Background and overview
JR Hokkaido developed intercity AC electric multiple unit (EMU) trainset, 785 series, to shorten the total journey time and provide additional capacity on Hakodate line between Sapporo and Asahikawa in 1990. Five 4-car sets consisting of 2 motored vehicles and 2 trailer vehicles, and five 2-car sets consisting of a motored vehicle and a trailer vehicle were delivered over the period from June 1990 until August.
Car body
They have 2954mm wide body, incorporating unpainted light weight stainless
construction. They have dark brown wide band around side windows, lavender
violet and light green coloured waistline band running the length of each
car below the windows and lavender violet coloured headline band above
the windows. Their gangwayed end section painted in silver is constructed
by steel, featuring dogleg streamline shape and wide curved windscreens.
Headlights featuring rectangular sealed beam are fitted above the gangway
and at the lower part behind the windscreen. Rectangular LED trail lights
are also fitted at the lower part behind the windscreen. A built-in classification
headboard is fitted below the control desk. Each vehicle is equipped with
two stepped sliding doors. The rear door of trailer vehicles is 1000mm
wide and the others are 700mm wide. Door operating equipments, TK103A,
are fitted above the door header of the sliding doors. They are also equipped
with fixed double-glazing windows aligned two seating on each side of their
body, having glass-covered pier panels to make horizontal band windows.
The destination rollsigns are fitted on the side of the body. Louver window
for air intake to cool their traction motors having the equipment to remove
airborne snow are located at the left front and right rear of the powered
vehicles. "SWA" logos derived from "Super White Arrow"
are applied to the sides of each vehicle. They are equipped with an air
conditioner, N-AU785 rated at 26,000kcal/h on their roof. Electric fans
of air conditioner supply fresh air into the passenger room, instead of
ventilators on the roof. Powered vehicles are also equipped with a traction
resistor unit, N-MR785, for rheostatic brake on the roof.
Bogies
Motored bogies are N-DT785 and trailer bogies are N-TR785, featuring bolster-less secondary air suspension, corn-shaped multilayered rubber spring journal supporting system, and the Z link traction device. These bogies adopt the ant-yaw dampers to ensure smooth ride characteristics even at 130km/h. 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 4.21 to get high acceleration performance at the range of middle and high speed and the maximum service speed at 130km/h. Their bogies employ double tread brake riggings. Trailer bogies also employ a disk brake rigging
Traction unit and ancillary equipments
Their traction system consisting of a thyristor phase control converter featuring 2 stage hybrid bridge rectifier direct connection powered by 1100VAC and a Variable Frequency Drive (VFD) employing Gate Turn Off (GTO) thyristor. Powered end vehicles, class kumoha785-100, of 2-car sets are equipped with a traction system, N-CI785-1, under the floor and powered end vehicles, class kumoha785-0, and powered intermediate vehicles, class moha785-0, of 4-car sets are N-CI785-2. These traction system controls 4 AC asynchronous traction motors, N-MT785, with a power output of 190kW on vehicle basis. Trailer end vehicles, class kuha784-0, of 2-car sets are equipped with a traction transformer, N-TM785-1, under their floor and trailer intermediate vehicles, class saha784-0, of 4-car sets are N-TM785-2. Their traction transformer features forced oil cooling. Class kuha784-0 and saha784-0 are also equipped with a cross-arm current pickup, N-PS721B, on their roof. Trailer vehicles are equipped with an auxiliary power supply, N-APS721A, and a motor driven air compressor, N-C2000ML, under their floor. They feature the electric command pneumatic brake with rheostatic brake, employing anti-slip control by axle-driven tachometer generator fitted to each axle in order to achieve brake performance efficiently even at 130km/h.
