The JNR Class DD91 was a diesel-hydraulic locomotive operated by the Japanese National Railways from June 1962 to 1965.
History[]
The DD91 was a prototype diesel-hydraulic locomotive used by the JNR, with a single locomotive prototyped while the company developed its own locomotives for domestic sales as well as potentially for export. A total of ten locomotives were prototyped; these were Hitachi's DF90, DF91 and DF93, Kawasaki's DF40, Kisha Seizō's DF41, Nippon Sharyo's DD42 and DD93, Shin-Mitsubishi's DD40 and DD91 and Toshiba's DD41.
Numbered DD91 1, the locomotive was built by Shin-Mitsubishi Jukōgyō in 1962 and used on passenger services on the Fukuchiyama Line and San'in Main Line from June 1962, with the JNR entering into a loan agreement. Stationed at Fukuchiyama Rolling Stock Depot, the locomotive was returned to Shin-Mitsubishi in 1965 and presumably scrapped afterwards. Many of the design traits of the locomotive were carried over to the later DD54 locomotives, which would be considered a failure.
Design[]
The DD91 featured a semi-streamlined design, being painted in beige with red accents.
Specifications[]
The DD91 was fitted with a single high-output Maybach MD870 V16 prime mover producing about 1,820 HP (1,357 kW), mated to a Mekydro K184U hydraulic transmission. This type of engine and transmission was also used on the British Rail Class 35 locomotives.