Re: (erielack) New tunnel

["Jim Guthrie" <jguthrie_@_pipeline.com>]

> Since it's in N Korea, I wonder if it doubles as a fallout shelter; that 
> appears to be consistent with the mindset over there. I think I read that 
> the PRR Hudson tunnels are actually fabricated tubes that sit in the mud 
> on the river bottom.

No -- they were dug through the silt and rock beneath the surface in 
traditional methods. The MTA's 63rd Street tunnel of the subway and LIRR was 
prefabricated and laid in a trench in the East River.

Modern tunnelling technique generally goes deep and is cheaper because it is 
(a) more safe and (b) can be largely automated by machine. That's how the #7 
and the LIRR tunnel to Grand Central are being dug, as well as the new water 
tunnel. But it's also how tunnels are dug elsewhere around the worls, and 
how some countries can get subways finished in a fraction of the time it 
takes in the U.S.

Quite a few subways around the world are very deep for security reasons --  
Moscow was built as one large fallout shelter, for example. But one need 
only travel to Washington DC to find fairly deep stations in the United 
States.

Cheers,
Jim Guthrie
ELHS#1296


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