J F Prettyman & Company 2-6-2 "Prairie" Locomotives of the USA

Class Details by Steve Llanso of Sweat House Media

Class 6 (Locobase 14706)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University, Volume 62, p. 378. See Yale Snowden in collaboration with H G Cutler, History of South Carolina, Volume V (Chicago: Lewis Publishing Company, 1920), p. 79, as digitized at http://archive.org/stream/historysouthcar07cutlgoog/historysouthcar07cutlgoog_djvu.txt . (Thanks to Chris Hohl for his 9 May 2015 email and spreadsheet showing that the proper ID for the owner was J F Prettyman.) Works number was 53208 in April 1920.

This engine supported the lumbering operations of the J F Prettyman company based in Summerville.The Summerville & St John had operated in the 19th Century, but was reported abandoned in 1896. The line was sold to J F Prettyman in 1909.

That it was primarily a logging road is suggested by the 40 lb/yard (20 kg/metre) rail. Its main line had relatively gentle maximum curves of 10-12 degrees. This bi-fuel logging Prairie (wood and coal) was well suited to such duty.

The South Carolina history described the operation: "This lumber plant is of strictly modem construction, and turns out a high grade of material. The timber is supplied by about twenty miles of standard gauge railroad, all of which is owned and operated by the firm, as a, means of bringing in their logs and timber, of which they have a sufficient supply to operate the manufacturing plant indefinitely."

The 6 later operated for Charleston, SC's A C Tuxbury Lumber Company.

Specifications by Steve Llanso of Sweat House Media
Locobase ID14706
RailroadJ F Prettyman & Company
Number in Class1
Road Numbers6
Number Built1
Valve GearStephenson
Locomotive Length and Weight
Driver Wheelbase 9.17'
Engine Wheelbase23.50'
Ratio of driving wheelbase to overall engine wheebase 0.39
Overall Wheelbase (engine & tender)45.06'
Axle Loading (Maximum Weight per Axle)
Weight on Drivers61500 lbs
Engine Weight88400 lbs
Tender Light Weight60000 lbs
Total Engine and Tender Weight148400 lbs
Tender Water Capacity3000 gals
Tender Fuel Capacity (oil/coal)
Minimum weight of rail (calculated)34 lb/yard
Geometry Relating to Tractive Effort
Driver Diameter42"
Boiler Pressure170 psi
Cylinders (dia x stroke)14" x 22"
Tractive Effort14835 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.15
Heating Ability
Firebox Area77 sq. ft
Grate Area13.30 sq. ft
Evaporative Heating Surface1071 sq. ft
Superheating Surface
Combined Heating Surface1071 sq. ft
Evaporative Heating Surface/Cylinder Volume273.23
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation2261
Same as above plus superheater percentage2261
Same as above but substitute firebox area for grate area13090
Power L14420
Power MT475.34

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