JNR Class D51


The Class D51 is a type of 2-8-2 steam locomotive operated by the Japanese Government Railways and later by the Japanese National Railways. Designed by JGR's chief mechanical engineer Hideo Shima, they were built by Kawasaki Heavy Industries [Rolling Stock Company], Kisha Seizo, Hitachi, Nippon Sharyo, Mitsubishi Heavy Industries and JGR's factories from 1936 to 1945.
Although surpassed in speed, power, and size by other locomotives, it is recognised as the most mass-manufactured locomotive in Japanese rail history. A total of 174 units are preserved in Japan, including five operational examples. An additional 6 are preserved in Russia and Taiwan, bringing the total number of preserved units to 180.

Classification

The classification consists of a "D" for the four sets of driving wheels and the class number 51 for tender locomotives that the numbers 50 through 99 were assigned to under the 1928 locomotive classification rule.

Design and production

Background of Development

Following the Great Depression of 1929, Japan's rail freight demand declined. This delayed plans for the development and production of new freight locomotives, which were set to become successors to the Class D50. By the mid-1930s, economic recovery led to increased transport demand. Although electrification was in progress, steam locomotives remained the backbone of railway operations. The result was the D51, a mechanically simple, versatile and fuel-efficient freight locomotive. The D51's chief designer, Hideo Shima, later described it as one of his most satisfying designs.

Design

The D51 was based on the earlier Class D50, with which it shares many design fundamentals, such as a parallel boiler and a 1D1 wheel arrangement. Notable changes from the Class D50 included:
  • Boiler pressure and tractive effort: The boiler pressure was initially raised from the and later to in wartime models. Despite a smaller cylinder bore, these changes enhanced tractive effort.
  • Weight reduction and adaptability: Electric welding replaced traditional riveting, which resulted in reduction of axle load and overall weight. The maximum axle load was reduced from, which allowed operation on lighter secondary lines previously inaccessible to the D50.
  • Length reduction: The D51 was shorter than the D50 to fit on standard branch line turntables, thus broadening its operational range.
  • Wheel design: The D51 adopted boxpok wheels, which distributed force more evenly across the wheel circumference.
Other issues identified in the D50, such as derailments during reverse operations, were also addressed in the D51's design.

Variants

The D51 is divided into three types based on the production period and design changes: early type, standard type, and wartime type.

Early type (''Namekuji'')

Units produced: D51 1–85, 91–100
Period produced: 1936–1937
Early models are noted for their semi-streamlined appearance, with the feedwater heater positioned between the sand dome and chimney and enclosed in a long casing. This design earned the nickname "Slug". Two locomotives, D51 22 and 23, had an extended casing reaching the cab, referred to as "Super Slug" or "Big Slug." These were later modified to match other units because the extended casings required extra maintenance. To balance the shortened overall length compared to the D50, the cab was made smaller. While this reduced weight, it also made the cab more confined, which some crews found uncomfortable. The weight of the first driving axle was lighter than the others, which caused wheel slip under heavy loads. The air-powered reverser was also found to be difficult to use due to its sensitivity. Later modifications, such as adding weight to the front deck, improved traction.

Standard type

Units Produced: D51 86–90, 101–954
Period produced: 1937–1944
The feedwater heater was relocated to a crosswise position in front of the chimney, and the suspension system was adjusted to improve axle weight distribution. The air-powered reverser was replaced with a manual version for better control. From D51 101 onwards, this updated design became standard, and most of the class was built to this specification. Wartime versions of these later units used simplified materials and construction methods, including wooden components and the omission of some design details to conserve resources.

Wartime type

Units Produced: D51 1001–1161
Period produced: 1944–1945
Wartime models were built with substitute materials and reduced decorative elements. The dome was reshaped to a flat design, and wooden parts were used for components such as the smoke deflectors. Some tenders adopted a simpler 'ship-bottom' design. To increase hauling capacity, boiler pressure and axle load were raised, but the use of substandard materials and simpler welding caused reliability issues. This resulted in several boiler explosions, notably with D51 1140. After the war, many of these units were retrofitted with standard parts to improve safety and reliability.

