A steam locomotive is a locomotive powered by steam. The term usually refers to its use on railways, but can also refer to a "road locomotive" such as a traction engine or steamroller.
Steam locomotives dominated railroad usage from the start of the 19th century, until the end of the 20th Century. From the world's first ever railway journey in Wales Great Britain in 1804, Steam locomotives were gradually improved and developed in their over 150 years of development and use. Starting in about 1930 other types of engines were developed and steam locomotives were gradually superseded by diesel and electric locomotives.
The earliest railways employed horses to draw carts along railed tracks.
As the development of steam engines progressed through the 1700s, various attempts were made to apply them to road and railway use. William Murdoch a Scottish inventor built a prototype steam road locomotive in 1784. The first-known working model of a steam rail locomotive was designed and constructed by John Fitch in the United States in 1794, although it did not lead to further developments.
The first full scale working railway steam locomotive was built by British inventor Richard Trevithick, on 21 February 1804 the world's first railway journey took place as Trevithick's unnamed steam locomotive hauled a train along the tramway of the Penydarren ironworks, near Merthyr Tydfil in Wales. Accompanied with Andrew Vivian, it ran with mixed success. Then followed the successful twin cylinder locomotive by Christopher Blackett's team built at Wylam in 1811, closely followed by Matthew Murrays' rack locomotive for the edge railed Middleton Railway in 1812. These early efforts culminated in 1829 with the Rainhill Trials and the opening of the Liverpool and Manchester Railway a year later making exclusive use of steam power for both passenger and freight trains.
The United States started developing steam locomotives in 1829 with the Baltimore and Ohio Railroad's Tom Thumb. This was the first locomotive to run in America, although it was intended as a demonstration of the potential of steam traction, rather than as a revenue-earning locomotive. The first successful steam railway in the US was the South Carolina Railroad whose inaugural train ran on December 25, 1830 hauled by the Best Friend of Charleston. Many of the earliest locomotives for American railroads were imported from England, including the Stourbridge Lion and the John Bull, but a domestic locomotive manufacturing industry was quickly established, with locomotives like the DeWitt Clinton being built in the 1830s.