Aaron,
Maybe I can give you a little “nudge” if you want to find a small critter to run in 1-1/2 inch scale. West Bend Railcar Shops in West Bend, Wisconsin, builds very nice all steel critters and welded that are battery powered (battery seems to be the way to go now to get away from the “lawnmower” sound and the battery technology has greatly improved! These engines can be operated wirelessly, just like our garden trains and have full sound. If you go to his website and scroll through his photos, you can see what he can do. His prices are very fair. I have NO connection with him…just a satisfied customer.