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The JNR Class DE50 is a diesel-hydraulic locomotive operated by the Japanese National Railways from February 1971 to May 1986.

History[]

The DE50 was designed as a locomotive which could replace the DD51, intended to be a heavy switcher locomotive. The locomotive was intended to be significantly more powerful than the DD51 while retaining the same light weight and being as easy to maintain as the DD51s.

One locomotive was manufactured by Hitachi at their Kasado factory in July 1970; numbered DE50 1, the locomotive was numbered as such as it was intended to be a mass-production prototype. Assigned to Inazawa Rolling Stock Depot, DE50 1 was used to pull freight trains on a trial basis before it was introduced into service in February 1971. The locomotive was transferred to Okayama Rolling Stock Depot on 20 November 1971, where it was used on the Hakubi Line.

Although DE50 1 was of an ambitious design, the rapid electrification of many of the JNR's lines, an oil crisis and JNR's worsening financial situation meant that any plans for full production of the DE50 were called off, leading to DE50 1 being the only locomotive built; any diesel locomotives to be produced for the JNR would be DD51s. Despite this, DE50 1 would remain in use on the Hakubi Line where its hydrodynamic brakes were tested; a malfunction with the locomotive put it out of service, whereupon it was stored at Okayama Rolling Stock Depot and officially withdrawn on 26 May 1986, having not operated for more than ten years. DE50 1 would be stored at Okayama Station for a number of years before it was moved to the Tsuyama roundhouse in 2011 for preservation. DE50 1 remains at the roundhouse, now known as the Tsuyama Railroad Educational Museum, where it is preserved alongside a number of other diesel locomotives and railcars.

Design[]

DE50 1 features 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. Unlike the similar-looking DD51 and DD13 locomotives, DE50 1 features a long hooded design due to it only having one engine as opposed to two. The driver's cab is notably off-center; it was designed as such to allow for switching and short turnaround operations.

Specifications[]

DE50 1 is fitted with a single V16 prime mover, designated the DMP81Z. Total power output is about 2,000 PS (1,471 kW). DE50 1 uses a DW7 hydraulic transmission; the transmission works similarly to a Voith turbo transmission. Cooling of the engine and other components is done through a pair of fans forcing air into the components via cooling shafts.

Preservation[]

The following Class DE50 locomotives have been preserved:

Number Manufacturer Date manufactured Date retired Location Notes
DE50 1 Hitachi 21 July 1970 26 May 1986 Tsuyama Railroad Educational Museum, Okayama, Japan Displayed in roundhouse; only DE50 built
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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