Jsoflo, thanks for the photography tips. I am going to experiment with natural light on my deck. Not brave enough to haul a set up to the ground floor from my third story unit.

For techniques I tried various combinations just to understand them more. The rusted roof models relied heavily on the airbrushing of acrylics to start and finish, with lots of weathering powder. The two others were light airbrushing coupled with hand-applied washes.
Take away from a first-time airbrusher: don't see how this would have been possible had I not gone this route.
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Ed, I appreciate the kind words. On the Seaboard boxcar I couldn't find an exact prototype car to follow, so I worked from a few examples. I expanded minor overpaint areas I saw that I guess covered graffiti or something to help hide a man-made blemish or two.

The wheel faces were fun to see the results, but got a bit monotonous. Next time I am going to try another paint color formula for a less obvious impact and mix it up a bit.
I agree Pelle Soeborg's techniques can be quick and easy - that's the reason I started with his concepts. I see them as a great way to get my baseline fleet moving forward - I have a lot of cars! Tom's rust is so realistic, I want to use it on the main players.
Shawn