JNR Class DE10

The JNR Class DE10 is a diesel-hydraulic locomotive operated by the Japanese National Railways and its various successors since 1966.
==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 DE10s were developed as a versatile freight locomotive for use on the Japanese rail network. Largely replacing the older DD13 diesel-hydraulic locomotives, a total of 708 locomotives were manufactured from 1966 to 1978.
The locomotives were designed based on trial results obtained from testing the DD20 diesel locomotives; wheel slips were frequent due to insufficient adhesion coefficient and excessive axle load made the locomotives too heavy and as a result mass production was abandoned for those locomotives. With this in mind and the DD13's inability to enter certain branch lines due to its weight, the DE10 was designed to solve these issues.
When initially introduced, the locomotives were used to haul passenger trains such as the Akatsuki and Nihonkai, as well as switching duties; their versatility however meant that they were used for numerous other jobs as well, such as pulling long freight trains and charter trains. When the JNR was privatized and split in 1987, all seven of the newly-formed JR Group's constituent companies took ownership of DE10s, making this the only locomotive to be operated by all seven companies of the JR Group. 
Despite their age, the DE10 remains a mainstay of the JR Freight fleet, and is a common sight pulling freight trains, special trains, switching and towing out-of-service trains. 186 locomotives remain in service, while nine locomotives have been preserved; three other locomotives were preserved in the past but have since been scrapped. Many DE10 locomotives withdrawn from service on the main JR network have been resold to other private companies; within the JR network, the DE10 locomotives are being replaced with DD200 locomotives.
==Design==
The DE10 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, the DE10 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==
The DE10s are fitted with a single V12 prime mover, designated the DML61Z, based on the DMF31S prime mover used on the earlier DD13 locomotives; this engine features strengthened pistons and a differently mounted intercooler to increase power output. Total power output is about 2,200 PS (1,600 kW). The DE10 uses a DW6 hydraulic transmission; the transmission works similarly to a Voith turbo transmission and features three built-in torque converters and two speed switching valves to change the locomotive's running characteristics for different applications such as switching or pulling heavy freight or passenger trains. As a redundancy measure to prevent overheating, a mechanism is built into the locomotive which sprays water on the engine; five portholes are used to drain the water.
==Preservation==
The following Class DE10 locomotives have been preserved:
Number 	Manufacturer 	Date manufactured	Date retired 	Location 	Notes
DE10 1 	Nippon Sharyo 	13 October 1966 	7 February 1987 	The Railway History Park, Ehime, Shikoku, Japan 	Prototype locomotive; displayed under shelter
DE10 30 	Nippon Sharyo 	28 June 1968 	24 October 1986 	Poppo-no-oka, Chiba, Japan 	Displayed outdoors, coupled to passenger cars ORoNe 24 2 and OHaNeFu 24 2; formerly displayed on Floating Pavilion Yotei Maru museum ship
DE10 88 	Kisha Seizō 	9 April 1969 	7 February 1987 	Kotsu Park, Miyagi, Japan 	Displayed outdoors, coupled to caboose Yo 13797; cab open for public viewing
DE10 95 	Nippon Sharyo 	9 July 1969 	3 February 1987 	Mōka Station, Tochigi, Japan 	Stored on siding
DE10 503 	Nippon Sharyo 	16 July 1968 	9 December 1986 	Otaru City General Museum, Otaru, Hokkaido, Japan 	Displayed outdoors coupled to various freight cars
DE10 1014	Nippon Sharyo 	21 May 1970 	30 November 1993 (JR Freight)Fall 2010 (KFS)	SL Kyurokukan, Tochigi, Japan 	Displayed outdoors, used as parts donor; painted in unique variation of the Kansai Freight Service paintscheme
DE10 1511	Nippon Sharyo 	6 November 1970 	20 October 1993 	JR Freight Central Training Center, Tokyo, Japan 	Painted in JR Freight paintscheme, used for training purposes; not open for public viewing
DE10 1677	Nippon Sharyo 	28 September 1974	31 March 1987 	Kotsu Park, Saroma, Hokkaido, Japan 	Displayed outdoors
DE10 1702	Kawasaki Heavy Industries	13 July 1974 	5 February 1987 	Mikasa Railway Memorial Hall, Mikasa, Hokkaido, Japan	Displayed outdoors coupled to freight cars SeKi 6657 and WaMu 66172
The following Class DE10 locomotives were preserved in the past but have since been scrapped:
Number 	Manufacturer 	Date manufactured	Date retired 	Last location 	Notes
DE10 11 	Kisha Seizō 	16 February 1968 	31 March 1987 	Konosu Shiritsu Fukiage Elementary School, Saitama, Japan 	Displayed outdoors; scrapped 2015 due to deterioration
DE10 26 	Nippon Sharyo	19 March 1968 	31 March 1987 	Kurate Town History and Folklore Museum, Fukuoka, Kyushu, Japan	Displayed outdoors; scrapped 2003 due to deterioration
DE10 1005	Nippon Sharyo	26 January 1970 	31 March 1991 (JR Freight)16 March 1996 (Kamioka)	Former Okuhida-Onsenguchi Station, Gifu, Japan 	Displayed outdoors as Kamioka Railway KMDE101; scrapped 2007
Category:JR Group trains
Category:C-B locomotives
Category:Diesel locomotives
Category:Diesel-hydraulic locomotives
Category:Hitachi locomotives
Category:Kawasaki locomotives
Category:Kisha Seizō locomotives
Category:Nippon Sharyo locomotives
Category:Japanese locomotives