‘We do not take Isambard Kingdom Brunel for either a rogue or a fool but an enthusiast, blinded by the light of his own genius, an engineering knight-errant, always on the lookout for magic caves to be penetrated and enchanted rivers to be crossed, never so happy as when engaged … in conquering some, to ordinary mortals, impossibility.’I thought I’d look at one of my hero’s failures. Oh yes, Brunel had them. Contrary to what commentators with perfect hindsight might have you believe, you need to take risks to be a successful entrepreneur and innovator, and sometimes those risks go wrong.
–The Railway Times
By 1844, Brunel was highly respected and admired for his Great Western Railway, his steamships Great Western and Great Britain, and his wonderful bridges and tunnels. He began work on his next project, a new railway in South Devon, England. Because of the rugged terrain - always challenging for railway route design and motive power - he decided to adopt a radical technology developed by Clegg and Samuda. Instead of self-propelled steam-engines to move rail wagons, they used air pressure from a pipe laid along the track. A fixed air pumping station at either end of a short railway track in Ireland created a vacuum in the pipe ahead of the train. One wagon was attached to a piston inside the pipe, and the air pressure difference moved the piston and the train forward. The system was very powerful, meaning steeper gradients could be climbed, and the trains were very quiet and clean.
Unfortunately, Victorian materials were not up to the task. The connection between the piston and the train passed through a slot which ran the length of the pipe. To maintain vacuum, the slot was covered by a greased leather flap which the connector pushed put of the way as it moved forward. Unlike in Ireland, the flap quickly deteriorated in Devon’s warm coastal air, needing frequent repair and disrupting train schedules. Also unlike the short Irish track, the much longer South Devon railway needed multiple pumping stations. Because of vacuum loss through the flap and not knowing when the next train would enter its section of track (a telegraph was not initially installed), each pumping station ran far longer than planned, consuming more fuel and requiring more maintenance. Instead of being competitive with conventional rail operations, Brunel’s Atmospheric Railway cost 3 times as much to run, and switched to conventional self-propelled steam-engine traction. Of course, the newspapers of the time lambasted Brunel for this failure. Brunel shrugged, and moved on to his next venture.
Air-powered public transport is an idea whose time may yet still come. MDI in France is developing a range of vehicles driven by compressed air, including a road train. Ahead of your time as usual, Isambard.