RAILROAD SIGNALS of the U.S.
MEMBER SIGNAL ASPECTS
I picked up an CORA rulebook a couple of years ago off of EBay, this is from page 1-3 out of it.
This is page 2-5 out of the CORA book.
This is page 4-11 out of the CORA book.
These are pages 5-5 and 5-7 out of the CORA book.