Yup, Canadian Porcelain. They were located in Hamilton, Ontario, set up with assistance from Locke in Victor, NY. active 1912-1958. Couldn't give you a precise date but this sort of style began in the 1930s and continued for a long time. I think that style of CP logo is a little later but I haven't seen exact dates. Just a guess on my part, but I'd say 1940s-1950s.
I think it's a U-281. Current book is 5-10 but usually a pretty blue like that will be closer to 10. Nice find!!