JNR Class DD20

The JNR Class DD20 was a diesel-hydraulic locomotive operated by the Japanese National Railways from 1963 to 1977.
==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 DD20s were developed as a versatile diesel locomotive for use on the Japanese rail network. Intended to replace the Class 9600 steam locomotives, the DD20s were designed to be able to pull as much as them on various lines, while also being able to perform switching duties; in comparison to the DD13s, they were intended to be mass-produced at a low cost and were designed to reduce maintenance costs and be lightweight.
DD20 1 was manufactured by Kisha Seizō in 1963, with serial number 2969, while DD20 2 was manufactured by Nippon Sharyo in 1965, with serial number 3127; DD20 1 was placed at Tabata Rolling Stock Depot before being moved to Nagaoka Rolling Stock Center in 1971. Under testing it was discovered that their axle load was too heavy for some local lines and the locomotives were prone to wheel slip; as a result, mass-production was canceled after only two locomotives were built. Following this the DD20 would be used as pusher locomotives for snowplows. DD20 1 was converted to a dual engine layout to allow it to be used as a pusher locomotive for the DD53 snowplows before both were retired in 1977 and stored. Although the DD20's performance was considered unsatisfactory, data from testing the DD20 would be used to develop and produce the highly-successful DE10.
DD20 1 would be stored at Niitsu Works after its withdrawal from service, being scrapped in the 1990s, while DD20 2 was scrapped around 1988.
==Design==
The DD20 featured a steeplecab-like design, giving it an appearance similar to that of a switching locomotive; this design was chosen to help the locomotive reduce its weight by reducing its axle load. Both locomotives were largely based on the DD51 and feature a different appearance.
==Specifications==
The DD20s are fitted with a single V12 prime mover, designated the DML61. Both locomotives used many parts from the DD51, such as the prime mover and the Voith DW2A hydraulic transmission.
DD20 2 was designed from the get-go to be compatible with the DD53 snowplow locomotives and features a longer body than DD20 1. DD20 1 would be modified to have two engines at Nagaoka to allow it to perform snow removal.
==Gallery==
File:DD20 1 1980s.jpg|DD20 1 c.1980s
Category:JR Group trains
Category:B-B locomotives
Category:Diesel locomotives
Category:Diesel-hydraulic locomotives
Category:Kisha Seizō locomotives
Category:Nippon Sharyo locomotives
Category:Japanese locomotives
Category:Built in 1963
Category:Built in 1965
Category:Scrapped diesel locomotives