History of rail transport
James Watt, a Scottish inventor and mechanical engineer, greatly improved the steam engine of Thomas Newcomen, hitherto used to pump water out of mines. Watt developed a reciprocating engine in 1769, 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 separate condenser 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.
The first full-scale working railway steam locomotive was built in the United Kingdom in 1804 by Richard Trevithick, a British engineer born in Cornwall. 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 steam-powered 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. 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.
The first commercially successful steam locomotive was Matthew Murray's rack locomotive "Salamanca" built for the Middleton Railway in Leeds 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. Thus it was also the first rack railway.
History of rail transport in Great Britain to 1830
The first steam railway locomotive was introduced by Richard Trevithick in 1804. He was the first engineer to build a successful high-pressure stationary steam engine, in 1799. He followed this with a road going steam carriage in 1801. Although that experiment ended in failure, in 1802 the Coalbrookdale Company built a locomotive for him, but little is known about it, including whether or not it actually ran. In 1804, he built a successful unnamed rail going steam locomotive for the narrow gauge Merthyr Tramroad in South Wales (sometimes - but incorrectly - called the "Penydarren Tramroad"). The Penydarren locomotive used a high-pressure cylinder without a condenser, the exhaust steam being used to assist the draught via the firebox, increasing efficiency even more. These fundamental improvements in steam engine designs by Trevithick did not change for the whole of the steam era. Amid great interest from the public, on 21 February 1804 it successfully carried 10 tons of iron, 5 wagons and 70 men a distance of from Penydarren to Abercynon in 4 hours and 5 minutes, an average speed of nearly . This locomotive proved that steam traction was a viable proposition, although the use of the locomotive was quickly abandoned as it was too heavy for the primitive plateway track. A second locomotive, built for the Wylam colliery, also broke the track.