Rod
boilermaker1: Rod's comment is SOOOO important! A few years ago I bought a Railking switcher and it would heat up so much that it would eventually completely stop running. I had a 4% grade and it would punk out going up it. My other 8 engines didn't have any issues with that grade.
I came to this forum asking for comments. I was ready to cut holes for openings because people were thinking that there was no escape route for the heat - just as you stated.
But then one person asked me the question that Rod asked (hmmm, wonder if it was him!) about voltage. I was running at 14V or 15V and once that I upped it to 18V the engine never got hot again.
I still can't run a lashup with it, but it runs fine.
- walt