Troubleshooting intermittent running on OLD 2 rail

Clean the wheels first.  Then check axles and bolster contacts.  Make sure commutator is clean on open-frame motors. Clean track and put a film on Wahl clipper oil on railheads.

Do you have any other power sources?  That sure looks like an All Nation engine and the open frame motor in it may just be drawing too much current for your throttle.  It might be going into current limit which could cause the start/stop.  It doesn't seem like dirty wheels or track is the only reason since it does it with the power source directly connected to the engine.

Control Power 20 may be a 2 amp power supply.     If that is the case, it may be as mentioned above, the power supply is not quite capable of running these locos.    Many of the older locos draw 2 amps or a little more.     Cleaning and lubing the motors so all runs freely does help reduce the load a little but probably enough.

That behavior certainly seems like the breaker on the power may be going in and out.

The locos would draw a bit more under load also.

Try running them jumped off a 12 volt car battery if you don't have another DC power supply.

@prrjim posted:

Control Power 20 may be a 2 amp power supply.     If that is the case, it may be as mentioned above, the power supply is not quite capable of running these locos.    Many of the older locos draw 2 amps or a little more.     Cleaning and lubing the motors so all runs freely does help reduce the load a little but probably enough.

That behavior certainly seems like the breaker on the power may be going in and out.

The locos would draw a bit more under load also.

Just checked to confirm, there are several of the MRC Control  Master  (not  "power")  20 power packs on my RR and each one is listed as 56 VA in the 0-14 volt DC  range.

IF it is working right, that should be plenty of power.   It should be over 4 amps at 12 v.

I opened it up and pulled the motor. Cleaned the commutator and brushes. Applied power directly to the brushes and the motor turned then stopped. Same behavior as when mounted in the chassis.

I've ruled out track, dirt, and power source I believe.  Think I'll send it off to a pro. Any suggestions?  I like the old motors, but am open to a can. Just don't know what would fit.

PUt a meter in line with the motor and try it to see what amperage it is drawing.    There is an off chance that the breaker in the power supply is going off at too low an amperage.    The behavior you describe sounds just like an overload.     Does the power supply have a short indicator?    And does it come on when the motor stops?     If the amperage goes way up, over 4.5 or so, it is probably the motor.   If the breaker trips at 2 amps or so, then the power supply breaker might have an issue.    56 VA should give you more than 4 amps at 12 Volts if all on same throttle.

If all your other stuff is newer (2000s) give or take, they might draw less than 2 amps and the breaker may ignore them.

This won't help you with your issue, but I've got an assortment of (nice) DC power packs, yet this old thing seems to be  able to handle my Varney/All Nation Ten Wheeler (like the one in your video) better than any of them.

I think I paid 20 bucks for it...

Mark in Oregon

No accursed pulse width modulation in that unit, by gummy!

Right!  I like sound, smoke, etc., but I also just like a loco that acts a little like a model.  Still like the Lionel e-unit in moderation, and the open frame motors have the same appeal as vehicles that I could completely service myself 20 years ago.