dkdkrd, sorry if there was any confusion on how I worded the title of this thread. What I meant was how my oil had gotten into my commutator (and mainly the brush houses) and was causing the motor to smoke. I never actually oiled the commutator or brushes as this can lead to the motor being damaged. I did however oil the axles, gears, and side rods, but never the commutator. I agree with you in saying that commutators and brushes should not be oiled as it can cause harm. Unfortunately oiled commutators and brushes seem to be a common occurrence, especially in older locomotives.
Trainfam