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A
Traction engine may be defined as a steam driven road locomotive for
hauling trailers and for use as a power source. Steam rollers and steam
trucks are now also included in the definition although steam cars are
not.
Thomas
Savery first patented a crude form of steam engine in 1698; his
inspiration came from Denis Papin’s previous invention of a pressure
cooker in 1679. Thomas Savery was a military engineer who was looking for
a way to pump water from coal mines, his invention was a closed vessel,
filled with water into which pressurised steam was introduced; the steam
forced water in the mine upwards and out of the shaft. A cold water
sprinkler was then used to condense the steam, which in turn created a
vacuum that sucked more water out of the mine through a bottom valve.
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Traction Engines can be
divided into six main groups as following:- |
1/The Portable.
This was the first type of engine to be used on and around farms in
Britain. They were not self propelled and needed to be pulled by horses.
They were used to drive threshing equipment and to operate saw mills. They
were still in use well into the twentieth century.
2/The
Agricultural General Purpose Engine. These
engines were the most common types to be seen around the countryside. they
were basically used as a mobile power plant for threshing, tree pulling
and general farm duties. Though not generally owned by the farmers
themselves, contractors operated them touring from farm to farm.
3/Road
Locomotives. These were designed for heavy
haulage on the public highways. They were usually larger than the normal
traction engine and fitted with three speed gearing. They were also sprung
on both front and rear axles. An extra water tank was fitted under the
boiler so that greater distances could be travelled between water stops.
These were very powerful traction engines capable of pulling loads of up
to 120 tons. Showmen’s engines though highly decorated and adorned with
brass, fall into the category of road locomotive. Apart from hauling fair
rides etc. from one venue to another, they were also used for generating
the power for the rides and the lighting.
4/Steam
Tractors. These engines were built as small road
locomotives and were operated by one man, provided that the engine was
less than 5 tons in weight. They were used for general road haulage and in
particular by the timber trade. The most popular steam tractor of its time
was the Garrett 4CD.
5/Road Rollers.
Perhaps the best known of all steam traction engines. They were still
working into the 1960’s and part of the M1 motorway was made with the use
of steamrollers. The early rollers tended to be very heavy; one even
weighing 30 tons was built. But it was soon discovered that weight alone
did not make the best roller. 12 or 15 tons was the most favoured. With
the introduction of tarmac, rollers became even lighter and some of the
smaller ones weighed as little as 3 tons.
6/Ploughing
Engines. The largest of all, and were used, as
the name suggests, for ploughing. A cable spanning the field would be
attached to each engine on a winding drum with a plough joined in the
middle which would be pulled up and down the field. One engine was built
to pull on its right hand side, and the other on its left, so they were
referred to as right or left hand engines, though the positions were
reversed when working. These engines weighed around 22 tons each and
ploughed up to 30 acres a day.
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In addition to these main groups
developed in the 20th Century was the steam wagon or lorry. The first of
these were ‘overtypes’, having the engine mounted on top of the boiler in
the same way as a traction engine. These engines were chain driven, and
were capable of speeds of up to 30 mph. The designs included four and six
wheelers, artics and tippers. By far the most popular builder of
‘overtypes’, were Foden of Cheshire. The ‘undertype’ wagon that followed
was made with a vertical boiler with the engine mounted under the chassis,
not unlike a modern lorry.Later models were fitted with pneumatic tyres
and could reach speeds of up to 60 mph.
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