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. Steam locomotives are less efficient than modern diesel and electric locomotives, and a significantly larger workforce is required to operate and service them. The steam locomotive remained by far the most common type of locomotive until after World War II. The Liverpool & Manchester Railway, built by Stephenson, opened a year later making exclusive use of steam power for passenger and goods trains. 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. Rocket was entered into, and won, the Rainhill Trials. In 1829, his son Robert built The Rocket in Newcastle upon Tyne.

1 for the Stockton & Darlington Railway in the north-east of England, which was the first public steam railway in the world. This locomotive is the oldest preserved, and is on static display in the Science Museum, London.

Another well-known early locomotive was Puffing Billy, built 1813–14 by engineer William Hedley for the Wylam Colliery near Newcastle upon Tyne. In 1812, Matthew Murray's twin-cylinder rack locomotive Salamanca first ran on the edge-railed rack-and-pinion Middleton Railway this is generally regarded as the first commercially successful locomotive.

1 at Darlington Railway Centre and Museum The word locomotive originates from the Latin loco – 'from a place', ablative of locus 'place', and the Medieval Latin motivus, 'causing motion', and is a shortened form of the term locomotive engine, which was first used in 1814 to distinguish between self-propelled and stationary steam engines.

Tiny rails engine