KiHa 391 series

The KiHa 391 series was an experimental articulated Japanese tilting gas turbine trainset operated by the Japanese National Railways from March 1972 to March 1973.
==History==
R&D was carried out by the Japanese Ministry of Transport (now the Ministry of Land, Infrastructure, Transport and Tourism) and the Japan Association of Rolling Stock Industries starting in 1967 to develop a gas turbine locomotive, following in the vein of related locomotives in the United States and Canada, such as the Union Pacific GTELs and UAC TurboTrains. JNR would use this idea to develop a potential gas turbine-powered train for use as a feeder train for Shinkansen services, especially on non-electrified lines; this development led to the creation of what would be the KiHa 391 series, of which development was completed in 1972.
One set was built, designated KiHa 391-1; it comprised of three articulated sections, numbered T1, M2 and T3, and was treated as a single car. T1 was manufactured by Fuji Heavy Industries, M2 by JNR's own Ōmiya Works and T3 by Niigata Tekkō. KiHa 391-1 was completed on 24 March 1972 and shown off to the public for the first time the same day at Ōmiya Works; its first official test run was on 30 March 1972 on the Kawagoe Line. Following stationary testing at Ōmiya Works, KiHa 391-1 left the works on 17 May 1972; KiHa 391-1 was then assigned to Yonago Depot on 18 May 1972. KiHa 391-1's first tests were a series of general performance tests for the gas turbine on the San'in Main Line and Hakubi Line, taking place from 6 to 28 June 1972; during one such test where KiHa 391-1 was made to stop and start on an uphill gradient of 25‰ in a tunnel, its turbine stopped multiple times due to it inhaling hot exhaust gases causing the protection systems to engage. KiHa 391-1 was then used on a speed test on 2 August 1972 where its clutch failed; its clutch was then replaced with an improved clutch. KiHa 391-1 was intended to be used in another series of tests starting 5 October 1972; on the first day of tests its clutch failed again, rendering KiHa 391-1 unable to move under its own power.
Following this incident KiHa 391-1 was taken out of service and moved to Gotō Works; while out of service its clutch was modified again as well as fundamentally redesigning some of the parts of the set to solve some of its issues such as the installation of mufflers to reduce noise and the redesigning of the air intakes to prevent engine stalling problems. Modifications were completed by late January 1973, with stationary testing conducted at Gotō Works on 27 and 28 January 1973 and performance testing on 29 and 30 January 1973 on the Hakubi Line and San'in Main Line. KiHa 391-1 was then moved to the Morioka area in February 1973 where cold and snow resistance tests were due to be conducted on the Ōu Main Line and Tazawako Line; a warm winter that year meant that tests could not be conducted on snow accumulation on the air intakes and the tilting system, although speeds were reduced for the tests due to frost heave. Ride comfort was noted to be poorer on these lines than on the Hakubi Line.
The final tests for KiHa 391-1 for the year were conducted in March 1973 in the Chūgoku region, with tests conducted on the San'in Main Line and Hakubi Line for high-speed tilting testing; its last tests were high-speed tests conducted on the San'yō Main Line conducted from 22 to 26 March 1973, it reaching a speed of 120 km/h (75 mph). Following these tests, KiHa 391-1 was stored at Yonago Depot, where the data from the tests would be collected to develop a pre-production vehicle using these technologies; some time in 1973 however the concept of a vehicle of this type was changed from an articulated train to a two-car non-articulated set due to a number of problems that arose with KiHa 391-1's construction mainly arising from it being articulated. As such, a plan was drawn up to modify the 591 series tilting set to fit these specifications, it too having also completed its tests for the year and was sitting unused at Okaya Station.
This plan to modify the 591 series set was finalized in mid-1973, with the set being modified to fit gas turbines as a result; however the outbreak of the Yom Kippur War caused an oil crisis, resulting in rising oil prices and leading to any sort of gas turbine railcars becoming uneconomical. With this in mind JNR decided to electrify the Hakubi and Tazawako Lines and the gas turbine testing program was unofficially canceled; KiHa 391-1 would remain stored at Yonago Depot as a result, not to run again, with its gas turbine later removed. KiHa 391-1 would later be moved to Ōmiya Works (now the Ōmiya General Rolling Stock Center) on 10 April 1986, where it remained until 2015 when it was scrapped on site; the cab of car T1 is preserved within the compound.
==Design==
The set featured a raised cab design similar to other diesel railcars of the time; the nickname of Tsuchinoko was given to it by railfans due to its unique appearance.
==Specifications==
KiHa 391-1 is the only gas turbine trainset ever built or prototyped by the JNR. It used an IHI IM100-2R gas turbine engine producing 1,100 PS (1085 HP). Car construction was of steel.
KiHa 391-1 was comprised of three articulated sections (T1, M2, T3) mounted on a set of shared bogies; KiHa 391-1 cannot be separated into three separate cars without the use of specialist equipment. All three articulated sections are treated as a single car. T1 was a cab car with a capacity of 60 passengers; air conditioning units and two 700 L (185 gal) fuel tanks to feed the gas turbine were mounted underneath the floor of T1. M2 housed the gas turbine and other equipment, such as the air intake and diesel generator rooms accessible via a single aisle accessible from doors from both cab cars. The roof and sides of the car could be removed for unloading and loading of equipment and was surrounded by 50 mm thick walls for soundproofing. Five doors in the aisle were present to allow access to the equipment rooms from inside the car. T3's interior furnishings were virtually identical to T1 with the exception of the addition of a toilet, leading the car to seat only 52. Air conditioning units and a 700 L water tank were mounted under the floor.
==Preservation==
The following KiHa 391 series cars have been preserved:
Car number	Manufacturer 	Date manufactured	Date retired	Previous sets	Location 	Notes
T1 	Fuji Heavy Industries	March 1972 	March 1973 	KiHa 391-1 	Ōmiya General Rolling Stock Center, Ōmiya, Japan	Cab only, not usually open for public viewing; full car formerly preserved until 2015
The following KiHa 391 series cars were preserved in the past but have since been scrapped:
Car number	Manufacturer 	Date manufactured	Date retired	Previous sets	Last location 	Notes
M2 	Ōmiya Works 	March 1972 	March 1973 	KiHa 391-1 	Ōmiya General Rolling Stock Center, Ōmiya, Japan	Scrapped 2015
T3 	Niigata Tekkō	March 1972 	March 1973 	KiHa 391-1 	Ōmiya General Rolling Stock Center, Ōmiya, Japan	Scrapped 2015
==References==
Category:Gas turbine trainsets
Category:Gas turbine locomotives
Category:Unique locomotives
Category:Tilting trainsets
Category:Built in 1972
Category:Japanese locomotives
Category:Japan
Category:Locomotives
Category:Articulated locomotives
Category:Experimental locomotives
Category:Ōmiya Works locomotives
Category:Fuji Heavy Industries locomotives
Category:Niigata Tekkō locomotives