Cotton Belt 4-4-2 "Atlantic" Locomotives of the USA

Class Details by Steve Llanso of Sweat House Media

Class E1 (Locobase 3483)

Data from an Excel spreadsheet prepared by Chris Hohl and emailed 18 March 2015, citing DeGolyer, Volume 32, pp. 94+. Works numbers were 33335-33337, 33373-33375 in April 1909.

The St Louis-Southwestern ordered these Atlantics with slide valves and Stephenson gear,Westcott (Model Railroading Cyclopedia Vol 1, 1960) comments that this small class "broke rules because they were built as late as 1909 with narrow fireboxes, small drivers, and slide valves -- all rare features as Atlantics go." Drury (1993) provides insight when he notes "they were not so much Atlantics as they were Americans with trailing axles."

They were later refitted with 12" (305 mm) diameter piston valves, superheaters, and Walschaerts outside valve gear; see Locobase 16016.

Class E1 - superheated (Locobase 16016)

Data from StL&SW 1 - 1932 Folio 725 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Raildata collection.

Delivered by Baldwin in 1909 with saturated boilers, the class was later updated with superheaters, outside radial valve gear, and 12" (305 mm) piston valves. An increase in cylinder volume preserved the tractive effort as boiler pressure dropped by 15 psi. By then, their firebox heating surface areas included 16 sq ft (1.5 sq m) of arch tubes. Compared to other American 4-4-2s submitted to superheating, these engines had a relatively high percentage of superheater area. All were converted to oil burning.

While two of the sextet -- 600 and 603 -- were scrapped in September 1934 and January 1933, respectively, the other four served well into the 1940s, past the end of World War II, before being scrapped in November 1948 (602), July and August 1949 (605, 604), and February 1952 (601).

Specifications by Steve Llanso of Sweat House Media
ClassE1E1 - superheated
Locobase ID3483 16,016
RailroadCotton Belt (StLSW)Cotton Belt (StLSW)
Number in Class66
Road Numbers600-605600-605
Number Built6
BuilderBaldwinCotton Belt
Valve GearStephensonWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft) 6.25 6.25
Engine Wheelbase (ft)26.0826.09
Ratio of driving wheelbase to overall engine wheebase 0.24 0.24
Overall Wheelbase (engine & tender) (ft)58.60
Axle Loading (Maximum Weight per Axle) (lbs)52,900
Weight on Drivers (lbs)90,000105,800
Engine Weight (lbs)168,000195,000
Tender Loaded Weight (lbs)120,000169,600
Total Engine and Tender Weight (lbs)288,000364,600
Tender Water Capacity (gals)60007000
Tender Fuel Capacity (oil/coal) (gals/tons)123500
Minimum weight of rail (calculated) (lb/yd)7588
Geometry Relating to Tractive Effort
Driver Diameter (in)7070
Boiler Pressure (psi)200185
High Pressure Cylinders (dia x stroke) (in)20" x 26"21" x 26"
Tractive Effort (lbs)25,25725,758
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.56 4.11
Heating Ability
Firebox Area (sq ft)200216
Grate Area (sq ft)30.3031.20
Evaporative Heating Surface (sq ft)24812109
Superheating Surface (sq ft)496
Combined Heating Surface (sq ft)24812605
Evaporative Heating Surface/Cylinder Volume262.43202.34
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation60605772
Same as above plus superheater percentage60606869
Same as above but substitute firebox area for grate area40,00047,552
Power L1859215,848
Power MT420.94660.47

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