Imperial Government Railways / Japanese Government Railways / Nippon 4-6-2 Locomotives in Japan


Class Details by Steve Llanso of Sweat House Media

Class 18900/C51/T9/SL 9) (Locobase 2876)

Data from Hiroshi Takagi, both from his website ([]) and personal communication August 2000. His indispensable assistance is gratefully acknowledged. See also "JNR Class C51" in Wikipedia at [], last accessed 22 June 2023; and Naito Hiroshi, "Locomotives in Ome Railway Park", Japanese Railway Society website at [], last accessed 22 June 2-23.

Information from Ejii Nozawa's web site ([]) notes that these were built from 1919-1928 by JNR's Hamamatsu Works, KSK, and Mitsubishi.

A successful design that had a rated speed of 60 mph (97 kph), although it could be driven faster.

The firebox area includes 10.8 sq ft (1 sq m) of arch tubes. Note that from 1931 on heating surface areas on Japanese locomotives were calculated on the fire side of the tubes and flues. This followed German practice. A direct comparison with surface areas of North American and British locomotives requires adding approximately 6-10% to the figures shown.

Akira Saito, in an overview of Japan's modern steam locomotives published in December 2002 on [], argues that this design marked the point at which the goal of conversion to standard gauge in Japan was abandoned. Kiichi Asakura was the designer. (Yasujiro Shima, his boss and leading locomotive developer in Japan, had resigned.)

Saito noted the high aspect ratio of the drivers; that is, the driver diameter was 1.64 times the gauge of the track. This almost unprecedented ratio, Saito argued, stems directly from the adoption of a conservative allowable maximum of 300 rpm for the drivers. This in turn derived from Shima's earlier adoption of Prussian practice in preference to British/US tendencies.

Naito's Ome Railway Park description also singles out the design's tall drivers. C51's was design responded "to the demands for more powerful passenger locomotives under the situation of increasing passenger traffic resulting from the booming economy just after World War 1." Compared to the earlier 8900s [Locobase 3813], he claimed, "the C51 was superior in every aspect of performance" .The design became the principal passenger express engine, pulling the Tsubame Super Express, which went into operation in 1930. It soon took over all express work on the Tokaido Main Line.

Wikipedia states that motive power shortages in China led to the converstion of sixteen C51s (8, 28, 30, 33 - 35, 88, 95, 96, 116, 130 - 132, 173, 175, and 178) to the standard gauge to operate between Nanjing and Shanghai. The class later received the Chinese class name Pashina. The account added that all were equipped with a Sumiyama feedwater heater (Locobase doesn't know if that number was part of a larger refit program).

After World War II's surrender by Japanese occupiers, the liberation of China, and the Chinese Communist takeover in 1949, the C51s were redesignated T9 and later SL9 (translates as "Victory").


Class 8200/C52 (Locobase 4387)

Data from Takagi Hiroshi, both from his website ([]) and personal communication August 2000. His indispensable assistance is gratefully acknowledged. See also A Profile of Japanese Steam Locomotives website put up in 2007 by "Toki S." at [], last accessed 27 September 2015; and Naotaka Hirota, Steam Locomotives of Japan (Tokyo and Palo Alto: Kodansha International Ltd, 1972), p. 38.; and American Locomotive Company, Class 4-6-2 S 180, Order No. S-1516 (October 1925. (Thanks to Alexander Blessing for his 2 April 2023 email noting the correct valve gear and supplying the Alco builder's card.) Works numbers were 66409-66414 in November 1925.

A pristine American narrow-gauge Pacific for export that offers an interesting contrast to the 4-6-2s Japan was building for itself at the same time. It was bigger and carried a more tightly packed boiler. No doubt its higher maximum axle load limited the number of lines on which the 8200 could.run. The Profile website states that the C52's driver diameter was too small to suit passenger "or even freight trains."

Hirota offered a similar assessment: "They were difficult to handle and their performance was not as good as anticipated. But," he continued, "they did provide valuable models to Japanese railway engineers, for they were equipped with Elesco feed water heaters, Franklin power fire doors, Alco power reverse gears, and power rocking grate gears."

