The JNR Class ED74 was a Japanese AC electric locomotive operated by the Japanese National Railways from 1962 to October 1978.
History[]
The ED74 was designed specifically for use on the Hokuriku Main Line due to the use of AC electrification on that line. Manufactured to increase the number of locomotives on that line, the locomotives were intended to be able to pull trains through the Hokuriku Tunnel when it opened.
Six locomotives were built from 1962 to 1963; Mitsubishi manufactured both the mechanical and electrical equipment of the locomotive under their Shin-Mitsubishi and Mitsubishi Denki arms. Heavily based on the ED70, the locomotives were based at Tsuruga Rolling Stock Depot when introduced and used to pull passenger trains; in the late-1960s the locomotives on the line were standardized to EF70 locomotives and the locomotives were moved to Kyushu to operate on the Nippo Main Line with the 1 October 1968 timetable revision. The locomotives were based at Ōita during this time.
While they were stationed in Ōita, the locomotives were used to pull freight trains, some passenger trains such as the Fuji and Suisei and acted as towing or pusher locomotives; they could not pull standard passenger trains which required steam-generated heating as the locomotives were not equipped with a steam generator. Their axle load meant the locomotives were unable to travel south of Ōita Station; after the line was fully electrified, the locomotives were withdrawn on 2 October 1978 with the introduction of the Gōsantō timetable revision.
No ED74s have been preserved.
Design[]
The ED74s featured large box-shaped bodies with a slight rake with dual large circular headlights mounted on the top of the cars in two recesses.
Specifications[]
The ED74s used a nose suspension drive system with MT52 traction motors; the use of the nose suspension drive was due to maintenance problems involving the Quill drive, so all locomotives after the earlier EF70 would use the nose suspension drive. This however came at the cost of keeping the rated rotation speed of the traction motors low.