The diesel era brought a measure of uniformity to the motive power fleets of North American railroads. In the days of steam, however, each railroad pursued its own distinctive motive power policy. As a case in point, the Canadian National Railway System owned 203 4-8-4s, more than any other railroad. Traversing the same territory under the same conditions, the Canadian Pacific rostered only two, Nos. 3100 and 3101 of class K1a. Oddly enough, both of these rare CPR 4-8-4s survive. No. 3100, shown here, is displayed at the National Museum of Science and Technology in Ottawa, Canada's capital city.

Built in 1928 in the CPR's own Angus Shops, these engines have 75-inch drivers, 25½x30-inch cylinders, and a boiler pressure of 275 pounds per square inch. With a 93.5-square-foot grate area, they have 4931 square feet of evaporative heating surface and 2112 square feet of superheater surface. The total weight of locomotive and tender is 709,000 pounds, and they are rated at 60,800 pounds of tractive effort. Reportedly they held down a nighttime passenger and mail run between Toronto and Montreal through most of their careers, so photos of them in action are scarce. This view of No. 3100 on the turntable in Toronto was provided by Tom Rock of T.D.R. Productions, but there is no information concerning the photographer and date.