Accommodation
Open plan accommodation is 2+2 abreast adjustable reclining seating with 960mm seating pitch. Their seating of 4-car sets is covered with violet fabric and 2-car sets are green. They adopt sliding curtains at the side window. Florescent lights are fitted inside the louvers at the centre of ceiling for cabin lighting, featuring the combination of direct lighting through louvers and indirect lighting. 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. Class saha784 vehicles are equipped with a linen room and a telephone booth having a payphone inside located next to the front doorway. Class kumoha785 vehicles are equipped with a catering room. Each trailer vehicle is equipped with a western style toilet with a flip-up diaper-changing station, a flush urinal, and a wash room. Each toilet has a chemical holding tank. Their cab is equipped with a one handle master controller operated by the left hand.
Additional delivery
JR Hokkaido started "Super White Arrow" interrunning service through Shin-Chitose located at New Chitose Airport as rapid services named "Airport" to shorten the total journey time between Shin-Chitose and Asahikawa from the revised timetable in March 2002. Due to this change, JR Hokkaido reformed 785 series train sets into 5-car sets with the addition of newly built intermediate vehicles to provide "u-seat" services, because existing "Airport" rapid services operated by 721 series EMU were providing "u-seat" service. In addition, additional intermediates vehicle for "u-seat" services should have been powered to retain the total journey time between Sapporo and Asahikawa despite of increasing a few stops. 5 newly built powered intermediate vehicle, class moha784-500, employing "u-seat" accommodation were inserted into existing five 4-car sets to make 5-car sets. Two newly built powered intermediate vehicles, class moha785-500, were inserted into existing 2-car sets to make 3-car sets and they were coupled with other 2-car sets to make totally 5-car sets in 2002.
class moha785-500/moha784-500
Car body
They have 2954mm wide body, incorporating unpainted light weight stainless
construction. They have dark brown wide band around side windows, lavender
violet and light green coloured waistline band running the length of each
car below and above the windows and lavender violet coloured headline band
above the windows. Each vehicle is equipped with two stepped sliding doors
and small fixed double-grazing windows having polycarbonate reinforcement
for the protection against the breakdown of the windowpane. Their rear
door is 1000mm wide and the other is 700mm wide employing the cylinders
to press the door preventing ice-clogged. A door chime is fitted above
the door header of the sliding doors. They are also equipped with a hinged
door for the conductor room located at the rear. The destination rollsigns
are fitted on the side of the body. Louver window for air intake to cool
their traction motors having the equipment to remove airborne snow are
located at the left front and right rear of the powered vehicles. They
are equipped with an air conditioner, N-AU785 rated at 26,000kcal/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
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
Powered bogies are N-DT785A featuring bolster-less secondary air suspension, axle arm type journal box supporting system, the single link traction device, 1950mm wide (50mm wider than former N-DT785) distance between two secondary air suspension, and the yaw dampers to ensure smooth ride characteristics even at 130km/h. 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 4.21. Their bogies employ double tread brake riggings.
Traction unit and ancillary equipments
Class moha785-500 vehicles inserted into 2-car sets are equipped with a
traction system, N-CI785-1A, and class moha784-500 vehicles inserted into
4-car sets are N-CI785-2A. These traction systems control 4 AC induction
motors, N-MT731, with a power output of 230kW on truck basis. This traction
system consists of a 3-level converter employing Insulated Bipolar Transistor
(IGBT) and a 2-level Variable-frequency drive (VFD) employing IGBT. When
the system failure occurred on the one of two circuits of the traction
system, a failed circuit is disconnected to achieve higher redundancy.
Each traction system features fields-oriented control. The traction system
of class moha784-500 vehicles is powered by its own traction transformer,
N-TM785-1, fitted under their floor. On the other hand, the traction system
of class moha785-500 vehicles is powered by the traction transformer of
class kuha784. The traction rectifier fitted on class kuha784 vehicles
supplies electricity to a converter employing clyster phase control causing
phase delay and a PWM converter. For this reason, the traction system,
N-CI785-1A, is controlled in order to retain power factor at the current
pickup at 100% and the traction transformer of class kuha784 vehicles supplying
electricity to class moha785-500 was displaced with N-TM785-2. Class moha784-500
and moha785-500 vehicles are equipped with an auxiliary power supply, N-APS721A.
