Thompson Brothers Logging Company / Thompson Brothers Lumber Company 2-6-2 "Prairie" Locomotives of the USA

Class Details by Steve Llanso of Sweat House Media

Class 10 (Locobase 13642)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University Volumes 34, p. 295. See also the Tap-Line Case summary at . (Thanks to Chris Hohl for his 28 February 2015 email giving the tender's fuel capacity.) Works numbers were 34465, 34555 in April 1910; 35574 in November; and 36571 in May 1911.

This lumber company was based in Doucette, Texas and clearly had some money - at least enough to buy four small wood-burning Prairies. The relatively light tenders held only 2 1/4 cords of wood.

They logged about 38,500 acres of timber in Tyler County. The 6 worked for the Thompson & Tucker Lumber Company. 11 and 12 were eventually sold to the Rock Creek Lumber Company of Trinity, Texas, which was bought out by Texas Long-Leaf Lumber Company.

Class 100 (Locobase 14305)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University, Vol 52, pp. 340. (Thanks to Chris Hohl for his 22 February 2015 email supplying the tender's fuel capacity.) Works number was 42615 in October 1915.

When this Texas timber company came back to Baldwin for another locomotive, they opted for a larger engine than the design they'd stocked up with in 1910-1911 (Locobase 13642). It too was a wood-burner and its tender held 3 1/2 cords of wood.

In its first couple of years of service, the 100 served several lumber companies in the area, starting with Rock Creek Lumber of New Willard, then its parent Texas Long Leaf Lumber. Texas Long Leaf's Burton Swartz Supply sold the 100 to Carbur Logging.

Specifications by Steve Llanso of Sweat House Media
Locobase ID13642 14305
RailroadThompson Brothers Lumber CompanyThompson Brothers Logging Company
Number in Class41
Road Numbers10, 6, 11-12100
Number Built41
Valve GearStephensonWalschaert
Locomotive Length and Weight
Driver Wheelbase 9.17' 9.17'
Engine Wheelbase23.75'24.67'
Ratio of driving wheelbase to overall engine wheebase 0.39 0.37
Overall Wheelbase (engine & tender)48.83'
Axle Loading (Maximum Weight per Axle)
Weight on Drivers63300 lbs88000 lbs
Engine Weight87600 lbs117500 lbs
Tender Light Weight60000 lbs80000 lbs
Total Engine and Tender Weight147600 lbs197500 lbs
Tender Water Capacity3000 gals4000 gals
Tender Fuel Capacity (oil/coal)
Minimum weight of rail (calculated)35 lb/yard49 lb/yard
Geometry Relating to Tractive Effort
Driver Diameter41"44"
Boiler Pressure180 psi170 psi
Cylinders (dia x stroke)15" x 20"16" x 24"
Tractive Effort16793 lbs20177 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.77 4.36
Heating Ability
Firebox Area93 sq. ft120 sq. ft
Grate Area14 sq. ft15.60 sq. ft
Evaporative Heating Surface1000 sq. ft1602 sq. ft
Superheating Surface
Combined Heating Surface1000 sq. ft1602 sq. ft
Evaporative Heating Surface/Cylinder Volume244.46286.84
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation25202652
Same as above plus superheater percentage25202652
Same as above but substitute firebox area for grate area1674020400
Power L144054915
Power MT460.25369.40

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