A steam locomotive is a type of railway locomotive that produces its pulling power through a steam engine. These locomotives are fueled by burning combustible material – usually coal, wood, or oil – to produce steam in a boiler. The steam moves reciprocating pistons which are mechanically connected to the locomotive's main wheels (drivers). Both fuel and water supplies are carried with the locomotive, either on the locomotive itself or in wagons (tenders) pulled behind. The first steam locomotive, made by Richard Trevithick, first operated on 21 February 1804, three years after the road locomotive he made in 1801. The first practical steam locomotive was created in 1812–13 by John Blenkinsop. Built by George Stephenson and his son Robert's company Robert Stephenson and Company, the Locomotion No. 1 is the first steam locomotive to carry passengers on a public rail line, the in 1825.
Steam locomotives were first developed in Great Britain during the early 19th century and used for railway transport until the middle of the 20th century. From the early 1900s they were gradually superseded by electric and diesel locomotives, with full conversion to electric and diesel power beginning in the late 1930s. The majority of steam locomotives were retired from regular service by the 1980s, though several continue to run on tourist and heritage lines.
The earliest railways employed horses to draw carts along railway tracks. In 1784, William Murdoch, a Scottish inventor, built a small-scale prototype of a steam road locomotive. A full-scale rail steam locomotive was proposed by William Reynolds around 1787. An early working model of a steam rail locomotive was designed and constructed by steamboat pioneer John Fitch in the US during 1794. His steam locomotive used interior bladed wheels guided by rails or tracks. The model still exists at the Ohio Historical Society Museum in Columbus. The authenticity and date of this locomotive is disputed by some experts and a workable steam train would have to await the invention of the high-pressure steam engine by Richard Trevithick, who pioneered the use of steam locomotives.