The holes in the underframe strengthening plates presented a small problem. How do you get an even coverage of paint on the solebars that will be seen behind the plates? I put the nozzle of the airbrush right up against the holes and sprayed through them onto the solebar. The consistency of the paint allowed it to spread far enough inside the gap to cover the whole area.
The Railmatch frame dirt was applied first, to give an overall tint to the whole area. Wheels were done by using the airflow from the airbrush to turn the wheels and then applying the paint and watching the excess fly all over the inside of the spraybooth. Railmatch weathered black was mixed in with the frame dirt and then randomly airbrushed over the top to introduce a change in tone to the accumulated grime. The photographs show this much better than (my) words can explain: