JNR Class DF50

The JNR Class DF50 is a diesel-electric locomotive operated by the Japanese National Railways from 1957 to January 1985.
==History==
Designed to promote JNR's campaign of a "smokeless railway" to eliminate steam locomotives on the Japanese National Railways as part of their Power Modernization Plan, the DF50s were developed as a passenger locomotive for use on the Japanese rail network. Acting as the JNR's first diesel locomotive capable of carrying passengers, 138 locomotives were manufactured from 1957 to 1963, split over two different subseries with two different prime movers. These were deployed on lines such as the Fukuchiyama Line, Nippō Main Line, Yosan Line, Dosan Line and the Kisei Main Line.
Despite some initial performance issues, these were quickly rectified, and the locomotives would mainly be used to pull passenger trains on non-electrified lines; in addition to passenger trains, they also pulled the occasional freight train. The locomotives were quickly replaced by the DD51 locomotives in freight service, with the expanding electrification of the JNR network reducing their use even further; withdrawals began in 1976. Although operations were reduced, the locomotives were still used on the Kii express service.
DF50 operations around the west of Japan ended in October 1978, with the locomotives on the Kii service replaced with DD51s. In Kyushu, the locomotives were used on the Suisei service, with the DF50-500 locomotives used due to their superior pulling power; these were withdrawn in 1979. On Shikoku, the locomotives were used until 9 October 1983 in passenger service, with a special final run using DF50 1 and DF50 65, the first and last DF50-0 locomotives built. Following this, the DF50s were used exclusively to pull freight trains; DF50 34 pulled the last freight service for a DF50 on 21 January 1985.
Two locomotives have been preserved.
==Design==
The DF50 features a semi-streamlined design in what is known as the "Shōnan style".
==Specifications==
The DF50s are fitted with two different types of prime movers; the DF50-0s use Sulzer 8LDA25A I8 prime movers and the DF50-500s use MAN V6V 22/30 mA V12 prime movers. The locomotives use the same electric transmission as the DD50. The Sulzer prime movers produce 1,060 PS (780 kW) whule the MAN prime movers produce 1,200 PS (883 kW); both are said to produce a unique sound, with the Sulzer prime movers sounding more rhythmic while the MAN prime movers producing a low drone.
The locomotives were heavily based on the prototype DF40 locomotive.
==Preservation==
The following Class DF50 locomotives have been preserved:
Number 	Manufacturer 	Date manufactured	Date retired 	Location 	Notes
DF50 1 	Shin-Mitsubishi Jukōgyō	22 March 1950 	9 October 1983 	The Railway History Park, Ehime, Shikoku, Japan 	Remains on JR Shikoku's fleet register; displayed indoors next to front third of 21-141
DF50 18	Shin-Mitsubishi Jukōgyō	22 April 1950 	26 January 1984	Tsuyama Railroad Educational Museum, Okayama, Japan	Displayed in roundhouse; formerly located at the Modern Transportation Museum
The following Class DF50 locomotives were preserved in the past but have since been scrapped:
Number	Manufacturer 	Date manufactured	Date retired 	Last location 	Notes
DF50 4	Shin-Mitsubishi Jukōgyō	17 May 1950 	17 March 1980	Sugaharatenmangu Park, Osaka, Japan	Displayed in enclosure, damaged by typhoon in 2018; removed and scrapped January 2024
==Gallery==
File:DF50 18 2013.jpg
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