Akira Saito, in an overview of Japan's modern steam locomotives published in December 2002 on [], spells out the fascinating reason for procuring this sextet. In the mid-1920s, Japanese engineers joined a world-wide trend toward adopting a three-cylinder simple-expansion layout to get more power out of the boiler. They saw that Nigel Gresley of Great Britain's LNER had developed very successful express passenger locomotives using a conjugated valve gear to time the valve motions. What they didn't appear to consider what producing a relatively high tractive effort would mean for the reltively light locomotive's factor of adhesion.

Recognizing that the LNER didn't build locomotives for other customers, the JNR engineers turned to Alco, which had secured the US license for the Gresley gear. In keeping with a widespread pattern of reverse engineering, they bought the six locomotives in order to study the valve motion. Saito added: "In Japan it was an easygoing introduction of the technology from Alco without deeply learning the original philosophy." See Locobase 2877 (the C53 entry) for the unfortunate consequences.

Information from Ejii Nozawa's web site ([]) shows that these six came from Alco in 1925.


Class 8900 (Locobase 3813)

Data from Hiroshi Takagi, both from his website ([]) and personal communication August 2000. His indispensable assistance is gratefully acknowledged. See also Akira Saito, "Overview of Japan's Modern Steam Locomotives" downloaded from krc.gr.jp/library/jpmodernsl/jpmodernsl.pdf, last confirmed 7 March 2019; and R Kitterman, "Japanese Governmert Railways 8850", published 9 July 2019 on the Deviant Art website at [], last accessed 14 October 2022. Alco-Brooks's works numbers were 49805-49828 in March 1911. Alco-Richmond added works numbers (50535-50546 in December 1912. Japanese builders Hamamatsu kojo, Kisha kaisha, Mitsubishi zosen all supplied locomotives in this class.

Kitterman's post provided key context information by recounting the IGR's 1911 decision to try out several passenger locomotive designs for the Cape gauge with an eye to licensed construction in Japan. Locobases 3806, 3808, 3810, and 3813 describe the four designs, each by a different builder.

These Pacifics offer an interesting comparison with the 4-6-0s acquired just before and reflecting American practice rather than the European emphasis. The firebox was much shallower although the grate area was considerably larger. Tube length grew, which led to more heating surface. Note that the axle loading stayed about the same, as did the adhesion weight. 8900s later had their boiler pressure reduced to 170 psi.

Akira Saito noted Yasujiro Shima, the leading JNR designer, preferred a 4-6-0 with a narrow firebox for at least two reasons. The 4-6-2 design had a trailing axle that "should not be adopted because it was clearly a kind of dead weight."

Saito continues:"It is natural to guess that there must be another aim hidden behind the words." And he offers one: Keeping the firebox inside the frame was a principal goal of Shima's design philosophy -- the center of gravity was lower, for one thing. If a 4-6-0 design were adopted, the firebox could be widened by 370 mm (14 1/2"), yielding the same grate area but maintaining the inside location.

So committed was Shima to the standard-gauge plan that when the JNR ultimately decided in 1919 to stick with the Cape gauge, he resigned. Saito argues that Shima was mistaken in his stubborn adherence to the narrow firebox, pointing to practice in New Zealand, Australia, and South Africa.


Class C53 (Locobase 2877)

Data from Hiroshi Takagi, both from his website ([]) and personal communication August 2000. His indispensable assistance is gratefully acknowledged. See also A Profile of Japanese Steam Locomotives website put up in 2007 by "Toki S." at [], last accessed 27 September 2015.

A powerful narrow-gauge passenger express engine that used Gresley's conjugated valve gear for the inside valve.

Because the measurements above represent the fire side of tubes and flues, a direct comparison with tube & flue heating surface areas of North American and British locomotives requires adding approximately 6-10% to the figures shown.

In his notes, Takagi says the following about the C53: "I have also argued against a well-established theory in this country - Japanese-built three-cylinder Pacific Class C53 was excellent, far better than the American-built fore-runner Class 8200 (later C52) [See Locobase 4387]."

