Background and overview
JR Hokkaido developed 789-1000 series with substantial improvements over previous 789-0 series in order to displace superannuated 781 series which had been used on the intercity services linking Asahikawa and Muroran via Sapporo since 1978. 7 five-car sets consisting of 2 powered vehicles and 3 trailer vehicles were delivered in 2007.
Car body
They have 2812mm wide body, incorporating light weight stainless steel
construction and same cross-section shape considering tilting up to three
degrees as that of 789-0 series EMU. Anti-fall plates between vehicles
are also introduced excepting the cab end. Laser beam welding is applied
for side construction of the vehicle to reduce distortion of the skin.
The cross member of the underframe, side column, and carline are positioned
longitudinally to form ring shape construction for more intense strength
against lateral collision. Cab ends constructed by 3.2mm thick steel plate
differ from 789-0 series in having no gangway door and a high mounted driver's
cab against obstacles at the level crossing. A built-in classification
headboard is fitted on the centre of the cab end and two headlights applied
halogen light bulbs and high intensity discharge (HID) lamps longitudinally
are fitted each side of the headboard. Extra HID lamps are fitted above
the windscreen and tail lamps are behind the windscreen. They are equipped
with two single-leaf sliding stepped door employing the cylinders to press
the door against both ice-clogged in order to ease boarding and alighting
while used on "Airport" rapid services, and small fixed double-grazing
windows per each seating of u-seat class or wide fixed double-glazing windows
aligned two seating bays of standard class. The rear door of trailer end
vehicles and the front door of intermediate powered vehicles is 900mm wide
and the others are 700mm wide. These side windows have polycarbonate reinforcement
for the protection against the breakdown of the windowpane. The conductor
room in class moha789-2000 and the driver's cab in class kuha789-1000/-2000
are equipped with a hinged door except doorways. Three colure (red, green,
orange) LED destination displays are fitted on the side of their body.
They are equipped with an air conditioner, N-AU789A rated at 30,000kcal/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-DT789A and trailer bogies are N-TR789A, 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 4.43 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 moha789-1000/-2000 vehicles are equipped with a traction system,
N-CI789A, consisting of a 3-level converter and a 2-level Variable-frequency
drive (VFD) employing IGBT 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 and
featuring fields-oriented control. The trailer intermediate vehicles, class
saha885-0, are equipped with two travelling wind self-cooling traction
transformers, N-TM789-AN, under the floor, supplying to both class moha789-1000
and moha789-2000 vehicles. Motored vehicles are equipped with the equipments
on the floor to remove airborne snow from intake air. Class saha788 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-APS785 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 7.5kVA under their
floor. End vehicles are also equipped with a motor driven screw air compressor,
N-MHI785-C2000ML, under their floor. 789-1000 series feature the electric
commanding brake with regenerative brake to zero speed, featuring holding
brake and brake control of trailer priority.
Accommodation
All seats are adjustable reclining with the hand-grabs. U-seat class vehicles have 2+2 abreast seating with 1050mm seating pitch and standard class vehicles have 2+2 abreast seating with 960mm seating pitch. U-seat class seating is equipped with a power supply outlet behind the seat back. 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. Light colure florescent lights and LED lamps are alternately fitted for cabin lighting. Class kuha789-1000/-2000 vehicles are equipped with a western style toilet and flash urinal having a chemical holding tank. Class kuha789-1000/-2000 vehicles are also equipped with a washroom. Class moha789-2000 vehicles are equipped with a universal access toilet and a conductor room. Class moha789-2000 is also equipped with a baggage rack in their passenger room.
Operations
789-1000 series EMU entered "Super Kamui" intercity services linking Sapporo and Asahikawa, and "Airport" rapid services linking Sapporo and Shin-Chitose airport in October, 2007. 789-1000 series entered "Suzuran" intercity services linking Sapporo and Muroran in 2010. However, 789-1000 series withdrew from "Airport" rapid services because of the discontinuance of "Super Kamui" and "Airport" interrunning service. "Super Kamui" intercity services were divided into "Lilac" and "Kamui" intercity services. 789-1000 series are now used on "Kamui" and "Suzuran" intercity services. |
|
