D&RGW Rule Book says...

I looked at a 1938 D&RGW rule book I have and it says that "all sections except the last will display two green flags,and, in additiontwo green lights by night". As you can imagine multiple sections were not the norm on the narrow gauge so I doubt there were many green flags used.
As to the white flags, it says, "Extra trains will display two white flags, and, in addition, two white lights by night". There is no mention of any other color in the class lamps.
Additionally, the markers on the D&RGW are shown to be one red lens and three yellow lenses. I have a set of original D&RGW NG caboose markers that were used into the sixties and they are the one red and three yellow lens configuration.