An old engraving showing Clegg’s atmospheric railway in the 1830s. It is from a book of the 1880s. An atmospheric (or pneumatic) railway uses differential air pressure to propel a train. The Samuda brothers and Samuel Clegg developed a system. In 1840 they leased track in west London. The lead carriage had a piston inserted in a tube between the rails. The pipe’s leather flap opened in front of the piston and sealed again behind it (bottom illustrations). A pumping station at the railhead created a vacuum in the tube ahead of the train. Air pressure behind the piston pushed a train forward.
An old engraving showing the workings of Clegg’s atmospheric railway in the 1830s. It is from a Victorian mechanical engineering book of the 1880s. An atmospheric railway (sometimes called a pneumatic railway) uses differential air pressure to provide power to propel a railway vehicle. A static power source can provide power, avoiding the need for an engine on the vehicle. Jacob and Joseph Samuda were shipbuilders and engineers, and owned the Southwark Ironworks, London, England, UK. Samuel Clegg was a gas engineer and they worked in collaboration on their atmospheric system. In about 1835 they developed a small-bore vacuum pipe system. Clegg worked on a longitudinal flap valve, for sealing the slot in the pipe. In 1840, Jacob Samuda and Clegg leased half a mile of railway track in west London (Wormwood Scrubs). Their system involved a continuous cast iron pipe with a slot on the top laid between the rails. The leading vehicle (the piston carriage) carried a piston on a bracket that inserted in the tube. The slot was sealed from the atmosphere by a continuous leather flap that was opened immediately in advance of the piston and closed again behind it (see bottom cross-section illustrations). A pumping station ahead of the train pumped air from the tube creating a vacuum. Air pressure behind the piston pushed a train forward. The Wormwood Scrubs demonstration ran for two years. The gradient on the line was 1 in 115. With just one pumping station system worked in one direction only – gravity was used for a train’s return. A number of similar schemes were implemented in the 1800s – including one by Isambard Kingdom Brunel. All had problems and were discontinued within a few years.
Size: 4252px × 3505px
Location: Wormwood Scrubs, London, England, UK
Photo credit: © M&N / Alamy / Afripics
License: Licensed
Model Released: No
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