An atmospheric railway is a railway in which air pressure or vacuum is used to drive trains. The best known attempt was that by Brunel in the 19th century on a 52-mile section of the South Devon Railway between Exeter and Plymouth, England. It was also tried on the London & Croydon Railway in 1845, but was soon abolished.

The supposed advantage of the atmospheric system was its hillclimbing ability; however Brunel chose to test the system on a relatively flat section. Brunel did however assume that the system would work, because the mainline to Cornwall was designed to contain some very challenging gradients of up to 1 in 38.

The atmospheric system proved to be a complete disaster:

• the seals on the tube failed - amongst other reasons, rats liked to eat the sealing grease.
• shunting the trains into atmospheric formation was a nuisance.
• the pump stations every few kilometres has to be run continously and were expensive.
• as mentioned above the hillclimbing abilities of the system were not put to the test.
• it is not clear how atmospheric railway tubes could be compatible with railway turnouts.
• telegraphy may not have been advanced enough to co-ordinate the pump stations and trains properly.

External links

• railway history site (http://mikes.railhistory.railfan.net/r027.html)
• Brunel's Atmospheric Railway (http://www.whoosh.care4free.net/brunel%27s.htm)