rust

If you're going for a merit award with your rolling stock models, take a very close look at the prototype you're modeling. Most cars have quite a bit more detail than ever get modeled, like on this detail shot of an airplane parts car. The brake chain is probably on the model, but is the AEI tag (in the upper left corner of the photo) on the model? Did you add the embossed numbers or the car's reporting marks to the truck sideframes? Also notice the different shades of rust colors on the truck parts; most of the sideframe is a fairly even dark gray color while more orange and red appears around the axle bearings. In NMRA Achievement Program judging, the AEI tag will help with the detail grading while the color variations and reporting marks will help with the paint and finishing grading. These aren't big additions to a model, but they could add that extra 1/2 point where it's needed.

Rust streaks often start at points on a car where two pieces of metal intersect, such as where the roofwalk supports meet the top of the car or along the weld joints in the side panels on this covered hopper. From the origin point, the rust normally flows downward, pulled by water and gravity.