Operations

The D51 was widely used across Japan and was a common sight throughout the country. Primarily a freight locomotive, the D51 was occasionally assigned to passenger services, particularly on steeply graded lines such as the Chūō Main Line and the mountainous section of the Hakodate Main Line. On some flatter lines, such as the Uetsu Main Line, it also hauled passenger trains. Notable examples of its service include locomotives assigned to royal trains and units used at yards on main lines, such as Shintsurumi and Suita, for hump shunting.
From the 1960s, D51 locomotives began to be retired as electrification and dieselisation progressed. However, many remained in service until the final years of steam operation in Japan. During the 1960s and 1970s, they were particularly prominent on steeply graded lines such as the Sekihoku Main Line, Tōhoku Main Line, Ōu Main Line, and Hakubi Line, often operating in double- or triple-headed configurations. These operations attracted railway enthusiasts, photographers, and media attention during the 'SL boom' period. While its ubiquity made the D51 an iconic machine, some enthusiasts seeking rarer locomotive classes expressed disappointment when encountering D51s.

Hokkaidō

The first D51s in Hokkaidō were assigned to the Otaru-Chikkō and Iwamizawa depots, with units such as D51 6 at Otaru-Chikkō and Nos. 48 and 126 at Iwamizawa. On the Nemuro Main Line, D51 locomotives assigned to the Shintoku depot were used on the old Karikachi Pass section without smoke deflectors and with limited installations of oil-fired systems. D51 241 at the Oiwake depot hauled JNR' final steam-hauled train on 24 December 1975, on the Yūbari Line.

Tōhoku

D51s were extensively used on major lines such as the Tōhoku Main Line, Ōu Main Line, Jōban Line, and Uetsu Main Line. On the Tōhoku Main Line, triple-heading operations were notable at Jūsanbongi Pass in Ichinohe, Iwate, with locomotives from Morioka, Ichinohe, and Shiriuchi depots. Similarly, triple-heading was common at Yatate Pass on the Ōu Main Line until 1971, by locomotives from depots such as Aomori, Hirosaki, and Akita.

Kantō

In the Kantō region, D51s were assigned to depots including Takasaki, Utsunomiya, Mito, Ōmiya, Hachiōji, Tabata, Shintsurumi, and Shinkoiwa. At Mito, some units were fitted with automatic coal-feeding equipment in 1957 to accommodate the low-calorific coal from the Jōban coalfield. The electrification of lines such as the Sōbu Main Line and Takashima Line in 1970 led to the withdrawal of D51s from depots such as Shintsurumi. D51 791 was used for farewell passenger services in October 1970, which operated between Tokyo and Yokohama.

Chūbu

D51s were assigned to the Hokuriku Main Line, including depots at Tsuruga, Fukui, and Kanazawa, where they handled freight operations over steep passes such as the Yanagase and Yamano Tunnels. The electrification of the Hokuriku Main Line was completed by 1964, but some D51s remained in use for local and yard duties until 1971. On the Takayama Main Line, they replaced C58s and 9600s from 1959 until dieselisation in 1969.

Kansai

In Kansai, D51s were used on lines like the Kansai Main Line, San'in Main Line, and the Fukuchiyama Line. On the Kansai Main Line, they operated in double-headed configurations to manage the steep gradients of the Kabuto Pass.

Chūgoku

D51s operated on lines such as the Sanyō Main Line, Hakubi Line, and Mine Line. On the Hakubi Line, D51s based at Niimi depot were used for triple-headed limestone freight trains, which attracted significant attention from railway enthusiasts.

Shikoku

Thirteen D51s were assigned to the Dosan Line, based at the Kōchi depot. These locomotives were eventually replaced by DF50 diesel locomotives by 1960.

Kyūshū

In Kyūshū, D51s were assigned to depots including Mojikō, Tosu, and Kumamoto. On the steeply graded Hisatsu Line, D51s replaced older locomotives such as the Class 4110 for services over the Yatake Pass. These locomotives were equipped with smoke collectors and oil-firing systems.

Outside Japan

Soviet Railways D51

The 30 specially built D51s that were left on Sakhalin by the retreating Japanese at the end of the Second Sino-Japanese War (1937-1945) and after the Soviet-Japanese War (1945), were used from 1945 until 1979 by Soviet Railways. One was left outside Yuzhno-Sakhalinsk railway station, and one is in running condition and is kept at the Yuzhno-Sakhalinsk railway station. Additionally two wrecks were left to the north of the city.

Korean National Railways Mika7

Two locomotives were built for the Korean National Railroad in 1950 by Mitsubishi for South Korea during the Korean War. Designated Mika7 class, they were nearly identical to JNR class D51 except for the gauge.

Manila Railroad 300 class (1951)

According to the a journal published in 1956, ten locomotives were built by Nippon Sharyo for the Manila Railroad Company. These entered service in 1951. Numbered the 300 class, they were named after the cog locomotive class built in the 1910s for the Manila Railway. These locomotives differed from the rest of the D51 builds through the lack of smoke deflectors.
The locomotives had a short service life in the Philippines as Manila Railroad ordered the dieselization of its entire network, having all steam locomotives retired by 1956.

