Philadelphia & Reading 2-8-8-2 "Chesapeake" Locomotives of the USA

Class Details by Steve Llanso of Sweat House Media

Class N1-sa/-sb, sc, sd (Locobase 326)

Data from RDG 11 - 1926 Locomotive Diagram book and various editions of the Reading Equipment Lists supplied in May 2005 by Allen Stanley from his extensive Raildata collection. See also DeGolyer, Volume 58, pp. 377+ and 387+. (Thanks to Chris Hohl for his 30 January 2016 email noting tender differences, sb and sc number series, and a typo in a reference to the sc.) Works numbers were:


January 44890; February 45058, 45118; March 45278-45279, 45341


June 48941, 49088; July 49238, 49349; August 49487, 49546; September 49735; October 50133; December 50875, 50940


January 51080; February 51203, 51406; March 51515; April 51648, 51715; May 51769, 51827; June 51905, 51939, 51975, 51993, July 52073, 52095; August 52238

Thirty-one engines built for the Reading from 1917 to 1919. Wootten firebox heating surface included 94 sq ft (8.7 sq m) of arch tubes and syphons. This was one of the biggest examples of details that the Baldwin specification stated should be the same as those on the M-1sb Mikados shown in Locobase 9548.

Even with the enormous grate and combustion chamber, these engines were still short of breath. Their duty included pushing service on some of the Reading's 3% grades and heavy traffic.

The class was broken up in the late 1920s when the first eleven engines were converted to K1-sa and K1-sc Santa Fe-type 2-10-2s; see Locobase 83. The remaining compounds were redesignated N1-sb (1816-1830) if they had Standard stokers and N1-sc (1811-1815) if they used the Street Duplex stoker.

All of the twenty remaining engines were eventually rebuilt as N1-sd simple-expansion articulateds with four 23' x 32" cylinders; tractive effort was recalculated as 111,400 lb (50,530 kg), adhesion weight rose to 465,430 lb (211,116 kg) and engine weight grew to 500,700 lb (227,114 kg). The first four engines to be rebuilt --1811, 1816, 1818, and 1821-- were converted by 1936 with the rest completed by 1945.

All of the N1-sd locomotives lost a trailing truck between 1940 and 1944 and operated as 2-8-8-0s. Adhesion weight rose to 477,846 lb (216,748 kg) and engine weight dropped to 495,180 lb (224,610 kg).

Thanks to Chris Hohl, whose September 2012 email alerted me to the ambiguities in the original entry.

Specifications by Steve Llanso of Sweat House Media
ClassN1-sa/-sb, sc, sd
Locobase ID326
RailroadPhiladelphia & Reading
Number in Class31
Road Numbers1800-1830
Number Built31
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft)15
Engine Wheelbase (ft)55.83
Ratio of driving wheelbase to overall engine wheebase 0.27
Overall Wheelbase (engine & tender) (ft)82.98
Axle Loading (Maximum Weight per Axle) (lbs)
Weight on Drivers (lbs)435,200
Engine Weight (lbs)478,500
Tender Loaded Weight (lbs)170,000
Total Engine and Tender Weight (lbs)648,500
Tender Water Capacity (gals)8500
Tender Fuel Capacity (oil/coal) (gals/tons)15.50
Minimum weight of rail (calculated) (lb/yd)91
Geometry Relating to Tractive Effort
Driver Diameter (in)55.50
Boiler Pressure (psi)210
High Pressure Cylinders (dia x stroke) (in)26" x 32"
Low Pressure Cylinders (dia x stroke) (in)40" x 32"
Tractive Effort (lbs)97,818
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.45
Heating Ability
Firebox Area (sq ft)385
Grate Area (sq ft)108
Evaporative Heating Surface (sq ft)5747
Superheating Surface (sq ft)1436
Combined Heating Surface (sq ft)7183
Evaporative Heating Surface/Cylinder Volume292.26
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation22,680
Same as above plus superheater percentage27,216
Same as above but substitute firebox area for grate area97,020
Power L18596
Power MT348.36


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