Rumor: High-speed tube travel concept in the works

[backscatter712]

44. I think it can be done, just that it'll be expensive.

Airliners do a similar trick all the time - they go through repeated cycles of going from about 1 atm of pressure on the ground at an airport to about 0.2 atm at 35,000 feet or so. And they have to keep the cabin full of air sufficiently pressurized as to be breathable. And they have to do it over and over and over, causing stress and flexing of the airframe.

It's doable, and even doable at a light-enough weight to fly. I don't think that the train vehicle itself will be very hard to put together. It's the tube-tracks & the infrastructure required to keep them pumped free of air. You cannot have leaks of consequence. Leaks are Bad. You have to do this for thousands of miles. And the tracks have to be almost perfectly laser-straight, with only gradual curves with a turn radius of 100+ miles, with no bumps. That will be hard.