Single engine auto rack train

My first photo of single engine trains is this shot of a Norfolk Southern auto rack train near Huron, Ohio, pulled a train of pickups and small trucks away from the Ford plant there.  Having grown up in the moutains of Idaho and Oregon and seeing multiple units on every train because of the terrain, it was a wonder that the land was flat enough that one unit as capable of pulling an entire train, even something as light as an auto rack train.