Seaboard System was a short-lived grouping of Seaboard Coast Line and affiliated properties that superseded the ‘Family Lines’ name prior to the amalgamation of these railroads into CSX Transportation.
In December 1984, I exposed this view of Seaboard System GE diesels switching south of downtown Orlando, Florida on the former Atlantic Coast Line main line.
Just luck. Last summer John Gruber and I were along the mighty Mississippi at Savanna, Illinois and photographed a westward BNSF freight with DASH9-44CW 4444.