I bought a HO scale S4, but the paint on the front of the boiler is do dark for the real thing. I would like to know if anyone knows what that color is. Here is a picture of the prototype. It is the paint right on the front of the boiler.
Because the smokebox (front area of the boiler) and the firebox (area between the bottom front of the cab and the drivers) were normally left unjacketed, and got really really hot, paint generally didn't work there. It would just peel off. So railroads covered those areas with a mixture of graphite (kinda like what's in a pencil) and oil, producing a silvery-gray color. My guess is the engine in the picture had those areas painted with light gray paint when the engine went on display, to protect the metal. I wouldn't go by that as a definitive guide to coloring your model.
Thanks, I am a member of the group that is restoriong the engine, and I talked to a fellow member and said we painted it bright so it would look better.
I'm thinking a graphite and oil mixture would be relatively dark,so your probably pretty much good to go!