After the Central of Georgia came under the control of the Illinois Central Railroad in 1909, tracks and bridges were strengthened which made it possible for the railroad to use heavier locomotives. Beginning in 1912, heavier "Pacifics" designated as Class P-2 started to arrive. There were ten, road numbers 1651 through 1660 (later renumbered 431 through 440) delivered from Baldwin in 1912 and 1913 and four, road numbers 1661 through 1664 (later renumbered 441 through 444) built by the Lima Locomotive Works and delivered in 1916. These locomotives had 23 x 28 cylinders, 69" drivers, a 200 psi boiler pressure, exerted 36,493 lbs of tractive effort and each weighed 222,300 pounds.
Two Class P-1 locomotives, numbers 419 and 425, were destroyed on July 23, 1936 as a result of a head on collision between the two passenger trains they were leading. The rest of the Class P-1 and Class P-2 "Pacifics" were retired beginning in the late 1940's and all were scrapped by 1952.
Drury (1993) describes these as "typical early Pacifics" that had slide valves and inside bearings. The specs included the builder's guarantee that the engines would "haul 12 cars not exceeding 675 tons at an average speed of 40 mph between Macon and Atlanta, a helper to be used on the 40 ft [sic] grade out of Macon."
The diagram book shows the superheated upgrade (Locobase 4227). Most received 12" (305 mm) piston valves.
They lasted throughout the steam era, the first being retired in 1939, the last in 1952.
When the C of Ga superheated its slide-valve, Stephenson-motion Pacifics (Locobase 7938), they transacted the usual trade-off between boiler tubes and superheater flues. Unlike many such Pacific overhauls, the resulting heating surface total dropped considerably because of the small diameter of the boiler. Most received 12" piston valves.
Drury (1993) comments that despite the higher weight these engines were still light Pacifics. Still, these P-2s had much bigger grates and larger cylinders (and superheaters when delivered) than the P-1s they joined on the C of Ga (Locobase 7938).
Direct heating surface area in the spacious modified-Wootten firebox included a short Gaines half-wall combustion chamber that subdivided the 132" (3.35 m) length of the firebox. The R&ER's 1912 description of the Gaines half-wall is about as clear as any Locobase has seen. An even more detailed discussion is available in Anthony's dissection of combustion in fireboxes.
As noted in other entries, the wall's height fell well short of the internal firebox dimensions. In this case, it stood 31" (787 mm) behind the boiler's rear tube sheet. Its top had a ledge that extended 6" (152 mm) to the rear. Five equally spaced 2" (50.8 mm) diameter ducts standing vertically within the wall drew air from below and let it escape through openings under the ledge.
"This air," the description explained, "mingles with the gases just as they pass over the [Gaines brick ] arch and furnishes the oxygen needed to complete combustion. At the same time, the projecting ledge tends to deflect the [heated] gases against the back sheet and the rear of the crown sheet, and so increases the value of these parts as heating surfaces."
Locobase wonders if deflecting hot gas so it struck part of the back sheet and crown sheet caused problems through stresses induced by differing temperatures.
The grate area was figured on the 88" (2.235 m) length behind the Gaines wall.
Some time after the Lima quartet was delivered to fill out the P-2 stud in 1916 (Locobase 4228), all of the engines were updated beginning in the late 1920s or early 1930s with more grate area and firebox heating surface area. It now included 13.3 sq ft (1.25 sq m) of arch tubes and 53 sq ft (4.9 sq m) of syphons. Tube count decreased by 12 while adhesion weight rose by over four tons.
Most ran to the end of steam in the early 1950s, although at least one engine was scrapped in 1935. (Likely a casualty of some accident ...).
|Principal Dimensions by Steve Llanso of Sweat House Media|
|Class||P-1||P-1 - superheated||P-2||P-2 - syphons|
|Railroad||Central of Georgia (CofGa)||Central of Georgia (CofGa)||Central of Georgia (CofGa)||Central of Georgia (CofGa)|
|Number in Class||15||15||14||15|
|Road Numbers||1614-1628/414-428||1614-1628||1651-1664 / 431-444||1651-1664|
|Builder||Burnham, Williams & Co||C of Ga||several||Lima|
|Locomotive Length and Weight|
|Driver Wheelbase (ft / m)||11.83 / 3.61||11.83 / 3.61||12 / 3.66||12 / 3.66|
|Engine Wheelbase (ft / m)||30.37 / 9.26||30.37 / 9.26||31.50 / 9.60||31 / 9.45|
|Ratio of driving wheelbase to overall engine wheebase||0.39||0.39||0.38||0.39|
|Overall Wheelbase (engine & tender) (ft / m)||57.96 / 17.67||64.87 / 19.77||64.87 / 19.77|
|Axle Loading (Maximum Weight per Axle) (lbs / kg)||44,530 / 20,198|
|Weight on Drivers (lbs / kg)||113,660 / 51,555||117,000 / 53,070||134,850 / 61,167||143,200 / 64,955|
|Engine Weight (lbs / kg)||187,560 / 85,076||192,500 / 87,317||222,300 / 100,834||230,500 / 104,553|
|Tender Loaded Weight (lbs / kg)||150,000 / 68,039||150,000 / 68,039||150,000 / 68,039||151,000 / 68,493|
|Total Engine and Tender Weight (lbs / kg)||337,560 / 153,115||342,500 / 155,356||372,300 / 168,873||381,500 / 173,046|
|Tender Water Capacity (gals / ML)||7500 / 28.41||7500 / 28.41||7500 / 28.41||7500 / 28.41|
|Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)||12.50 / 11.40||12.50 / 11.40||13 / 11.80||13 / 11.80|
|Minimum weight of rail (calculated) (lb/yd / kg/m)||63 / 31.50||65 / 32.50||75 / 37.50||80 / 40|
|Geometry Relating to Tractive Effort|
|Driver Diameter (in / mm)||68 / 1727||68 / 1727||69 / 1753||69 / 1753|
|Boiler Pressure (psi / kPa)||200 / 13.80||200 / 13.80||200 / 13.80||200 / 13.80|
|High Pressure Cylinders (dia x stroke) (in / mm)||21" x 28" / 533x711||21" x 28" / 533x711||23" x 28" / 584x711||23" x 28" / 584x711|
|Tractive Effort (lbs / kg)||30,870 / 14002.41||30,870 / 14002.41||36,493 / 16552.97||36,493 / 16552.97|
|Factor of Adhesion (Weight on Drivers/Tractive Effort)||3.68||3.79||3.70||3.92|
|Firebox Area (sq ft / m2)||197 / 18.31||197 / 18.31||163 / 15.15||240.90 / 22.39|
|Grate Area (sq ft / m2)||46.80 / 4.35||46.80 / 4.35||50.75 / 4.72||66 / 6.13|
|Evaporative Heating Surface (sq ft / m2)||3386 / 314.68||2414 / 224.35||2751 / 255.67||2834 / 263.38|
|Superheating Surface (sq ft / m2)||531 / 49.35||605 / 56.23||599 / 55.67|
|Combined Heating Surface (sq ft / m2)||3386 / 314.68||2945 / 273.70||3356 / 311.90||3433 / 319.05|
|Evaporative Heating Surface/Cylinder Volume||301.66||215.06||204.32||210.48|
|Computations Relating to Power Output (More Information)|
|Robert LeMassena's Power Computation||9360||9360||10,150||13,200|
|Same as above plus superheater percentage||9360||11,045||11,977||15,444|
|Same as above but substitute firebox area for grate area||39,400||46,492||38,468||56,371|