The Oil Drum

16 comments on Gentle Folk, allow me to introduce . . . .

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spooky on October 26, 2005 - 3:39pm

HO -

Other than it was first proposed that way, and it might help in the event of nuclear war, why do this whole thing underground where the tunneling expenses are so high, the material that needs to be sealed is wildly variable (rock formations and fractures), and water pressure must be fought back while pulling a vacuum? Maintenance and construction are very problematic underground. And who wants to be underground on the quake-prone west coast, moving at 400 MPH?

Why not just run this thing on pylons above ground? That way you are piecing together sections of tubes designed to hold lower pressure? If you're going to do it, at least do it in a practical and common sense fashion.

But the expense is so phenomenal compared to standard rail construction - why do this at all? Why do we need to be able to go from NY to LA in an hour? I would think our productivity is good enough, thanks, and we really don't need this at all.

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Heading Out on October 26, 2005 - 3:54pm

Any time you have to do surface construction in a city it becomes very expensive, in more ways than just money. Running tunnel boring machines (TBM's) these days is a well-known art and they can bore tunnels quite rapidly and safely through a wide variety of rock. Techniques have evolved for coping with water and they are now routine - mainly you inject either cement or a chemical resin into the ground ahead of the TBM (depending on how permeable it is) and these seal the flow channels. Sub-surface the excavation can proceed without having to buy a right of way and demolish houses, or interfering with existing traffic as the tunnel is driven.

The sub-surface location makes a lot of sense in mountainous terrain (since it is the shortest distance and does not involve traffic grades) - and Switzerland is a logical site for that reason. It also makes sense in highly urbanized locations such as the US East Coast and parts of Europe. It would not probably be as good an idea across the midwest, but there are debatable points on both sides of that issue.