Lionel Santa Pylon (6-85412)

Hard to tell from a 4 sec clip but they are not whisper quite between the motor and the gearing.  I doubt another one would make much difference. 

Thanks, Chris.  I also thought about taking it apart and trying some lube.  I'm unsure what's inside.  If I fail (which is LIKELY ), then I'm stuck with it.

They are generally loud, but I'm not sure that rhythmic sort of thing you have going is normal or not.  (it might be -it's been a while since I've had mine out and running)

Taking these apart (at least the old ones - I doubt they changed the mechanicals) is not terribly difficult.  IIRC, remove the sleigh/rod, and also turn upside down to remove the protective "sleeve" around the shaft that runs down into the house.  There are I think 4 screws underneath that will release the roof and tower which capture the shaft with the coupling to the motor mounted to the base.  (again, it's been a while)

The old ones used to be a sort of "clutch" interface.  Motor and shaft have a cup on one side with slots that mate with gear teeth on the other piece.  If there is resistance, the "cup" with the slots gives way so it turns and doesn't break anything(stall motor, etc). (softer plastic, not quite as rigid - so it flexes just enough to not halt the motor and kill it - it's still a larger drag than when it's normally spinning). 

I am pretty sure you DO NOT want to lube this clutch part, or the slipping will occur more easily.  If there is a gearbox between the motor and this interface (memory is fuzzy), that might be a candidate for lube check and add.

That slip action is almost what the rhythm you have sounds like might be happening, but I'm not 100% sure (and if it was always slipping, you would not have it turning).

-Dave