Taiwan Railways Administration DT650

From 1936 to 1944, Kawasaki, Kisha Seizō and Hitachi had built 32 D51s for Imperial Taiwan Railway. After World War II, they were taken over by Taiwan Railways Administration, and were classified DT650. In 1951, Kisha Seizō built three DT650s and Mitsubishi Heavy Industries built two DT650s for Taiwan Railways Administration.

Preserved examples

Over 173 Class D51 locomotives are preserved in Japan.
The following is a list of preserved locomotives as of July 2023.

Taiwan

Russia

D51-4: Sakhalin D51-22: Sakhalin

Japan

Operational

D51 146: Operated on the Mooka Railway, runs on compressed air. D51 200: Preserved in operational condition by JR West at the Kyoto Railway Museum, and was operating on Yamaguchi Line from November 2017 to May 2022, when a crack in one of its bogies was discovered. Restoration work and trial runs are continuing at the Railway Museum. Re-entered service in 2024.D51 320: Operated at a railway museum in Abira, Hokkaido on compressed air. D51 498: Restored by JR East, based at Takasaki Rolling Stock Center, and pulls special-event trains on JR East lines.D51 827: Operated at Aridagawa Railway Park in Wakayama Prefecture, runs on compressed air.
Built in 1938 at the JNR Hamamatsu Works, locomotive number D51 200 has been overhauled and restored to operational condition for use as SL Yamaguchi and SL Kitabiwako starting in 2017.

