Canadian Pacific 4-6-4 "Hudson" Type Locomotives

Class H1a/H1b (Locobase 5874)

These locos -- designed by Chief of Motive Power & Rolling Stock Henry Blaine Bowen -- were considered to be the cream of CPR passenger engines. The first set of 10 was delivered by MLW in 1929 with another 10 following in 1930.

This next set of 10 locomotives continued the Bowen Hudson design with slight differences. In one test reported by Railway Age in 1931, reported on a 130-mile run in which an H1 pulling a 19-car, 1,652-ton train. It's a summary of contemporary steam worked to its limit: Average steam pressure 274 psi, feedwater temperature 222 deg F, and average superheat temperatuture of 675 deg F.

One detail of the design were baffle walls under the grate and over the ashpan that diverted incoming air downward toward the center. Working in combination with 38.5 sq ft of arch tubes spaced to offer a wide brick span in the center and narrow ones at the side, the baffles kept cool air away from the sides, which reduced temperature differences and cracking. Much attention was paid during running to maintain an even temperature in the firebox.

Class H1c/H1d (Locobase 5875)

After a 7-year pause, Henry Bowen ordered another 30 Hudsons with the principal difference being the streamlining. Consisting mostly of rounded corners, the treatment was quite handsome when combined with the CP livery of black and red. Ten more came in 1938. As in the earlier engines, the firebox heating surface included 38.5 sq ft of arch tubes.

Runs of 811 miles (Toronto to Fort William) and 832 miles (Winnipeg-Calgary) made full use of the larger tenders.

The class earned British royal permission to call themselves the "Royal Hudsons" and to bear the Royal coat of arms after several of the class pulled the royal visitors around Canada in 1939.

Some of these engines ran into the mid-1960s.

Class H1e (Locobase 178)

These were the last five of Bowen's Hudsons. Like the others, the firebox heating surface included 38 sq ft of arch tubes. They were not very different from the 1937-1938 locomotives and were bought to flesh out express passenger rosters by taking on the British Columbian run between Revelstoke and Vancouver.

Specifications
Class	H1a/H1b	H1c/H1d	H1e
Locobase ID	5874	5875	178
Railroad	Canadian Pacific	Canadian Pacific	Canadian Pacific
Whyte	4-6-4	4-6-4	4-6-4
Road Numbers	2800-2819	2820-2859	2860-2864
Gauge	Std	Std	Std
Builder	Montreal LW	Montreal LW	Montreal LW
Year	1929	1937	1940
Valve Gear	Walschaert	Walschaert	Walschaert
	Locomotive Length and Weight
Driver Wheelbase	13.17'	13.17'	13.17'
Engine Wheelbase	39.50'	39.50'	39.50'
Ratio of driving wheelbase to overall engine wheebase	0.33	0.33	0.33
Overall Wheelbase (engine & tender)	80.52'	80.52'	80.88'
Axle Loading (Maximum Weight per Axle)
Weight on Drivers	183800 lbs	186800 lbs	185800 lbs
Engine Weight	351200 lbs	354000 lbs	365400 lbs
Tender Light Weight	291900 lbs	288650 lbs	229600 lbs
Total Engine and Tender Weight	643100 lbs	642650 lbs	595000 lbs
Tender Water Capacity	14400 gals	14400 gals	14400 gals
Tender Fuel Capacity (oil/coal)	20 tons	21 tons	5400 gals
Minimum weight per yard of rail on which locomotive could run	102.11 lb rail	103.78 lb rail	103.22 lb rail
	Geometry Relating to Tractive Effort
Driver Diameter	75"	75"	75"
Boiler Pressure	275 psi	275 psi	275 psi
Cylinders (dia x stroke)	22" x 30"	22" x 30"	22" x 30"
Tractive Effort	45254 lbs	45254 lbs	45254 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort)	4.06	4.13	4.11
	Heating Ability
Firebox Area	326 sq. ft	326 sq. ft	326 sq. ft
Grate Area	80.80 sq. ft	80.80 sq. ft	80.80 sq. ft
Evaporative Heating Surface	3834	3791	3791
Superheating Surface	1640	1640	1542
Combined Heating Surface	5474	5431	5333
Evaporative Heating Surface/Cylinder Volume	290.48	287.22	287.22
	Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation	22220	22220	22220
Same as above plus superheater percentage	28877.07	28929.78	28644.76
Same as above but substitute firebox area for grate area	116508.97	116721.63	115571.68
Power L1	52670.45	52558.46	50261.42
Power MT	1895.29	1860.89	1789.14