Locobase believes Takagi means he does not think the C53 was a good design, a supposition supported by the discussion in Akira Saito's overview of Japan's modern steam locomotives published in December 2002 on [] . Saito identifies a misplaced economy in weight in the conjugating gear used to drive the third cylinder. To reduce inertia, the builder bored lightening holes in the arm. Unfortunately, the arm was then prone to bending and breakage, at the very least complicating efforts at timing the three cylinders and often resulting in stuffing too much steam in the center cylinder. Bearings on the center crank also tended to fail.

Information from Ejii Nozawa's web site ([]) shows that these were built from 1928-1931 byKawasaki and KSK.


Class C54 (Locobase 3829)

Data from Hiroshi Takagi, both from his website ([]) and personal communication August 2000. His indispensable assistance is gratefully acknowledged. See also A Profile of Japanese Steam Locomotives website put up in 2007 by "Toki S." at [], last accessed 27 September 2015.

Because the measurements above represent the fire side of tubes and flues, a direct comparison with tube & flue heating surface areas of North American and British locomotives requires adding approximately 6-10% to the figures shown.

The firebox area includes 10.8 sq ft (1.0 sq m) of arch tubes. These C54s appear to have been attempts to lighten the C51 design considerably while retaining the same heating surface dimensions. Toki S comments that the weight economy was a "fatal flaw". Its lower adhesion weight led to driver slippage. In one case in April 1959, the engine struggled to climb a 2.5% grade with a light train. The slipping drivers led to the C54-5 stalling in a tunnel and nearly asphixiating the engineer (driver).

Information from Ejii Nozawa's web site ([]) notes that these were built from 1930-1932 byKawasaki and KSK..


Class C55 (Locobase 3831)

Data from Hiroshi Takagi, both from his website ([]) and personal communication August 2000. His indispensable assistance is gratefully acknowledged. See also A Profile of Japanese Steam Locomotives website put up in 2007 by "Toki S." at [], last accessed 27 September 2015.

Because the measurements above represent the fire side of tubes and flues, a direct comparison with tube & flue heating surface areas of North American and British locomotives requires adding approximately 6-10% to the figures shown.

The firebox area includes 10.8 sq ft (1.0 sq m) of arch tubes. Another in a series of Pacifics that had the same boiler and grate dimensions. This appears to be a slightly heavier, and possibly more durable, version of the C54 (Locobase 3829).

Akira Saito, in an overview of Japan's modern steam locomotives published in December 2002 on [], describes an interesting wrinkle in steam-passage design associated with this class. Steam exhausting from either cylinder was led first into a chamber located between them and then to the exhaust nozzle. The goal was to "average the pulsatory ejection of combustion gas" -- i.e. smooth out the draft. Saito notes that such innovations as the Giesl or Kylchap sought the same improvement. Saito says that this chamber appeared in all later JNR designs.

Information from Ejii Nozawa's web site ([]) notes that these were built from 1935-1937 by Hitachi, Kawasaki, KSK, and Mitsubishi.


Class C57 (Locobase 2879)

Data from Hiroshi Takagi, both from his website ([]) and personal communication August 2000. His indispensable assistance is gratefully acknowledged. See also A Profile of Japanese Steam Locomotives website put up in 2007 by "Toki S." at [], last accessed 27 September 2015.

OS Nock (RWC VI, pl 119) noted that these engines steamed freely, "albeit to the accompanyment of dense clouds of black smoke," despite the poor quality of the coal, "a standard far below the worst customary in Great Britain." The design showed a surprisingly low-pitched boiler topped by a single dome for steam and sand. For most Japanese, the design's lines expressed a certain grace that led to the C57's popular nickname of "Noble Lady."

They were the latest in a series of Pacifics all of which used the same boiler and grate, but which weighed more or less. Also, the C57s had cylinders 1.2" smaller than the original C51s, which may account for their free steaming.The firebox area includes 10.8 sq ft (1.0 sq m) of arch tubes. Probably because of changes in steel composition during wartime, the last 12 C57s has a 92,065-lb adhesion weight, 150,642 lb engine weight, and 30,688-lb maximum axle load.

