Background and overview
JR Hokkaido developed the Kiha261-0 series diesel multiple unit (DMU) tilting train for intercity services on the Soya Line, aiming to reduce journey times following track upgrades for speed enhancement. A four-car pre-production set was delivered in 1998.
Compared with the higher-cost Kiha281 and Kiha283 series DMUs, the Kiha261-0 series was based on the Kiha201 series and employed a pneumatic tilting system. It was designed to offer improved curve-running performance and enhanced protection against heavy snow and extreme cold, all at a lower cost. The carbody design was developed in collaboration with the Danish State Railways (DSB).
The Kiha261 series adopts a married-pair configuration, consisting of an end car and an intermediate car. A total of 14 vehicles of the Kiha261-0 series were delivered by 2001. Of these, twelve vehicles delivered between 1998 and 1999 were owned by the Hokkaido High-Speed Railway Development Company and leased to JR Hokkaido.
Car body
The carbody of the Kiha261-0 series measures 20,800 mm in length and 2,800 mm in width, with a bogie centre distance of 14,400 mm. It shares the same cross-sectional profile as the Kiha201 series tilting DMU, designed to accommodate up to 2 degrees of tilting. The structure is primarily composed of lightweight stainless steel, except for the bolster beams, end sections of the centre beam, and selected cross members, which are fabricated from corrosion-resistant steel plate. The exterior features unpainted bead-processed stainless panels.
The cab ends, which include a gangway door and a high-mounted driver's cab for improved protection against level crossing obstacles, are constructed from 3.2 mm thick steel plate and painted in cobalt blue. A built-in classification headboard is mounted on the gangway, flanked by sealed beam headlights and high-intensity discharge (HID) lamps on each side. Additional HID lamps are installed above the windscreen, with tail lamps positioned behind it.
Standard-class end cars (Class KiHa261-100) are equipped with an automatic gangway connection device to facilitate rush-up operations. Each car features a 930 mm wide single-leaf sliding door, with pneumatic cylinders pressing the door against the frame to prevent ice intrusion. Side windows include small fixed double-glazing units for each first-class seat and wide fixed double-glazing windows aligned with two standard-class seating bays.
Class Kiha260-200 vehicles are fitted with a hinged door for the catering
room, while Class Kiha260-100 vehicles include a hinged door for the conductor's
room, which features a shunting control position. Traditional destination
rollsigns are mounted on the carbody sides.
Each car is equipped with a roof-mounted air-conditioning unit (N-AU201) rated at 30,000 kcal/h. Fresh air is supplied to the passenger compartment via electric fans integrated into the air-conditioning system, replacing conventional roof ventilators.
Bogies
Powered bogies are designated as N-DT261A/B/C, and trailer bogies as N-TR261. All bogie types feature a pneumatic tilting system, bolster-less secondary air suspension, a trailing arm–type journal box support system, a single-link traction device, and yaw dampers to ensure smooth ride characteristics even at speeds up to 130 km/h.
The wheel diameter is reduced to 810 mm to lower the vehicle's centre of
gravity. Tilting control is achieved through an inclination control system
using gyroscopes and accelerometers mounted at both ends of the train,
combined with a leader-follower control logic that defines a unified "tilting
curve" for the entire formation. This system enables curve negotiation
at speeds up to 25 km/h faster than conventional limits, with a maximum
tilt angle of 2 degrees.
All bogies are equipped with double-tread brake rigging.
Powertrain and ancillary equipment
Class Kiha260-100 vehicles are powered by a single diesel engine (N-DMF13HZH) rated at 460 PS and equipped with an intercooler to enhance power output. All other vehicles are powered by two such engines. Power is transmitted via a hydraulic transmission unit (N-DW14), which features natural air cooling and a four-stage direct-coupled range, enabling a maximum service speed of 130 km/h and high gradient performance.
Each vehicle is equipped with one or two generators (N-DM283G3) that supply electricity to the ancillary power system (N-INV261), and one or two air compressors (C1000H) that are hydraulically driven by the prime mover, eliminating the need for belt drive mechanisms.
The braking system is electrically commanded and includes a jake brake function.
Accommodation
All seats are adjustable reclining types. First-class vehicles feature 1+2 abreast seating with a pitch of 1,145 mm, while standard-class vehicles have 2+2 seating with a pitch of 960 mm. First-class seats are upholstered in navy leather and equipped with a power outlet beneath the windowsill and a reading light mounted under the luggage rack.
The door between the vestibule and passenger saloon is automatic, activated by a photo sensor. An LED passenger information display is installed above this door. Cabin lighting consists of alternating fluorescent and halogen lamps.
Class Kiroha261-200 vehicles include a catering room—equipped with a sink, refrigerator, microwave oven, and a counter with a coffeemaker—and a designated smoking room, both located between the first- and standard-class compartments.
Class Kiha260 vehicles are fitted with western-style toilets featuring
chemical holding tanks. The toilet in Class Kiha260-100 is designed for
universal access. Class Kiha260-200 vehicles are additionally equipped
with a washroom containing a baby bed, and a conductor’s room with a shunting
control position. Class Kiha260-100 vehicles also include a telephone room
with a shunting control position..
Mass-Production sets
Mass-production sets of the Kiha261-0 series were delivered in 1999. Several notable differences were introduced compared to the pre-production set. Class Kiha260-100 vehicles were additionally equipped with a designated smoking room. The air-conditioning unit was upgraded to type N-AU201A, allowing independent climate control for each compartment.
"Tilt261 Active Air Suspension System" logos were newly applied to the sides of the cab sections.
Additional delivery
In 2001, JR Hokkaido delivered one Class Kiha261-100 and one Class Kiha260-100
vehicle to secure spare units for operational flexibility.
Modifications
From 2000, exterior side windows began to be additionally framed with polycarbonate reinforcement to prevent windowpane breakage. In 2006, the designated smoking room was converted into a free-access space. The public telephone installed in the telephone room was removed in 2009.
In 2014, the tilting system was deactivated on all sets due to the stress it imposed on the bogies. Concurrently, the cab-side logos were changed to "HET261 Hokkaido Express Train" From 2016, JR Hokkaido refurbished the prime mover to type N-DMF13HZL, reflecting the elimination of the tilting system. The automatic gangway connection device was also removed.
High-intensity discharge (HID) lamps were replaced with LED units, and traditional destination rollsigns were replaced with colour-selectable LED destination screens.
Operations
The first pre-production set of the Kiha261-0 series entered service between
1998 and 1999 for testing and evaluation of curving performance and cold-weather
resistance. In 2000, the sets were introduced into revenue service on "Super
Soya" intercity operations linking Sapporo and Wakkanai.
In 2017, two round-trip "Super Soya" services were rerouted to
operate between Asahikawa and Wakkanai and renamed "Sarobetsu".
The remaining services between Sapporo and Wakkanai were rebranded as "Soya". |
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