I have a Lionel #18000 Pennsylvania B-6 Switcher from 1989. Great little engine.
Although, like all AC motor engines, I felt it was time to clean the commutator or check if the brushes needed changing since it was being a bit too noisy.
Unfortunately, the drawbar pin secured at the back of the engine is blocking any access to the open frame motor:
I'm not sure how Lionel attached this in their design. Does anyone know how to remove it?