The following is taken from “Maintenance of way and structures” by William Clyde Willard published 1915 – page 231 – Chapter XIII – Signs, Fences, and Highway Crossings
I will be quoting directly from the text for the most part. I’m going to mostly delete bits out that are not really usefull for modeling – I’ll indicate that with a [snip].
—Roadway signs are used for three general purposes: (1) To mark special points of boundaries, distance, and track alignment for reference purposes and particularly for the information of the maintenance forces. (2) As fixed signals or signs to convey certain information to the trainmen. (3) To convey certain information and warnings to patrons of the railway and to other persons.
Signs should be placed in a conspicuous place, and once established must not be moved without permission from the division superintendent or other proper authority. The exact location, position, distance from the track, wording and side of track depend on the purpose for which the sign is used. In some States one or more of these is fixed by law. All signs governing the movements of trains must be placed on the engineman’s side of the track. The signs must be painted often enough to keep them perfectly legible. One painting each 3 years will usually be sufficient. Plain black letters on a white background are used for most signs, though black letters on a red or yellow background, and white letters on a black or blue background are occasionally used.
Most of this is pretty much common sense – for example the fact that even by 1915 that State law had fixed certain rules. The fact that plain black letters on a white background also makes sense since that is more legible.
|Design, Material, Life, and Cost of Signs.|
—Signs are of three general forms: a simple post; a plate or board fastened to a special post; a plate or board fastened to an object primarily used for other purposes, as to a bridge, building, telegraph-pole, etc. Decorative signs of floral designs or of whitewashed hand-placed stones are often used in stationgrounds.
The materials used are wood, metal, and concrete. Stone mileposts are used by a few railways. Wood was first used, is still mostly used and is the most satisfactory and economical material for large signs. Metal is used considerably for signs of medium size and complicated form, and is satisfactory. Concrete is the least used of all, but its use, particularly for posts and small signs of simple form, is practical and is increasing.
The ends of the posts carrying large signs should be set in concrete. Wood and metal are subject to deterioration from the action of the elements, while concrete is affected to a much less extent. Metal and concrete signs and posts have not been used long enough to determine their life. The quality of the concrete has an important bearing on the life of all concrete structures. Concrete signs must be designed along mathematical lines in order to keep the cost within reasonable bounds. In general, this means first-class material and workmanship throughout, and a light structure. Metal signs are made of cast iron, wrought iron, wrought steel, a combination of the three, old rails, and old boiler flues. A combination of a wrought post and cast plate is a common practice.
[snip]The life of all metal and wood posts will be increased if they are set in a block of concrete extending several inches above the ground. All exposed surfaces should be protected by paint. The life of metal signs protected in this manner is probably from 30 to 40 years. The life of well-designed concrete signs is about the same, while the life of wood signs is from 10 to 20 years, depending on the protection employed and whether the posts are treated or untreated. The one thing that jumped out at me was the statement that “in a block of concrete extending several inches above the ground”. Makes sense to me – and is another small detail that you can include.
Concrete posts and signs should be allowed to season from 30 to 60 days before being installed. They must be handled very carefully to avoid damaging them. [snip] This could make for a scene. You could have a business/area where the concrete posts are being poured and seasoned.