Imperial Government Railways 0-6-2 Locomotives in Japan


Class Details by Steve Llanso of Sweat House Media

Class AC/B6/2100 (Locobase 4792)

Data from "New Locomotives for Imperial Railways of Japan," The Locomotive Magazine, Vol VI (February 1901), p. 28 and []. Class data from spreadsheet archived at [], last accessed 7 March 2019. See also Hirota Naotaka, Steam Locomotives of Japan (Tokyo and Palo Alto: Kodansha International Ltd, 1972), p.27. Works numbers were 2682-2687 in 1890, 2771-2776 in 1891.

See Locobase 10520 for the 1905 account of very similar locomotives. Hirota wrote that purchasing a radial tank was spurred by the opening of the Tokaido trunk line opened in Eastern Japan. "Because of its great power," he wrote,"it was used for pulling freight cars as well as shunting. Although the axle [loading] was heavy [sic] and the weight distribution not good, it was very active throughout Japan."

The all-locomotive spreadsheet shows twelve ACs numbered as shown above. The class was later given even numbers from 154-176. But only the 1890 engines are shown to have been taken into the JGR as the first six 2100 class.


Class B6/2120 (British and Japanese) (Locobase 10520)

Data from "Tank Locomotives, Imperial Japanese Railways," The Locomotive Magazine, Vol XI (15 July 1905 ), p. 123. See also "Six-Wheels-Coupled Radial Tank-Engines; Japanese State Railways". Railway Engineer, Volume 27, No 12 (December 1906), pp. 383-385; and Hirota Naotaka, Steam Locomotives of Japan (Tokyo and Palo Alto: Kodansha International Ltd, 1972), p.93.

Dubs works numbers were 3623-3640 in 1898, 4142-4165 in 1902;

Sharp, Stewart works numbers were 4443-4460 in 1899;

Kobe works numbers 10-21 in 1899; and

NBLC works numbers were 15913-15942 in 1904, 16735-16752, 16767-16816, 16973-17072 in 1905

Original road numbers were 362-391, 466-483, 1000-1099

This was a big order for the biggest private locomotive builder in the British Isles. In addition to the 68 already delivered by mid-1905, NBLC had another 100 on order.


Class B6/2400 (German builders) (Locobase 5491)

Data from Akira Tanji & Akira Suzuki, "Repair and Working Preservation of Locomotive No. 2019", Japan Railway & Transport Review 33 (December 2002). See "Tank Locomotives for Japan", The Practical Engineer", Vol 26, No 825 (19 December 1902), p. 593; Hirota Naotaka, Steam Locomotives of Japan (Tokyo and Palo Alto: Kodansha International Ltd, 1972), p. 27; and Naito Hiroshi, "2221, 0-6-2 tank, 49.2 tons, 10.439 m", on the Locomotives of Ome Railway Park at [] . Berliner works number were 3292-3303 in 1903

Hanomag works numbers were 4150-4155

Henschel & Sohn works numbers wer 6679-6690 in 1904; 7033-7042, 7296-7210, 7301-7320 in 1905.

According to the Tanji and Suzuki article, Richard Francis Trevithick, then advisor to the Kobe Railway in Japan, drew up the design for this locomotive. Dubs & Company modified his plans to allow for series production as the 2120 and supplied many of the over 500 locomotives in this class

Germany (Schwarzkoff (Berliner Maschinenbau), Henschel, Hanomag (75 as the 2400 class) and in Japan at the Kobe works.

See Locobases 10933-10934 for two variants of the 2100 design and see Locobase 10983 for the Baldwin 2500s.

In addition to the short tanks and the classic British cab, a noticeable feature of the engine at Oume is the dustbin-shaped sand dome.

Taiwanese engines of this design were class BK80.

The engine proved to be a good size for the relatively lightly built, steeply graded alignments hauling both passenger and freight trains. Tonnage ratings at 20 mph (32.2 km/h) were 310 tons on a 1% grade, 155 tons on 2 1/2%. Many lasted into the 1960s as switchers.

Tanji & Suzuki comment that the vertical Stephenson gear still preserved on engine 2109 is relatively uncommon. They note that the gear featured "both good durability (sic) at high speeds and easy serviceability. However, because this type of valve gear is large and heavy it later was replaced by Walschaert's valve gear."

The locomotive's lack of a leading truck caused the lead axle to wear down quickly, so engineers ran the class in reverse as often as possible. John Daniel of the Great Western site observed that the 0-6-2T arrangement was adopted for the better starting traction it afforded.

[] says the first of the type were imported in 1889 to work the Tokaido main line. So reliable and hard-working did the design prove to be that more than half of them survived World War II.


Class B6/2500, 2900 (US) (Locobase 10983)

Data from Record of Recent Construction #54 (Baldwin Locomotive Works, 1905), p. 18-19; DeGolyer, Volume 27, pp. 290+, and "Double-End Narrow Gauge Tank Locomotive for Japan", Railway Age, Volume 39,(10 March 1905), pp. 307-309 . 2900 class information from rkitterman, " JGR Baldwin-Tottori 2-6-2T No. 2914 at Plaza Loco", Deviant Art website at [], last accessed 15 March 2019. Baldwin works numbers for the 2500 class were:

1904

December 24851-24852, 24859, 24863-24870, 24882-24886, 25288

1905

March 25289, 25327, 25342-25346, 25357-25358, 25378-25382, 25413-25415, 25419-25423

April 25444-25446, 25462-25463, 25472-25475, 25498-25501, 25527-25529, 25538, 25561-25562, 25577, 25599-25600

May 25619-25623

June 25916-25917

July 25951-25952, 25970-25971, 25987-25989, 25998, 26017-26019, 26029, 26032-26038, 26057-26058, 26082-26084, 26100-26101

