Reading Railroad green paint match ???

 Scale Coat offers Reading Green in both spray can and bottles. Problem is everyone's not on the same page as far as color. You mentioned spray.  Are you airbrushing or using a rattlecan ?

 If you have access to an airbrush. Green is tough to match. I can spray okay but have little knowledge of mixing paints. You really need to have mixing bottles and use droppers for mixing. Record your results so you can duplicate them.  I needed to match green on a passenger car. I ended up using Mission Models paint. The paint dries flat so will need to gloss over it.  Micro Mark carries it.  They are into military equipment. Tons of shades of green available. I purchased 4 bottles and was able to get a decent match by mixing a couple together. Still if it is a simple touch up. A big investment to go this route.

 If you have a decent paint sample, look around and find an auto parts supply store in your area that can match paint samples and make you a can of spray paint. I do this all the time and the spray paint that they make is of highest quality,it has all the additives, it’s difficult to make it run, you never get fish eyes and it dries reasonably quick. It will cost you around $25 a can. It will have about three times as much paint as a rattle can from the hardware store or the big boxes. The shelf life is excellent.  I have some that’s over 10 years old and still works fine. The spray nozzle is a much higher quality than you get on the rattle cans at the hardware store. 

Jim