Adam:
When I was researching some Porter locos in 1985, I found that the Porter records, drawings and archives were in the Public Archives of Canada, 395 Wellington St., Ottawa, Ontario K1A 0N3, CANADA. Ref: Andrew A. Merrilees Collection. Some parts of the collection were in the National Museum.
It's been a long time, but they were very helpful at the time. Good Luck!
Vern