St. Paul & Tacoma Logging Co 2-6-6-2 Locomotives of the USA

Class Details by Steve Llanso of Sweat House Media

Class unknown (Locobase 4063)

Data from . See also DeGolyer, Vol 71, pp. 358+. Works numbers were 56322 in March 1923 and 57600 in January 1924.

This was an unusual variant on the basic Baldwin articulated-tank in several ways. Whereas the typical example had superheaters and piston valves on all cylinders and were equipped with either saddle tanks or long rectangular tanks, this pair had saturated boilers and slide valves feeding both HP and LP cylinders. Boxy tanks relatively high on the boiler and separated into two units per side. The 7's tanks were connected side-to-side by 5" (127 mm) pipes at the bottom and 6" (152 mm) pipes between the ends on each side at the bottom. 10 had larger pipes.

Two "Hereafter" notes entered in the specs on 16 February 1926 suggested raising questions, one "as to raising cab roof and windows" and the other "about changing articulation joint to a hinged construction. Company reported broken frames on 16 28 46 1/4 DD 13."

The pair operated out of Ohop, Wash until 1950, when they were both retired and scrapped.

Specifications by Steve Llanso of Sweat House Media
Locobase ID4063
RailroadSt. Paul & Tacoma Logging Co
Number in Class2
Road Numbers7, 10
Number Built2
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase8'
Engine Wheelbase37.75'
Ratio of driving wheelbase to overall engine wheebase 0.21
Overall Wheelbase (engine & tender)37.75'
Axle Loading (Maximum Weight per Axle)
Weight on Drivers176000 lbs
Engine Weight208000 lbs
Tender Light Weight
Total Engine and Tender Weight208000 lbs
Tender Water Capacity2500 gals
Tender Fuel Capacity (oil/coal)1000 gals
Minimum weight of rail (calculated)49 lb/yard
Geometry Relating to Tractive Effort
Driver Diameter44"
Boiler Pressure200 psi
High Pressure Cylinders (dia x stroke)17" x 24"
Low Pressure Cylinders (dia x stroke)26" x 24" (2)
Tractive Effort37545 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.69
Heating Ability
Firebox Area126 sq. ft
Grate Area26.20 sq. ft
Evaporative Heating Surface2083 sq. ft
Superheating Surface
Combined Heating Surface2083 sq. ft
Evaporative Heating Surface/Cylinder Volume330.37
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation5240
Same as above plus superheater percentage5240
Same as above but substitute firebox area for grate area25200
Power L12698
Power MT202.77

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