Had some fun weathering trucks this evening. The center pair shipped with nickel-plated wheels, the left set shipped shiny black and the right set shipped flat black. The first two sets left-to-right are Aristocraft-style plastic trucks with metal wheels. The set on the right is Kadee, and is all metal. Even with weathering, the Aristos still look like crap next to the Kadees.
The shiny tread is prototypical, but the black wheels both shipped with black treads. The finish you see here was achieved by chucking the wheels in my drill press and applying some fine sandpaper.
The rust effect starts from a solid coat of Rustoleum Camo Brown (Walmart) that closely mimics the grimy green/brown of the dust covering everything on the rails around here. After it's set a bit, it's followed by applications of Liquitex acrylic paint from the kind of tubes you get at the art supply store. Burnt umber and burnt sienna are dry-dabbed to taste via foam makeup applicator wedges. You can achieve a wide range of age with this technique, and I had to resist the temptation to really age these babies. I wanted something that looked ready for mainline service.
Before the track-powered folk decide that sandpapering my wheels is a terrible idea, I should mention I only run live steam, and really don't care about microscopic scratches in my wheels or track.