Because the measurements above represent the fire side of tubes and flues, a direct comparison with tube & flue heating surface areas of North American and British locomotives requires adding approximately 6-10% to the figures shown.

Information from Ejii Nozawa's web site ([]) notes that these were built from 1937-1946 by Hitachi, Kawasaki, KSK, and Mitsubishi.


Class C59/1 (Locobase 3833)

Data from Hiroshi Takagi, both from his website ([]) and personal communication August 2000. His indispensable assistance is gratefully acknowledged. See also A Profile of Japanese Steam Locomotives website put up in 2007 by "Toki S." at [], last accessed 26 September 2015.

C59s were built in two large batches, and one pair of experimental engines. This entry covers the first 98, which had the bigger boilers and the larger flues; all C59s admitted steam to the cylinders through 280 mm piston valves. Toki's website says that these Pacifics were designed to pull expresses over long distances and thus replace the troublesome three-cylinder C53s (Locobase 2877). The long tender was the largest possible given the 20-m turntable diameters.

Information from Ejii Nozawa's web site ([]) notes that C59s were built from 1941-1945 by Hitachi, Kawasaki, and KSK.

Because the measurements above represent the fire side of tubes and flues, a direct comparison with tube & flue heating surface areas of North American and British locomotives requires adding approximately 6-10% to the figures shown.


Class C59/101 (Locobase 3835)

Data from Hiroshi Takagi, both from his website ([]) and personal communication August 2000. His indispensable assistance is gratefully acknowledged. . See also A Profile of Japanese Steam Locomotives website put up in 2007 by "Toki S." at [], last accessed 26 September 2015.

The later C59s had among the highest percentages of superheated heating surface and a large firebox and their piston valve diameters were a capacious 280 mm. There's no obvious physical difference between the two large groups of C59s, but the performance must have seen a considerable bump with the later design. On the other hand, as lubricants became scarcer during the latter part of World War II, these engines might have demanded much more maintenance.

Information from Ejii Nozawa's web site ([]) notes that C59s were built from 1941-1945 by Hitachi, Kawasaki, and KSK.

Because the measurements above represent the fire side of tubes and flues, a direct comparison with tube & flue heating surface areas of North American and British locomotives requires adding approximately 6-10% to the figures shown.


Class C59/79 (Locobase 3834)

Data from Hiroshi Takagi, both from his website ([]) and personal communication August 2000. His indispensable assistance is gratefully acknowledged. . See also A Profile of Japanese Steam Locomotives website put up in 2007 by "Toki S." at [], last accessed 26 September 2015.

Clearly, these two were built to compare a design closer in principle to the "superpower" boilers the US was using, which had many more, but smaller-diameter flues. The design wasn't repeated.

Information from Ejii Nozawa's web site ([]) notes that C59s were built from 1941-1945 by Hitachi, Kawasaki, and KSK.

Because the measurements above represent the fire side of tubes and flues, a direct comparison with tube & flue heating surface areas of North American and British locomotives requires adding approximately 6-10% to the figures shown.


Class CT250 (Locobase 3866)

Data from Hiroshi Takagi, both from his website ([]) and personal communication August 2000.

Because the measurements above represent the fire side of tubes and flues, a direct comparison with tube & flue heating surface areas of North American and British locomotives requires adding approximately 6-10% to the figures shown.

Information from Ejii Nozawa's web site ([]) notes that these 5 were duplicates of the JNR's C55 Pacifics. Kawasaki and Mitsubishi split this small order.


Class Db3/6//3800 (Locobase 10297)

Data from "British Locomotives in Japan," The Locomotive Magazine, Volume VIII [8] (21 March 1903), p. 199; and "JGR Class 3800" in Wikipedia at [], last accessed 26 June 2023. Works numbers were 3653-3655, 3659 in 1898.

