Planetran is a fantastic idea thought up by Robert Salter in 1978 while working at Rand. I heard about it from a friend who is pretty smart himself and has ideas to bring Planetran that much closer to reality.

Basically, Planetran is a super-fast train that would travel in a vacuum and theoretically reach infinite speeds - up to or better than 10,000 mph in practice. The plan was to built a sprawling network of underground and under-ocean tubes that would make up the Planetran system. The stations could even be shared with existing metro (subway) stations. The trains would travel in a near vacuum and use maglev technology to further reduce drag and also to provide the thrust. Due to its super-low drag, it would be amazingly efficient and therefore be cheap to operate and produce a minimum of pollutants. A 3000 mile journey that would take only a few minutes might cost about the same as a cab ride of several city blocks.

Can you imagine going from LA to Boston underground in 21 minutes? What about popping over to France for lunch?

By the way, the Planetran is still just an idea. I can't wait for the day it is built so that I can change its classification to "thing".