You know, it's funny and sad at the same time. Not too long ago, the U.S. was on the cutting edge of the most advanced technologies. Now the French, Germans and Japanese are all light years ahead of us in high-speed rail technologies and systems.
I for one would love to see an alternative to airplane travel, if for no other reason than to give the airlines some competition and give some of us an alternative to flying if we choose. The previous contributors to this thread are right on, this would have to have its own corridors without heavy freight traffic and the corresponding wear to contend with. The government sure won't do it, so it would have to be built and run by the private sector.
On the other hand, the French don't have space shuttles or space stations, but their Ariane rocket program seems to do pretty well.
I'll have to settle for rides on our amazing narrow gauge lines and living in the past, that should keep me in fairly good spirits...
Norm in Denver