I wanted to draw your attention to the Canadian Pacific Historical Assocation's web site. The CPHA used to be known as the CP SIG, and one of their major efforts is to publish the excellent CP Tracks magazine. I've never been a subscriber but I have purchased quite a few at hobby shops.
The CPHA has undertaken a new project in the last few years, and is now making their documents library available online. The library contains a wide assortment of scanned documents, from freight and passenger car diagrams to dispatcher sheets to timetables and a lot more. A free registration is required. Check it out!