There is Bus service between a number of cities and they make money. If they are subsidized by taxpayers then maybe we should cut that subsidy too. Railroads are an albatros and antiquated form of transportation. We might as well subsidize horse buggy service between cities as well with that logic. Let the market determine need and price and someone will provide for it. I don't think the taxpayer should be subsidizing anything whether it's trains, airlines or buses. Let the market determine what should be charged. If some people can't afford to travel then so be it.
Tell that to the companies who want their coal hauled, their grain hauled, or their new cars hauled. Put those comodities on trucks, and the interstates will gridlock.