Hoghead: I took these out of the 1962 revision. The Canadian Trackside Guide has the current Canadian rules -- All the numbers have been changed and the station protection signals and grade signals have been dropped. There are a lot of additions (I count 30 rules) including 409 Advance clear to stop which is flashing yellow, flashing yellow over red, or flashing yellow over red over red.
(If anyone wants the current version, the Trackside Guide 2005 is Cdn $29.95.)
I saw a comment that the most efficient railway would have every train coming on every signal just as it turned from red to yellow.