Philadelphia & Reading 4-6-2 "Pacific" Locomotives of the USA

The first 30 of Reading class G1sa Pacifics were built at the Reading shops from 1916-1922. The last five of this class were built by Baldwin in 1924. With 40,900 lbs starting te and 80 inch drivers, these were certainly not light Pacifcs. They had a Wootten type firebox, designed for burning an anthracite waste product, "culm", and anthracite coal in general. Similar Pacifics were to be found on the Central New Jersey, the Lehigh Valley the Delaware, Lackawanna & Western

In 1948, Reading Shops built Class G3 (no more "s", just as on the Pennsy)) 210-219. Basically, these were developments of a later version of 124, class G2sa. They had higher boiler pressure, and such details as a Worthington SA feedwater heater and cast steel engine beds. Under the combined onslaught of diesels and the debilitating effect of declining passenger traffic, they were all gone within nine years. One of the places where they worked was on the Pennsylvania- Reading Seashore Line, during the summer rush. Actually, on PRSL runs which served PRR 30th Street, they may well have been the last steam locomotives to haul passenger trains in Philadelphia.

Class Details by Steve Llanso of Sweat House Media

Class G1-sa (Locobase 445)

Data from Railway Age Gazette (21 July 1916), pp 107-109. See also DeGolyer, Vol 74, pp. 89 + and RDG 11 - 1926 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Raildata collection. Wooten type boiler

First Pacifics (five in the order) bought by the Philadelphia and Reading. RA's report commented that the valve gear and reciprocating parts had been made as light as possible to "reduce the ill effects from the counterbalancing." The piston load per pound of reciprocating parts was 79 lb (35.8 kg) and 65% of the reciprocating parts was balanced. The result was a dynamic augment of 41.5% of the static weight at 80 mph (129 kmh). Inside-admission piston valves measured 12" (306 mm) in diameter.

Used on the Boardwalk Flyer between Philadelphia and Atlantic City. Reading built 25, Baldwin the last five in a batch (works #57756-57760) in April 1924. Baldwin built another five in 1925 with 74" drivers; see Locobase 9411.

Class G1-sb (Locobase 9411)

Data from Reading 11 - 1926 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Raildata collection. See also DeGolyer, Volume 74, pp. 102+. (Thanks to Chris Hohl for his 26 November 2015 email reporting the original tender capacity.) Works numbers were 58264-58266, 58291-58292 in March 1925.

Locobase 445 shows the lion's share of this design, the version that rolled on 80" (2,032 mm) drivers. To finish the class in 1925, the Reading bought five from Baldwin with smaller drivers. Otherwise they were repeats of the G1-sa down to the 12" (305 mm) inside-admission piston valves and wide Wootten fireboxes in a conventional-cab layout. The combustion chamber contributed 78 sq ft (7.25 sq m) to firebox heating surface area.

Original tender coal capacity was 15 tons. The entire class added brick arch and arch tubes and a Standard MB automatic stoker. 204 was later equipped with thermic syphons.

Class G2-sa (Locobase 158)

Data from tables in 1930 Locomotive Cyclopedia, supplemented by Reading 11 - 1926 Locomotive Diagram book supplied in May 2005 by Allen Stanley from his extensive Raildata collection.

Built 10 years after the first Pacifics on the Reading (Locobase 445), these Baldwins (works 59226, 59254-59258) differed only in small details. They were fitted with the large Wootten firebox fitted to most Reading engines. Westcott (1960) says these engines "were carefully designed so they could run as fast as the Reading's Atlantics". Used on the Boardwalk Flyer between Philadelphia and Atlantic City.

Specifications by Steve Llanso of Sweat House Media
Locobase ID445 9411 158
RailroadPhiladelphia & ReadingPhiladelphia & ReadingPhiladelphia & Reading
Number in Class3055
Road Numbers105-134200-204175-179
Number Built3055
Valve GearWalschaertWalschaertWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft)13.8313.8313.83
Engine Wheelbase (ft)35.5835.5835.92
Ratio of driving wheelbase to overall engine wheebase 0.39 0.39 0.39
Overall Wheelbase (engine & tender) (ft)67.9867.9872.20
Axle Loading (Maximum Weight per Axle) (lbs)61,00059,12064,860
Weight on Drivers (lbs)176,900177,210192,540
Engine Weight (lbs)273,600288,120306,360
Tender Loaded Weight (lbs)160,000183,000154,000
Total Engine and Tender Weight (lbs)433,600471,120460,360
Tender Water Capacity (gals)800090009000
Tender Fuel Capacity (oil/coal) (gals/tons)12.901615
Minimum weight of rail (calculated) (lb/yd)9898107
Geometry Relating to Tractive Effort
Driver Diameter (in)807480
Boiler Pressure (psi)220220230
High Pressure Cylinders (dia x stroke) (in)25" x 28"25" x 28"25" x 28"
Tractive Effort (lbs)40,90644,22342,766
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.32 4.01 4.50
Heating Ability
Firebox Area (sq ft)282282314
Grate Area (sq ft)94.5094.5095
Evaporative Heating Surface (sq ft)292629263045
Superheating Surface (sq ft)652652745
Combined Heating Surface (sq ft)357835783790
Evaporative Heating Surface/Cylinder Volume183.93183.93191.41
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation20,79020,79021,850
Same as above plus superheater percentage24,53224,53226,220
Same as above but substitute firebox area for grate area73,20773,20786,664
Power L118,81617,40421,822
Power MT703.48649.55749.60



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