Since my window-of-opportunity to spray paint track outside in Central PA is coming to a close, I want to decide on a spray paint color soon. As someone here pointed out, color looks different inside -on the layout - vs. outdoors. So using my local ex-PRR track as a desired "goal" (see photo) I tried 2 different colors, Rustoleum Camo Brown (#1918 Earth Brown) & Rustoleum Red auto primer (#2067830)The red primer looked too red outside, but inside in my basement lighting I thought it looked pretty good. My "ballast" was free & it may be too coarse for O-scale. It is a poultry feed additive called Calcium Chips. I'm still considering it.