Over the weekend I primed the train with gray Tamiya primer (2 cans) and then did a matt coat of Tamiya black (3 cans). I opted to do this outside because: 1. The train doesn't fit in my spray booth! 2. It was a beautiful day 3. The amount of paint needed to do this is much more than say a model tank. It went much quicker by using spray cans instead of the airbrush.
The base coat (field gray) was applied leaving the black showing through to produce a random weather effect. The resulting gray was too bluish for my taste so I loaded the airbrush with the remaining gray mixed with some white and buff color. I then LIGHTLY went over the middle sections of panels etc. with this warm tone. It warmed the whole color scheme up a hair. I will push it more when I start weathering it.