Hot Collector Roller

 If it was me I would first check the amp draw of the f3 and then use process of elimination from there. I would also check wiring and continuity with a ohm meter from the pick up to the motor then probably switch out the pick-up assembly if the wiring checks ok.

 before doing all that you could just go ahead and replace the wire from the pick up roller to the brush on the motor, then pull the roller off and replace it but make sure the axle is clean that the roller slides onto and that the spring pressure holding the pick up to the middle rail is sufficient .

The motors should be wired together in parallel inside the locomotive so both rollers power both motors.  I would put a piece of masking tape 4" long or so on the center rail and run your loco slowly over it.  This will verify that both pickups are indeed picking up power.  If the loco stalls when the rear pickup is on the tape then the front roller is not doing anything and the rear is carrying the whole load. 

If both pickups are working then the problem could be pitting of the roller axle on the rear pickup.  The pitting causes lots of tiny sparks between the roller and the axle which generates the heat.  I had this happen once with a twin motor diesel.  Replacing the pickup assembly fixed the problem.

Bob Bartizek

Paul,

Bob Bartizek has some good points. Check the spring on the hot pickup side. If this spring has been annealed then it is not getting pressure on the track.

Skip

I had the same problem with a command control engine and contacted the Lionel service center. They said as long as there was no sparking or shorting, a little heat is expected. I keep the rollers clean and so far I have no problems.

My first F3 was under the Christmas tree in 1951, and the rollers routinely got very hot.  It was apparently a manufacturing defect.  The rollers on all F3s at the time sparked like heck.  We just put up with it and kept our fingers away from the rollers.

All the advice above is great, but the heating is not new.

I would try my miracle cure for poor conductivity, DeoxIT D5 on the roller shaft.  I had one that the rollers got too hot to touch, this cooled them down to where you can't tell they're any different temperature than the room.  Works on any contact area like this.

gunrunnerjohn, did you purchase DeoxIT D5S-6?

There's only one reason the roller's getting hot. A short. Nothing else could cause it.

Define "short".

Smoke unit -> heat = short?

Yep, I've used it for some time.  I believe I got it on Amazon HERE.

Not true at all.  I have a KW on my bench right now, when I load it to 9 amps, the rollers are getting very hot.  I'm going to replace them since they're well worn.  All it takes for the roller to get hot is enough current and enough voltage drop.

I don't think CRC has the same properties as DeoxIT D5.

Hi Paul, I've experianced this a few times. If the loco runs normal otherwise the heat is due to excessive restance at the axle/roller interface. If the spring tension of the arm feels normal  compared to the other arm the spring is not the issue. Even though the roller looks rust free & you spray tuner cleaner or the like on the axle, you can still have a dirty/rusty axle/roller connection.

      I've not used the cleaner John suggests. I'd try that 1st of course. If that doesn't help spread the arms & slide the roller off & clean the hole with a small round file or the like & clean the axle with some crocus cloth or the like. I've had a few locos that I'd for sure thought the axle was clean. Repeated cleaning with tuner cleaner & compressed air didn't help. At the suggestion of a freind I removed the roller & cleaned. This cured it 100%. There was a thin layer of rust inside the roller hole that you couldn't see peeking in at the side with the roller installed.  However, it sounds like you already did all that.

    As one person said there are some rollers that tend to do this. Again, due to a poor connection to axle, but this time due to the material of the metal. Some of the late postwar 736s with the small roller/pickup were quite bad for this. Those rollers looked visually much more open pore sintered metal than the denser sintered roller we usally see. My 736 got so hot there was no way you could touch them. Cleaning helped, but still rather hot. I replaced them with solid steel repro ones & they don't get hot anymore. I wouldn't have thought the metal of the roller would cause this.

    If you are sure the cleaning is perfect, I'd replace the roller. I've used both sintered steel & turned solid steel repro rollers from the parts guys. Both has worked well for me. Sometimes I think the steel ones last longer, meaning don't groove as fast. Axle wear has not been an issue with either type.  

   Let us know how it turns out.

     Very best, Don Johnson

Hi KD, Wow! That was a well written piece. Very very intersting. I get exactly what you are saying. Thanks for the input. FWIW...  that was worth a lot!

    Very best, Don Johnson