Mmmmmm...Trains.
Hey, TC, I'm no diesel expert either, but number 5533 is an SD 60. There were 3 locomotive types that had the "Draper Taper" carbodies...SD 50s, SD 60s, and GE Dash 8s. Have a look on the angled part of the roof, between the top of the cab, and the grilles at the rear. The SD 60s were flat. The SD 50s had vertical lines along this roof section, and I identify the GE Dash 8s by the fact that their engine numbers are in the 2400 series.
I will dig up an aborted, furtive attempt at a GMD-1 kitbash I tried years ago and post it, if you like.