August 26122-26126, 26151, 26160-26162, 26168-26169, 26172, 26184-26186, 26195-26196, 26205-26207, 26213, 26230, 26236-26237, 26254-26255, 26285-26286, 26303-26304, 26314-26315, 26334-26335, 26348-26349, 26364-26367

September 26402-26403, 26420-26421, 26432-26433, 26452, 26458, 26475-26476

October 26516-26517, 26538-26542, 26592-26593, 26608-26609, 26661, 26683-26687, 26742

November 26782-26783, 26830, 26840

See Locobase 5491 for the main entry on this large class. The 2500s were the Baldwin-built contingent, which constituted about 30% of the total. RA's 1905 report noted that the Philadelphia builder had constructed the class based on the earlier British engines. Among many differences between British and American practice were the use of water spaces around the firebox that seemed "unusually small". One key feature of the design was a steeply angled grate to a "considerable depth" at the front, which was "necessary for burning inferior grades of Japanese coal."

All of the order was produced or delivered in 1905. Baldwin's spec noted that the maximum axle loading was to be 13 tons 6 cwt. This was a main-line value on many US trunk lines.

Seventeen of the class underwent a modification program at the Yokkaichi and Takatori workshops of the JGR. The shops added a leading truck. This installation added 2.210 m (7 ft 3 in) to the engine's wheelbase, extending it to 8.230 m (27 ft 0 in ). Very little additional adhesion weight was added, but the locomotive now carried an extra seven metric tons on the leading axle.

The 2900s' duties were to haul local freight and mixed-traffic service between Hiroshima, Mitajiri, and Shimonoseki. In the 1930s, C11 and C12 Moguls replaced most of the class in road service, relegating the 2900s to construction trains. Three survived World War II and were scrapped in 1948.

Principal Dimensions by Steve Llanso of Sweat House Media

ClassAC/B6/2100B6/2120 (British and Japanese)B6/2400 (German builders)B6/2500, 2900 (US)
Locobase ID4792 10520 5491 10983
RailroadImperial Government Railways (JGR)Imperial Government Railways (JGR)Imperial Government Railways (JGR)Imperial Government Railways (JGR)
CountryJapanJapanJapanJapan
Whyte0-6-2T0-6-2T0-6-2T0-6-2T
Number in Class528268336168
Road Numbers154-176 (even)/101-111 (odd)/2100-21162171-2198, 2217-2234, 2283-2365395-434, 451-483, 1200-1219/2400-2471435-450, 700-749, 1100-1199/2500-2667
Gauge3'6"3'6"3'6"3'6"
Number Built528268336168
BuilderseveralseveralseveralBurnham, Williams & Co
Year1890190419041905
Valve GearStephensonStephensonStephensonStephenson
Locomotive Length and Weight
Driver Wheelbase (ft / m) 8.42 / 2.5712.50 / 3.8112.53 / 3.8212.50 / 3.81
Engine Wheelbase (ft / m) 8.42 / 2.5719.75 / 6.0219.75 / 6.0219.75 / 6.02
Ratio of driving wheelbase to overall engine wheelbase1 0.63 0.63 0.63
Overall Wheelbase (engine & tender) (ft / m)19.75 / 6.0219.75 / 6.02
Axle Loading (Maximum Weight per Axle) (lbs / kg)29,792
Weight on Drivers (lbs / kg)89,705 / 40,69092,109 / 41,78087,082 / 39,50082,700 / 37,512
Engine Weight (lbs / kg)109,945 / 49,870112,943 / 51,230108,467 / 49,200102,000 / 46,266
Tender Loaded Weight (lbs / kg)
Total Engine and Tender Weight (lbs / kg)109,945 / 49,870112,943 / 51,230108,467 / 49,200102,000 / 46,266
Tender Water Capacity (gals / ML)2060 / 7.802059 / 7.802059 / 7.801811 / 6.86
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) 2.10 / 2 2.10 / 2 2.20 / 2 2.10 / 2
Minimum weight of rail (calculated) (lb/yd / kg/m)50 / 2551 / 25.5048 / 2446 / 23
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)49.20 / 125049.20 / 125049 / 124549 / 1245
Boiler Pressure (psi / kPa)160 / 11159.50 / 11140.70 / 9.70160 / 11
High Pressure Cylinders (dia x stroke) (in / mm)16" x 24" / 406x61015.98" x 24.02" / 406x61015.98" x 24.02" / 406x61016" x 24" / 406x610
Tractive Effort (lbs / kg)16,983 / 7703.3716,902 / 7666.6314,971 / 6790.7417,053 / 7735.12
Factor of Adhesion (Weight on Drivers/Tractive Effort) 5.28 5.45 5.82 4.85
Heating Ability
Tubes (number - dia) (in / mm)192 - 1.772" / 45192 - 1.75" / 44
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m)10.30 / 3.1410.45 / 3.19
Firebox Area (sq ft / m2)93.65 / 8.7093 / 8.64
Grate Area (sq ft / m2)14.10 / 1.3114.42 / 1.3414.10 / 1.3114.50 / 1.35
Evaporative Heating Surface (sq ft / m2)1000 / 92.941000 / 92.94992 / 92.19994 / 92.38
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)1000 / 92.941000 / 92.94992 / 92.19994 / 92.38
Evaporative Heating Surface/Cylinder Volume179.05179.35177.91177.98
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation2256230019842320
Same as above plus superheater percentage2256230019842320
Same as above but substitute firebox area for grate area14,93714,880
Power L134443413
Power MT247.30272.95

All material Copyright © SteamLocomotive.com
Wes Barris