Using the same boiler and running gear as the 4-4-0s supplied by Dubs at the same time (Locobase 10295), this was a heavier locomotive with a longer wheelbase. Wikipedia notes that these were the only Pacific tanks to operate on Japanese railways. They served the coal traffic from the Joban coal fields. In later years, the quartet was based in Sendai.

They were "extremely powerful for their size", but enjoyed relatively short service lives. Wikipedia pointed to their frequent derailments "due to design oversights and their boilers used low quality coal, "resulting in poorer performance."

All four had been withdrawn by 1922.

Principal Dimensions by Steve Llanso of Sweat House Media

Class18900/C51/T9/SL 9)8200/C528900C53C54
Locobase ID2876 4387 3813 2877 3829
RailroadImperial Government Railways (JGR)Japanese Government Railways (JGR)Imperial Government Railways (JGR)Japanese Government Railways (JGR)Japanese Government Railways (JGR)
CountryJapanJapanJapanJapanJapan
Whyte4-6-24-6-24-6-24-6-24-6-2
Number in Class2896369717
Road NumbersC51C52 1 - C52 68900-8935C54 1 - C54 17
Gauge3'6"3'6"3'6"3'6"3'6"
Number Built2896369717
BuilderseveralAlco-Schenectadyseveralseveralseveral
Year19191925191219281931
Valve GearWalschaertWalschaert & GresleyWalschaertWalschaertWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)12.47 / 3.8012.11 / 3.6911 / 3.3513.06 / 3.9812.47 / 3.80
Engine Wheelbase (ft / m)32.81 / 1032.58 / 9.9329 / 8.8432.81 / 1032.81 / 10
Ratio of driving wheelbase to overall engine wheelbase 0.38 0.37 0.38 0.40 0.38
Overall Wheelbase (engine & tender) (ft / m)58.31 / 17.7757.32 / 17.4754.82 / 16.7157.91 / 17.6558.32 / 17.77
Axle Loading (Maximum Weight per Axle) (lbs / kg)32,761 / 14,86035,076 / 15,91028,726 / 13,03033,995 / 15,42029,586 / 13,420
Weight on Drivers (lbs / kg)98,282 / 44,580105,249 / 47,74086,157 / 39,080102,008 / 46,27088,758 / 40,260
Engine Weight (lbs / kg)153,442 / 69,600181,969 / 82,540139,773 / 63,400178,530 / 80,980143,962 / 65,300
Tender Loaded Weight (lbs / kg)109,018 / 49,45088,978 / 40,360107,585 / 48,800
Total Engine and Tender Weight (lbs / kg)290,987 / 131,990228,751 / 103,760251,547 / 114,100
Tender Water Capacity (gals / ML)
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)
Minimum weight of rail (calculated) (lb/yd / kg/m)55 / 27.5058 / 2948 / 2457 / 28.5049 / 24.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)68.90 / 175063 / 160063 / 160068.90 / 175068.90 / 1750
Boiler Pressure (psi / kPa)185.60 / 12.80188.50 / 13179.80 / 12.40203.10 / 14200.20 / 13.80
High Pressure Cylinders (dia x stroke) (in / mm)20.87" x 25.98" / 530x66017.72" x 25.98" / 450x660 (3)18.5" x 24.02" / 470x61017.72" x 25.98" / 450x660 (3)20.08" x 25.98" / 510x660
Tractive Effort (lbs / kg)25,910 / 11752.5931,121 / 14116.2619,943 / 9046.0030,660 / 13907.1625,872 / 11735.36
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.79 3.38 4.32 3.33 3.43
Heating Ability
Tubes (number - dia) (in / mm)84 - 2.008" / 5197 - 2.252" / 57.299 - 2.244" / 5788 - 2.008" / 5184 - 2.008" / 51
Flues (number - dia) (in / mm)18 - 5.157" / 13126 - 5.157" / 13116 - 5.512" / 14028 - 5.157" / 13118 - 5.157" / 131
Flue/Tube length (ft / m)18.01 / 5.4918.04 / 5.5016.14 / 4.9218.01 / 5.5018.01 / 5.49
Firebox Area (sq ft / m2)133.47 / 12.40163.61 / 15.2095.01 / 8.83163.61 / 15.20133.47 / 12.40
Grate Area (sq ft / m2)27.23 / 2.5340.90 / 3.8027.22 / 2.5334.98 / 3.2527.23 / 2.53
Evaporative Heating Surface (sq ft / m2)1371 / 127.401868 / 173.501408 / 130.901680 / 156.101371 / 127.40
Superheating Surface (sq ft / m2)446 / 41.40569 / 52.90320 / 29.73693 / 64.40446 / 41.40
Combined Heating Surface (sq ft / m2)1817 / 168.802437 / 226.401728 / 160.632373 / 220.501817 / 168.80
Evaporative Heating Surface/Cylinder Volume133.28167.94188.41151.03143.98
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation50547710489471045451
Same as above plus superheater percentage63179483582491656814
Same as above but substitute firebox area for grate area30,96537,93420,32942,86633,401
Power L112,54013,89212,03318,31514,612
Power MT843.88872.97923.721187.481088.82

