Central of Georgia 4-6-2 "Pacific" Locomotives in the USA

The Central of Georgia Railway operated two classes of "Pacifics" for over 40 years. The first of these classes was designated as Class P-1 and consisted of 15 light weight 4-6-2 locomotives. These locomotives were assigned road numbers 1614 through 1628 (later renumbered 414 through 428) and were delivered from the Baldwin Locomotive Works during 1905 and 1906. They had 21 x 28 cylinders, 68" drivers, a 200 psi boiler pressure, exerted 30,870 lbs of tractive effort and each weighed 192,500 pounds.

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.


Class Details by Steve Llanso of Sweat House Media

Class P-1 (Locobase 7938)

Data from "Passenger and Freight Locomotives - Central of Georgia Railway," American Engineer and Railroad Journal, Vol 81, No (January 1907), pp. 31-33. See also DeGolyer, Volume 27, p. 243. Works numbers were 25793-25794, 25889, 25903 in June 1905; 25967 in July, 29300-29301, 29360, 29365-29366 in October; and 29380, 29454, 29466-29468 in November.

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.


Class P-1 - superheated (Locobase 4227)

Data from Central of Georgia's 1927 locomotive diagram book, supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange

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.


Class P-2 (Locobase 4228)

Data from CofGa 12-1925 locomotive diagram book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. Baldwin works numbers were 37619-37624 in April 1912 and 40660-40684 in September 1913. Lima's works numbers were 5217-5220 in 1916.

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). Firebox heating surface included a short Gaines half-wall combustion chamber that subdivided the 132" (3.35 m) length of the firebox. The grate area was figured on the 88" (2.235 m) on the back side of the Gaines wall.


Class P-2 - syphons (Locobase 6677)

Data from CofGa 4-1932 locomotive diagram book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. See also DeGolyer, Vol 42, pp. 195+.

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 ...).

Specifications by Steve Llanso of Sweat House Media
ClassP-1P-1 - superheatedP-2P-2 - syphons
Locobase ID7938 4227 4228 6677
RailroadCentral of Georgia (CofGa)Central of Georgia (CofGa)Central of Georgia (CofGa)Central of Georgia (CofGa)
CountryUSAUSAUSAUSA
Whyte4-6-24-6-24-6-24-6-2
Number in Class15151415
Road Numbers1614-1628/414-4281614-16281651-1664 / 431-4441651-1664
GaugeStdStdStdStd
Number Built1514
BuilderBurnham, Williams & CoC of GaseveralLima
Year1905192419121916
Valve GearStephensonStephensonWalschaertWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)11.83 / 3.6111.83 / 3.6112 / 3.6612 / 3.66
Engine Wheelbase (ft / m)30.37 / 9.2630.37 / 9.2631.50 / 9.6031 / 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 / 17.6764.87 / 19.7764.87 / 19.77
Axle Loading (Maximum Weight per Axle) (lbs / kg)44,530 / 20,198
Weight on Drivers (lbs / kg)113,660 / 51,555117,000 / 53,070134,850 / 61,167143,200 / 64,955
Engine Weight (lbs / kg)187,560 / 85,076192,500 / 87,317222,300 / 100,834230,500 / 104,553
Tender Loaded Weight (lbs / kg)150,000 / 68,039150,000 / 68,039150,000 / 68,039151,000 / 68,493
Total Engine and Tender Weight (lbs / kg)337,560 / 153,115342,500 / 155,356372,300 / 168,873381,500 / 173,046
Tender Water Capacity (gals / ML)7500 / 28.417500 / 28.417500 / 28.417500 / 28.41
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)12.50 / 11.4012.50 / 11.4013 / 11.8013 / 11.80
Minimum weight of rail (calculated) (lb/yd / kg/m)63 / 31.5065 / 32.5075 / 37.5080 / 40
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)68 / 172768 / 172769 / 175369 / 1753
Boiler Pressure (psi / kPa)200 / 13.80200 / 13.80200 / 13.80200 / 13.80
High Pressure Cylinders (dia x stroke) (in / mm)21" x 28" / 533x71121" x 28" / 533x71123" x 28" / 584x71123" x 28" / 584x711
Tractive Effort (lbs / kg)30,870 / 14002.4130,870 / 14002.4136,493 / 16552.9736,493 / 16552.97
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.68 3.79 3.70 3.92
Heating Ability
Firebox Area (sq ft / m2)197 / 18.31197 / 18.31163 / 15.15240.90 / 22.39
Grate Area (sq ft / m2)46.80 / 4.3546.80 / 4.3550.75 / 4.7266 / 6.13
Evaporative Heating Surface (sq ft / m2)3386 / 314.682414 / 224.352751 / 255.672834 / 263.38
Superheating Surface (sq ft / m2)531 / 49.35605 / 56.23599 / 55.67
Combined Heating Surface (sq ft / m2)3386 / 314.682945 / 273.703356 / 311.903433 / 319.05
Evaporative Heating Surface/Cylinder Volume301.66215.06204.32210.48
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation9360936010,15013,200
Same as above plus superheater percentage936011,04511,97715,444
Same as above but substitute firebox area for grate area39,40046,49238,46856,371
Power L1882716,51415,39316,107
Power MT513.64933.52754.97743.92

Reference