Kelly,
I've looked at that picture since 1982 when I bought my copy of Mineral Belt II, I've always figured it to be one of the second group of Mason Bogies but it is hard to tell, and my eyes aren't not getting any younger. However it could also be the Rotary #064 poked back into the stall.
EDIT: After looking at the Mineral Belt II again, there is another picture showing a standard C&S airtank on boiler Loco sans Tender with the fireman's cab door opened outwards and no Driving wheels visible and this is in better light. Certainly not a Rotary or Mason haha.
Edited 1 time(s). Last edit at 08/18/2016 06:37PM by Chris Walker.