Principal Dimensions by Steve Llanso of Sweat House Media

ClassC55C57C59/1C59/101C59/79
Locobase ID3831 2879 3833 3835 3834
RailroadJapanese Government Railways (JGR)Japanese Government Railways (JGR)Japanese Government Railways (JGR)Japanese Government Railways (JGR)Japanese Government Railways (JGR)
CountryJapanJapanJapanJapanJapan
Whyte4-6-24-6-24-6-24-6-24-6-2
Number in Class6220198732
Road NumbersC55 1 - C55 62C57 1 - C57 201C59 1 - C59 78, 81-100C59 101 - C59 173C59 79 - C59 80
Gauge3'6"3'6"3'6"3'6"3'6"
Number Built6220198732
Builderseveralseveralseveralseveralseveral
Year19311937194119451941
Valve GearWalschaertWalschaertWalschaertWalschaertWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)12.47 / 3.8012.47 / 3.8012.47 / 3.8012.47 / 3.8012.47 / 3.80
Engine Wheelbase (ft / m) / 1032.81 / 10 / 10.0132.84 / 10.01
Ratio of driving wheelbase to overall engine wheelbase 0.38 0.38
Overall Wheelbase (engine & tender) (ft / m) / 17.7958.35 / 17.79 / 18.7361.47 / 18.73
Axle Loading (Maximum Weight per Axle) (lbs / kg)29,917 / 13,57030,358 / 13,77035,649 / 16,17035,340 / 16,03035,671 / 16,180
Weight on Drivers (lbs / kg)89,772 / 40,72091,095 / 41,320106,924 / 48,500106,020 / 48,090107,034 / 48,550
Engine Weight (lbs / kg)145,593 / 66,040148,812 / 67,500176,921 / 80,250175,818 / 79,750177,251 / 80,400
Tender Loaded Weight (lbs / kg) / 47,700109,041 / 49,460 / 61,100
Total Engine and Tender Weight (lbs / kg)257,853 / 116,960
Tender Water Capacity (gals / ML)
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)
Minimum weight of rail (calculated) (lb/yd / kg/m)50 / 2551 / 25.5059 / 29.5059 / 29.5059 / 29.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)68.90 / 175068.90 / 175068.90 / 175068.90 / 175068.90 / 1750
Boiler Pressure (psi / kPa)200 / 13.80227.70 / 15.70227.70 / 15.70227.70 / 15.70227.70 / 15.70
High Pressure Cylinders (dia x stroke) (in / mm)20.1" x 26" / 510x66019.69" x 25.98" / 500x66020.47" x 25.98" / 520x66020.47" x 25.98" / 520x66020.47" x 25.98" / 520x660
Tractive Effort (lbs / kg)25,918 / 11756.2228,294 / 12833.9630,580 / 13870.8730,580 / 13870.8730,580 / 13870.87
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.46 3.22 3.50 3.47 3.50
Heating Ability
Tubes (number - dia) (in / mm)84 - 2" / 5184 - 2.008" / 5190 - 2.008" / 5152 - 2.008" / 5121 - 2.008" / 51
Flues (number - dia) (in / mm)18 - 5.16" / 13118 - 5.157" / 13128 - 5.157" / 13133 - 5.157" / 13180 - 3.268" / 83
Flue/Tube length (ft / m)18 / 5.4918.01 / 5.4919.69 / 618.01 / 5.4918.01 / 5.49
Firebox Area (sq ft / m2)133.42 / 12.40133.47 / 12.40154.94 / 14.40175.45 / 16.30179.69 / 16.70
Grate Area (sq ft / m2)27.22 / 2.5327.23 / 2.5335.19 / 3.2735.20 / 3.2735.19 / 3.27
Evaporative Heating Surface (sq ft / m2)1371 / 127.401371 / 127.401676 / 155.801473 / 136.801655 / 153.80
Superheating Surface (sq ft / m2)445 / 41.40446 / 41.40765 / 71.10871 / 80.90790 / 73.40
Combined Heating Surface (sq ft / m2)1816 / 168.801817 / 168.802441 / 226.902344 / 217.702445 / 227.20
Evaporative Heating Surface/Cylinder Volume143.58149.74169.36148.85167.24
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation54446200801380158013
Same as above plus superheater percentage6805775010,49710,98110,577
Same as above but substitute firebox area for grate area33,35537,98946,21754,73154,008
Power L114,53517,28424,66826,92325,534
Power MT1070.851254.891525.861679.541577.80

