I spent time fixing my Lionel operating lumberjacks today. They went from working to occasionally starting/stopping on their own to completely non-functional. I extracted the unit from the scenery, opened it up and found the gears all in good order, well-lubed, so I bypassed the internal board and put 3.5v straight to the motor leads, and little lumberjacks sprang to life. Since I'm operating the lumberjacks off a triggered timer, I just ran the DC 12v line that powers the relay timer to a small buck transformer and adjusted it down to about 3.2v and fed that to the unit. Internally I hooked power terminal feeds directly to motor and the "sliding log pile" switch feeds. Oh and I labeled the underside of the logger unit indicating terminal polarity and the fact that it's now a 3.5v DC accessory just in case i need to revisit this in the future. 
Side note: I found that if you over-tighten the screws in the base of this unit, the gears start to bind and you get a stuttering of the movement.
