I agree that rail isn't the only solution. Rail is a solution to state highway overcrowding and conditions, but not feasible for local transit.
It would take a lot of systems cooperating, but I wouldn't say it's insane. People do it all over the nation everyday. Seattle has what I consider to be one the best in the nation, almost all of New England has a superb network of transportation alternatives that make transprotation a breeze. People "commute" into NYC from, literally, all over the neighboring states. You can be from any street in Massachusetts down to any street in DC in just a couple hours.
A well-planned transit system can get you places FAR faster than driving could and with far less hassle. Unfortunately we're so far behind the curve it will take decades for most of the cities in the US to get to that point, let alone all the outlying areas.
For example, it's expected to take 17 years to build a 30 mile rail-line from Denton to Dallas. And the huge NAFTA Corridor that our Governor wants to build straight through the state and carry on to Canada (10 lane freeway with 4 rail lines in the middle) is expected to take 50-75 years just for the Texas portion.
And I'm also not just talking about a fuel issue. Simple fact is that we can't build roads fast enough to satisfy the population growth. Interstate commerce will no longer be very viable within 20 years at the rate we're going. Our roads are getting crowded, and the ones we have we can't afford to shut-down and repair even if we had the money to do it.