Principal Dimensions by Steve Llanso of Sweat House Media

ClassCT250Db3/6//3800
Locobase ID3866 10297
RailroadJapanese Government Railways (JGR)Nippon (JGR)
CountryJapanJapan
Whyte4-6-24-6-2T
Number in Class54
Road Numbers201-204/3800-3803
Gauge3'6"3'6"
Number Built54
BuilderseveralDubs & Co
Year19351898
Valve GearWalschaertStephenson
Locomotive Length and Weight
Driver Wheelbase (ft / m)9 / 2.54
Engine Wheelbase (ft / m)28.62 / 6.58
Ratio of driving wheelbase to overall engine wheelbase 0.31
Overall Wheelbase (engine & tender) (ft / m)28.62 / 11.73
Axle Loading (Maximum Weight per Axle) (lbs / kg)29,917 / 13,570
Weight on Drivers (lbs / kg)89,772 / 40,720
Engine Weight (lbs / kg)145,593 / 66,040120,792 / 39,677
Tender Loaded Weight (lbs / kg) / 30,082
Total Engine and Tender Weight (lbs / kg)120,792 / 69,759
Tender Water Capacity (gals / ML)1560 / 13.64
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) 2.80 / 6
Minimum weight of rail (calculated) (lb/yd / kg/m)50 / 25
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)68.90 / 175054 / 1372
Boiler Pressure (psi / kPa)200.20 / 13.80140 / 9.70
High Pressure Cylinders (dia x stroke) (in / mm)20.08" x 25.98" / 510x66017" x 23" / 432x584
Tractive Effort (lbs / kg)25,872 / 11735.3614,648 / 6644.23
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.47
Heating Ability
Tubes (number - dia) (in / mm)84 - 2.008" / 51
Flues (number - dia) (in / mm)18 - 5.157" / 131
Flue/Tube length (ft / m)18.01 / 5.49
Firebox Area (sq ft / m2)133.42 / 12.40
Grate Area (sq ft / m2)27.22 / 2.5326 / 2.42
Evaporative Heating Surface (sq ft / m2)1371 / 127.40996 / 92.57
Superheating Surface (sq ft / m2)445 / 41.40
Combined Heating Surface (sq ft / m2)1816 / 168.80996 / 92.57
Evaporative Heating Surface/Cylinder Volume143.98164.84
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation54493640
Same as above plus superheater percentage68123640
Same as above but substitute firebox area for grate area33,388
Power L114,590
Power MT1074.90

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