Welcome to ModelEngineMaker !If you have problems registering or logging in, please use the contact menu option to request assistance.
Very impressive parts! Are the little circles air holes through the doors?
On the original cast iron fire doors the holes may have been used as part of the core sand. The door would have been hollow, cored with a flat plate shaped sand core, and several round posts and possibly some cast in chaplets on the top of the core would be needed to hold it in place while the iron flowed around it. The round posts would leave the holes after casting. After casting the sand core would be poked out through the holes. In use, the holes would vent cab air to the hollow in each door to help insulate it a bit by making an air gap between inner and back walls of the door. If the door were solid, the inner face would radiate a LOT of heat into the cab. You would not want to brush up against a red hot fire door while running the engine!