Static preservation

Sakhalin D51-1: Niigata PrefectureSakhalin D51-2: HokkaidoSakhalin D51-23: HokkaidoSakhalin D51-25: HokkaidoSakhalin D51-26: HokkaidoSakhalin D51-27: HokkaidoD51 1: Preserved at Kyoto Railway MuseumD51 2: Previously preserved at the Modern Transportation Museum in Osaka, and moved to the Tsuyama Roundhouse next to Tsuyama Station in Okayama Prefecture in March 2015D51 6: Preserved in a park in Asahikawa, HokkaidoD51 8: Preserved in a park in Amagasaki, HyogoD51 10: Preserved at a community centre in Yukuhashi, FukuokaD51 11: Preserved in a park in Sapporo, HokkaidoD51 14: Preserved in a park in Nagareyama, ChibaD51 18: Preserved in Tokiwa park, Ube, YamaguchiD51 25: Preserved in a park in Sanda, HyogoD51 47: Preserved in a park in Iwamizawa, HokkaidoD51 59: Preserved in a park in Tatsuno, NaganoD51 66: Preserved at Kawanishi Elementary School in Seika, KyotoD51 68: Preserved at Koiwai Farm in Shizukuishi, IwateD51 70: Preserved at Sakura Transport Park in Tsukuba, IbarakiD51 75: Preserved in a park in Joetsu, NiigataD51 86: Preserved at "Flower Park" in Hamamatsu, ShizuokaD51 89: Preserved in a park in Toyohashi, AichiD51 95: Preserved at Shintoku Ski Slope in Shintoku, HokkaidoD51 96: Preserved at Usui Pass Railway Heritage Park in Annaka, GunmaD51 101: Preserved in Chuo Park in Shimada, ShizuokaD51 103: Preserved in a park in Iwakuni, YamaguchiD51 113: Preserved in Chuo Park in Misawa, AomoriD51 118: Preserved in Kotesashi Park in Tokorozawa, SaitamaD51 125: Preserved next to the Funabashi Historical Museum in Funabashi, ChibaD51 140: Preserved in Arakawa Park in Kumagaya, SaitamaD51 155: Preserved outside Shiojiri City Office in Shiojiri, NaganoD51 158: Preserved outside a community centre in Ibaraki, OsakaD51 159: Preserved in a park in Iwanai, HokkaidoD51 165: Preserved in a park in Nanto, ToyamaD51 170: Preserved in front of Yatake Station in Hitoyoshi, KumamotoD51 172: Preserved in a park in Matsumoto, NaganoD51 176: Preserved in a park in Hita, OitaD51 187: Preserved in front of JR East's Omiya Workshops, Saitama, SaitamaD51 194: Preserved in front of Tsuwano Station in Tsuwano, ShimaneD51 195: Preserved in a park in Yonago, TottoriD51 201: Preserved outside Gamagori Museum in Gamagori, AichiD51 206: Preserved in a park next to Saga City Office in Saga, Saga D51 209: Preserved in a park in Ina, NaganoD51 211: Preserved at Oji Zoo in Kobe, HyogoD51 222: Preserved in Yogi Park, Naha, OkinawaD51 231: Preserved outside the National Museum of Nature and Science in Taito, TokyoD51 232: Preserved at Omoriyama Zoo in Akita, AkitaD51 237: Preserved at Naebo Works in Sapporo, HokkaidoD51 238: Preserved at a community centre in Kiso, NaganoD51 243: Preserved in Izu, ShizuokaD51 244: Preserved at a children's museum in Kitakyushu, FukuokaD51 245: Preserved at a community centre in Sakaki, NaganoD51 254: Preserved in Suginami Jidō Kōtsū Park in Suginami, TokyoD51 260: Preserved in a park in Namerikawa, ToyamaD51 264: Preserved in a park in Koriyama, FukushimaD51 266: Preserved in a park in Nakatsugawa, GifuD51 270: Preserved in Yokote Park in Yokote, AkitaD51 272: Preserved in Setagaya Park in Setagaya, TokyoD51 286: Preserved in Otaru, HokkaidoD51 296: Preserved in Fuchū Transport Park in Fuchū, TokyoD51 297: Preserved in Takikawa, HokkaidoD51 300: Preserved in a park in Sanyo-Onoda, YamaguchiD51 303: Preserved in a park in Tottori, TottoriD51 311: Preserved in SL Park in Kitami, HokkaidoD51 312: Preserved in Sakurayama Park in Fukagawa, HokkaidoD51 333: Preserved in Shiraoi, HokkaidoD51 337: Preserved in Wassamu, HokkaidoD51 345: Preserved in Taishiyama Park in Taishi, HyogoD51 349: Preserved in Okaya, NaganoD51 351: Preserved in SL Park in Nagiso, NaganoD51 370: Preserved in a park in Akita, AkitaD51 385: Preserved in a park in Kamagaya, ChibaD51 395: Preserved at Tokuyama Zoo in Shunan, YamaguchiD51 397: Preserved in a park in Shibetsu, HokkaidoD51 398: Preserved in Nayoro Park in Nayoro, HokkaidoD51 401: Preserved at Suzaka Zoo in Suzaka, NaganoD51 402: Preserved at a community centre in Iida, NaganoD51 403: Preserved in a park in Ritto, ShigaD51 405: Preserved in a park in Matsudo, ChibaD51 408: Preserved at a museum in Kawasaki, KanagawaD51 409: Preserved at Yamazaki Mazak Corporation Minokamo Factory in Minokamo, GifuD51 422: Preserved in a park in Onomichi, HiroshimaD51 426: Preserved at JR East Railway Museum, Saitama, Saitama D51 428: Preserved in Higashi-Chofu Park in Ota, TokyoD51 444: Preserved at the SL Hiroba in Kitami, HokkaidoD51 451: Preserved in Showa Park in Akishima, TokyoD51 452: Preserved at Ome Railway Park in Ōme, TokyoD51 453: Preserved in Nishiguchi No. 1 Park in Kashiwa, ChibaD51 469: Preserved in a park in Takaishi, OsakaD51 470: Preserved in Bairin Park in Gifu, GifuD51 481: Preserved in Minamiechizen, FukuiD51 483: Preserved in Azumino, NaganoD51 485: Preserved in a park in Nobeoka, MiyazakiD51 486: Preserved at JR East's Nagano Depot in Nagano, NaganoD51 488: Preserved at the Wako Museum in Yasugi, ShimaneD51 499: Preserved in a park in Tsu, MieD51 502: Preserved in Kamichiba Sunahara Park in Katsushika, TokyoD51 512: Preserved in a park in Shibata, NiigataD51 513: Preserved in a park in Itabashi, TokyoD51 515: Preserved in a park in Mito, IbarakiD51 516: Preserved in Honmoku Shimin Park in Yokohama, KanagawaD51 522: Preserved in a park in Kanazawa, IshikawaD51 541: Preserved in a park in Hyuga, MiyazakiD51 542: Preserved inside JR Kyushu's Okura Works in Kitakyushu, Fukuoka D51 549: Preserved outside an elementary school in Nagano, NaganoD51 560: Preserved in Muroran, HokkaidoD51 561: Preserved in Kawaba, Gunma D51 565: Preserved in a park in Saroma, HokkaidoD51 566: Preserved in Akabira, Hokkaido D51 592: Preserved in Kudamatsu, YamaguchiD51 603: Preserved in the "19th Century Hall" at Torokko Saga Station in Kyoto D51 607: Preserved in a park in Fukui, FukuiD51 609: Preserved in a park in Narita, ChibaD51 663: Preserved at a culture centre in Towada, AomoriD51 688: Preserved in Minami Park in Okazaki, AichiD51 691: Preserved in a park in Tenri, NaraD51 714: Preserved in a park in Kagoshima, KagoshimaD51 718: Preserved in a park in Ichinomiya, AichiD51 720: Preserved in a park in Hiroshima, HiroshimaD51 724: Preserved in Ekimae Park in Shibukawa, GunmaD51 735: Preserved in Murakami, NiigataD51 737: Preserved in Nagi Park in Yuasa, WakayamaD51 745: Preserved in front of Minakami Station in Minakami, GunmaD51 762: Preserved in a park in Hachinohe, AomoriD51 764: Preserved in Suita, OsakaD51 768: Preserved in Shimonoseki, YamaguchiD51 769: Preserved outside a museum in Omi, NaganoD51 774: Preserved outside the former Taisha Station in Izumo, ShimaneD51 775: Preserved in front of Kiso-Fukushima Station in Kiso, NaganoD51 777: Preserved in a park in Kariya, AichiD51 787: Preserved in Miyota, NaganoD51 792: Preserved in a park in Kasugai, AichiD51 793: Preserved at Nagahama Railway Square in Nagahama, ShigaD51 813: Preserved outside a community centre in Yamaguchi, YamaguchiD51 822: Preserved in front of Mattō Station in Hakusan, IshikawaD51 823: Preserved in a park in Inazawa, AichiD51 824: Preserved in Suwa, NaganoD51 828: Preserved in Heiwa Kannon Temple in Awaji, Hyogo D51 831: Preserved in a park in Iga, MieD51 837: Preserved in a park in Komagane, NaganoD51 838: Preserved in a car park in Niimi, OkayamaD51 842: Preserved in a park in Kurashiki, OkayamaD51 849: Preserved in a park in Toyota, AichiD51 853: Preserved in Asukayama Park in Kita, TokyoD51 859: Preserved in a park in Engaru, HokkaidoD51 860: Preserved in a park in Fukuyama, HiroshimaD51 862: Preserved in Machida, TokyoD51 882: Preserved in Ibaraki, OsakaD51 885: Preserved in Fukaya, SaitamaD51 889: Preserved in a park in Sōja, OkayamaD51 892: Preserved in a park in Hirosaki, AomoriD51 895: Preserved in a park in Oji, NaraD51 916: Preserved in a park in Maebashi, GunmaD51 917: Preserved in a park in Kita-ku, Okayama, OkayamaD51 921: Preserved outside Shinonoi Community Centre in Nagano, NaganoD51 923: Preserved in Kurume, FukuokaD51 930: Preserved in a park in Iwade, WakayamaD51 943: Preserved in a park in Fuji, ShizuokaD51 946: Preserved at the Coal and Fossils Museum in Iwaki, FukushimaD51 947: Preserved in Hakone, KanagawaD51 953: Preserved outside Chuo Community Centre in Toyoura, HokkaidoD51 954: Preserved outside a community centre in Furano, HokkaidoD51 1001: Preserved in front of the Koshoku Gymnasium in Chikuma, NaganoD51 1032: Preserved in a park in Yufu, ŌitaD51 1052: Preserved in Kirin Beer Park Chitose in Chitose, HokkaidoD51 1072: Preserved in front of Kobe Station in Kobe, HyogoD51 1085: Preserved in Aridagawa Railway Park in Aridagawa, WakayamaD51 1101: Preserved at Mikasa Park in Yokosuka, KanagawaD51 1108: Preserved at Sendai Shinkansen Depot in Rifu, MiyagiD51 1116: Preserved at The Hirosawa City, Chikusei, IbarakiD51 1119: Preserved in a park in Atsugi, KanagawaD51 1142: Preserved in a park in Sasebo, NagasakiD51 1149: Preserved in Taga SL Park in Taga, Shiga

In fiction

Hiro, a character based on the Class D51 and voiced by Togo Igawa, appears in the 2009 animated film Thomas & Friends: Hero of The Rails and thereafter became one of the show's mainstays and the first character introduced after the change to CGI.
In the anime Hikarian the character Dozilas is based on the D51 498.
The Transformers Decepticon Astrotrain transforms into a Class D51 and a space shuttle.
The Gobots aka Machine Robo character Loco has a vehicle mode based on the D-51 steam train and has the number D-5147 on him.
It also appeared in Initial D Stage 3 at Shibukawa Station as the actual engine.
In the Netflix anime adaptation of Junji Ito Maniac, the second episode portrays a D51 1611 (a numeration that not exists in the reality, likely a reference of the last unit built, the D51 1161.