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Robert Stephenson's Rocket marks one of the key advances in railway technology. It also confirmed Stephenson as one of the premier engineers of his age and as a major engineering contractor for the emerging railway network, both in Britain and abroad.
The locomotive was built to compete in the Rainhill Trials, held by the new Liverpool & Manchester Railway, to choose between competing designs. The performance of Rocket showed it to be the most successful of the contestants. It also convinced the railway company that the alternative possibility of using stationary steam engines to haul carriages by cables was not worth pursuing.
Rocket established the basic architecture for the steam locomotive. The main features were: a multi-tubular boiler, to improve the heat transfer from the firebox gases into the boiler water; the 'blast pipe' which used the steam exhaust to improve the air draught through the firebox; and direct coupling, by connecting rods, from the pistons to the driving wheels.
The result was a dramatic improvement on contemporary locomotives, and at Rainhill a speed of 29 mph was achieved. The basic design principles embodied in Rocket carried through to the last steam locomotives built in Britain during the 1960s.