Illinois Central 2-6-2 "Prairie" Locomotives in the USA

Class Details by Steve Llanso of Sweat House Media

Class 1001 (Locobase 5327)

Data from "Recent Locomotives of the Illinois Central Railroad," Railway Age, Volume 33, No. 23 (6 June 1902), pp. 860-862; "Prairie Type Passenger Locomotive", American Engineer and Railroad Journal, Volume 76, No 6 (June 1902), p. 199; and "Two Large Rogers Locomotives", Railway and Locomotive Engineering, Volume XV [15], No. 6 (June 1902), pp. 235, 261, and 264 . (Thanks to Chris Hohl for his 30 June 2021 email correcting the valve gear.) Works number was 5737 in April 1902.

John S Ingles (in Drury (1993)) tells us that this locomotive was procured to be compared against a single Atlantic delivered by Baldwin in the same year. After a year of trials, the Atlantic layout won and Rogers produced the batch.

RA's report conceded that the Prairies offered greater adhesive weight, as was "to be expected." "However," the report continued, " the advantage somewhat offset by a larger number of driving whels and the dependent parts, with a probable increase in cost of repairs. Moreover, the first cost for this reason is greater."

Another weakness of the Prairie arrangement was its unsteadiness. RA noted the introduction of three-point suspension hangers for the trailing truck and AERJ described the pair of yokes for each axle box saying that "from these yokes the load is applied to the boxes through initial stability links or 'three-point' hangers. RA commented that "It is believed that this manner of connecting the box to the equalizers will overcome much of the side motion and contribute to the steady riding of the engine."

This single Prairie was converted into a 4-6-2 in July 1907 and took the number of the experimental Atlantic.

Principal Dimensions by Steve Llanso of Sweat House Media

Locobase ID5327
RailroadIllinois Central (IC)
Number in Class1
Road Numbers1001
Number Built1
Valve GearStephenson
Locomotive Length and Weight
Driver Wheelbase (ft / m)13.50 / 4.11
Engine Wheelbase (ft / m)30.75 / 9.37
Ratio of driving wheelbase to overall engine wheelbase 0.44
Overall Wheelbase (engine & tender) (ft / m)62.12 / 18.93
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)140,200 / 63,594
Engine Weight (lbs / kg)210,800 / 95,617
Tender Loaded Weight (lbs / kg)147,600 / 66,950
Total Engine and Tender Weight (lbs / kg)358,400 / 162,567
Tender Water Capacity (gals / ML)7000 / 26.52
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)15 / 14
Minimum weight of rail (calculated) (lb/yd / kg/m)78 / 39
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)75 / 1905
Boiler Pressure (psi / kPa)200 / 13.80
High Pressure Cylinders (dia x stroke) (in / mm)20" x 28" / 508x711
Tractive Effort (lbs / kg)25,387 / 11515.36
Factor of Adhesion (Weight on Drivers/Tractive Effort) 5.52
Heating Ability
Tubes (number - dia) (in / mm)335 - 2" / 51
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m)19 / 5.79
Firebox Area (sq ft / m2)201.20 / 18.68
Grate Area (sq ft / m2)51.08 / 4.74
Evaporative Heating Surface (sq ft / m2)3535 / 328.44
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)3535 / 328.44
Evaporative Heating Surface/Cylinder Volume347.25
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation10,216
Same as above plus superheater percentage10,216
Same as above but substitute firebox area for grate area40,240
Power L111,152
Power MT526.09

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