Posting in Government
More than 140 years ago, promises of passengers quietly whisked between stations on pressurized air.
There's plenty going on in terms of establishing more high-speed rail networks within the United States, and we see plenty of monorails at airports. Experimentation also continues with new technologies such as maglev trains that float to their destinations on magnetically charged runways. Of course, places such as Japan have had high-speed rail since the bullet trains began running in the 1960s.
But a novel approach was first attempted under the streets of New York, and may have even caught on if not for politics and an economic crisis that dried up funding. As far back as 1870, Alfred Ely Beach demonstrated and opened a subway line under Broadway that employed a large pneumatic tube to propel riders. Trains would be swished from stop to stop by air pressure, just as documents in plastic capsules are whisked around buildings or to bank tellers at drive-ins.
Wired ran this account of Beach's project on the 140th anniversary of the line's first launch, and there is a wealth of information maintained by Joseph Brennan at the Columbia University Website -- and lots of great illustrations.
As accounts have it, Beach constructed a tubular subway and station, with a train powered by a massive air blower at one end. The line ran for a couple of years, but Beach apparently had powerful interests arrayed against him -- and support from the state was vetoed. The Long Depression of the 1870s furthered curtailed his plans, and the tunnel was eventually closed.
The pneumatic-tube line built by Beach may have been centuries ahead of its time. Gravity-vacuum transit remains a mode that still entices thinkers looking for more efficient ways to move people from point to point. We have the big-budget government projects (such as $8 billion for high-speed rail), but perhaps the world needs more entrepreneurial thinkers and doers such as Alfred Beach to bring new concepts to reality.
(Trivia: the Beach Pneumatic Transit line was the inspiration for the band Klaatu's 1977 hit, "Sub-Rosa Subway." I first thought the concluding lyrics were "..it runs in tubes," which makes total sense, and hence, the inspiration for title to this article. It was only years later I found out the final lyrics were actually "to Brahmsian tunes." )
Mar 15, 2010
Sounds great! What limitations exist for passengers in regard to age and health issues? What security measures may need to be taken in the current political climate? Hope it's not the TSA (Totally Silly Agency)! Pity that I may not be around long enough to take a trip! I do love travel, but do not enjoy flying!
Two problems with this (except the practical matters you've highlighted): 1. The approximation that a pendulum's period is independent of its peak deflection only applies for small deflections, i.e. short journeys in terms of your train. 2. If moving under gravity alone, it would take a very long time for short journeys and longer for long ones (see point one), so you'd be wise to power (and brake) your train like a regular one. However, I'm pretty sure it would be quicker, for a given energy input, than a train travelling on the surface, so it's not totally without merit.
You'd have to ensure there were no air leaks etc. Although I've often wondered about the cost the air in tunnels adds to running a subway. I've wondered what the costs would be to build and run a mag-lev in vacuum tunnels.
An interesting fact which i first encountered in Martin Gardner's note in the original "Annotated Alice" is that a train running on an absolutely straight track between two points (that is, one which cuts a chord of the Earth's surface), under the influence of gravity alone, will roll from one end to the other. And a trip for any distance will take precisely the same time as a trip over any other distance, because, essentially, the train is the bob on a pendulum with a length equal to the Earth's radius. Wouldn't be all that great for trips across town, but NYC to LA, it would be faster than Concorde. And free, powered only by gravity. (Well, once you spent the trillions to dig the tunnel, which would get pretty far down around Kansas City...)