I've been looking at the Sn3 locomotive kits made by Railmaster Exports, and noticed that they offer two styles of D&RG T-12s. One has the wagon top boiler, and the other has a straight boiler. I've also seen both types in photographs. But, I haven't been able to determine; 1) Did all T-12s have straight boilers at one time, if not, which had them? 2) When did these straight boilers get replaced by the wagon tops?
I've seen a builder's photo of 174 that shows the straight boiler and shotgun stack. I've also seen early photos of another (16?) that had a wagon top boiler and diamond stack.
Does anyone out there know the story?