Class moha785-500 vehicles are also equipped with a single arm current
pickup, N-PS785, on their roof. Class moha784-500 and moha785-500 vehicles
feature the electric command pneumatic brake with regenerative brake, employing
anti-slip control by axle-driven tachometer generator fitted to each axle
in order to achieve brake performance efficiently even at 130km/h.
Accommodation
They have an open plan accommodation featuring 2+2 abreast adjustable reclining seating with 1050mm seating pitch, 20 mm wider per person than existing 785 series, larger seat back and the hand-grabs. Their seating is equipped with a power supply outlet behind the seat back. They adopt roller blinds. Florescent lights are fitted inside the louvers at the centre of ceiling for cabin lighting, featuring the combination of direct lighting through louvers and indirect lighting. 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. They are equipped with a universal access toilet employing the vacuum toilet system toward the front of vehicle, and a conductor room at the rear.
Modification and refurbishment
Their head lights were changed into high intensity discharge (HID) lamps over the period from March 1999 until January 2000. Side windows outside excepting 785-500 series also began to be additionally framed with polycarbonate reinforcement for the protection against the breakdown of the windowpane from 2000. Additional stainless cover plates were fitted between equipments of 785 series excepting -500 subseries fitted under their floor to reduce the waving for preventing snow and ice from sticking thereon over the period from October 2003 until April 2004. Furthermore, the current pick up of class kuha784 and saha784 vehicles was replaced with a single arm current pickup, N-PS785S over the period from August 2004 until August 2005.
In April 2005, 785 series EMU started to undergo extensive refurbishment
programme. Their traction system classified into N-CI785-1/N-CI785-2 were
displaced with a new traction system classified into N-CI785-3 for -0 subseries
and N-CO785-4 for -100 subseries, consisting of a 3-level converter employing
Insulated Bipolar Transistor (IGBT) and a 2-level Variable-frequency drive
(VFD) employing IGBT. A traction resistor unit fitted on the roof was removed
because regenerative brake was applicable by introducing new traction system.
Their traction transformer was changed new one classified into N-TM785-1-AN
for class784 vehicles and N-M785-2-AN for class kuha784 vehicles, employing
travelling wind self-cooling. They feature the electric commanding brake
with regenerative brake to zero speed, featuring brake control of trailer
priority.
Some improvements were introduced for their accommodation. Their seating excepting U-seat was replaced with new one supported by a center leg to widen the leg room. Their seating fabric was changed into brown and hand-grabs on the edge of seats were introduced. A chemical holding tank for the toilet was replaced with the vacuum system. Furthermore, the audible entryway signal fitted on the ceiling at the doorway and anti-fall plates between vehicles excepting the cab end were introduced for the blind.
In addition, the control desk of end vehicles connected at the middle of a rain set, class kumoha785-100 and kuha784-100, caused by U-seat car addition were removed and windscreens and hinged doors located at these vehicle's cab were filled with the plate by welding over the period in June 2007 and March 2008.
Operations
They entered "Super White Arrow" intercity services linking Sapporo and Asahikawa in September 1990. "Super White Arrow" started through services to Shin-Chitose as "Airport" rapid services by using 785 series 5-car set with u-seat service in March 2002. The "Super White Arrow" services were combined with the "Lylac" services operated by 781 series EMU to form the new "Super Kamui" services operated by 785 series and 789-1000 series, and 781 series used on "Suzuran" services linking Sapporo and Muroran were displaced with 785 series in October 2007. However, 785 series were withdrawn from "Airport" rapid services because of the discontinuance of "Super Kamui" and "Airport" interrunning service. Surplus 789-0 series 6-car sets completely withdrawn at the opening of the Hokkaido Shinkansen were relocated to Sapporo depot end entered "Lilac" services linking Sapporo and Asahikawa to displace 25 superannuated 785 series vehicles. Remaining 10 785 series vehicles are now used on "Suzuran" intercity services along with 789-1000 series. |
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