On August 15, 2009, I took a trip to the Toy Train Collectors Association (TCA) Museum in Lancaster, PA, for a Saturday "work day."  The repair slots were full of engines and cars that needed fixing for the operating displays in the Museum. 

 

My first engine was a NYC F3 that had only one truck operational.  I took it apart and found the brass worm wheel totally worn out.  This required pressing the old one off and finding a new one somewhere in the parts bins - the hardest part of the repair.  After replacing the wheel, it still would stall.  I found a tiny piece of metal in one of the idler gears that caused the whole problem.  Removed it and the locomotive runs like new.

 

The second engine was a Rock Island F3 powered unit that only had one truck operating.  After taking it apart, I found the armature frozen in the field winding and the armature plate melted.  It needed a new motor - there were only used ones in a bin.  I found one that had a bad field winding, took it apart, put the new armature in the old field winding, but it was too tight - the field winding had closed .001" with all the heat and was binding the armature.  Pressed the field apart slightly and put in the used armature and armature plate.  With new brushes and rewiring, it was back in service.  One of the more challenging repairs I have had up there.

 

They run those locomotives until they go no more!  If you want to have some fun, join me - they do it once a month.