Although often described as "Prairie Tanks", this pair can lay only a small claim to that characterisation. The diagram's outline suggests that this was a Mogul tank with a trailing axle added to hold up the bunker. Baldwin delivered them separately to the California Northwestern as 33-34. Operating in the Redwood Empire, the two engines were med with 4% grades and 30 deg curves.
Both of these engines were sold to the Northwestern Pacific in January 1907 and renumbered 201-202. The NWP scrapped the 201 in January 1930 and sold the 202 in October 1937.
The only set of Prairies to operate for an Espee line, this quartet was produced for the EP&NE in single units fin 1902. The EP&NE added two more in September 1904 as class Pr-2; see Locobase 13635
The class soon came under the El Paso & Southwestern when that railroad bought the EP&NE in 1905 and were renumbered 134-137. At some later date, the quartet was superheated; see Locobase 8671.
Entering service on the El Paso & Northeastern with saturated boilers (Locobase 10785), this quartet was superheated relatively early, receiving the units between February 1912 and June 1913. In the process, they acquired outside radial valve gear, cylinders with 2" greater diameter, but less heating surface and lower boiler pressure.
They wore the EP & SW herald until the Southern Pacific bought the EP & SW in 1925. At that point they were assigned to the Southern Pacific de Mexico as 700-703, where, except for the 703, they ran until scrapping in 1934-1935. 703 had one more stop to make. Modified for oil-burning and re-re-numbered 1903, this engine operated on Bay Area commuter lines until 1934.
|Specifications by Steve Llanso of Sweat House Media|
|Class||PR-3||Pr-1||Pr-1/Pr-2 - superheated||Pr-2|
|Railroad||California Northwestern (SP)||El Paso & Northeastern (SP)||El Paso & Northeastern (SP)||El Paso & Northeastern (SP)|
|Number in Class||2||4||4||2|
|Road Numbers||33-34/201-202||20-23||134-39/ 1900-1905||24-25 / 138-139|
|Builder||Burnham, Williams & Co||Burnham, Williams & Co||EP&NE||Burnham, Williams & Co|
|Locomotive Length and Weight|
|Ratio of driving wheelbase to overall engine wheebase||0.37||0.42||0.42||0.42|
|Overall Wheelbase (engine & tender)||22.50'||58.96'||58.96'|
|Axle Loading (Maximum Weight per Axle)|
|Weight on Drivers||84000 lbs||125190 lbs||136800 lbs||125190 lbs|
|Engine Weight||117100 lbs||183865 lbs||200500 lbs||183865 lbs|
|Tender Light Weight||116135 lbs||116135 lbs|
|Total Engine and Tender Weight||117100 lbs||300000 lbs||300000 lbs|
|Tender Water Capacity||6000 gals||7000 gals|
|Tender Fuel Capacity (oil/coal)|
|Minimum weight of rail (calculated)||47 lb/yard||70 lb/yard||76 lb/yard||70 lb/yard|
|Geometry Relating to Tractive Effort|
|Boiler Pressure||160 psi||180 psi||170 psi||180 psi|
|Cylinders (dia x stroke)||17" x 22"||21" x 28"||23" x 28"||21" x 28"|
|Tractive Effort||18398 lbs||27380 lbs||30576 lbs||27380 lbs|
|Factor of Adhesion (Weight on Drivers/Tractive Effort)||4.57||4.57||4.47||4.57|
|Firebox Area||91.60 sq. ft||188.30 sq. ft||188 sq. ft||185 sq. ft|
|Grate Area||14.40 sq. ft||53.50 sq. ft||53.90 sq. ft||53.40 sq. ft|
|Evaporative Heating Surface||1099 sq. ft||3520 sq. ft||2669 sq. ft||3516 sq. ft|
|Superheating Surface||494 sq. ft|
|Combined Heating Surface||1099 sq. ft||3520 sq. ft||3163 sq. ft||3516 sq. ft|
|Evaporative Heating Surface/Cylinder Volume||190.15||313.60||198.23||313.24|
|Computations Relating to Power Output (More Information)|
|Robert LeMassena's Power Computation||2304||9630||9163||9612|
|Same as above plus superheater percentage||2304||9630||10629||9612|
|Same as above but substitute firebox area for grate area||14656||33894||37074||33300|