First of all, welcome to our little family and the forums!
As to your question, the future of North American railroads (IMHO) is very, very bright…especially with the growing diesel fuel pricing and the consequent pressure on truckers.
Also, orders for diesel-electric freight locomotives are very strong with G.E. and E.M.D. pushing as many as possible out the doors of their factories.
I also think if gasoline pricing continues to rise, Amtrak will have no choice but to order more cars and locomotives in order to keep up with demand for its services by the general traveling public.
Welcome Heavy Metal! I don’t see locomotive power going alway anytime soon if ever. The question is whether or not electrification will come back to North America on freight lines. That was recently being discussed on another thread.
If worst come to worst railroads might actually consider electrifying their most heavily-used mainlines, but I don’t see it happening unless the government covers some of the costs.
Rail is the most fuel effiecient and least pollutant way of moving things and people long distances. It will be around for a long time.
But to make a comparison to Europe note that Europian railroads concentrate on the movement of people while trucks (highways) are more involved in freight movements. It is just the opposite of the situation in the U.S.
Answering your question, since rail is the most efficient of land transportation movers, expect increase fuel costs to direct more frieght to rail. But if increased fuel costs adversely affect the overall economy then expeect the total amount of freight moved to decrease, including rail.
If rising costs of fuel were to dampen the movement of merchandise of any kind at any time we would have eliminated all transportation years ago while in fact all transportation has grown: rail, highway, water, and air. Market has determined use of mode. Speed of service, reliability of service, and need of particular services have more been factors than cost of fuel. More freight moves now than did in WWII and look at the relative and actual costs of fuel.