I’ve come across a website, Railroaded, that has information about derailments in Canada and related reports issued by Transport Canada. It’s a good read and highlights the types of issues that can and do lead to derailments. It’s worth a look.
Crossing the Seguin on a Misty Day (November 2012)
For detailed info, Transportation Safety Board reports are available on their website:
http://www.tsb.gc.ca/eng/rapports-reports/rail/index.asp