KiHa 31 series

The KiHa 31 series was a low-capacity commuter diesel multiple unit initially operated by the Japanese National Railways and later the Kyushu Railway Company from February 1987 to March 2019.
==History==
The KiHa 31 series was developed to replace older diesel railcars currently in service on JNR lines in Kyushu as well as to strengthen JNR's diesel fleet. Fuji Heavy Industries and Niigata Tekkō were thus tasked to manufacture the cars, of which 20 cars were manufactured from 1986 to 1987; these were some of the last diesel railcars produced for the JNR before its eventual privatization.
Commercial operation for the cars began on 15 February 1987, with these cars mainly used on lines with wanman operation. After JNR's privatization, ownership of the 20 cars was assumed by JR Kyushu. An additional three cars were manufactured in 1988 to make a total of 23 cars. The cars were assigned to Hakata and Kumamoto Depots. One car, 31 20, was transferred to the Kumagawa Rail Road in 2004, where it was renumbered KT-311; its career there was short-lived however, with the car withdrawn from service in 2013 and scrapped, becoming the first of the KiHa 31 series cars to be scrapped.
More scrapping continued starting 2017, with the targets now being the JR Kyushu-owned cars. With the introduction of the revised timetable on 17 March 2018, the Hakata-based cars were withdrawn from regular operation. 31 19 was then used for some small-scale training after retirement, training JR employees and engineers how to properly re-rail a derailed train, with the railcar being used to crash into a small car.
The cars were retired from regular service on 16 March 2019, before being finally retired for good on 23 March 2019 with a special last run service. The last few cars were subsequently towed to Kokura Depot, where they awaited their final fate. No KiHa 31 series cars have been preserved.
==Design==
The KiHa 31 series use a squared-off design similar to many other railcars of the time, with dual top-mounted sealed beam headlights and dual end-of-train lights. The cars are unpainted but feature blue accents.
==Specifications==
Construction is of stainless steel. The cars are of a dual cab design and can be operated in single car units. Many parts from scrapped trains, such as seats, bogies, transmissions, doors and air conditioning are used to save costs. The cars also use parts originally intended for use on buses to decrease costs even further. The cars feature two-abreast seating; the seats on these cars are actually reduced from scrapped 0 Series Shinkansen sets.
The KiHa 31 series cars are equipped with a DMF13HS prime mover producing 247 HP (250 PS); this is actually a Niigata Tekkō prime mover produced under license. This same prime mover is used in the KiHa 37 series cars. An existing hydraulic transmission from scrapped railcars is also used, but features a strengthened clutch. Due to a number of design changes, such as weight reduction of the car bodies and the engine, the cars can accelerate at a speed nearly equivalent to that of a two-car KiHa 58 series consist.
Category:Diesel trainsets
Category:JR Group trains
Category:Fuji Heavy Industries locomotives
Category:Niigata Tekkō locomotives
Category:Passenger locomotives
Category:Locomotives