This Yacolt, Washington company obviously saw the relatively new Mikado wheel arrangement as a way to spread the power of a 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).
Like many loggers from this period, the 101 was oil fired using the Von Boden-Ingles burner. Its inside link valve motion actuated Richardson balanced slide valves.
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.
A pair 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"." Another note, one typical of logging company experience, involved beefing up components: "Apply heavier cast steel rear equalizing beams."
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.
|Principal Dimensions by Steve Llanso of Sweat House Media|
|Railroad||Twin Falls Logging Company||Twin Falls Logging Company|
|Number in Class||1||1|
|Locomotive Length and Weight|
|Driver Wheelbase (ft / m)||13.08 / 3.99||12.08 / 3.68|
|Engine Wheelbase (ft / m)||27 / 8.23||27.25 / 8.31|
|Ratio of driving wheelbase to overall engine wheebase||0.48||0.44|
|Overall Wheelbase (engine & tender) (ft / m)||23.62 / 7.20||49.96 / 15.23|
|Axle Loading (Maximum Weight per Axle) (lbs / kg)|
|Weight on Drivers (lbs / kg)||138,500 / 62,823||111,000 / 50,349|
|Engine Weight (lbs / kg)||174,650 / 79,220||139,000 / 63,049|
|Tender Loaded Weight (lbs / kg)||80,350 / 36,446||70,000 / 31,752|
|Total Engine and Tender Weight (lbs / kg)||255,000 / 115,666||209,000 / 94,801|
|Tender Water Capacity (gals / ML)||4000 / 15.15||3500 / 13.26|
|Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)||2000 / 7.60||1600 / 6.10|
|Minimum weight of rail (calculated) (lb/yd / kg/m)||58 / 29||46 / 23|
|Geometry Relating to Tractive Effort|
|Driver Diameter (in / mm)||48 / 1219||44 / 1118|
|Boiler Pressure (psi / kPa)||170 / 11.70||180 / 12.40|
|High Pressure Cylinders (dia x stroke) (in / mm)||20.5" x 28" / 521x711||18" x 24" / 457x610|
|Tractive Effort (lbs / kg)||35,424 / 16068.08||27,039 / 12264.70|
|Factor of Adhesion (Weight on Drivers/Tractive Effort)||3.91||4.11|
|Firebox Area (sq ft / m2)||149 / 13.85||140 / 13.01|
|Grate Area (sq ft / m2)||41.30 / 3.84||25.50 / 2.37|
|Evaporative Heating Surface (sq ft / m2)||3157 / 293.40||2108 / 195.84|
|Superheating Surface (sq ft / m2)|
|Combined Heating Surface (sq ft / m2)||3157 / 293.40||2108 / 195.84|
|Evaporative Heating Surface/Cylinder Volume||295.14||298.22|
|Computations Relating to Power Output (More Information)|
|Robert LeMassena's Power Computation||7021||4590|
|Same as above plus superheater percentage||7021||4590|
|Same as above but substitute firebox area for grate area||25,330||25,200|