The Canadian National Railways purchased only five Hudsons (road numbers 5700 through 5704) and designated them Class K-5a. These 4-6-4s were built by the Montreal Locomotive Works (which was part of the American Locomotive Company) and were used on fast passenger trains on the Toronto to Montreal corridor. Over all, the Hudsons were not well received by the CNR and it passed on them in favor of the 4-8-4 Northerns.

There are two surviving CNR Hudsons, number 5700 (really, 5703) at the Elgin County Railway Museum in St. Thomas, ON and number 5702 at the Canadian Railway Museum in Constant, QB.