DeRoI-class locomotive (Mitsubishi)

Mitsubishi DeRoI Type
Builder's photo of DeRoI-33
Type and origin Power type Electric Designer Shinichi Matsuda, Saneyoshi Hirota Builder Mitsubishi Build date 1946
Specifications Configuration: ​  • UIC 1C-C1 Gauge 1,435 mm (4 ft 8+1⁄2 in) Wheelbase: ​  • Axle spacing (Asymmetrical) 1-2: 2,050 mm (6 ft 9 in) 2-3: 1,880 mm (6 ft 2 in) 3-4: 2,600 mm (8 ft 6 in) Pivot centres 9,780 mm (32 ft 1 in) Length: ​  • Over body 16,000 mm (52 ft 6 in) Width 3,100 mm (10 ft 2 in) Height: ​  • Pantograph 4,600 mm (15 ft 1 in)  • Body height 4,050 mm (13 ft 3 in) Loco weight 135 t (297,600 lb) Electric system/s 3,000 V DC Current pickup(s) Pantographs Couplers AAR knuckle
Performance figures Maximum speed 75 km/h (45 mph) Power output 2.25 MW (3,020 hp)
Career Operators Chosen Gov't Railway Korean State Railway Class CGR: デロイ DeRoI KSR: 전기서 Chŏngisŏ Number in class 3 Numbers CGR: デロイ31 - デロイ33 KSR: 전기서1 - 전기서3

The Mitsubishi DeRoI-class (Template:Lang-ja) was a group of three boxcab-style electric locomotives with regenerative braking (type EL14AR) and the capability for multiple-unit control manufactured by Mitsubishi in 1946. They were very similar to the Toshiba-built DeRoI-class locomotives and the DeRoNi-class locomotives built by Hitachi. They were built for the Chosen Government Railway (Sentetsu), and after the partition of Korea were inherited by the North Korean State Railway, where they were known as the Chŏngisŏ (Template:Lang-ko, "Electric 3") class.

Description

Sentetsu had issued its requirement for an electric locomotive in 1938, beginning discussions with Mitsubishi in that year regarding the development of a plan to electrify certain rail lines in Korea. 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.

When the electrification of rail lines in Korea was begun in 1943, Sentetsu ordered twenty DeRoI class locomotives of 135 tons - sixteen from Toshiba and four from Mitsubishi 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 Japanese roku, 6), and I (from Japanese ichi, 1), indicating the first class of electric locomotive with six powered axles.

Design work was undertaken by Mitsubishi, with Shinichi Matsuda designing the control circuits and Saneyoshi Hirota designing the main motor. 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.

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.

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. Mitsubishi-built units 31 and 32 were delivered in August 1946, while number 33, although likewise completed in June 1946, wasn't delivered until June 1948. 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.

As the Korean War caused the destruction of the electrification of North Korea's rail lines, they sat disused until 1956. In that year they were reclassified Chŏngisŏ (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.

No information on the subsequent disposition of these locomotives is available at present.