KiHa 90 series

The KiHa 90 series was a prototype low-capacity express diesel multiple unit operated by the Japanese National Railways from 1966 to September 1976.
==History==
The KiHa 90 series cars were developed based on previous experiments with high-power diesel engines and two-engined railcars, such as the highly unsuccessful KiHa 60 series cars with their prototype high-output V12 prime movers. Previous railcars featuring 2 engines were also more difficult and expensive to maintain, as two sets of prime movers and transmissions had to be installed. Because of this, the length of the cars had to be increased and there was not much space to install additional equipment such as generators for air conditioning. JNR's Engineering Bureau, which was developing other railcars at the time, decided to design a new prototype railcar that could be competitive in the transport situations at the time while correcting the various faults as detected from the failed KiHa 60 series cars.
In 1966, two cars were produced (one by Fuji Heavy Industries, the other by Niigata Tekkō), numbered KiHa 90 1 and KiHa 91 1; these were equipped with the DMF15HZA and DML30HSA prime movers respectively and competed against each other. KiHa 91 1 was declared to be the superior car and thus mass production was ordered with the cars based on KiHa 91 1; KiHa 90 1 was thus renumbered KiHa 91 9 and given a new prime mover and transmission matching those of KiHa 91 1. Engine troubles with the cars were noted to have occurred frequently. The remaining ten cars were manufactured shortly after, with manufacturing continuing until 1967.
The cars were then placed in the Chiba Kidosha Ward, with performance testing occuring on the Uchibō Line. The cars were subsequently relocated to Nagoya Depot, where they were used on the Shinano service; based on the test results gathered by the KiHa 90 series, the KiHa 65 and KiHa 181 series cars were designed, developed and entered into service. After the KiHa 181 series cars replaced the KiHa 90 series cars on the Shinano service, they were relegated again to the Chūō Main Line. After electrification works on that line was completed, the cars were replaced by 165 series cars and relegated again.
The cars's final operations were conducted on the Takayama Main Line, where they performed one round trip between Nagoya and Takayama Stations. Despite this, engine troubles continued and the reserve of spare parts for the cars were depleting. As a result, JNR made the decision to retire all the KiHa 90 series cars on 3 September 1976, about a month before the slated timetable revision in October. After retirement, the cars were stored for a time in Tajimi Depot; it was difficult to dispose of the cars as they were barely 10 years old from their introduction. Finally, on 31 August 1978, the cars were towed to Nagoya Depot, where they awaited their final fates.
No KiHa 90 series cars survive today. However, the cars can be considered a highly important class of cars in JR history as these paved the way for future highly successful diesel railcars with notably extremely long service lives.
==Design==
The KiHa 90 series use a squared-off design similar to many other railcars of the time, with twin sealed beam headlights mounted on top of the cabs. The cars were painted in a Cream No.4 "Wheat" base coat with Vermillion No.11 "Scarlet" accents, the standard livery for JNR's diesel express cars. KiHa 91 9 (ex-KiHa 90 1) featured a slightly different design with a more streamlined front end with recessed headlights.
===Variations===
KiHa 91 9 1970s.jpg|Pre-production car KiHa 91 9 circa 1977
==Specifications==
Construction is of steel. Their appearance is very similar to that of the various diesel rail cars introduced at the time. The interior of the cars feature ventilation in the form of fans and two abreast seating.
The cars were equipped with three different types of prime movers for evaluation purposes, with each car getting a different prime mover. The cars were also mounted with three different types of hydraulic transmissions and three different types of bogies; these were all used for evaluation purposes to determine which parts would be suitable for a mass-production diesel railcar.
Category:JR Group trains
Category:Diesel trainsets
Category:Fuji Heavy Industries locomotives
Category:Niigata Tekkō locomotives
Category:Nippon Sharyo locomotives