The JNR Class DD21 was a diesel-hydraulic locomotive operated by the Japanese National Railways from 1963 to 1986.
History[]
The DD21 was a prototype snow-clearing locomotive used by the JNR. One locomotive was built by Nippon Sharyo in 1963, based on DD20 1, another prototype locomotive built around the same time by Nippon Sharyo.
DD21 1 was deployed at Higashi-Niigata Rolling Stock Depot for trial runs; mass production of the DD21 was abandoned when it was discovered that seeing out the locomotive's windows was difficult when clearing snow as well as the heavy axle load making it difficult for the locomotive to enter certain lines. As a result, only DD21 1 was produced.
The locomotive was mainly used in the Niigata region but similar to the DD20 the locomotive was not used often and was withdrawn around 1986. DD21 1 was scrapped in 1992 when a new facility within the depot was being constructed.
Design[]
The DD21 featured a steeplecab-like design similar to most switcher locomotives.
Specifications[]
The DD21 was fitted with a single V12 prime mover, designated the DML61S. Being based on DD20 1, it used many parts from the DD51, such as the prime mover and the Voith DW2A hydraulic transmission.
Similar to many of JNR's other snow-clearing locomotives, the snowplow was a Russell-type snowplow. Unlike most of JNR's other snow-clearing locomotives, DD21 1's snowplow was permanently attached to the locomotive and a coupler attached to the snowplow; the idea was for the locomotive to be able to perform switching duties with the snowplow attached so that there was no need to have the snowplow removed just to perform switching duties during periods with little or no snow.