I agree with Ben here. There are places for high speed rail, such as areas that should have passenger service, but the tracks are long gone because they were foolishly ripped up before people realized their value. When I say this, I think of the great New York-New Jersey area, Boston and its suburbs, and many other very congested urban areas in the country.
The other thing too is there are plenty areas that already have tracks and RsOW in place, so why not make use of existing infrastructure? In reality rail lines eat up a heck of a lot less space than any highway. Even a 4-track mainline is quite a bit narrower than a 4 line highway even without a median strip. This allows the trains to run in tighter areas, leaving the rest of the area unchanged or damaged. This saves everyone money because there are less EPA hoops and other building regulations to meet before actually starting the project. I'm sure a lot of the politicians wouldn't want to hear this because they have people who need endless consulting jobs at various states of the project. I say this thinking of the many unfinished highway projects in Connecticut.
If they're planning on running rail up the highway median, why not use that for rapid transit or light rail with park and ride stations strategically placed a long the way? To me this would make more sense because this park and rides will act as funnels to move commuters off the interstate and on to the public transit and commuter rail service.
John
The secrete is as Mike said, a well developed and run high-speed freight railroad can run passenger too.