Even Brunel got it wrong some times!!!!
Brunel’s Atmospheric Railway
This month’s speaker needed no introduction since it was History Society member, Mr Glyn Williams. Glyn has spoken several times on his favourite subject Isambard Kingdom Brunel. The difference this time was that the talk concerned one of Brunel’s less successful ventures.
The Great Western Railway, of which I.K. Brunel was its chief engineer was built between Bristol and Paddington in the period from 1835-41. During the period several smaller lines were built which came under the attention of Brunel including the Bristol and Exeter Railway completed in 1844, the South Devon railway and the Exeter to Plymouth Railway completed in 1844. It was the last railway which was the object of Brunel’s experimentation with a vacuum pipe as against a locomotive to propel the train.
The vacuum pipe which was located between the rails had piston within a cast iron tube and a leather valve connected to the first carriage. The vacuum itself was obtained by a series of uniquely designed Italianate pumping stations of which there were a dozen along the 21 mile length of track between Exeter and Newton (Abbott) at a distance of around three miles apart ( four were never used). The towers for the steam engines were around 30’ high though they only produced some 30 horse power to drive the train.
|Italianate style pumping stations|
Brunel did not invent the system which was designed as a system of propelling items in shops by George Medhurst in 1799. In 1812 a prototype was developed to carry passengers through a tube, this was not patented and was later discarded. In 1830, Samuel Clegg employed a company from the Isle of Dogs and a new patent under Samuda and Clegg was licenced. In all, the vacuum scheme was tried in four locations including one in France and another in Ireland with varying degrees of success. Brunel deemed the system to be profitable much to the disdain of another famous GWR engineer, Gooch, who thought rightly that it was a doubtful proposition
Its failure, was in part mechanical in that the 13” pipes were replaced by a15” ones making the production of a vacuum more difficult.The inclement winter of 1847 caused the leather valves to become brittle and dessicated causing more costs as locomotives had to be hired for the line which was totally dependent on the atmospheric railway. In the end it proved too expensive and ran for only eighteen months.
Mr Gwyn Thomas thanked Mr Glyn Williams for a fascinating talk.