JNR Class DD13

The JNR Class DD13 is a diesel-hydraulic locomotive operated by the Japanese National Railways from 1958 to March 1987.
==History==
The DD13 was designed primarily for use as a switching locomotive for use in yards. Prior to this, locomotives used for switching were the 8620, 9600 and B20 steam locomotives, while their only diesel locomotives in use were the DD11 and the American-made DD12, which had insufficient power output for switching and were thus not used.
As part of JNR's Power Modernization Plan, the DD13 was conceived; a target of a locomotive with a higher power output than the DD11 was set for switching, as well as a locomotive that could be used for short runs on branch lines. Produced from 1958 to 1967, a total of 414 locomotives were produced, although all of them have never co-existed at the same time; major design changes were enacted in 1961. Despite being billed as the definitive switching locomotive to replace steam locomotives, a number of issues, such as the axle load made the DD13 unsuitable for work in large scale yards and it being too heavy for certain branch lines. Production was discontinued in 1967 due to the introduction of the DE11, designed specifically for switching; the later DE10 locomotives were designed to fix the faults with this locomotive and the experimental DD20 locomotives.
When they entered service, the DD13s were mostly used for switching and pulling freight trains, rarely pulling passenger trains. From 1963 to 1977, twenty DD13s were modified to become Class 912 locomotives for maintenance-of-way on the Shinkansen network. With the rapid progress of electrifying the Japanese rail network, the DD13s were rapidly retired starting 1979; all were retired by 31 March 1987, one day before the JNR's privatization and division.
Despite none serving under JR ownership, the DD13 is remembered as a significant locomotive in Japanese railway history, for lessons learned from the development of the DD13 led to the creation of the DD51, showing that JNR could succeed through the use of diesel-hydraulic locomotives. A number of ex-JNR DD13s would be resold to private railways, and many other minor private railways would order similar locomotives based on the DD13 design which continue to serve today.
==Design==
The DD13 featured a steeplecab-like design, giving it an appearance similar to that of a switcher locomotive; this design was chosen to help the locomotive reduce its weight by reducing its axle load.
==Specifications==
The DD13s are fitted with two V12 prime movers, designated the DMF31S. From 1961, all DD13s manufactured (DD13 111 onwards) would use the DMF31SB prime mover, equipped with a turbocharger. Total output was about 1,000 PS (736 kW). Total power output is about 2,200 PS (1,600 kW). The DD13 uses a Shinko DS1.2/1.35 hydraulic transmission; the transmission works similarly to a Lysholm-Smith hydraulic torque converter and features two speeds and a single direct gear. 
==Preservation==
The following Class DD13 locomotives have been preserved:
Number 	Manufacturer 	Date manufactured	Date retired 	Location 	Notes
DD13 1 	Kisha Seizō 	20 March 1958 	11 June 1984 	The Railway Museum, Saitama, Japan 	Prototype locomotive; displayed under shelter with Kiha 11 25
DD13 353	Nippon Sharyo	13 June 1967 	31 March 1986 	Mikasa Railway Memorial Hall, Mikasa, Hokkaido, Japan	Displayed indoors in same compound as 59609, C12 2 and ED76 505, cab open for public viewing
DD13 611	Nippon Sharyo	20 June 1966 	31 March 1986 	Otaru City General Museum, Otaru, Hokkaido, Japan 	Displayed outdoors near DD16 17
DD13 638	Nippon Sharyo	18 April 1967 	19 November 1986	Tsuyama Railroad Educational Museum, Okayama, Japan 	Displayed in roundhouse; formerly located at the Modern Transportation Museum
The following Class DD13 locomotives were preserved in the past but have since been scrapped:
Number 	Manufacturer	Date manufactured	Date retired 	Last location 	Notes
DD13 381	Kisha Seizō 	16 October 1967 	31 March 1986	Suita Locomotive Depot, Osaka, Japan	Stored in roundhouse; scrapped 1998 with demolition of roundhouse
==Trivia==
*Hokuriku Heavy Industries produces a locomotive designated a "56 ton locomotive for main line use" based on the DD13, but with different dimensions and engines.
==Gallery==
File:JNR DD13 1 2022.jpg
File:DD13 638 2003.jpg
Category:JR Group trains
Category:B-B locomotives
Category:Diesel locomotives
Category:Diesel-hydraulic locomotives
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Category:Kawasaki locomotives
Category:Kisha Seizō locomotives
Category:Mitsubishi locomotives
Category:Nippon Sharyo locomotives
Category:Japanese locomotives
Category:3 foot 6 inch gauge