Weed Lumber 2-6-2 "Prairie" Locomotives in the USA

Class Details by Steve Llanso of Sweat House Media

Class 3 (Locobase 13041)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University Vol 29, p. 286. Works numbers were 30509 and 30519 in March 1907.

Weed Lumber began operation in 1901 under direction of Abner Weed in the town of Weed, California. Its railroad soon was sold to the California Northwestern, but the timbering lines themselves stayed under Weed control until being sold to Long-Bell Lumber.

Both engines retained their tanks but later added tenders. Perhaps with profile that included 6% grades and 20-degree curvatures, Weed wanted to maintain as much weight on their drivers as possible.

Class 7 (Locobase 14718)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University Volume 62, p. 411 and Volume 65, pp. 328+. Works numbers were 52851 in January 1920 and 53347 in June.

Weed Lumber's first two logging engines were Prairie tanks delivered in 1907 (Locobase 14718). Although satisfactory in many respects, Weed's next Baldwin logging Prairies, which arrived thirteen years later retained some of the basic dimensions, but greatly expanded others. Power dimensions (cylinder volume, driver diameter) were unchanged, although the slide valves were now operated by outside radial gear, but the boiler was pressed a little harder for more tractive effort. The tube count in the boiler remained the same as well, but each tube was longer by 42" (1.067 metres). This increased evaporative heating surface area was matched by a larger grate, but the firebox area grew by very little.

Adhesion wheelbase grew by only 3" (76 mm), but an increase in engine wheelbase reflected the longer boiler. And the engine was delivered with a separate slope-back oil-fuel tender to feed the Heintzelman System burner in the front of the firebox. (Most Baldwins used the Von Boden Ingles burner.) The fuel was described as containing 18,990 BTU per pound (more than the best Welsh coal) and a relatively heavy 19 gravity. The 8's tender held 4,000 US gallons of water (15,140 liters).

The operating environment still included 50 lb/yard (25 kg/metre) rail, 6% grades, and 20 deg curves. Once delivered, the "twins", as they were known, never left the property until successor Long Bell Lumber scrapped them in 1955.

Principal Dimensions by Steve Llanso of Sweat House Media
Locobase ID13,041 14,718
RailroadWeed LumberWeed Lumber
Number in Class22
Road Numbers3-47-8
Number Built22
BuilderBurnham, Williams & CoBaldwin
Valve GearStephensonWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m) 9.25 / 2.82 9.50 / 2.90
Engine Wheelbase (ft / m)21.67 / 6.6124.50 / 7.47
Ratio of driving wheelbase to overall engine wheebase 0.43 0.39
Overall Wheelbase (engine & tender) (ft / m)21.67 / 6.6146.50 / 14.17
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)90,000 / 40,82396,000 / 43,545
Engine Weight (lbs / kg)124,000 / 56,246123,000 / 55,792
Tender Loaded Weight (lbs / kg)72,000
Total Engine and Tender Weight (lbs / kg)124,000195,000
Tender Water Capacity (gals / ML)1600 / 6.063500 / 13.26
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)1200 / 4.501000 / 0.40
Minimum weight of rail (calculated) (lb/yd / kg/m)50 / 2553 / 26.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)44 / 111844 / 1118
Boiler Pressure (psi / kPa)160 / 11175 / 12.10
High Pressure Cylinders (dia x stroke) (in / mm)17" x 24" / 432x61017" x 24" / 432x610
Tractive Effort (lbs / kg)21,439 / 9724.5823,448 / 10635.85
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.20 4.09
Heating Ability
Firebox Area (sq ft / m2)102.50 / 9.52104 / 9.66
Grate Area (sq ft / m2)14 / 1.3021 / 1.95
Evaporative Heating Surface (sq ft / m2)1222 / 113.531664 / 154.59
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)1222 / 113.531664 / 154.59
Evaporative Heating Surface/Cylinder Volume193.81263.92
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation22403675
Same as above plus superheater percentage22403675
Same as above but substitute firebox area for grate area16,40018,200
Power L132284445
Power MT237.22306.24

All material Copyright © SteamLocomotive.com
Wes Barris