Nippon 4-4-2 Locomotives in Japan

Class Details by Steve Llanso of Sweat House Media

Class Hatracks (Locobase 3871)

Data from Hiroshi Takagi, both from his website ([]) and personal communication August-September 2000. His indispensable assistance is gratefully acknowledged. See also DeGolyer, Volume 20, p. 251; "Baldwin Locomotives for Japan", Railroad Gazette, Volume XXIX [29], No (26 February 1897), pp. 149-150; and "Locomotive for Japan Railway Company", Locomotive Engineering, Volume X [10], No 4 (April 1897), p. 289. Works numbers were 15175-15198 in February 1897.

Built at the same time as the South African 04 class, these engines offered similar advantages to the Japanese railroad they ran on.

According to Takagi, "The reason why they were nicknamed Hatracks should be due to their thin boiler in contrast with fat ones of the existing CGR/SAR classes."

LE referred to the layout as the "Columbia" type (which usually applied to 2-4-2s) and described it as a "narrow gage" engine. Each is a variant of a more common identification or phrase as railroad journalists dealt with the increasing pace of change in the late 19th Century.

LE commented that although the new 4-4-2s were of "decidedly prominent American characteristics exteriorly [sic]," they showed a "home-bred" (i.e., Japanese) influence in the copper fireboxes with their copper stayboltes and brass tubes. Baldwin's specification shows the firebox fitted with copper "air tubes above fire". Three opened to each side, 2 in the throat, and 4 in the back.

The engines were quite large for their cylinder volume in both heating surface and grate areas, which the editor correctly attributed to the low-calorie fuel. "In any event," he added, "the engine should be a good steamer with even ordinary fuel."

He suggested that "our friends on the other side will be able to use all of this heating surface to advantage." A caveat appeared when LE examined the low factor of adhesion, which showed that "the cylinders, small as they are, to be plenty large enough to slip the wheels under anything but the most favorable conditions."

Scaling 1% grades and smoothing 4 deg curves, the engines were expected to pull 270 ton trailing loads at maximum speeds of 35-40 mph (56-64 kph) and average speeds of 24-30 mph (39-48kph).

Four had their boilers modified to include combustion chambers. See Locobase 3872 for the result.

Class unknown (Locobase 3872)

Data from Hiroshi Takagi, both from his website ([]) and from

personal communication August-September 2000. His indispensable assistance is gratefully acknowledged.

Four of the Baldwin-built Atlantics that arrived in Japan in 1898 (Locobase 3871) were fitted with combustion chambers ahead of the fireboxes only a couple of years after their initial delivery. It's an interesting conversion in that the reduced boiler pressure and lower heating surface area reduce the amount of available boiler power, but the demand factors suggest an engine with a relatively easy time providing enough steam for the cylinders. In any event, the other 20 in the class were not so converted.

Principal Dimensions by Steve Llanso of Sweat House Media

Locobase ID3871 3872
Number in Class244
Road Numbers506-529/6600-6623
Number Built24
BuilderBurnham, Williams & CoNippon
Valve GearStephensonStephenson
Locomotive Length and Weight
Driver Wheelbase (ft / m)6 / 1.836 / 1.83
Engine Wheelbase (ft / m)22.50 / 6.8622.50 / 6.86
Ratio of driving wheelbase to overall engine wheelbase 0.27 0.27
Overall Wheelbase (engine & tender) (ft / m)45.96 / 14.0145.96 / 14.01
Axle Loading (Maximum Weight per Axle) (lbs / kg)30,464 / 13,81830,464 / 13,818
Weight on Drivers (lbs / kg)52,000 / 23,58760,883 / 27,616
Engine Weight (lbs / kg)100,980 / 45,804101,069 / 45,844
Tender Loaded Weight (lbs / kg)60,000 / 27,216
Total Engine and Tender Weight (lbs / kg)160,980 / 73,020
Tender Water Capacity (gals / ML)3000 / 11.362400 / 9.09
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) 5.80 / 5 5.80 / 5
Minimum weight of rail (calculated) (lb/yd / kg/m)43 / 21.5051 / 25.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)56 / 142256 / 1422
Boiler Pressure (psi / kPa)180 / 12.40165 / 11.40
High Pressure Cylinders (dia x stroke) (in / mm)16" x 22" / 406x55916" x 22" / 406x559
Tractive Effort (lbs / kg)15,387 / 6979.4314,105 / 6397.93
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.38 4.32
Heating Ability
Tubes (number - dia) (in / mm)189 - 2" / 51146 - 2" / 51
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m)14.92 / 4.5512.80 / 3.90
Firebox Area (sq ft / m2)98.15 / 9.12114 / 10.59
Grate Area (sq ft / m2)30 / 2.7930 / 2.79
Evaporative Heating Surface (sq ft / m2)1560 / 144.931093 / 101.58
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)1560 / 144.931093 / 101.58
Evaporative Heating Surface/Cylinder Volume304.71213.49
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation54004950
Same as above plus superheater percentage54004950
Same as above but substitute firebox area for grate area17,66718,810
Power L167305002
Power MT570.66362.25

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