GDT #4 is a modified HOn3 PFM Benson Shay

The HOn3 MDC shay is actually way too large to represent Gilpin shay #5 in Sn2. I've found that a PFM Benson Shay is a much closer match to #'s 4 and 5. In fact, very little needs to be done. Removal of the air pump, tanks and related piping, the bunker, and a few other parts. And the addition of S scale parts such as headlight, bell and other details. The model sports a rather large cab for HOn3. The cabs on Gilpin Shays were very tiny, and no major modification is really necessary. Problem with these models is price. Oh yes, plan on adding a can motor and NWSL gear set if you plan to actually use the thing. The PFM "Cowichan" Shay is basically the same model.

Smokebox details of GDT #4

Cab and Steam Dome details of GDT #4

GDT #4's bunker is loaded with coal.