Lehigh Valley 2-6-2 "Prairie" Locomotives in the USA

Class Details by Steve Llanso of Sweat House Media

Class I-1 (Locobase 12614)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University, Volume 24, p. 290. Works numbers were 20574-20575, 20600-20601 in June 1902; 22464, 22472, 22485, 22487 in July 1903; 24384-24385 in June 1904.

During the brief North American infatuation with the Prairie wheel arrangement for express passenger locomotives, the Lehigh Valley bought the only camelback 2-6-2s. And they didn't skimp, adopting a large grate and big boiler for the relatively small cylinder volume.

They were rebuilt in 1906 with a four-wheel leading truck and redesignated K-2, thus following the trend toward use of the Pacific wheel arrangement.

Principal Dimensions by Steve Llanso of Sweat House Media
Locobase ID12,614
RailroadLehigh Valley (LV)
Number in Class10
Road Numbers790-799 / 2230-2239
Number Built10
BuilderBurnham, Williams & Co
Valve GearStephenson
Locomotive Length and Weight
Driver Wheelbase (ft / m)13.50 / 4.11
Engine Wheelbase (ft / m)31.25 / 9.52
Ratio of driving wheelbase to overall engine wheebase 0.43
Overall Wheelbase (engine & tender) (ft / m)
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)135,000 / 61,235
Engine Weight (lbs / kg)200,000 / 90,719
Tender Loaded Weight (lbs / kg)130,000 / 58,967
Total Engine and Tender Weight (lbs / kg)330,000 / 149,686
Tender Water Capacity (gals / ML)6500 / 24.62
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)
Minimum weight of rail (calculated) (lb/yd / kg/m)75 / 37.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)76.50 / 1943
Boiler Pressure (psi / kPa)200 / 13.80
High Pressure Cylinders (dia x stroke) (in / mm)22" x 26" / 559x660
Tractive Effort (lbs / kg)27,964 / 12684.27
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.83
Heating Ability
Firebox Area (sq ft / m2)212.80 / 19.78
Grate Area (sq ft / m2)87.70 / 8.15
Evaporative Heating Surface (sq ft / m2)3670 / 341.08
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)3670 / 341.08
Evaporative Heating Surface/Cylinder Volume320.83
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation17,540
Same as above plus superheater percentage17,540
Same as above but substitute firebox area for grate area42,560
Power L110,553
Power MT517.01

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