I found a video titled How to Lubricate with Labelle, and I thought I would elaborate on how to adapt Labelle’s advice to Marx trains. You don’t have to use Labelle oil and grease necessarily, though I do like their products.
Lubrication is a more controversial topic than it needs to be, but what I find is that when I follow the advice I’m about to present, the train runs cooler, more quietly, with more pulling power, and starts at a lower voltage. All of those are good things. With a single reduction motor, I can pull six of the metal 3/16 scale cars at 7-8 volts. An unlubricated motor might not even start at 7 volts.