Missouri & North Arkansas 2-6-0 "Mogul" Locomotives in the USA

Class Details by Steve Llanso of Sweat House Media

Class M-20 (Locobase 6641)

Data from 1903 MO&NA locomotive diagram book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. Works number was 23354 in December 1903.

The Illinois Terminal operated terminal-railroad service in Alton, Ill, but for some reason sold this Mogul to the Missouri & Northern Arkansas in January 1907. Compared to Baldwin's 1903 estimate of firebox heating surface area, the M&NA's later diagram showed 39% less area. The diagram's math in adding tube heating surface area to firebox area shows that the latter isn't a typographical error, but Locobase's search of over 100 other entries in which US-operated 2-6-0s had evaporative heating surface areas of 1,500 to 1,650 sq ft show no other engines with anywhere near so small a firebox.

The M&NA operated the engine until the line was closed in 1929. It was scrapped in 1934.

Principal Dimensions by Steve Llanso of Sweat House Media
Locobase ID6641
RailroadMissouri & North Arkansas
Number in Class1
Road Numbers9
Number Built
Valve GearStephenson
Locomotive Length and Weight
Driver Wheelbase (ft / m)15.42 / 4.70
Engine Wheelbase (ft / m)23.50 / 7.16
Ratio of driving wheelbase to overall engine wheebase 0.66
Overall Wheelbase (engine & tender) (ft / m)47.67 / 14.53
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)102,000 / 46,266
Engine Weight (lbs / kg)120,000 / 54,431
Tender Loaded Weight (lbs / kg)80,000 / 36,287
Total Engine and Tender Weight (lbs / kg)200,000 / 90,718
Tender Water Capacity (gals / ML)4500 / 17.05
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)12 / 10.90
Minimum weight of rail (calculated) (lb/yd / kg/m)57 / 28.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)57 / 1448
Boiler Pressure (psi / kPa)180 / 12.40
High Pressure Cylinders (dia x stroke) (in / mm)18" x 24" / 457x610
Tractive Effort (lbs / kg)20,872 / 9467.39
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.89
Heating Ability
Firebox Area (sq ft / m2)84.50 / 7.85
Grate Area (sq ft / m2)17.66 / 1.64
Evaporative Heating Surface (sq ft / m2)1555 / 144.52
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)1555 / 144.52
Evaporative Heating Surface/Cylinder Volume219.99
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation3179
Same as above plus superheater percentage3179
Same as above but substitute firebox area for grate area15,210
Power L14784
Power MT310.20

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