I may be totally wrong on this but IIRC the Southern Rwy.'s passenger hauling “F” units came in two trim colors: green and brown. I remember from growing up in Southwestern Virginia near Bristol in the 1960s, the brown ones (A+B) hauling the Birmingham Special were the exception to the “change locomotives at Bristol” norm.
Later, in the Seventies, I had the pleasure of riding Mr. Graham Claytor’s baby, the refurbished “Southern Crescent,” and IIRC its motive power was green. The black units seem to have the exact same paint format, I just don’t recall any passenger units of that day being black. Perhaps the black color was a sop to the N&W side of the family, because they had gone to whitish lettering on black bodies even before the N&W / Southern merger in 1982.
Also, and again IIRC, the Norfolk never owned locomotives of the EMD “E” or “F” variety. Stuart Saunders, almost from the minute he took office in 1955, started planning to dieselize the fleet. The engines that wound up hauling N&W varnish post-J class were not carbodies; they looked more like the typical freight-hauling locomotive of the period. (Those I remember from “The Pelican,” where the Norfolk did indeed use its own head-end power between Lynchburg, VA and Bristol, VA/TN.)
