This is a prototypical 1940s/50s (I'm guessing 1930s too?) US railroad crossing sign. As with the prototype the crossbuck is made with a wooden board attached to the back of the post that says 'RAIL ROAD', and one on the front that says 'CROSSING' to make the classic X shape.
Polygon count: 62 (very low)
Every D&RGW / RGS narrow gauge layout needs one of these!