Among the many items of Common Standard signage on the Southern Pacific were speed signs, as the railroad called them. These were simply speed limits. The same information was included in employee timetables in the form of Special Instructions, but the signs were reminders at trackside.
A 1952-era drawing for the standard speed sign, from the Fred Hill collection, was printed in the Southern Pacific Historical and Technical Society (SPH&TS) magazine Trainline, issue 23 (undated, but approx. 1989). I reproduce it below. There was a 1972-era drawing in Volume 2 of the Southern Pacific Lines Common Standard Plans series (Steam Age Equipment Company, Dunsmuir, CA, 1993), but that 1972 version does not include the “streamlined equipment” sign (round Type B) which is appropriate for my 1953 modeling. You can click to enlarge, and download if you like.
As the drawing explains, the oval sign with two numbers has the higher speed for trains with all passenger equipment, the lower speed for all other trains. The Type B sign applies only to streamlined equipment.
You can buy this back issue of Trainline, should you wish to do so, from the SPH&TS website, at this link: http://www.sphtsstore.org/servlet/the-Trainline-back-issues/s/17/Categories .
To model this sign, I simply reduced the image to HO size (dimensions are given right in the drawing), and applied it to a post. I used the Guadalupe Subdivision instructions from the 1953 timetable to choose the speeds on the sign. One can readily change the numerals to suit conditions, either from the drawing above or from the Egyptian lettering drawing in Volume 2 (citation above). [Digital versions of Egyptian are available on the internet.] Note on the drawing that the round Type B sign is to be yellow, the oval sign white; I applied the yellow color with a felt-tip highlighter pen. Here is my model sign, on the SP main line near my town of Shumala.
On the telephone pole across the track, the white paint and the number sign designate a milepost sign, though this particular milepost number is not correct for my present layout, and will have to be changed (probably I will write a post about mileposts when I make the correction). And in the far distance, a black rectangle on the side of the tunnel portal contains a white tunnel number, standard SP practice.
Trackside signs are sometimes neglected, but they should be part of the trackside scene for Southern Pacific modeling.