This class originally entered service in the German Army to support narrow-gauge supply routes leading up to the front. They were similar to several other Mallet designs of the same era. After World War I, the Bavarian State System took over these engines to operate on the Eichstaett-Kinding line. At that point they were designated GTS 2x3/3. One eventually worked the Zell-und-Todtnau railway as 105 and was preserved on the Blonay-Chambay museum railway in Switzerland.
Reder's (1974) inclusion of a similar locomotive built for the Zell-und-Todtnau in his discussion of narrow-gauge Mallets, when taken with the 0-4-4-0T from the same line but 29 years older, illustrates how the basic layout could grow to meet requirements. In this case, oddly enough, although total cylinder volume grew, it was all in piston diameter as the stroke remained the same at a relatively short 17.7 in. The drivers, too, didn't grow, but the boiler and overall weight did, the weight more than doubling. This engine had the typical closed-in cab and a not-so-typical vase-like stack. The side tanks were relatively deep, but ended short of the forward, LP cylinders.
Principal Dimensions by Steve Llanso of Middle Run Media | |
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Class | K66/BR 99.20 |
Locobase ID | 3256 |
Railroad | German Field Railway |
Country | Germany |
Whyte | 0-6-6-0T |
Number in Class | 20 |
Road Numbers | |
Gauge | Metre |
Number Built | 20 |
Builder | Henschel & Sohn |
Year | 1917 |
Valve Gear | Heusinger |
Locomotive Length and Weight | |
Driver Wheelbase (ft / m) | 8.20 / 2.50 |
Engine Wheelbase (ft / m) | 22.97 / 7 |
Ratio of driving wheelbase to overall engine wheelbase | 0.36 |
Overall Wheelbase (engine & tender) (ft / m) | |
Axle Loading (Maximum Weight per Axle) (lbs / kg) | 19,841 / 9000 |
Weight on Drivers (lbs / kg) | 119,048 / 53,999 |
Engine Weight (lbs / kg) | 119,048 / 53,999 |
Tender Loaded Weight (lbs / kg) | |
Total Engine and Tender Weight (lbs / kg) | |
Tender Water Capacity (gals / ML) | |
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | |
Minimum weight of rail (calculated) (lb/yd / kg/m) | 33 / 16.50 |
Geometry Relating to Tractive Effort | |
Driver Diameter (in / mm) | 35.40 / 899 |
Boiler Pressure (psi / kPa) | 203 / 1400 |
High Pressure Cylinders (dia x stroke) (in / mm) | 15.75" x 17.71" / 400x450 |
Low Pressure Cylinders (dia x stroke) (in / mm) | 24.41" x 17.71" / 620x450 |
Tractive Effort (lbs / kg) | 30,239 / 13716.20 |
Factor of Adhesion (Weight on Drivers/Tractive Effort) | 3.94 |
Heating Ability | |
Tubes (number - dia) (in / mm) | 85 - 1.81" / 46 |
Flues (number - dia) (in / mm) | 18 - 5.25" / 133 |
Flue/Tube length (ft / m) | 13.78 / 4.20 |
Firebox Area (sq ft / m2) | 75.75 / 7.04 |
Grate Area (sq ft / m2) | 19.91 / 1.85 |
Evaporative Heating Surface (sq ft / m2) | 890 / 82.71 |
Superheating Surface (sq ft / m2) | 366 / 34.01 |
Combined Heating Surface (sq ft / m2) | 1256 / 116.72 |
Evaporative Heating Surface/Cylinder Volume | 222.86 |
Computations Relating to Power Output (More Information) | |
Robert LeMassena's Power Computation | 4042 |
Same as above plus superheater percentage | 5214 |
Same as above but substitute firebox area for grate area | 19,837 |
Power L1 | 5697 |
Power MT | 633.01 |