Tobu Steam Light Railway 4-4-0 Locomotives in Japan


Class Details by Steve Llanso of Sweat House Media

Class 20 (Locobase 14223)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University, Volume 49, p. 208. For a general history of Japanese light railways, see Eiichi Aoki, "Construction of Local Railways," Japanese Railway History 5 (July 1995), pp. 34-37, archived at [link] . Works numbers were 38851-38853 in November 1912 and 38921-38923 in December.

Locomotive brokers Frazer & Company negotiated the purchase of this half-dozen Eight-wheelers, which equipped one of the first light railways built under the Light Railway Act ("enforced" 3 August 1910 and its corollary, the Light Railway Subsidy Act of 1 January 1912. The level of construction approved under these programs was deliberately scaled to require less infrastructure than the JNR level of service, but more than the tramways, which were seen as too light and unsafe in populated areas. The first president of Japan's Railway Bureau, Goto Shinpei, was most interested in promoting trunk line growth and saw the light-railway program as a way to satisfy a pressing demand relatively inexpensively.

Perhaps the key feature of these light railways (keiben tetsudo) was their local character. Individual communities formed local railway societies that raised capital, often accumulated through many small donations, to build feeder liners that linked the town or small city with the national railway network. Because even the lightly built lines that resulted often required more financing than the communities' could muster, the Subsidy Act allowed government support.

Principal Dimensions by Steve Llanso of Middle Run Media
Class20
Locobase ID14223
RailroadTobu Steam Light Railway
CountryJapan
Whyte4-4-0
Number in Class6
Road Numbers20-25
Gauge3'6"
Number Built6
BuilderBaldwin
Year1912
Valve GearStephenson
Locomotive Length and Weight
Driver Wheelbase (ft / m) 6.83 / 2.08
Engine Wheelbase (ft / m)19.83 / 6.04
Ratio of driving wheelbase to overall engine wheelbase 0.34
Overall Wheelbase (engine & tender) (ft / m)38.83 / 11.84
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)52,000 / 23,587
Engine Weight (lbs / kg)73,000 / 33,112
Tender Loaded Weight (lbs / kg)55,000 / 24,948
Total Engine and Tender Weight (lbs / kg)128,000 / 58,060
Tender Water Capacity (gals / ML)2760 / 10.45
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)3 / 3
Minimum weight of rail (calculated) (lb/yd / kg/m)43 / 21.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)60 / 1524
Boiler Pressure (psi / kPa)180 / 1240
High Pressure Cylinders (dia x stroke) (in / mm)15" x 22" / 381x559
Tractive Effort (lbs / kg)12,623 / 5725.70
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.12
Heating Ability
Tubes (number - dia) (in / mm)155 - 2" / 51
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m)10.50 / 3.20
Firebox Area (sq ft / m2)98 / 9.10
Grate Area (sq ft / m2)17 / 1.58
Evaporative Heating Surface (sq ft / m2)943 / 87.61
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)943 / 87.61
Evaporative Heating Surface/Cylinder Volume209.57
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation3060
Same as above plus superheater percentage3060
Same as above but substitute firebox area for grate area17,640
Power L15732
Power MT486.03

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