How many ligging lines actually had rule books? We're not aware that the Diamond & Caldor Ry. ever had such a book.
I suspect that short line narrow gauge line had rule books.
We're collecting period mailine rule books to use in our proposed tourist railway and using them as a guide. Although I'm not an expert at such things, I'm sure that we'll also have to make sure our rules meet FRA regulations when everything comes to fruition.
Steven