Missouri & North Arkansas 2-8-2 "Mikado" Locomotives in the USA

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Class Details by Steve Llanso of Sweat House Media

Class 19 (Locobase 13269)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University, Volume 34, p. 122. See Locobase 6638 for a short history of the road, including a discussion of the 1914 accident that took 43 lives. Works numbers were 34201-34202 in January 1910.

This is an interesting follow-on to an earlier locomotive. The M & NA had bought several Consolidations (Locobase 11409) in 1907 that presumably had the power the railroad needed. The Mikados in this entry were identical in power and boiler dimensions. The only difference was the addition of a trailing truck under the firebox and substitution of an outside radial valve gear arrangement for the earlier link motion.

Both were scrapped in 1933.


Class 21 (Locobase 13270)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University, Volume 43, p. 207. See Locobase 6638 for a short history of the road, including a discussion of the 1914 accident that took 43 lives. Works numbers were 38827-38828 in December 1912 and 41315-41317 in April 1914.

When the M&NA adopted a superheated boiler for their Mikado design, they followed the prevailing practice of exchanging boiler pressure for the installation of superheating. But the design also introduced larger cylinders and balanced the loss of small tubes with the area provided by the big flues.

These served the M&NA and its successor Missouri & Arkansas until 1949.

Specifications by Steve Llanso of Sweat House Media
Class1921
Locobase ID13,269 13,270
RailroadMissouri & North ArkansasMissouri & North Arkansas
CountryUSAUSA
Whyte2-8-22-8-2
Number in Class22
Road Numbers19-20 / 30-3121-22, 34-36 / 32-36
GaugeStdStd
Number Built22
BuilderBaldwinBaldwin
Year19101912
Valve GearWalschaertWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)15.33 / 4.6715.33 / 4.67
Engine Wheelbase (ft / m)30 / 9.1430 / 9.14
Ratio of driving wheelbase to overall engine wheebase 0.51 0.51
Overall Wheelbase (engine & tender) (ft / m)59.75 / 18.2159.92 / 18.26
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)162,000 / 73,482162,000 / 73,482
Engine Weight (lbs / kg)194,000 / 87,997194,000 / 87,997
Tender Loaded Weight (lbs / kg)120,000 / 54,431120,000 / 54,431
Total Engine and Tender Weight (lbs / kg)314,000 / 142,428314,000 / 142,428
Tender Water Capacity (gals / ML)6000 / 22.736000 / 22.73
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)14 / 12.7014 / 12.70
Minimum weight of rail (calculated) (lb/yd)6868
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)56 / 142256 / 1422
Boiler Pressure (psi / kPa)180 / 12.40170 / 12.40
High Pressure Cylinders (dia x stroke) (in / mm)22" x 28" / 559x71123" x 28" / 584x711
Tractive Effort (lbs / kg)37,026 / 16794.7338,220 / 17336.32
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.38 4.24
Heating Ability
Firebox Area (sq ft / m2)194.90 / 18.11187 / 17.37
Grate Area (sq ft / m2)34.90 / 3.2435 / 3.25
Evaporative Heating Surface (sq ft / m2)2792 / 259.382239 / 208.01
Superheating Surface (sq ft / m2)459 / 42.64
Combined Heating Surface (sq ft / m2)2792 / 259.382698 / 250.65
Evaporative Heating Surface/Cylinder Volume226.64166.29
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation62825950
Same as above plus superheater percentage62826962
Same as above but substitute firebox area for grate area35,08237,194
Power L151378608
Power MT279.63468.58