St Louis-San Francisco 4-6-4 "Hudson" Locomotives of the USA

The St. Louis-San Francisco Railroad converted 10 of its older 4-6-2 Pacifics into 4-6-4 Hudsons. These Pacifics were built by the Baldwin Locomotive Works in 1917. Five of the conversions were completed in 1937, two more in 1940 and the last three in 1941. These 10 new oil burners were given road numbers 1060 through 1069.

Class Details by Steve Llanso of Sweat House Media

Class 1060 (Locobase 165)

Data from 1947 and 1951 St L-SF locomotive diagram books supplied in May 2005 from the extensive collection of Allen Stanley. (Thanks to Chris Hohl for correcting the valve gear ID.) See also, Springfield-Greene County Library District Springfield, Missouri, last accessed 15 September 2014 at, which archives photos of many of the class.1062, 1064-1066 were converted in 1937, 1063 and 1068 in 1940, and 1060-1061, 1067 in 1941.

Originally delivered in 1917 as Pacifics with Jacobs-Shupert fireboxes; see Locobase 8535. These leaked and were generally unsatisfactory. Only in 1937, however, were these rebuilt as the powerful 4-6-4s as shown here. Frisco mechanics substantially increased grate and firebox areas and the firebox heating surface was enhanced by one thermic syphon. Inside the boiler, installation of ten more superheater flues in place of several dozen tubes resulted in an increase in superheater area of 240 sq ft (22.3 sq m). 13" (341 mm) piston valves supplied steam to the cylinders.

A cosmetic update featured a wide valence above the running gear on both sides that had "The Frisco Lines" enclosed in a long red diamond. Its tender was also emblazoned with similar livery, except that the red diamond embraced the engine's number.

Photographs show that the class retained the color bands up to the time the engines were scrapped. The 1951 diagram book notes that the class was "dismissed from service" between 23 October 1950 and 23 January 1952.

Specifications by Steve Llanso of Sweat House Media
Locobase ID165
RailroadSt Louis-San Francisco (Frisco/(SLSF)
Number in Class10
Road Numbers1060-1069
Number Built
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase13'
Engine Wheelbase38.83'
Ratio of driving wheelbase to overall engine wheebase 0.33
Overall Wheelbase (engine & tender)83.71'
Axle Loading (Maximum Weight per Axle)64000 lbs
Weight on Drivers189400 lbs
Engine Weight360960 lbs
Tender Light Weight242000 lbs
Total Engine and Tender Weight602960 lbs
Tender Water Capacity13300 gals
Tender Fuel Capacity (oil/coal)4500 gals
Minimum weight of rail (calculated)105 lb/yard
Geometry Relating to Tractive Effort
Driver Diameter74"
Boiler Pressure225 psi
Cylinders (dia x stroke)26" x 28"
Tractive Effort48919 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.87
Heating Ability
Firebox Area351 sq. ft
Grate Area82.55 sq. ft
Evaporative Heating Surface3976 sq. ft
Superheating Surface1235 sq. ft
Combined Heating Surface5211 sq. ft
Evaporative Heating Surface/Cylinder Volume231.08
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation18574
Same as above plus superheater percentage23031
Same as above but substitute firebox area for grate area97929
Power L127169
Power MT948.74



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