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Document summary:
- Title: 13 Vehicles That Went Nowhere (extract)
- Author: John Rennie, Scientific American
- Source: http://www.sciam.com/
- Copyright: Scientific American
- Date: 1997?
13 Vehicles That Went Nowhere
Perhaps "nowhere" is too harsh. But all these transportation concepts - however brilliant or eccentric - fell far short of their enthusiasts' great hopes. Some ran afoul of technical glitches or practical constraints. Some couldn't compete with other transports. Some had bad luck. Some evolved into different types of vehicles. And some... well, maybe they weren't very good to start with. In any case, they illustrate one of the most important lessons of transportation technology: it takes more than a bright idea to get somewhere.
(...)
Pneumatic Trains
Background: In 1870 Alfred Ely Beach, then editor of Scientific American, financed the construction of a prototype subway in New York City. Based on experimental European pneumatic trains, it consisted of a block-long stretch of tunnel through which a cylindrical car was pushed and pulled by a huge fan. Though popular, this system failed to win over the municipal authorities, who later built elevated trains instead.
But the idea of using air pressure to propel a train never lost its appeal. In the mid-1960s Lockheed and the Massachusetts Institute of Technology, in conjunction with the U.S. Department of Commerce, contemplated the feasibility of pneumatic trains connecting cities along the Boston-to-Washington corridor. Train cars would snugly fit into evacuated tubes hundreds of miles long. Opening and closing valves would allow ambient air pressure to push the tube cars to their destination. For an added boost, the tubes would slope downward out of each station, creating a "gravitational pendulum" assist for the trains. Calculations suggested that on the run between Philadelphia and New York, for example, the average speed might be 390 miles per hour.
Problems: Boring tunnels to the required mechanical tolerances and then emptying them of air would have been expensive (to say the least). Any accident that compromised the vacuum or integrity of a tube at any point in its length would force a shutdown of the entire intercity line. Improving the highway, rail and air transit systems seemed like a better bet.