Background and overview
JR Kyushu developed next generation suburban AC electric multiple unit (EMU) trains, 821-0 series, to replace superannuated 415 series EMU trains used on Kagoshima line reginal services in Fukuoka. Their train sets consist of a powered vehicle and two trailer vehicles. They can consist 2-car sets by removing a trailer intermediate vehicle. Tow pre-production sets were delivered in 2018.
Car body
The double-skinned aluminum alloy construction employing large hollow structural
angles is incorporated into the vehicle design in order to realize light
weight, thermal insulation, high noise reduction, and high recyclability.
Their front structure equipped with a gangway door, windscreens, and windscreen
wipers to name a few is constructed by steel and is fitted with the aluminum
body by using bolts and nuts. Their bodies are unpainted with vitreous
coating finish. The front of the cab is painted in black and equipped with
a gangway door. A full coloured LED destination display is fitted above
the gangway door. Two LED headlights are horizontally fitted each side
of the gangway and they were surrounded with twelve small LED tail lights.
These tail lights are changed into white decorative lights when facing
forward in the direction of travel. 69 decorative LED lights are also fitted
around the front. Anti-fall plates between vehicles are also introduced
excepting the cab end. They are equipped with three 1300mm wide double-leaf
automatic sliding doors painted in metallic deep red on each side of the
vehicles. Door operating equipments featuring motored screw drive mechanism
and a flashing alarm lamp while door opening/closing are fitted above the
door header of the sliding doors which can be operated manually by pushing
the buttons fitted beside the door. LED lights are fitted on the lower
part of both sides of sliding doors. A 3000 mm wide and 700 mm high large
fixed window is fitted between sliding doors and 760mm wide and 700mm high
small fixed windows are fitted at the end of their body. Each window features
gray tinted heat ray absorbing tempered glass having transmittance at 14%.
A full colour LED destination display, loudspeakers, providing guidance
broadcast for passengers waiting at a station, and external security cameras
are fitted on each side of the body. They are equipped with an air conditioner,
AU413K rated at 47,300kcal/h on their roof. No ventilators are fitted on
the roof. End cars are equipped with the automatic jumper coupler having
ethernet connectors for high-speed digital transmission to ease rush-up
operations.
Bogies
Motored bogies are DT410K and trailer bogies are TR410K featuring bolster-less
secondary air suspension, axle arm type journal box supporting system,
and the single link traction device. Their bogie employing smaller diameter
wheels and bow-shaped bogie frame to lower the fitting position of bolster
suspension realizes to lower the floor level. These bogies feature the
yaw dampers to ensure smooth ride characteristics even at 120km/h. Quiet
Westinghouse-Natal drive is applied for power transmission device. The
gear ratio is 6.5 to get high acceleration performance. Their bogies employ
single tread brake rigging adopting automatic gap-adjusting unit. A bogie
state monitor applying accelerometers is fitted near their bogies to detect
flaws such as oil spillage of dampers, oil spillage and abnormal vibration
of gears, wheel dimples and flats to name a few.
Traction unit and ancillary equipments
Class kumoha821-0 vehicles are equipped with a traction system, PC409K, consisting of a 3-level PWM converter employing Silicon carbide (SiC) MOSFET which has lower loss than silicon device existing before, a 2-level Variable-frequency drive (VFD) employing SiC, and a brake chopper reactor. This traction system controls 4 AC totally enclosed asynchronous traction motors, MT406K, with a power output of 150kW on truck basis. Their taction motors feature improved workability in maintenance featuring non-destructive bearing replacement. When the system failure occurred on the one of two circuits, a failed circuit is disconnected and remaining sound circuit controls 4 traction motors with retaining prescribed acceleration performance. Class kumoha821-0 vehicles are also equipped with a traction transformer, TM412K, featuring natural air cooling under their floor and a single-arm current pickup, PS403K, on their roof. Trailer end vehicles, class kuha821-0, are equipped with two ancillary power units, SC412K, consisting of a PWM converter and a PWM inverter with a power output of 57kVA under their floor, and trailer intermediate vehicles, class saha821-0, are equipped with an ancillary power unit under their floor. Each ancillary power supply unit synchronizes with the other ancillary power supply units. When the system failure occurred on one of ancillary power supplies, a failed ancillary power supply is disconnected and two remaining sound ancillary power units supply enough electricity to achieve higher redundancy. In addition, when the train set needs low electricity load, the train communication network cuts off an ancillary power supply to realize energy saving. Trailer end vehicles, class kuha821-0, are also equipped with another ancillary power unit, SC413K, converting from 440V single-phase electricity supplied from the third wiring of the traction transformer into 100VDC and 100V single-phase electricity under their floor. SC413K ensures redundancy by adapting a standby redundancy system that duplicates the power conversion section and the control section. Class kuha821-0 and saha821-0 vehicles are also equipped with a motor-driven oil-free reciprocating air compressor, VV80-T, of Knorr-Bremse. Ordinarily, one of two compressors is operating. However, if the failure occurred on a compressor under operation, operation switches to the other standby compressor automatically. They employ the electric commanding brake with mixed regenerative-dynamic braking under low possibility of regeneration. Each bogie is equipped with a brake controller to ensure redundancy.
Accommodation
Passenger accommodation consists of longitudinal bench seating with two
stanchions to divide seating into three-four-three-seater having 460 mm
wide per person throughout. The seat and backrest are made of fire-resistant
wood and have cushions covered with fabric. Seats located at door cases
have a headrest. A 17-inch liquid crystal display for providing passenger
information is fitted above the door header of each sliding door. Straps
were fitted throughout their body. The passenger saloons use LED recessed
lighting. A universal access toilet and a wheel chair space are located
at the rear of the trailer end vehicles, class kuha821-0. Another wheel
chair space is also located at the trailer intermediate vehicles, class
saha821-0. Their cab is a full-size type and the control desk of the driver's
cab is equipped with a one handle master controller operated by the left
hand and two liquid crystal displays showing the speed meter, the pressure
gauge, and the other information instead of analogue indicators. A rubbish
bin is fitted beside the doorway.
Additional delivery
2 additional three-car sets were delivered in February 2020. In addition,
3 more three-car sets were delivered over the period from January 2022
until February.
Operations
They were delivered to Minami-Fukuoka depot and entered revenue services
on Kagoshima line between Kokura and Arao in March 2019. They also entered
rural services in Kumamoto region in March, 2021. Then, all 821-0 series
vehicles were reallocated to Kumamoto depot in September 2022. They are
now used on the rapid and regional services of Kagoshima line between Moji-ko
and Arao, Chikuhou line, Sasaguri line, and Houhi line between Kumamoto
and Higo-Otsu. |
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