CNR/GTW Hudson Specifications

Canadian National / Grand Trunk Western 4-6-4 “Hudson” Locomotives in Canada

Class Details by Steve Llanso of Sweat House Media

Class K-5-a (Locobase 177)

Data from CN to 1953 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. (Thanks to Chris Hohl for his 30 January 2016 noting the booster’s tractive effort and for his 22 September 2017 email reporting unlikely boiler pressure values for 177 entries. A Locobase macro caused the error .)) Works numbers were 68394-68396 in September 1930, 68540-68541 in October. The Canadian National’s only essay in Hudsons, these were clearly express machines and ran for years trailing the expresses from Montreal to Toronto. K-5s also pulled the International Limited that ran from Toronto through Windsor and Detroit to Chicago on the Grand Trunk’s metals. But, according to Wes Barris of, the CNR wasn’t crazy about the 4-6-4 arrangement and bought only 4-8-4s from that point on. Even so, the last K-5 wasn’t retired until 1967. When the class was headed for the ferroequine knacker’s yard, the CN had decided to preserve the class leader. Well, as often happens in such things, someone failed to get the word and 5700 had already been sliced into with the cutting torch when the mistake was discovered. To preserve appearances, 5703, which was still whole, was renumbered 5700 and is now on display at the Elgin County Railway Museum in St Thomas, Ontario. 5702 went on display for the Canadian Railroad Historical Association in Delson, PQ.

Class K2/X-10a (Locobase 2454)

Data from CNR locomotive diagram published on [] (confirmed 3 March 2003). This is part of a Steamtown special report on this class. (Thanks to Chris Hohl for the valve gear ID.) See also “Grand Trunk,” Railway Age Gazette, Volume 58 (19 March 1915), pp. 628-629. Works numbers were 54894-54896 in September 1914. The RAG report notes an increase in demand, the use of heavier cars (137,000 lb vs 75,000 lb/62,142 kg vs 34,019 kg for the older cars), and longer trains led to the replacement of the 4-4-2Ts then in service with this design. The result was the ability to pull seven cars instead of the five hauled by earlier locomotives. It had a Gaines combustion chamber and the Security brick arch. “This combination secures complete combustion,” the report continued, “the back end of the firebox being more fully utilized with a resulting increase in the generation of steam; and the amount of smoke is reduced to a minimum.” (For a full description of the Gaines combustion chamber’s intended effect on combustion, see Locobase 4228.) Built for commuter service from Montreal where they ran until they were retired in 1956-1961.

Principal Dimensions by Steve Llanso of Sweat House Media
Locobase ID177 2454
RailroadCanadian National (CNR)Grand Trunk Western (CNR)
Number in Class56
Road Numbers5700-57041540-1545/45-47
Number Built56
BuilderMontreal LWMontreal LW
Valve GearBakerWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)14 / 4.2715.67 / 4.78
Engine Wheelbase (ft / m)40.17 / 12.2439.37 / 12
Ratio of driving wheelbase to overall engine wheelbase0.350.40
Overall Wheelbase (engine & tender) (ft / m)79.53 / 24.2439.37 / 12
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)188,600 / 85,548146,000 / 66,225
Engine Weight (lbs / kg)356,400 / 161,661275,000 / 124,738
Tender Loaded Weight (lbs / kg)303,500 / 137,665
Total Engine and Tender Weight (lbs / kg)659,900 / 299,326275,000
Tender Water Capacity (gals / ML)16,800 / 63.642900 / 10.98
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)19.80 / 185 / 5
Minimum weight of rail (calculated) (lb/yd / kg/m)105 / 52.5081 / 40.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)80 / 203263 / 1600
Boiler Pressure (psi / kPa)275 / 19210 / 14.50
High Pressure Cylinders (dia x stroke) (in / mm)23″ x 28″ / 584×71121″ x 26″ / 533×660
Tractive Effort (lbs / kg)43,279 / 19631.0532,487 / 14735.87
Booster (lbs)10,000
Factor of Adhesion (Weight on Drivers/Tractive Effort)4.364.49
Heating Ability
Tubes (number – dia) (in / mm)44 – 2.25″ / 57191 – 2″ / 51
Flues (number – dia) (in / mm)146 – 3.5″ / 8926 – 5.375″ / 137
Flue/Tube length (ft / m)19.08 / 5.8211.83 / 3.61
Firebox Area (sq ft / m2)345 / 32.05160 / 14.86
Grate Area (sq ft / m2)73.60 / 6.8447 / 4.37
Evaporative Heating Surface (sq ft / m2)3377 / 313.731786 / 165.92
Superheating Surface (sq ft / m2)1465 / 136.10342 / 31.77
Combined Heating Surface (sq ft / m2)4842 / 449.832128 / 197.69
Evaporative Heating Surface/Cylinder Volume250.89171.40
Computations Relating to Power Output (More Information)
Robert LeMassena’s Power Computation20,2409870
Same as above plus superheater percentage26,31211,449
Same as above but substitute firebox area for grate area123,33838,976
Power L149,81611,986
Power MT1746.96542.97


All material Copyright © Wes Barris

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