When Ennis and I went up to Estes Park to check out the site for our BBQ next May, we passed a loooooong coal train on its way south from the Powder River Basin of Wyoming. It was a beautiful sight, even though it was, after all, a coal train. Winding snakelike alongside the river through the valley. The Powder River Basin, or PRB as it's called, has the finest coal in North America (sorry if I'm insulting you, Mr. Pennsylvania) and it's up where Lightning Flat is in the northeastern corner of the state, also in Montana.
I have a picture on my other computer that I'll hunt up and post...
I read a great, tho long story in The New Yorker this summer called "Coal Train" written by the incredible author John McPhee. I recommend it.