Mike & all:
What I would like to see would be the "locking Sheet" and "dog charts" for these "plants". I have never seen one for any prototype (12" = foot) type plant. I've only seen them in text/handbooks. (two partial reprints I have are Railroad Signaling by King and the 1911 Signal dictionary. Also, I have Railroad Operation and Railway signaling by Edmund J Philips (c) 1942.
The Locking Charts show all the "Lever Numbers" including two types of locks and "vacant" (for expansion, etc.)
The numbers adjacent to signal heads and switches are also the lever numbers.
Some locks lock the switches in the field while others lock the levers for switches and signals within the machine. Others called "master locks", as I remember, only the locks other locks.
The "Dog chart" is a schematic, mechanical drawing of the layout of the "Locking Bed" showing the locking rods (attached to the levers) and the locking "dogs" between the lever rods. You can see these at museums that have either mechanical or electro-mechanical" interlocking on display.
