}}
[[File:TrevithicksEngine.jpg|thumb|A replica of Trevithick's steam engine at the [[National Waterfront Museum]] in [[Swansea]], Wales]]
In 1784, [[James Watt]], a Scottish inventor and mechanical engineer, patented a design for a [[steam locomotive]]. Watt had improved the [[steam engine]] of [[Thomas Newcomen]], hitherto used to pump water out of mines, and developed a [[reciprocating engine]] in 1769 capable of powering a wheel. This was a large [[stationary engine]], powering cotton mills and a variety of machinery; the state of boiler technology necessitated the use of low-pressure steam acting upon a vacuum in the cylinder, which required a separate [[Condenser (heat transfer)|condenser]] and an [[air pump]]. Nevertheless, as the construction of boilers improved, Watt investigated the use of high-pressure steam acting directly upon a piston, raising the possibility of a smaller engine that might be used to power a vehicle. Following his patent, Watt's employee [[William Murdoch]] produced a working model of a self-propelled steam carriage in that year.<ref>{{cite book
 | last=Gordon
 | first=W. J.
 | year=1910
 | title=Our Home Railways, volume one
 | publisher=Frederick Warne and Co
 | location =London
 | pages =7–9
 }}</ref>

The first full-scale working railway [[steam locomotive]] was built in the United Kingdom in 1804 by [[Richard Trevithick]], a British engineer born in [[Cornwall]]. This used high-pressure steam to drive the engine by one power stroke. The transmission system employed a large [[flywheel]] to even out the action of the piston rod. On 21 February 1804, the world's first steam-powered railway journey took place when Trevithick's unnamed steam locomotive hauled a train along the tramway of the [[Penydarren]] ironworks, near Merthyr Tydfil in [[South Wales]].<ref>{{cite web|url=http://www.museumwales.ac.uk/en/rhagor/article/trevithic_loco/|title=Richard Trevithick's steam locomotive|work=National Museum Wales|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
| 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> Trevithick later demonstrated a locomotive operating upon a piece of circular rail track in [[Bloomsbury]], London, the ''[[Catch Me Who Can]]'', but never got beyond the experimental stage with railway locomotives, not least because his engines were too heavy for the cast-iron plateway track then in use.<ref>{{cite book |title=The Pictorial Encyclopedia of Railways |author=Hamilton Ellis |publisher=The Hamlyn Publishing Group |year=1968 |page=12}}</ref>

The first commercially successful steam locomotive was [[Matthew Murray]]'s [[rack railway|rack]] locomotive ''[[The Salamanca|Salamanca]]'' built for the [[Middleton Railway]] in [[Leeds]] in 1812. This twin-cylinder locomotive was light enough to not break the [[edge rail (edgeways)|edge-rail]]s track and solved the problem of [[Rail adhesion|adhesion]] by a [[cog-wheel]] using teeth cast on the side of one of the rails. Thus it was also the first [[rack railway]].

This was followed in 1813 by the locomotive ''[[Puffing Billy (locomotive)|Puffing Billy]]'' built by [[Blackett of Wylam|Christopher Blackett]] and [[William Hedley]] for the [[Wylam]] Colliery Railway, the first successful locomotive running by [[Rail adhesion|adhesion]] only. This was accomplished by the distribution of weight between a number of wheels. ''Puffing Billy'' is now on display in the [[Science Museum (London)|Science Museum]] in London, and is the oldest locomotive in existence.<ref>{{Cite web|title='Puffing Billy' locomotive {{!}} Science Museum Group Collection|url=https://collection.sciencemuseumgroup.org.uk/objects/co8247941/puffing-billy-locomotive-steam-locomotive|access-date=26 May 2021|website=collection.sciencemuseumgroup.org.uk|language=en|archive-date=19 May 2023|archive-url=https://web.archive.org/web/20230519104831/https://collection.sciencemuseumgroup.org.uk/objects/co8247941/puffing-billy-locomotive-steam-locomotive|url-status=live}}</ref><ref>{{cite book |title=The Pictorial Encyclopedia of Railways |author=Hamilton Ellis |publisher=The Hamlyn Publishing Group |year=1968 |pages=20–22}}</ref>

In 1814, [[George Stephenson]], inspired by the early locomotives of Trevithick, Murray and Hedley, persuaded the manager of the [[Killingworth]] [[Coal mining|colliery]] where he worked to allow him to build a [[Steam engine|steam-powered]] machine. Stephenson played a pivotal role in the development and widespread adoption of the steam locomotive. His designs considerably improved on the work of the earlier pioneers. He built the locomotive ''[[Blücher (locomotive)|Blücher]]'', also a successful [[flange]]d-wheel adhesion locomotive. In 1825 he built the locomotive ''[[Locomotion No 1|Locomotion]]'' for the [[Stockton and Darlington Railway]] in the northeast of England, which became the first public steam railway in the world in 1825, although it used both horse power and steam power on different runs. In 1829, he built the locomotive ''[[Stephenson's Rocket|Rocket]]'', which entered in and won the [[Rainhill Trials]]. This success led to Stephenson establishing his company as the pre-eminent builder of steam locomotives for railways in Great Britain and Ireland, the United States, and much of Europe.<ref name="Ellis">{{cite book |title=The Pictorial Encyclopedia of Railways |last=Ellis |first=Hamilton |publisher=Hamlyn Publishing Group |year=1968}}</ref>{{RP|24–30}} The first public railway which used only steam locomotives, all the time, was [[Liverpool and Manchester Railway]], built in 1830.<ref>{{Cite web |title=First in the world: The making of the Liverpool and Manchester Railway |url=https://www.scienceandindustrymuseum.org.uk/objects-and-stories/making-the-liverpool-and-manchester-railway |access-date=15 April 2022 |website=Science and Industry Museum |language=en |archive-date=2 May 2020 |archive-url=https://web.archive.org/web/20200502233609/https://www.scienceandindustrymuseum.org.uk/objects-and-stories/making-the-liverpool-and-manchester-railway |url-status=live }}</ref>

Steam power continued to be the dominant power system in railways around the world for more than a century.