I can vouch for all those schemes in the late 1970's. I was working for NC DOT as a summer hire in 1976 and 1977 on a survey work crew. One of our jobs was a new bridge over the railroad tracks in Cherryville, NC. Coal trains from the mountains came down the Clinchfield to Bostic, where they transferred to the SCL (old SAL) line to Charlotte and return. Saw all these schemes and SCL units mixed in, maybe about 3 or 4 trains a day or more back then.
Not so much now.
Steve Burr, PE - Clinton, MD
Southern Serves the South