That is amazing Ed. Excellent work.
I mentioned the Plasticville switch tower earlier in this tread. I used three of them on my layout, which rather followed B&O practices.
Here is 1906 B&O drawing for a 12' x 15' switch tower, on which the Plasticville tower is based.
In a 8 1/2" x 11" copy of B&O's 1917 book of "Standard Plans for Maintenance of Way and Construction" (Barnard Roberts & Co., Trains and Stuff Limited, 1996) there is a set of standard towers, all built t to the same design and vary only by floor size: 12' x 12', 3 windows on side and on front. Next is the 12' x 15', 3 side windows, 4 in front. The 12' x 18' has 3 side windows and 5 in front. There was also a 12' x 21' tower with 3 side windows and 6 in front. The largest of the 12' wide towers had 3 side windows and 7 in front.
I often have toyed with the idea of bashing two or more Plasticville towers to make a larger one.
OK So now we see how the prototype tower was designed. These B&O drawings also show just how the footers, framing, siding and roof were done.
In the field, a crew would drop off materials needed to build the structure. Other crews came to set the foundation, yet another to erect the structure and other crews to finish and equip it. For the most part, elaborate sets of plans were not used, unless there was some unusual thing to consider for it's location or functionality. "Mirror Image" structures were easily built as well, if that fitted the situation. All crews knew well how to build to B&O standards.
Plasticville's execution of the B&O switch tower is close in appearance, but it's not exact. The Plasticville tower is wider, using a 4 window side (and front) making it a 15' x15" tower. B&O did use a 15' wide design but it was 30' long, with 9 windows! Still, for me it was 'livable.' I changed the tower's original stack to a plain stove pipe, and added a propane tank at it's base. So a gas heater has replaced the old coal stove up in the tower! This tower is painted B&O Indian Red with black trim. The colors were used from the 1920's to the 1940's. Some B&O structures still in red by the 1950's when light buff with dark brown or black trim was coming into favor.