George: That looks alot better then my first try at weathering rolling stock with my Paasche air brush. My first attempt was horrible...no where near as good as yours. So since that first try I have stuck to using the air brush on painting/weathering structures. And I still do not have it right. I tend to do things on the cheap. I use Walmart acrylic paint and a thinner recipe that I picked up on Youtube. I am still working on it. I am finding that the distance I have the air brush away from the structure I am weathering, makes a big difference. Also, I do alot of practice "misting" the air brush on plastic cups until I get the spray pattern/paint consistency where I want it before air brushing a structure. What kind of air brush equipment are you using? What brand of paint and thinner?