(Apologies if this is a repeat; I thought I posted it but I can't see it)
I opened up one of my old Märklin locos (prototype: Swedish "StatensJärnvägar" Da 884, 1955; model from ~1967) and one of the items I thought might be worth an overhaul was the brushes, so I took them out and to my surprise they were different from one another. One is a simple graphite rod (which is what I expected) but the other is made of what looks like rolled-up brass mesh. Is this "normal" in a 60's Märklin loco? Does it serve a purpose?
I opened up one of my old Märklin locos (prototype: Swedish "Statens