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 pulled behind. 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. 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 commercially successful 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 Stockton and Darlington Railway in 1825. George also built the first public inter-city railway line in the world to use locomotives, the Liverpool and Manchester Railway, which opened in 1830. Stephenson established his company as the pre-eminent builder of steam locomotives for railways in the United Kingdom, the United States, and much of Europe. In the 20th century, Chief Mechanical Engineer of the London and North Eastern Railway (LNER) Nigel Gresley designed some of the most famous locomotives, including the Flying Scotsman, the first steam locomotive officially recorded over 100 mph in passenger service, and a LNER Class A4, 4468 Mallard, which still holds the record for being the fastest steam locomotive in the world (126 mph). From the early 1900s steam locomotives were gradually superseded by electric and diesel locomotives, with railways fully converting to electric and diesel power beginning in the late 1930s.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.