Hi PoStat
The one I use for the majority of my collection is titled "Catalogue of Canadian Railway Cancellation and Related Transportation Postmarks" by Lewis M. Ludlow - F.R.P.S.L. and there is another one, long out of print, but still informative and quite useful titled "A History of Canadian R.P.O.s 1853 - 1967" by L.F. Gillam - F.C.P.S.
You might want to try this link:
http://www.iankimmerly.com/books/ This dealer has a lot of Canadian philatelic reference books for sale.
Chimo
Bujutsu