High pitched squeal from older trolley

[gthomson]

I have an older Bachmann Brill trolley HO, DC that was running OK a while back but now runs with a high pitched squeal (it's about to get shot off the track! ha ha).

Probably a cracked gear or maybe something got up in the engine? I did put some oil on it and wondering if it ran into the engine?

one of those pancake style plastic engines