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You could call it a pipe dream.

That's how the BBC refers to it on its website, where a feature story reports that one day soon, trains traveling through vacuum tunnels could whisk passengers from New York to London in an hour, hitting speeds of up 2,500 mph.

Reverse the journey, and you could leave the UK at noon and arrive in Manhattan at 8 a.m. the same day.

The key is in the vacuum. Suck the air out of a transatlantic tunnel, and you eliminate resistance to the vehicle. In the oceanic version, engineers would tether the tunnel at a fixed depth.

The "vactrain" is not a new concept. Robert Goddard, who created the first liquid fuel rocket, designed a prototype over 100 years ago, with the idea of zipping people around between U.S. cities. But they haven't been economically feasible, or even fast enough.

Now, the latest concept in vactrains could make the difference. It combines the technology with magnetic levitation, in theory supporting speeds of up to 2500 mph according to the BBC. That's an order of magnitude faster than today's high speed rail, which tends to travel at just under 200 mph.

American engineer Daryl Oster has designed a 6-person capsule traveling through a 1.5 meter (5 feet) diameter vacuum tube. He has sold 60 licenses for his patented evacuated tube transport (ETT) technology, including 12 to China.

Oster likes to refer to it as "space travel on Earth." The website for his Crystal River, Fl. company ET3 (it describes itself as an "open consortium'), boasts possible speeds of up to 4,000 mph, faster even than the 2,500 mph reported by the BBC.

It claims that it could "provide 50 times more transportation per kWh (kilowatt hour) than electric cars or trains," that construction would cost a tenth of high-speed rail and a quarter of freeways, and that a New York-to-Beijing trip would take 2 hours.

"New York to L.A. in 45 minutes," it states.

In the BBC story, Oster says the train could be ready in less than 10 years. The most ideal implementations would be between cities separated by dry, flat unpopulated terrain that doesn't freeze, he notes, adding that China and India hold the most promise.

Another vactrain developer, Dr. James Powell - the co-inventor of Maglev transportation technology and also a nuclear inventor - has proposed a system called Startram that would launch objects into orbit from a cannon-like tunnel.

The idea has plenty of supporters, including MIT's Ernst G. Frankel, emeritus professor of mechanical engineering and ocean engineering, who experimented with "evacuated tubes" in the 1990s. Frankel proposed a Boston-to-New York vactrain that would take 40 minutes, compared to the normal 4 hours. But it would not have outperformed existing bullet train technologies from Japan and China.

MIT's Frankel says the time is now right.

"Our rail technology is almost 100 years old," he tells the BBC. "Our airways are becoming terribly congested, and getting to, from and through airports is very time consuming."

Vactrains certainly have been a fixture of science fiction.

"Vacuum trains do feature in movies like Star Trek and Logan's Run," notes the BBC. "Whilst in the dystopian future of Farenheit 451, Ray Bradbury describes a 'silent air-propelled train' that 'slid soundlessly down its lubricated flue in the earth'."

Is this the last step before teleporting? While "beam me up Scotty" isn't around the corner, perhaps "Hoover me up" is. Vactrains may one day give a whole new, positive, meaning to H. Ross Perot's old derogatory "giant sucking sound" phrase.

Images: ET3 website

In the 1870s a similar system, based on pneumatics, ran under New York City for a few years:

More SmartPlanet high speed rail coverage here





This post was originally published on Smartplanet.com