Just two Atlantics were ever delivered to the Monon. They were middle-of-the-pack engines that endured for more than three decades. They were superheated in the 1920s (Locobase 8314).
"Monon" is the common name for the Chicago, Indianopolis, and Louisville Railroad.
According to Drury (1993), the two Monon Atlantics (Locobase 7088) were retrofitted with Baker valve gear at the same time the piston valves were moved outside and the inboard-bearing trailing truck was replaced with a cast truck using outside bearings. But the C I & L's diagram shows Walschaert gear. Superheating the boiler and adding some direct heating surface area to the firebox (probably in the form of arch tubes) signficantly increased available power without sacrificing too much grip on the rail.
Even so, heavier passenger trains doomed this pair to retirement in 1936.
|Specifications by Steve Llanso of Sweat House Media|
|Railroad||Chicago, Indianapolis & Louisville (Monon)||Chicago, Indianapolis & Louisville (Monon)|
|Number in Class||2||2|
|Locomotive Length and Weight|
|Ratio of driving wheelbase to overall engine wheebase||0.24||0.25|
|Overall Wheelbase (engine & tender)||56.46'||59.25'|
|Axle Loading (Maximum Weight per Axle)|
|Weight on Drivers||92500 lbs||95000 lbs|
|Engine Weight||167300 lbs||177100 lbs|
|Tender Light Weight||162000 lbs||152000 lbs|
|Total Engine and Tender Weight||329300 lbs||329100 lbs|
|Tender Water Capacity||7400 gals||7400 gals|
|Tender Fuel Capacity (oil/coal)||18 tons||13 tons|
|Minimum weight of rail (calculated)||77 lb/yard||79 lb/yard|
|Geometry Relating to Tractive Effort|
|Boiler Pressure||200 psi||200 psi|
|Cylinders (dia x stroke)||20.5" x 26"||20" x 26"|
|Tractive Effort||25445 lbs||24219 lbs|
|Factor of Adhesion (Weight on Drivers/Tractive Effort)||3.64||3.92|
|Firebox Area||163 sq. ft||190 sq. ft|
|Grate Area||54.50 sq. ft||54.50 sq. ft|
|Evaporative Heating Surface||2801 sq. ft||2063 sq. ft|
|Superheating Surface||490 sq. ft|
|Combined Heating Surface||2801 sq. ft||2553 sq. ft|
|Evaporative Heating Surface/Cylinder Volume||282.00||218.22|
|Computations Relating to Power Output (More Information)|
|Robert LeMassena's Power Computation||10900||10900|
|Same as above plus superheater percentage||10900||12971|
|Same as above but substitute firebox area for grate area||32600||45220|