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
Class6
Locobase ID14,706
RailroadJ F Prettyman & Company
CountryUSA
Whyte2-6-2
Number in Class1
Road Numbers6
GaugeStd
Number Built1
BuilderBaldwin
Year1920
Valve GearStephenson
Locomotive Length and Weight
Driver Wheelbase (ft) 9.17
Engine Wheelbase (ft)23.50
Ratio of driving wheelbase to overall engine wheebase 0.39
Overall Wheelbase (engine & tender) (ft)45.06
Axle Loading (Maximum Weight per Axle) (lbs)
Weight on Drivers (lbs)61,500
Engine Weight (lbs)88,400
Tender Loaded Weight (lbs)60,000
Total Engine and Tender Weight (lbs)148,400
Tender Water Capacity (gals)3000
Tender Fuel Capacity (oil/coal) (gals/tons)
Minimum weight of rail (calculated) (lb/yd)34
Geometry Relating to Tractive Effort
Driver Diameter (in)42
Boiler Pressure (psi)170
High Pressure Cylinders (dia x stroke) (in)14" x 22"
Tractive Effort (lbs)14,835
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.15
Heating Ability
Firebox Area (sq ft)77
Grate Area (sq ft)13.30
Evaporative Heating Surface (sq ft)1071
Superheating Surface (sq ft)
Combined Heating Surface (sq ft)1071
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 area13,090
Power L14420
Power MT475.34


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