I apologize for not getting back here sooner. All testing done on an 031 oval with about 8 freight cars, all plastic with die-cast trucks/couplers. Transformer, etc changes make no difference.
FYI, one of my engines, that was "downgraded" from PS2 to a Dallee Reverse Board and Williams Sound Board also gets hot. I don't remember it getting how with PS2 but then again, I wasn't really paying attention to that then. The motors are original, MTH motors, One still even has the tach stripes and such on it. The loco is an F3 from 2004. It did have a Williams reverse board that also got very hot.
I purchased a NIB Williams GP9 from Mario's Trains a few months ago. It also got extremely hot after a short time in operation on an 031 oval. That went back to Mario.
My Williams Bachmann J also gets very hot, waiting on a new motor as a possible option.
My original Williams SD90 also gets hot although it doesn't seem to get AS hot as the rest.
I notice my el-cheapo but incredibly durable and reliable Lionel 4-4-2 RTR loco got kind of warm on the 031 oval with 3 plastic cars. Did not take it apart.
I also tested an MTH PS2 SW1 with the same train, cruise on and off. After about an hour, the motors were quite warm but not so hot that I couldn't touch it.
I know 031 isn't ideal and adds some extra drag but not as much to have issues. I don't have any die-cast cars, etc. I'd be curious to see results of GunrunnerJohn's test later.
