Canadian Pacific 4-8-4 "Northern" Type Locomotives


During the 1920's Canadian Pacific experimented with a number of designs, the 3100 series is a notable example of first engines built with a one piece cast steel frame in Canada, a marked improvement over the hundreds of individual parts in traditional frames. Despite its innovative design only two were built (3100 and 3101) in 1928 in the Angus Shops in Montreal.

These 4-8-4s, built with 75" drivers, were designed as dual-purpose locomotives. However, they were used continuously for 25 years on night passenger trains between Toronto and Montreal. In keeping with CPR practice they were later converted to burn oil.

CPR favored its fleet of Hudsons for passenger service and rejected the Northerns because it concluded that they were too heavy and too slow for main line passenger trains.

Both of these step-children from CPR's steam era survive today and are on display, one at IPSCO Inc. in Regina, SK and the other at the National Museum of Science and Technology in Ottawa, ON.

Class Details by Steve Llanso

Class K1a (Locobase 244)

Data from 1930 Locomotive Cyclopedia tables and "Canadian Pacific class K-1-a, 3100-3101, Angus Shops, 1928" from Canadian Rail, No 487 (March-April 2002), pp. 78-79. (Thanks to Chris Hohl for sending a PDF of the Rail Canada articles.)

Boiler had feedwater heater and the axles had roller bearings. F H Howard, in "Selkirk to Connaught Or, from 2-10-4 to 4-10-2," The Old-Time Trains website (, last accessed 25 October 2008) says that the K1s shared the same boiler with the T1 Selkirks. Its smokebox was flanked by tall smoke-lifters

These engines proved too heavy for all but the Montreal-Toronto line, where they pulled the night trains #21 Chicago Express and #22 Overseas Express for 25 years. Don Scott gives their later history in "Former Canadian Pacific Railway Passenger Services to Montreal Via State of Maine-Saint John-Halifax" of the ROCA Archives site --, last accessed 25 October 2008.

Scott reports they were supplanted on Montreal-Toronto runs by diesels in the mid-1950s. Hopes to run them on Montreal-St John service clear through to Saint John in New Brunswick reportedly ran afoul of the US ICC's reluctance to allow them to operate in Maine. So their portion of the run ended in Megantic, Quebec. Scott adds: "CPR later sent them to Western Canada and were converted to oil burners with 3101 on passenger trains Winnipeg-Moose Jaw, Sask. and other runs and 3100 shown as freight service"

In late 2007, a Canadian Pacific survey team was to visit IPSCO's 3101, on display outside in Regina, Saskatchewan, to see if it could be restored to service.

Specifications by Steve Llanso
Locobase ID244
RailroadCanadian Pacific
Road Numbers3100-3101
BuilderCanadian Pacific
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase19.75'
Engine Wheelbase45.80'
Ratio of driving wheelbase to overall engine wheebase 0.43
Overall Wheelbase (engine & tender)87.02'
Axle Loading (Maximum Weight per Axle)
Weight on Drivers250000 lbs
Engine Weight423000 lbs
Tender Light Weight286000 lbs
Total Engine and Tender Weight709000 lbs
Tender Water Capacity14400 gals
Tender Fuel Capacity (oil/coal)18.5 tons
Minimum weight of rail (calculated) on which locomotive could run104 lb/yard
Geometry Relating to Tractive Effort
Driver Diameter75"
Boiler Pressure275 psi
Cylinders (dia x stroke)25.5" x 30"
Tractive Effort60798 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.11
Heating Ability
Firebox Area422 sq. ft
Grate Area93.50 sq. ft
Evaporative Heating Surface4931 sq. ft
Superheating Surface2112 sq. ft
Combined Heating Surface7043 sq. ft
Evaporative Heating Surface/Cylinder Volume278.07
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation25713
Same as above plus superheater percentage33426
Same as above but substitute firebox area for grate area150865
Power L150496
Power MT1781.19




Introduction and roster provided by Richard Duley. Class details and specifications provided by Steve Llanso of Sweat House Media.