[red-beard]

So, we're building the trans-Canadian pipeline and using it for transportation. In the "non-technical" section, there are serious errors. You cannot "ignore" thermal expansion. Running along the same route as a highway, say over the Grapevine, at 350 mph would still subject people to many g's as they follow the terrain and curves, or it would require very large radius curves. Think of the structure required to keep curves and assents to less than 1%.

Also, since he is suggesting that it be a closed, welded, pneumatic system, there will be no views and no visual reference.

Costs. We're talking about a pipe which needs to hold a vacuum of around 14 psi. For a reasonable size cabin, let's call it 15 feet in diameter. Using A36 steel, you'd need about .28 wall pipe for working pressure (10 safety factor). At .28 lbs per cu in, and 604.8 cu in/ft, this leads to ~532 lbs/ft of tube. 300 miles of tube (LA to SF) would require ~850,000,000 lbs of steel just for the tube. Since this will have to be rolled from steel plates, it will be a around $2 per lb in a special mill. But transporting 15' diameter tubes would be costly and impractical, a mobile rolling system would be required to roll them at the point of installation.