Twin Falls Logging Company 2-8-2 "Mikado" Locomotives in the USA


Class Details by Steve Llanso of Sweat House Media

Class 101 (Locobase 12596)

Data from Baldwin Logging Locomotives 1913 Catalogue, p.49. Works number was 37539 in February 1912.

This Yacolt, Washington company obviously saw the relatively new Mikado wheel arrangement as a way to spread the power of large boiler over another axle. The low drivers certainly indicate a low-speed life, which is also suggested by the ruling grade of 5%, curves of 24 degrees radius (but the engine had to be designed for 30-degree curves), and rail weights of 56 lb/yard (28 kg/metre).

Twin Falls would be bought by Clark County Timber in 1917, and that line would be taken over by Weyerhaueser in 1924. At that point, 101 was be renumberd 103.


Class 102 (Locobase 13705)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University, Volume 41, p. 25. Works numbers were 37496-37497 in January 1912.

Apair of standard Baldwin oil-burning, saturated-boiler logging Mikados, these engines operated for the Twin Falls of Yacolt, Wash. The front truck had a swing of 5 1/4" to each side of center and the rear truck 5 7/8", leeway that suggests the tight, curvy alignment over which the 102-103 had to operate. In addition to the 35-degree curves, ruling grades of 4% and rail weights of 56 lb/yard (28 kg/metre) called for a light, but powerful design.

According to a "Hereafter" note entered in the specs on 1/17/1912: "In order to improve the appearance of the engine, and to give a better arrangement of sandbox and dynamo, the dome should be moved ahead about 12"."

In 1917, they went to the Clark County Timber Company of Klamath Falls, Ore. When Weyerhaeuser Timber Company took over the CCTC, the 102-103 became quite simply the 1 and 2.

Specifications by Steve Llanso of Sweat House Media
Class101102
Locobase ID12,596 13,705
RailroadTwin Falls Logging CompanyTwin Falls Logging Company
CountryUSAUSA
Whyte2-8-22-8-2
Number in Class11
Road Numbers101102-103
GaugeStdStd
Number Built11
BuilderBaldwinBaldwin
Year19121912
Valve GearWalschaertStephenson
Locomotive Length and Weight
Driver Wheelbase (ft / m)13.08 / 3.9912.08 / 3.68
Engine Wheelbase (ft / m)27 / 8.2327.25 / 8.31
Ratio of driving wheelbase to overall engine wheebase 0.48 0.44
Overall Wheelbase (engine & tender) (ft / m)23.62 / 7.2049.96 / 15.23
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)138,500 / 62,823111,000 / 50,349
Engine Weight (lbs / kg)174,650 / 79,220139,000 / 63,049
Tender Loaded Weight (lbs / kg)80,350 / 36,44670,000 / 31,752
Total Engine and Tender Weight (lbs / kg)255,000 / 115,666209,000 / 94,801
Tender Water Capacity (gals / ML)4000 / 15.153500 / 13.26
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)2000 / 7.601600 / 6.10
Minimum weight of rail (calculated) (lb/yd)5846
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)48 / 121944 / 1118
Boiler Pressure (psi / kPa)170 / 11.70180 / 12.40
High Pressure Cylinders (dia x stroke) (in / mm)20.5" x 28" / 521x71118" x 24" / 457x610
Tractive Effort (lbs / kg)35,424 / 16068.0827,039 / 12264.70
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.91 4.11
Heating Ability
Firebox Area (sq ft / m2)149 / 13.85140 / 13.01
Grate Area (sq ft / m2)41.30 / 3.8425.50 / 2.37
Evaporative Heating Surface (sq ft / m2)3157 / 293.402108 / 195.84
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)3157 / 293.402108 / 195.84
Evaporative Heating Surface/Cylinder Volume295.14298.22
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation70214590
Same as above plus superheater percentage70214590
Same as above but substitute firebox area for grate area25,33025,200
Power L149615244
Power MT315.87416.61