I can't cite sources for these opinions, but my understanding about the decline of rail in the US has always been that there were three root causes.

Trucks had an advantage over rail because, first, the rail unions were powerful enough to get high pay and lots of benefits, but since most long-haul truckers are independant owner-operators, and could charge whatever the market would bear, they had lower costs than the railroads. Added to this, railroads had to pay the costs for constructing and maintaining their track themselves, while the highways were built and maintained by government, with the cost spread over the whole population. That also gave the trucks a price advantage. Thirdly, the US is big enough that it can take two or three days to get from one place to another, within the country, by rail, so people turned to air travel for longer trips in-country that they would previously have done by rail, even as they turned to private automobiles for shorter trips. The railroads lost most of their passenger business.

Now, of course, commuters are taking two hours for what should be a half-hour trip on an uncrowded highway, because of congestion, and the airlines have turned into flying concentration camps whose departures and arrivals can't be relyed on. We need the railroads badly, but they're mostly gone.

Peter.