A tale of three signs...

So I was looking over my Standards Plans for the D&RGW and noted there were three sign types to indicate to engineers what they were approaching.

-"S".....indicates approaching a station
-"W"....approaching bridge, tunnel or curve
-"X".....approaching highway.

Was this the standard for the Narrow Gauge as well? I would think it would be, however I don't recall seeing those type of indications in photos.

I see the origination date on the drawing was Sept 4, 1942. However the drawing went through numerous revisions up to 1970. I'm wondering if the standards had changed and the drawings were changed accordingly.

Thoughts or other information on the subject would be greatly appreciated.

Craig
Somewhere up in NoCo