Atlanta & West Point / Georgia Railroad / West Point Route / Western Railway of Alabama 4-6-2 "Pacific" Locomotives of the USA

Class Details by Steve Llanso of Sweat House Media

Class P (Locobase 7319)

Data from A & WP-WRA 11 - 1949 locomotive diagrams supplied in May 2005 by Allen Stanley from his extensive Raildata collection. Works numbers were 54037-54038 in June 1913.

Although relatively small and possessing a modest amount of calculated tractive effort, this design seems to have struck a good balance between cylinder volume and boiler size. It was a light Pacific with passenger-train drivers that gave decades of good service.

Class P (Locobase 11418)

Data from "Locomotive Building," The Railroad Gazette, Vol XLII, No 23 (7 June 1907), p 784-785. The Western Railway of Alabama procured another Rogers Pacific at the same time; see Locobase 11419. Works number was 43024 in March 1907.

As the RG acknowledged, this locomotive had a big boiler for its cylinder volume, observing that the ratio of 287:1 was "...a figure which would indicate a large boiler capacity for sustained high speed." Accompanying the larger boiler was a large enough grate that "there should be no difficulty, with an average grade of bituminous coal, in generating plenty of steam without forcing the fire to an uneconomical rate of combustion."

The author helpfully "calls attention" to the flexible staybolts used along the front and top of the side sheets of the firebox, the forward slope of the tubesheet, as well as 38 sq ft of arch tubes, "... all indicative of current practice."

In 1922, the 250 was rebuilt with superheaters, piston valves, and Walschaert valve gear. Renumbered 251, the engine was sold to the Georgia Railroad in 1934, which reconditioned the engine in 1937, taking the opportunity to fit it with Southern valve gear, and renumbered it 254.

Class P (Locobase 11419)

Data from "Locomotive Building," The Railroad Gazette, Vol XLII, No 23 (7 June 1907), p 784-785. Works number was 43025 in March 1907.

See Locobase 11418 for details on this 2-locomotive class, one of which went to the West Point, the other to the WRA as shown in the specs. Alco-Richmond added the 151 in 1910 that was fitted with Walschaert gear from the beginning.

Like the 250 on the WPR, the 150 was updated with superheaters, piston valves, and Walschaert valve gear in 1922-1923. Renumbered 152, the engine was sold to the Georgia Railroad in 1934. 151 was sold to the GaR in 1936 - the locomotives were renumbered 252-253 and rebuilt one more time with 73" drivers. The two served out their time on the Georgia, retiring in 1953-1954.

Class P - updated (Locobase 7326)

Data from GA 5 - 1947 locomotive diagrams supplied in May 2005 by Allen Stanley from his extensive Raildata collection.

This trio of light Pacifics originally were delivered to the Atlanta & West Point in 1907 by Rogers (works #43024) as 251 and as Western Railway of Alabama 150 (works #43025); 151 was delivered to the WRA in 1910 by Richmond (works #48868). The A & WP rebuilt 251 with piston valves and Walschaerts gear and later sold it to the GRR in 1934. WRA sold its 151 to the GRR in 1934 and added the 150 (by then renumbered 252) in 1936.

In 1938, the GRR reworked them yet again, fitting them with outside-journal trailing trucks and 254 was fitted with Southern valve gear.

This variegated threesome then served the Georgia RR until the demise of steam in 1954.

Class P-74 (Locobase 6953)

Data from locomotive diagram published by Bill Dennington on George Gelwood's website accessed 21 September 2005. Supplemented by A&WP-WRA 10 - 1945 locomotive diagrams supplied in May 2005 by Allen Stanley from his extensive Raildata collection. Works numbers were 7008-7009 in March 1926.

Dennington explains that this two-locomotive order was split between the WPR constituents Atlanta & West Point (290) and the Western Railway of Alabama (190)

His summary comment on this pair suffices: "The USRA design on locomotives was classic and beautiful. Lima built a very good version of the design when they built 290 and 190." Compared to the Southern's more famous Ps-4s, these engines had a higher superheater area and ratio and 14" piston valves. The diagram does not show if the P-74s had arch tubes, but it seems likely given the total area of the firebox.

Like the Ps-4s, the valves had outside lap of 1 1/4", full-gear lead of 1/4", but a total travel of 7", 1/2" less than the Ps-4. Dennington's comment, recorded below, that they handled heavy trains effortlessly stems in large part from having a large boiler with generous steam admission.

Dennington's experience on the 290 in 1992 as she pulled the Southern Crescent was ".... a real thrill ...290 could easily handle 16 to 18 heavy-weight coaches. She was a powerful engine. Running at fifty and sixty mph seemed to be effortless and she rode well at those speeds." He noticed that her stack talk revealed "... a fairly loud exhaust, although deeper and more resonant than the bigger Freedom Train engines."

Specifications by Steve Llanso of Sweat House Media
ClassPPPP - updatedP-74
Locobase ID7319 11,418 11,419 7326 6953
RailroadAtlanta & West Point (WPR)Atlanta & West Point (WPR)Western Railway of Alabama (WPR)Georgia Railroad (WPR)West Point Route (WPR)
Number in Class21122
Road Numbers280-281250150253-255290, 190
Number Built2112
Valve GearBakerStephensonStephensonWalschaertBaker
Locomotive Length and Weight
Driver Wheelbase (ft)1312.6712.6712.6714
Engine Wheelbase (ft)33.2532.4632.4633.7937
Ratio of driving wheelbase to overall engine wheebase 0.39 0.39 0.39 0.37 0.38
Overall Wheelbase (engine & tender) (ft)68.46606069.1772.44
Axle Loading (Maximum Weight per Axle) (lbs)54,40052,20064,500
Weight on Drivers (lbs)163,000130,000130,000151,300192,500
Engine Weight (lbs)258,000212,000212,000248,600303,500
Tender Loaded Weight (lbs)196,300133,000133,000181,100200,500
Total Engine and Tender Weight (lbs)454,300345,000345,000429,700504,000
Tender Water Capacity (gals)10,0007000700010,00011,000
Tender Fuel Capacity (oil/coal) (gals/tons)1712121515
Minimum weight of rail (calculated) (lb/yd)91727284107
Geometry Relating to Tractive Effort
Driver Diameter (in)7472727374
Boiler Pressure (psi)200200200200200
High Pressure Cylinders (dia x stroke) (in)24" x 28"22" x 28"22" x 28"23" x 28"27" x 28"
Tractive Effort (lbs)37,05131,99831,99834,49446,892
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.40 4.06 4.06 4.39 4.11
Heating Ability
Firebox Area (sq ft)273276276271327
Grate Area (sq ft)56.5555555470.80
Evaporative Heating Surface (sq ft)34583532353227373669
Superheating Surface (sq ft)894894990
Combined Heating Surface (sq ft)43523532353236314659
Evaporative Heating Surface/Cylinder Volume235.87286.71286.71203.28197.74
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation11,31011,00011,00010,80014,160
Same as above plus superheater percentage13,68511,00011,00013,50017,134
Same as above but substitute firebox area for grate area66,06655,20055,20067,75079,134
Power L121,6529570957021,93618,896
Power MT878.55486.88486.88958.90649.22



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