Overheating Lionel F3 6-14588

If the motor isn't getting hot, the most likely suspect to me would be the worm gear lubrication.  For that kind of running, I'd be repacking the worm gear at least every month!

If the gear is already worn, you may have to apply the above advice to the new truck & motor.

Thanks John, it is one mega project to get to the worm gear location.  I wish I had a grease tip with a flexible 1.5" tip that would make the job easier to do on a routine basis.

That doesn't sound right, if the gears are getting so hot that the wheels are hot the grease should be oozing out of the truck.

I'd recommend  lucas red n tacky grease but I still think you have something else going on, if you used a good quality grease in there it should still be doing its job.

I wonder if theres some kind of weird  electrical resistance/short through the wheels or something, I've never had a gearbox or wheels get hot.

I would think a gear issue would heat up the motor from added drag more than the gears themselves.

I thought so too, but I'd be checking.   It's obviously easier when you have something like this in hand.  Measuring the resistance from the wheels to the motor frame would be one test.

Another thing that happens quite often is high resistance on the center rollers.  I had one that got the truck pretty hot, and the roller would burn your finger if you took it off and immediately touched it.

I kinda' discounted this as you had replaced the truck and motor, but who knows...

I agree that if there was something rubbing the motor would get hot. I would check the electrical resistence between the wheels and roller. Most TMCC engines read well over 20 ohms (many Kohms in most cases). Anything below 20-30 ohms indicates a partial short. A dead short would trip the breaker, of course.

While everyone is talking about electrical resistance, etc.; I've not read that the wheel axle bearings have been lubed!!! When you state that you repacked the gearbox and that the gears fell off, it sounds like something is wrong at the wheel/axle/bushing level, Just my thoughts.  Dennis M.

Update Gentlemen,  On this Lionel Model, accessing the worm gear requires removing the cover, crew seating, antenna, wiring harness and dropping the motor-truck off the body. Then you remove the truck detail on the drive gear side and you can reach an opening to the worm gear.  You could obviously remove the motor from the truck at this point, however that also requires more numerous steps.

I could see the worm gear opening through the top of the truck detail bracket.  After some creative thinking I took a grease gun removed the tip and inserted a needle tip.  I was able to slide one of those electrical black melt able insulating tubes over the tip and insert it into the worm gear.  I oiled all of the wheel bearings, also not easily accessible, with a Labelle needle nose tube.

After thirty minutes of continuous operation the unit did not stall and both trucks created approximately the same amount of heat.  Definitely less heat then previously reported.

Is this the problem, possibly...  I run this engine a lot, pulling a pretty heavy load and driving up a steep 5% grade.  The reference to the motor not getting hot is relative.  by the time I take the cover off to check the motor it had probably cooled down.  But it did not seem as hot as the trucks. 

I also though it was possibly a low grade electrical short.  I measured the resistance between the wheels and roller and the needle swung wide.. 

If you have the time and would not mind sharing some electrical information, my weak spot, I would be appreciative.  How do you measure resistance?  Yes, a meter I know but besides looking for the needle to swing wide or not swinging at all what are the norms for continuity between the ground and the positive.  I have some weak spots on my layout.  I can visually see where the engine slows but I can't measure where the week spot is.  I get 18 volts everywhere.  But, is it a resistance issue???

Thanks so much for your help....

Heavy load continuously on a 5% grade....yeah that might do it. I suggest adding a powered B unit to the consist to lessen the overload.

First off, I'd clean the rollers and wheels thoroughly so they're as clean as they can be.  Next, I'd put the locomotive on a short piece of really clean track.  Now, I'd measure the resistance from the truck frame connection to the outside rail, and the resistance from the hot lead from the truck to the center rail.  As I said previously, I've seen more than one locomotive where the center track roller gets too hot to touch after running a few minutes due to high resistance.  I've replaced several of them, but some I was able to cure using DeoxIT D5 on the roller.  Going up a steep grade with a load pulls a lot more current, which could exacerbate the heating issue.  Another trick that can be used is to actually pull current through the locomotive with a large low value resistor across the frame and roller connections and measure the voltage drop across them.

There can be many reasons for what you see, the only way to really determine what the cause is would be to start eliminating possibilities.  It may well be something totally different, there's no real way to know without checking all the possibilities.

Bingo...  Got it...  Thank you John...  Started the morning by thoroughly cleaning all the track.  Then picked up the engine to clean all the wheels and pick-up rollers.  I noticed the rear roller on the front truck, which was the one overheating, was occasionally catching in its spring mounting.  There were two grooves worn into the roller.  Clearly that accounts for the overheating.

I, fortunately, did not throw out the old truck I had replaced last year.  I removed the rollers, placed them on the trucks, ran the unit for an hour and it runs beautifully! 

As you said John, "There can be many reasons for what you see..."  It just took a lot of perseverance.  Thank you.... 

We love a happy ending.   It's amazing what a few amps flowing through a high resistance can do, makes thing really hot.

PS:  Never throw out old parts!