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.
FREIGHT railroads are an essential backbone of this country. There is simply no comparison between the cost of hauling 50 hopper cars full of coal by rail and the cost of hauling it by road. Depending upon the route, the cost difference could be well over an order of magnitude.
Railroads' cost advantage, however, is only significant when loads are consolidated into long trains. If a particular facility uses 10 cars of coal per day, it would be more cost-efficient to deliver a 50 cars load of coal every five days than two 5-cars of coal each day. People, however, aren't generally willing to travel on that sort of schedule. A train which runs once a week in this country will not get seven times as many people per run as one that runs daily; it might even get fewer.
Rail is an excellent means of transporting large quantities of non-time-critical freight. When no other modes of human transportation are unavailable, using the freight rail infrastructure for human transport will provide at least a transportation option. On some highly-traveled routes it may be competitive with other modes of transport, but the economics of scale usually do not kick in sufficiently for it to really be economical.