Background and overview
"Hatsukari" intercity services operated by 485 series EMU and "Kaikyo (means strait in English)" operated by Oha51 series coaches had been provided for the Tsugaru-Kaikyo line since opened in 1988. JR Hokkaido developed 789-0 series intercity AC electric multiple unit (EMU) for "Super Hakucho" intercity services linking Hachinohe and Hakodate in order to displace superannuated class ED79 electric locomotives and Oha51 series coaches used on "Kaikyo" rapid services in 2003. 789 series EMU train set is formed as a 2-car half set consisting of a trailer end vehicle, class kuroha789-100, and a motored intermediate vehicle, class moha788-100, and a 3-car half set consisting of a trailer end vehicle, class 789-200, and two motored intermediate vehicles, class moha789-200 and class moha788-200, which were coupled to produce 5-car or 8-car sets.
Car body
They have 2812mm wide body, incorporating light weight stainless steel
construction and same cross-section shape as that of kiha261-0 series DMU.
Externally, they differ noticeably from former kiha261-0 series in having
bead-less 2mm thick skin for noise reduction while running Seikan tunnel.
Their cross-sectional shape is considered for tilting up to three degrees.
Anti-fall plates between vehicles are also introduced excepting the cab
end. Cab ends having a gangway door and a high mounted driver's cab against
obstacles at the level crossing are constructed by 3.2mm thick steel plate
painted in JR Hokkaido company colure, namely light green, applied "HEAT789
Hokkaido Express Advanced Train" logos. A built-in classification
headboard is fitted on the gangway and two headlights applied halogen light
bulbs and high intensity discharge (HID) lamps longitudinally are fitted
each side of the gangway. Extra HID lamps are fitted above the windscreen
and tail lamps are behind the windscreen. In case of public use of front
gangway to ease rush-up operations, the adapter to fit with the bellows
connectors will be applied. They are equipped with a 700mm wide single-leaf
sliding stepped door employing the cylinders to press the door against
both ice-clogged and the fluctuation of atmospheric pressure, and small
fixed double-grazing windows per each 1st class seating or wide fixed double-glazing
windows aligned two seating bays. These side windows have polycarbonate
reinforcement for the protection against the breakdown of the windowpane.
Class moha789-200 vehicles are equipped with a telephone room having shunting
control position and class moha788-100 vehicles are equipped with a hinged
door for the conductor room having shunting control position. Three colure
(red, green, orange) LED destination displays are fitted on the side of
their body. They are equipped with two air conditioners, N-AU789 rated
at 19,000kcal/h on their roof. Electric fans of air conditioner supply
fresh air into the passenger room, instead of ventilators on the roof.
1mm thick stainless steel cover plates are fitted between equipments fitted
under their floor to reduce the waving for preventing snow and ice from
sticking thereon. The bottom level of underfloor equipments is limited
up to 234mm, 49mm higher than former vehicles.
Bogies
Motored bogies are N-DT789 and trailer bogies are N-TR789, bolster-less secondary air suspension, axle arm type journal box supporting system, the single link traction device, and the yaw dampers and to ensure smooth ride characteristics even at 140km/h. The wheel diameter is reduced to 810mm to lower the centre of the gravity of their body. Twin Disc (TD) flexible joint employing deflecting plates made of carbon-fiber reinforced plastic (CFRP) is applied for power transmission device. The gear ratio is 3.96 to get high acceleration performance at the range of middle and high speed and the maximum service speed at 140km/h. Their bogies employ double tread brake riggings. Trailer bogies also employ a disk brake rigging.
Traction unit and ancillary equipments
Class moha788-100 and moha788-200 vehicles are equipped with a traction
system, N-CI789-1/N-CI789-2, consisting of a 3-level converter employing
Intelligent Power Module (IPM) and a 2-level Variable-frequency drive (VFD)
employing IPM controlling 4 AC asynchronous traction motors, N-MT731, with
a power output of 230kW on truck basis. On the other hand, class moha789-200
vehicles are equipped with a traction system, N-CI789-3, consisting of
Insulated Gate Bipolar Transistor (IGBT) and a 2-level Variable-frequency
drive (VFD) employing IGBT controls traction motors on truck basis. Each
traction system features fields-oriented control. The motored intermediate
cars, class moha788-200, are equipped with a forced air-cooling traction
transformer, N-TM789-FN, under the floor, supplying to class moha788-200
and class moha789-200 vehicles. The other motored intermediate cars, class
moha788-100, are equipped with a travelling wind self-cooling traction
transformer, N-TM789-AN, under the floor, supplying to only class moha788-100
vehicles. Motored vehicles are equipped with the equipments on the floor
to remove airborne snow from intake air. Class moha788 vehicles are equipped
with a single arm current pickup, PS789, on the roof. End vehicles, class
kuroha789-100 and kuha789-200, are equipped with an auxiliary power unit,
N-APS789 which consists of the rectifier constituted by a hybrid bridge
circuit of a diode and a thyristor powered with the tertiary winding of
the traction transformer and supplying 100VDC with a power output of 12kW,
and the IGBT inverter featuring Pulse Width Modulation (PWM) having two
output circuits of 100VAC with a power output of IGBT under their floor.
