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STEAM ENGINES
Steam power introduced by
James Watt, a Scottish inventor and mechanical engineer, was responsible for improvements to the steam engine of Thomas Newcomen, hitherto used to pump water out of mines. Watt developed a reciprocating engine, capable of powering a wheel. Although the Watt engine powered cotton mills and a variety of machinery, it was a large stationary engine. It could not be otherwise: the state of boiler technology necessitated the use of low pressure steam acting upon a vacuum in the cylinder; this required a separatecondenser and an air pump. Nevertheless, as the construction of boilers improved, Watt investigated the use of high pressure steam acting directly upon a piston. This raised the possibility of a smaller engine, that might be used to power a vehicle, and he patented a design for a steam locomotive in 1784. His employee William Murdoch produced a working model of a self-propelled steam carriage in that year.[22]
The first full-scale working railway steam locomotive was built in the United Kingdom in 1804 by Richard Trevithick, an English engineer born in Cornwall. (The story goes that it was constructed to satisfy a bet by Samuel Homfray, the local iron master.) This used high pressure steam to drive the engine by one power stroke. The transmission system employed a large flywheel to even out the action of the piston rod. On 21 February 1804 the world's first railway journey took place when Trevithick's unnamed steam locomotive hauled a train along the tramway of the Penydarren ironworks, near Merthyr Tydfil in South Wales.[23][24] Trevithick later demonstrated a locomotive operating upon a piece of circular rail track in Bloomsbury, London, the "Catch-Me-Who-Can", but never got beyond the experimental stage with railway locomotives, not least because his engines were too heavy for the cast-iron plateway track then in use. Despite his inventive talents, Richard Trevithick died in poverty, with his achievement largely unrecognized.[25]
The Napoleonic Wars resulted in (amongst other things) a dramatic rise in the price of fodder. This was the imperative that made thelocomotive an economic proposition, if it could be perfected.
The first commercially successful steam locomotive was Matthew Murray's rack locomotive Salamanca built for the narrow gaugeMiddleton Railway in 1812. This twin cylinder locomotive was not heavy enough to break the edge-rails track, and solved the problem of adhesion by a cog-wheel using teeth cast on the side of one of the rails. It was the first rack railway.
This was followed in 1813 by the Puffing Billy built by Christopher Blackett and William Hedley for the Wylam Colliery Railway, the first successful locomotive running by adhesiononly. This was accomplished by the distribution of weight between a number of wheels. Puffing Billy is now on display in the Science Museum in London, the oldest locomotive in existence.[26]
In 1814 George Stephenson, inspired by the early locomotives of Trevithick, Murray and Hedley, persuaded the manager of the Killingworth colliery where he worked to allow him to build a steam-powered machine. He built the Blücher, one of the first successful flanged-wheel adhesion locomotives. Stephenson played a pivotal role in the development and widespread adoption of the steam locomotive. His designs considerably improved on the work of the earlier pioneers. In 1825 he built the Locomotion for the Stockton and Darlington Railway in the north east of England, which was the first public steam railway in the world. Such success led to Stephenson establishing his company as the pre-eminent builder of steam locomotives used on railways in the United Kingdom, United States and much of Europe.[27
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