Nippon Railway 2-8-2 Locomotives in Japan

Class Details by Steve Llanso of Sweat House Media

Class 9700 (Locobase 2565)

Data from from Baldwin Locomotive Works Specification for Engines, as digitized by the DeGolyer Library of Southern Methodist University, Volume 20, p. 250. Works numbers were 15203-15222.

Baldwin's history notes that these "Mikados", the first of their wheel arrangement ever, responded to the need to burn "a most inferior quality of coal, requiring large grate area and a firebox of ample depth and volume." The concept proved very successful; according to Hollingsworth (1982), more 2-8-2s were built in the 20th Century than any other wheel arrangement.

(NB: a 1907 history of the Lehigh Valley Railroad says that Alexander Mitchell's "Ant" and "Bee" decapods proved too easy to derail when they entered service in 1867. So the shops lopped off the rearmost axle and substituted a pony truck for it. Although not so called, this was a 2-8-2 in most respects.)

Baldwin's specification noted the 2 1/2% ruling grade and 4 degree compensated curves to be climbed at an average speed of 16 mph (25.8 kph).

The 9700s served into the 1920s, but no other Mikados were produced for Japan's railways until the D50.

Principal Dimensions by Steve Llanso of Sweat House Media

Locobase ID2565
RailroadNippon Railway
Number in Class20
Road Numbers530-549/9700-9719
Number Built20
BuilderBurnham, Williams & Co
Valve GearStephenson
Locomotive Length and Weight
Driver Wheelbase (ft / m)11.83 / 3.61
Engine Wheelbase (ft / m)24.42 / 7.44
Ratio of driving wheelbase to overall engine wheelbase 0.48
Overall Wheelbase (engine & tender) (ft / m)56.17 / 17.12
Axle Loading (Maximum Weight per Axle) (lbs / kg)26,880 / 12,193
Weight on Drivers (lbs / kg)107,000 / 48,534
Engine Weight (lbs / kg)119,677 / 54,285
Tender Loaded Weight (lbs / kg)
Total Engine and Tender Weight (lbs / kg)
Tender Water Capacity (gals / ML)3000 / 11.36
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) 6.10 / 5.50
Minimum weight of rail (calculated) (lb/yd / kg/m)45 / 22.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)45 / 1143
Boiler Pressure (psi / kPa)180 / 12.40
High Pressure Cylinders (dia x stroke) (in / mm)18.5" x 24" / 470x610
Tractive Effort (lbs / kg)27,928 / 12667.94
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.83
Heating Ability
Tubes (number - dia) (in / mm)226 - 2.25" / 57
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m)16 / 4.88
Firebox Area (sq ft / m2)105.74 / 9.82
Grate Area (sq ft / m2)30 / 2.79
Evaporative Heating Surface (sq ft / m2)2216 / 205.87
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)2216 / 205.87
Evaporative Heating Surface/Cylinder Volume296.78
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation5400
Same as above plus superheater percentage5400
Same as above but substitute firebox area for grate area19,033
Power L14962
Power MT408.95

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Wes Barris