End vehicles are also equipped with a motor driven reciprocating air compressor,
N-MHI785-C2000M, under their floor. 789 series feature the electric commanding
brake with regenerative brake, featuring holding brake and brake control
of trailer priority. The end cars are equipped with the ATC-L and ATS-N
signaling systems under the floor. Their accelerating performance is 2.5km/h/s
for ATC signaling system section and 1.8km/h/s for ATS-N signaling section
and automatically switched by the signaling system.
Accommodation
All seats are adjustable reclining. 1st class vehicles have 1+2 abreast seating with 1145mm seating pitch and standard class vehicles have 2+2 abreast seating with 960mm seating pitch. 1st class seating is covered in navy leather and is also equipped with a power supply outlet under the windowsill and a reading light under the luggage rack. A door between a vestibule and a passenger saloon is automatic, detecting by the photo sensor. A LED display for providing passenger information is fitted above the door between a vestibule and a passenger saloon. Florescent lights and halogen lamps are alternately fitted for cabin lighting. A catering room and a multipurpose room are located in class kuroha789-100 vehicles. A segregated smoking room is located in class moha788-100 vehicles. Class kuroha789-100, moha789-200, and kuha789-200 vehicles are equipped with a western style toilet having a chemical holding tank. A toilet of class kuroha789-200 is universal access. Class kuha789-200 is also equipped with a flashing urinal. Class moha788-100 vehicles are equipped with a conductor room with shunting control position. Class moha789-200 is also equipped with a telephone room with shunting control position.
Additional delivery
JR Hokkaido delivered 11 vehicles of 2nd batch in order to provide additional
capacity of "Super Hakucho" intercity services on the Tsugaru-Kaikyo
line in 2005. Six trailer intermediate vehicles, class789-100, having shunting
control position were delivered to insert them into 2-car sets to make
3-car sets. Three 2-car sets consisting of class kuha789-300 and class
moha788-300 were delivered to make total 8-car sets for additional capacity
during peak seasons. Newly designed class moha788-300 vehicles are similar
to existing class moha788-200 with minor difference having prepared shunting
position. Class moha789-300 vehicles are equipped with a traction system,
N-CI789-3, consisting of Insulated Gate Bipolar Transistor (IGBT) and a
2-level Variable-frequency drive (VFD) employing IGBT controls traction
motors on truck basis and a forced air-cooling traction transformer, N-TM789-FN,
under the floor. Their acceleration performance is degraded to 2.2km/h/s
caused by introducing an additional trailer vehicle.
Modifications
A designated smoking room was changed into free space in 2007.
After discontinuance of "Super Hakucho" intercity services ahead of the opening of the Hokkaido Shinkansen, JR Hokkaido modified 789-0 series vehicles to reintroduce "Lilac" intercity services linking Sapporo and Asahikawa including some changes. ATC-L signaling system was removed and ATS-DN signaling system was fitted. The holding brake was also discontinued. The louver, fitted on the side of the body, of the equipments to remove airborne snow from intake air was covered with a plate and air intake ducks are fitted additionally. A built-in classification headboard was changed into a full-colure display.
Operations
789-0 series EMU entered "Super Hakucho" intercity services linking Hachinohe and Hakodate in 2002. From the start of the revised timetable on 4 December 2010, with the opening of the Tohoku Shinkansen from Hachinohe to Shin-Aomori, "Super Hakucho" services were also reorganized to operate from Shin-Aomori to Hakodate via Aomori. "Super Hakucho" services were discontinued in March 2016 ahead of the opening of the Hokkaido Shinkansen and all 789-0 series vehicles were completely withdrawn.
Surplus 789-0 series 6-car sets were relocated to Sapporo depot end entered "Lilac" services linking Sapporo and Asahikawa to displace superannuated 785 series EMU. 789-0 series are now used on "Lilac" intercity services. |
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