The RR up Old Fort Mtn has so many curves that it totals several complete circles, I've read. to make 4 miles distance. You can't camp there, but there's a little park at Andrews Geyser (actually a gravity-fed 60' fountain) that's inside one of the loops. The trains go by on one side, disappear, then come back on the other side, with maybe 100 yards between. Then you can hear but not see tham on yet another loop. This is the view across the road from the park:

This is a load of pulp chips going up the mountain across the Eastern Continental Divide to the paper mill.
For a rail fan in the east, I can highly recommend both the VA Transportation Museum (Roanoake) and the NC Museum of Transportation (AKA 'Spencer Shops; Salisbury). At Spencer, you can take a short ride, sometimes with steam traction, around the yard, and you can ride the old turntable. But I dunno about camping in either area.
Jim, "You can't be careful on a skateboard."