These Shays are all half-inch scale.  These were actually being developed for production prior to the popular modeling scale changing to 1:20.3.  Among the Shays  shown here are 32 ton specials, a 38 ton two truck, a 40 ton three truck, and a couple of 42 ton two truck Shays in different stages of completion.  Bob still hopes to have these Shays produced in quantity someday.