The first electrified railway in Korea was the 29.7 km (18.5 mi) 1,067 mm (42.0 in) narrow gauge streetcar line in
Seoul running from
Seodaemun to
Cheongnyang-ni via
Cheongno and
Dongdaemun, which was opened on 18 April 1898 by the
Hanseong Electric Company. This was actually the first railway of any type in Korea, having preceded the 33.2 km (20.6 mi)
Gyeongin Railway from
Noryangjin to
Jemulpo, which opened on 18 September 1899. The first electrified standard gauge mainline railway in Korea was the privately owned
Geumgangsan Electric Railway, which on 1 August 1924 opened a 28.8 km (17.9 mi) line from
Cheorwon to
Geumhwa electrified at 1,500 V DC. Later, the line was extended from Cheorwon to
Naegeumgang; the 116.6 km (72.5 mi) extension was opened on 1 July 1931.[3]
The
Government-General of Korea began working on a national electric power policy in November 1926, and the resulting plan was completed in December 1931. Chapter 4, "Utilising Electricity in Transportation in Korea" dealt with the electrification of Korea's railways. In 1937, a plan to electrify the
Bokgye–
Gosan section of the
Gyeongwon Line, the
Jecheon–
Punggi section of the
Gyeonggyeong Line and the
Gyeongseong–
IncheonGyeongin Line was submitted to the Imperial Diet, which approved it in 1940.[3] Sentetsu issued its requirement for an electric locomotive in 1938, beginning discussions with
Mitsubishi in that year regarding the implementation of the electrification plan. Part of the Railway Bureau's goal with the electrification plan was to set a new world speed record, and to go with that, a state-of-the-art locomotive was desired. The project entailed many Japanese firsts, including the first use of 3,000 V electrification, and, specific to the DeRoI class locomotive, the first use of regenerative brakes.[4][3] The resulting design was very similar to the
EF12 class of the
Japanese National Railways.
When the electrification of rail lines in Korea was begun in 1943, Sentetsu ordered twenty DeRoI class locomotives of 135 tons - sixteen from
Toshiba[5] and four from Mitsubishi[4] The original class name, デロイ (DeRoI), comes from the
Sentetsu classification system for electric locomotives: DeRoI = De, for "electric" (from 電気, denki), Ro, to indicate six powered axles (from
Japaneseroku, 6), and I (from Japanese ichi, 1), indicating the first class of electric locomotive with six powered axles.[6]
Design work was undertaken by Mitsubishi, with Shinichi Matsuda designing the control circuits and Saneyoshi Hirota designing the main motor.[4] The design was very similar to the
EF12-class of the
Japanese National Railways. The electrical components were manufactured by Mitsubishi Electric, while the mechanical components were produced by Mitsubishi's Mihara Vehicle Works.[7]
Though generally quite similar in appearance to the
Hitachi-built
DeRoNi type and the
Toshiba-built
DeRoI type locomotives, there were a number of features that distinguished the Mitsubishi-built DeRoI class from the others. These included: equal spacing of side windows; a distinctive ventilator shape, including two relatively large ventilators; and a distinctive arrangement of the deck railings.[7]
The four units ordered by Sentetsu were intended for use on the
Kyŏnggyŏng Line, but none were completed by the end of the
Pacific War; three were nearly complete. After the war, the
Allied General Headquarters (GHQ) in
Tokyo ordered the construction and delivery of a further ten units to Korea as war reparations, including the three near-complete Mitsubishi units.[5] Mitsubishi-built units 31 and 32 were delivered in August 1946, while number 33, although likewise completed in June 1946,[8] wasn't delivered until June 1948.[9] The remaining, unfinished unit was scrapped at the factory. These were all delivered to the southern zone of occupation, but during the Korean War all three of the Mitsubishi-built DeRoI locomotives were captured and taken to the North.[10]
Refurbishment of DeRoI and DeRoNi class locomotives at Yangdŏk in 1956.
As the Korean War caused the destruction of the electrification of North Korea's rail lines, they sat disused until 1956.[11] In that year they were
reclassifiedChŏngisŏ (전기서, "Electric-3") class and numbered 전기서1 through 전기서3, and were refurbished at the engine shops at
Yangdŏk for use on the Yangdŏk-
Ch'ŏnsŏng section of the
P'yŏngra Line, which had been electrified in 1956 as the first stage of North Korea's electrification plans.[11]
No information on the subsequent disposition of these locomotives is available at present.
Chosen Government Railway locomotives and rolling stock
Rolling stock of
Korail