The common killer of artillery tractors was that winch. Post service, it was in just the right place to make a tow truck. The turtle back was thrown off, and the jib was usually welded directly onto the frame rails, ensuring that the frame would get so twisted and bent up, with the ensuing cracks, fish plating, and more cracks, that the rails would be beyond restoration.
I have an artillery tractor project waiting in the wings now. The 15 cwt frame is identical, so will be the donor to make the artillery tractor whole again. And, thankfully, it is a Ford.
