Atlanta & St Andrews Bay 4-6-2 "Pacific" Locomotives in the USA


Class Details by Steve Llanso of Sweat House Media

Class 98 (Locobase 6665)

Data from 1923 A & St A B locomotive diagram book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. Also found in FEC 1926 locomotive diagram book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. (Thanks to Chris Hohl for spotting a mistake in the works numbers, tweaking the class's road numbers, and supplying the valve gear ID.)

Following up on the first 31 Pacifics of similar design (Locobase 5716), these batches differed primarily in the size of the cylinders (they were delivered with 22") and installed superheating.

The A & St A B Railway ran from Dothan, Alabama to Panama City, Florida. For such a short line, it had a surprisingly large number of light Pacifics. Alco delivered 46 locomotives to the same design over an eleven-year period:

Year No delivered works# road #

1911 5 50143-50147 98-102

1911 12 53892-53903 103-114

1913 6 115-120

1914 6 121-126

1920 10 61762-61771 141-150

1922 7 63260-63266 151-157

This profusion of Pacifics shows the line had a bustling passenger service into the late 1920s.

The tender was also rated at 10 tons of coal.

Specifications by Steve Llanso of Sweat House Media
Class98
Locobase ID6665
RailroadAtlanta & St Andrews Bay
CountryUSA
Whyte4-6-2
Number in Class46
Road Numbers98-126, 141-157
GaugeStd
Number Built46
BuilderAlco
Year1911
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)12.33 / 3.76
Engine Wheelbase (ft / m)32.58 / 9.93
Ratio of driving wheelbase to overall engine wheebase 0.38
Overall Wheelbase (engine & tender) (ft / m)60.17 / 18.34
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)129,000 / 58,513
Engine Weight (lbs / kg)204,000 / 92,533
Tender Loaded Weight (lbs / kg)162,000 / 73,482
Total Engine and Tender Weight (lbs / kg)366,000 / 166,015
Tender Water Capacity (gals / ML)7300 / 27.65
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)3500 / 13.30
Minimum weight of rail (calculated) (lb/yd / kg/m)72 / 36
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)68 / 1727
Boiler Pressure (psi / kPa)180 / 12.40
High Pressure Cylinders (dia x stroke) (in / mm)22" x 26" / 559x660
Tractive Effort (lbs / kg)28,314 / 12843.03
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.56
Heating Ability
Firebox Area (sq ft / m2)160 / 14.87
Grate Area (sq ft / m2)47.10 / 4.38
Evaporative Heating Surface (sq ft / m2)2111 / 196.19
Superheating Surface (sq ft / m2)442 / 41.08
Combined Heating Surface (sq ft / m2)2553 / 237.27
Evaporative Heating Surface/Cylinder Volume184.54
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation8478
Same as above plus superheater percentage9919
Same as above but substitute firebox area for grate area33,696
Power L112,285
Power MT629.85