Background and overview
Following the privatization of Japanese National Railways (JNR) in 1987, JR Hokkaido faced significant financial constraints due to its limited business foundation. To support stable operations under these conditions, JNR developed the class Kiha54-500 as a cost-effective diesel multiple unit (DMU) designed for low construction and operating costs. The class Kiha54-500 consists of double-ended single-car units, with a total of 29 vehicles manufactured.
Car body
The carbody measures 21,300 mm in length and 2,920 mm in width, with a
bogie centre distance of 14,400 mm to achieve weight reduction. The structure
is primarily composed of stainless steel, except for the bolster beams,
the end sections of the centre beam, and selected cross beams, which are
fabricated from weather-resistant steel plate (Steel Plate Atmospheric).
The exterior features unpainted bead-processed stainless panels with a
red, white, and brown waistline band running the length of each car below
the windows.
The cab end includes a gangway and is framed with decorative FRP panels. A low-profile driver's cab is adopted to accommodate future conductor-less operation. Flat windscreens are used to reduce manufacturing costs. Above the driver's windscreen, a destination rollsign is installed, while a separate window above the co-driver's windscreen displays conductor-less operation status. Two sealed-beam headlights are mounted above the gangway door, and taillights are positioned below the windscreens.
Each side of the vehicle is equipped with two 850 mm-wide automatic sliding stepped doors, which can also be operated manually via push-button controls adjacent to each door. Between the doors, 930 mm-wide single-hung windows are installed. All windows are double-paned to provide thermal insulation suitable for cold climates. Roof-mounted equipment includes forced-draught ventilators and two FRP water tanks enclosed within steel covers. Exhaust pipes from the prime movers are routed through the cab interior. Vehicles are coupled using tight-lock automatic couplers with rubber draft gear RD13.
Bogies
The vehicles are fitted with DT22F bogies, which are modified versions of DT22A or DT22C units repurposed from decommissioned DMUs. These bogies feature swing hanger suspension, coil springs as bolster springs, and pedestal-type journal support systems. Heat-shrink rubber is applied to the primary suspension springs to prevent snow accumulation. The gear ratio of powered bogies is 2.976. Braking is provided via single-tread brake rigging.
Traction unit and ancillary equipments
Each vehicle is powered by two DMF13HS four-cycle straight-six diesel engines mounted beneath the floor, each rated at 250 PS. These engines incorporate turbochargers driven by exhaust gas flow, direct fuel injection, and fuel control systems to optimize fuel efficiency. The engines are horizontally mounted to the carbody using rubber mounts.
Power transmission is handled by two DF115A hydraulic transmissions reused from retired DMUs. These units were upgraded with improved torque converters and clutches to accommodate the increased engine output. Compressed air is supplied by two C400 air compressors, each driven by a prime mover. The braking system consists of a DA1A automatic air brake, supplemented by a straight air reserve brake.
Accommodation
Vehicles numbered Kiha54 501 through 526 feature a combination of longitudinal bucket-style bench seating located near the doorways and transverse seating bays with a pitch of 1,500 mm located at the centre of the passenger compartment. In contrast, vehicles numbered Kiha54 527 through 529—used on the "Rebun" and "Taisetsu" services—feature longitudinal seating near the doors and transverse flip-over seating (type W12) salvaged from decommissioned 0 series Shinkansen cars, with a pitch of 940 mm.
Interior lighting is provided by two rows of fluorescent fixtures. Heating is achieved via a water-based system located beneath the seating. Air conditioning ducts are installed above the ceiling, with slit-shaped vents used to improve airflow and interior aesthetics. Toilet facilities consist of a Japanese-style unit constructed from fiber-reinforced plastic, located at the rear of the carbody. These units were designed with provisions for future installation of chemical holding tanks.
Modifications
Conductor less operation
Between June 1990 and November 1992, vehicles operating on the Nemuro Line between Kushiro and Nemuro were modified for conductor-less operation. These modifications included the installation of ticket vending machines near the doorways, fare chart displays and fare boxes behind the driver's cabs, and external loudspeakers replacing manual door-opening buttons.
Toilet upgrade
Between March 2000 and March 2002, the original Japanese-style toilets were replaced and fitted with chemical holding tanks mounted on the floor
Seating refurbishment
Between November 1993 and February 1994, vehicles assigned to rapid services underwent seating refurbishment. Transverse seats were replaced with either R51C reclining seats fixed to face the centre aisle or flip-over seats (type W12) salvaged from retired 0 series Shinkansen vehicles.
Bogies and transmission replacement
Between May 2003 and July 2006, the original DT22F bogies were replaced with newly manufactured N-DT54 bogies featuring bolster-less secondary air suspension and axle arm-type journal support systems. Hydraulic transmissions were also replaced with N-DW54 units featuring a two-stage direct-coupled range.
Cab end reinforcement
Following a severe level crossing collision involving a Kiha54-500 vehicle on the Sekihoku Line in March 2007, the remaining fleet underwent structural reinforcement. Between March 2003 and July 2009, reinforcing members were installed on the frieze boards between the cab ends and vertical gutters.
Operations
The class Kiha54-500 was delivered between November and December 1986 to Asahikawa, Naebo, Hakodate, and Kushiro Depots. Initially, the vehicles entered rural services alongside existing DMUs and operated on the "Rebun" express service linking Asahikawa and Wakkanai. Over time, JR Hokkaido reallocated the fleet to Asahikawa and Kushiro Depots for use on the Soya, Rumoi, Sekihoku, Furano, Nemuro, and Senmo Lines, as well as the "Kitami" special rapid service between Asahikawa and Kitami.
Subsequently, vehicles operating on the Furano Line were replaced by the class Kiha150-0, and those on the Sekihoku and Senmo Lines were replaced by the class H100. As of the present, the class Kiha54-500 remains in service on rural routes along the Soya, Rumoi, and Nemuro Lines. |
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