Hi folks!  My son recently acquired a beautiful vintage steam engine that actually steams! He was thrilled.  Problem is, after a small amount of track, it stopped moving, but you could hear the motor still whirring.  I disassembled and found the problem to be a gear with some melted teeth.  When put back together with teeth engaged, it moves for a bit before encountering the melted teeth again.  So I need a new gear.  Can anyone tell me how to find one?  It appears to be .75" in diameter with 36 teeth (we think) on the outer rung, and 9 teeth on the inner rung.

Thanks so much for taking time to open and read this post!  Hope someone can help.