Yesterday I resigned myself to trying whatever truck and wheel painting I could manage without a working airbrush. One of my weathering projects is an attempt and a “new” weathered hopper. So the wheels have very yellow toned rust on the wheel face (because darker rust is older), no rust on the trucks (but not out of the box glossy black), blue roller bearing caps, and minimal grime etc on the carbody.
Lacking an airbrush I didn’t touch any of the carbody weathering and instead stuck to the wheels and trucks. I mixed a wash of Model Master Engine Gray and Skin Tone Dark for the trucks and the wheel face base. Then I used a light rust powder on the face of the wheel, and finally a bright blue paint for the roller bearing caps.
Unfortunately while the blue was the right color for what I wanted it was just far to thin for my purposes and didn’t really cover. Still overall I’m happy with the look so far.