Post war Engine question

[Fred Bear]

The Blue Comet I've asked 80 bazillion questions about on here is making a "growling" noise every once in a while. I've noticed my 1666's also. When it makes the growling noise, it slows down. I just cleaned the brushes, slots and everything associated with the cleaning, but I cannot find replacement brushes. Is it the brushes?
Also, what was the name of that furnace filter used for making trees? Thanks again to all the great folks that allow the rest of us to pick your brains. Best Regards, Jake

[phillyreading]

Have you lubricated every moving part on this locomotive? Usually the brushes won't make a growling noise. To make the brush surface like new you must clean it first, then make sure the brushes are free of pit markings, place the brush upside down on sand paper and remove some of the brush surface to reface it as it is called in motor rebuilding, the brushes need to be flat across the mating surfaces. Where the armature
goes into can use a small drop of oil to keep it from binding, do all the gears have lubricant even behind a gear may help on post-war stuff, make sure that all axles have been lubed and wheel to assembly points or you may have the problem come back on you.
Le Fritz