The units were: SD40-2s 3176, 3486, and 3537 plus DDAX40 6931. A Roger Puta Photograph
This is a Gage Restraint Measurement Vehicle. I heard secondhand that Norfolk Southern had just bought it. What it is is at: http://www.ensco.com/index.cfm?page=319
Seaboard Coast Line(up): SCL 966(GP7) SCL 967(GP7) SCL 745(GP7) SCL 66(DS44-1000). 745 is ex-ACL and the others ex-SAL. Two have white flags.
These are 500 hp Whitcomb/Canadian Locomotive Co. Model Number 75DE12C. Note lack of symmetry at top of hood. Was this pair coupled this way on a long-term basis?