@ charles9 12:32 Re: My thoughts
The Swiss do quite well at running trains THROUGH mountains. OK, the present Gotthard was built before TGVs, but so what? With a known clear and safe run you could go faster through a tunnel. They are planning 250Km/h for the new Gotthard: http://www.alptransit.ch/en/project.html
The Channel Tunnel is quite long, although the Sei-kan is a mile or so more. I imagine that the USA can do 4 times the distance if it chose.
Biggest problem I see with tunnelling right through the Rockies are the fault lines. It's not very stable. You'd not want to re-align the tunnel every 10 years, and you might, just might, make california come loose and fall off.
You'd probably want to use tunneling to reduce the grades, rather than eliminate them altogether.