Instead of trying to match model paints and opinions, here are two suggestions:
Camo "Brown" or "Earth" (brand-dependent - go to hardware store) is what I use to
spray my track before it gets used. Do it outside. After it dries, I use a fine sanding
sponge or block to clean the rail tops.
Or, if the track is already in place, go to your local rail yards and mainlines. Observe.
Never mind Floquil or whatever. LOOK at the rails. Real rails. Take some good digital
photos. Go to different areas. Around here (warm, humid climate) the rails are a
dark blackish brown. In the desert, they will be a different color. Go to Home Depot (etc)
and get some paint sample cards that approximate the colors you want. Look at your
photos; go back to the REAL rails. When you have a card that 90%+ matches, go to your
favorite paint store and have them match it and mix up a quart of flat-as-possible latex. Use that to paint your rail sides. Thin it or not, as you like it. Last you forever. Cheap. Based on REAL rails, not someone else's interpretation of someone else's interpretation.
I'm sure that your digital photos could be used for matching somehow, but that's beyond me.
Don't use "Oxide Red" spray cans. Nothing is that color except some boxcars and cabooses.