JNR Class DE11

The JNR Class DE11 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 DE11s were developed as a versatile freight locomotive for use on the Japanese rail network. Intended to be a heavy switcher locomotive intended to switch larger loads, 116 locomotives were manufactured from 1967 to 1979.
The locomotives were designed based on trial results obtained from testing DE10 901. When initially introduced, the locomotives were mainly used for switching and pulling minor freight trains; due to a reform of the freight transportation network the locomotives were essentially relegated to switching at stations and depots. When the JNR was privatized and split in 1987, JR East and JR Freight took ownership of the DE11s, with the bulk going to JR East. By then, most of the DE11s had been withdrawn from service, with fourteen in operation by 1995.
Four locomotives remain in operation as of 2023. DE11 2 and DE11 10 were preserved in the past in various JR East depots but have since been scrapped.
==Design==
The DE11 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 DE11 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 DE11s 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 1,250 PS (919 kW). The DE11 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.
In comparison to the DE10s, the DE11s have had their multiple unit systems and train heating systems removed and replaced with concrete ballast; this ballast acts as dead weight to increase the axle load and as a result increase adhesion coefficient for heavy switching duties.
==Preservation==
The following Class DE11 locomotives were preserved in the past but have since been scrapped:
Number 	Manufacturer 	Date manufactured	Date retired 	Last location 	Notes
DE11 2 	Nippon Sharyo	13 August 1968 	3 February 1987	Shin-Tsurumi Locomotive Depot, Kanagawa, Japan	Used for derailment training with some parts removed; scrapped 2007
DE11 10	Nippon Sharyo	5 September 1969 	9 March 1987 	Takasaki Locomotive Depot, Gunma, Japan 	Scrapped at unknown date
Category:JR Group trains
Category:C-B locomotives
Category:Diesel locomotives
Category:Diesel-hydraulic locomotives
Category:Kawasaki locomotives
Category:Kisha Seizō locomotives
Category:Nippon Sharyo locomotives
Category:Japanese locomotives