I believe that the Private railroads in this country are actually profitable, and have been for decades. CSX was bought by private firms after a bidding contest (about 6 years ago if I remember correctly).
What the interstates did was, with the connivance of the Automakers et al, to destroy passenger rail. Where if you are in a hurry take a plane and auto is often just as fast and much more convenient and normally cheaper (especially with a family).
Actually, CSX and NS (Norfolk Southern) purchased the Pennsylvania Railway in the mid to late 90's. Orignally, NS made a bid for PRR, and CSX made one a bit higher. The state of PA forced both companies to purchase the old PRR at a much higher cost. The state of PA is very protective of its homestate businesses. Remember what they did to Hershey Foods a few years back?