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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[]

JR Group motive power
JNR Diesel prototype DB10DC10DC11DD10
4-axle diesel DD11DD12DD13DD14DD15DD16DD17DD20DD21DD40DD41DD42DD50DD51DD53DD54DD90DD91DD92DD93
5-axle diesel DE10DE11DE15DE50
6-axle diesel DF40DF41DF50DF90DF91 (gen 1)DF91 (gen 2)DF92DF93
Shinkansen 911912
Narrow-gauge diesel Ke DB10Ke DB11
Early 2/4-axle freight electric AB10EB10ED10ED11ED12ED13ED14ED15ED16ED17ED18 (gen 1)ED18 (gen 2)ED19ED23ED24
Early 4-axle passenger electric ED50ED51ED52ED53ED54ED55ED56ED57
Early 6-axle freight electric EF10EF11EF12EF13EF14EF15EF16EF18
Early 6-axle passenger electric EF20EF50EF51EF52EF53EF54EF55EF56EF57EF58EF59HEF10HEF50
Early 8-axle electric EH10EH50HEH50HEH150
Early Abt rack rail electric EC40ED40ED41ED42
Acquired from private railways ED20ED21ED22ED25 (gen 1)ED25 (gen 2)ED26 (gen 1)ED26 (gen 2)ED27 (gen 1)ED27 (gen 2)ED28 (gen 1)ED28 (gen 2)ED29 (gen 1)ED29 (gen 2)ED30 (gen 1)ED31ED32ED33ED34ED35ED36ED37ED38Ke ED10DeKi 1RoKo 1DeKi 501RoKo 1000
DC 4-axle ED60ED61ED62ED63ED95
AC 4-axle ED44ED45ED70ED71ED72ED73ED74ED75ED76ED77ED78ED79ED90ED91ED93ED94
DC 6-axle EF60EF61EF62EF63EF64EF65EF66EF67EF90
AC 6-axle EF70EF71
Dual-current ED30 (gen 2)ED46ED92EF30EF80EF81
Other AH100
JR Group Dual-current electric ED500EF500EF510EH500
DC electric EF200EF210EH200
DC EMU M250
AC electric EH800
Diesel DD18DD19DB500DD200DF200ENR-1000
Hybrid HD300
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