A steam locomotive is a railway locomotive that produces its power through a steam engine

Steam engine

A steam engine is a heat engine that performs mechanical work using steam as its working fluid.Steam engines are external combustion engines, where the working fluid is separate from the combustion products. Non-combustion heat sources such as solar power, nuclear power or geothermal energy may be...

. These locomotives are fueled by burning some combustible material, usually coal, wood or oil, to produce steam in a boiler, which drives the steam engine. Both fuel and water supplies are carried with the locomotive, either on the locomotive itself or in wagons pulled behind.

Steam locomotives were first developed in Britain

United Kingdom of Great Britain and Ireland

The United Kingdom of Great Britain and Ireland was the formal name of the United Kingdom during the period when what is now the Republic of Ireland formed a part of it....

 and dominated railway transportation until the middle of the 20th century.