Wabash 4-6-4 "Hudson" Locomotives of the USA

The Wabash Railroad, in need of passenger locomotives during World War II, coverted five of its older Class K-5 "Mikados" into 4-6-4s. These new locomotives, designated Class P-1 (road numbers 700 through 704), were rebuilt in the Decatur Shops during 1943 and 1944.

The five K-5s used to build these "Hudsons" were bought from the American Locomotive Company in 1925 and were the only three-cylinder 2-8-2s on the Wabash.

Later, in 1946 and 1947, a pair of the two cylinder Class K-5s were also converted into "Hudsons" and were assigned road numbers 705 and 706.

All seven of the Class P-1 "Hudsons" were scrapped in 1956.

Class Details by Steve Llanso of Sweat House Media

Class P1 (Locobase 189)

Five of these locomotives were rebuilt by the Wabash in 1943 from K-5 class 2-8-2 engines originally built by Alco in 1925. Two more followed after World War II, but were derived from earlier K-4s. They lost a cylinder and a driving axle, had larger drivers, and were fitted with roller bearings. The firebox heating surface included 32 sq ft of arch tubes.

The engines were semi-streamlined with long "elephant ears" and given a light blue paint scheme with a broad white stripe along the running boards; the tenders received a similar paint job.

They ran until 1956.

Specifications by Steve Llanso of Sweat House Media
Locobase ID189
Number in Class7
Road Numbers700-706
Number Built7
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase14'
Engine Wheelbase40.58'
Ratio of driving wheelbase to overall engine wheebase 0.34
Overall Wheelbase (engine & tender)75.46'
Axle Loading (Maximum Weight per Axle)65570 lbs
Weight on Drivers196390 lbs
Engine Weight374680 lbs
Tender Light Weight208000 lbs
Total Engine and Tender Weight582680 lbs
Tender Water Capacity12000 gals
Tender Fuel Capacity (oil/coal)16 tons
Minimum weight of rail (calculated)109 lb/yard
Geometry Relating to Tractive Effort
Driver Diameter80"
Boiler Pressure220 psi
Cylinders (dia x stroke)26" x 28"
Tractive Effort44244 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.44
Heating Ability
Firebox Area341 sq. ft
Grate Area71 sq. ft
Evaporative Heating Surface4225 sq. ft
Superheating Surface1051 sq. ft
Combined Heating Surface5276 sq. ft
Evaporative Heating Surface/Cylinder Volume245.55
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation15620
Same as above plus superheater percentage18744
Same as above but substitute firebox area for grate area90024
Power L126236
Power MT883.55



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