It's hard to mix your way to that color or just to paint it. The color of a RR tie varies so much from one end to the other. My brother and I used to use oil based paints, I don't remember what they were called, one was a chocolate brown, the other black. Dab little buttons of paint out along the length and spread it using and S stroke the one way then the other so you end up with lots of figure 8s end to end.Then diagonal strokes across the narrow to fill out. You'll have to try it a few times inorder to get it to work right. You know, the right size S, how much paint, you'll have to feel it all out. I hope if you try it it works for you.