While recently installing an American Flyer #566 Billboard Whistle I had purchased on eBay a few months ago, I noticed the unit was not operable (despite seller claims to the contrary, but that’s a separate issue). After re-checking the electrical connections and the control switch, I disassembled the electric motor and found the unit lacked one carbon brush and spring. Does anyone know where I can find a brush & spring set? (I may also need a commutator if I can’t clean up the existing unit.)
Try rfgco for American Flyer parts. Look under accessories, and his #K58 for brushes and springs for the whistling billboards. He will do a trade in on an armature if you need one.
The motor unit that activates the whistle is essentially the same as used in standard steam locomotives. Thus I would think the brush sets are interchangeable.