Fresh from the paint shop- GTW GP15 6150
My what-if model if DT&I traded in their GP7 units for 15's, around the the time of the GTW/DT&I merger. As a DT&I they would have been delivered in the 150-numbering series. When GTW bought DT&I they renumbered all the units by adding a 6, so this would be in line with the prototype practices.
I would have added fixed pilots, if I was able to track down the 2-rail parts for this model. Still needed is the 'F' frame marking and some touch-up, but its pretty much done.