The Turnout Identification post made me remember this subject. Since I live in Northeast [in NH], have always been interested in area railroads, yours truly eventually started noticing whistleposts along r-o-ws [ on family train trips when youngster, area tourist trains, walks along tracks and pictures in rr books ]. Ones I remember most are high posts, on r.h. side of r-o-w, either 4 x 4" or, possibly, metal pipe; usually painted black. Top ‘flag’ panel was about 5’ to 6’ from ground, usually a good sized white parallelogram, extending from left post edge, upward to right at, maybe, 45 degree angle, with large, level, black san serif W painted in panel center. This being the most common one that sticks in my mind. Plan to make/ install some of these along my switching layout r-o-w. TTFN. …papasmurf
The half-chevron is usually a warning to flanger operators to raise the blade to clear an obstruction. If there’s a W on it, it’s serving double duty.
In places where ice-crusted snow isn’t a problem, I’ve seen whistle posts thet simply had square or disc backgrounds for the W.
On my prototype, the half-chevron would indicate, “Grade starts/changes here.” It would be stenciled with the grade, in meters per kilometer of rise or fall (e.g., a 2.5% grade would be marked 25.) There would be another chevron, or possibly a level board, on the other side of the same post, indicating the grade (or L for level) in the opposite direction. I already mark that information on my subgrade, and will certainly be installing the grade posts where appropriate.
Chuck (Modeling Central Japan in September, 1964 - with appropriate right-of-way details)