Im making my custom PE using a 3D printer and this is why I need to know

It's probably very solidly glued in. So if I were you, I would probably buy an extra boiler shell to try this.  You probably need to tap it from the inside, pushing it out. I suspect that some kind of extension like a long screwdriver with some padding on the end of the blade might be needed.


I haven't seen this boiler, but I suspect that trying to get a knife blade between the smoke box door and the smoke box would probably ruin them both.

An exploded diagram of the boiler can be seen here:

https://www.bachmanntrains.com/home-usa/dwg/dwgs/HO%202-8-4%20BERKSHIRE%20with%20DCC%20SOUND.BOILER.pdf

The smokebox door appears to be held in place by a couple of nubs on each side that fit in the holes at the front of the boiler. So Trainman's suggestion of removing the boiler and tapping the smokebox door loose from the inside looks like the way to go.

Len