Background and overview
For the replacement of superannuated diesel multiple unit trains, JR Kyushu has been developing a battery electric multiple unit train by modified 817 series EMU train since 2012, instead of the replacement with alternating newly-built diesel multiple unit trains having a higher environmental impact or electric multiple unit trains requiring high-cost electrification work. As the result, JR Kyushu developed a BEC819 series suburban battery electric multiple unit train with the resolved problems such as insufficient battery capacity, current collector interference with the small tunnel existing on the unelectrified sections, and forgetting to lower the current collector in unelectrified sections to name a few. A 2-car pre-production set comprising a powered end vehicle and a trailer end vehicle, was built and delivered to Nogata depot in May 2016.
Car body
The double-skinned aluminum alloy construction is incorporated into the vehicle design. This construction by means of introducing the friction stir welding (FSW) technology introduces dovetail groove to be fitted with equipments and interior parts as a substitute for joining them by welding in order to reduce welding points and improve body rigidness compared with existing method to build the body by welding skins, columns, and ribs together for cost reduction. Their bodies are painted in while and the front cab section painted in black is equipped with a gangway door. An LED destination display is fitted above the gangway door. Two LED headlights are horizontally fitted each side of the gangway and two rectangular shaped LED trail lights below headlights. Anti-fall plates between vehicles are also introduced excepting the cab end. They are equipped with three 1300mm wide double-leaf automatic sliding doors on each side of the vehicles. Door operating equipments featuring electric screw drive are fitted above the door header of the sliding doors which can be operated manually by pressing the buttons fitted beside the door. A 3000 mm wide and 1000 mm high large fixed window is fitted between sliding doors. Each window features green tinted heat ray absorbing tempered glass having transmittance at 30-40%. LED destination displays and loudspeakers, providing guidance broadcast for passengers waiting at a station, are fitted on each side of the body. They are equipped with an air conditioner, AU411K rated at 42,000kcal/h on their roof. No ventilators are fitted on the roof. The low roof section where a current collector is fitted is 3366mm to realize a current collector lowered height of 3980mm to achieve without current collector interference with the small tunnel existing on the unelectrified sections. Cab ends are equipped with the automatic jumper coupler to ease rush-up operations.
Bogies
Motored bogies are DT409K and trailer bogies are TR409K, featuring bolster-less secondary air suspension, corn-shaped multilayered rubber spring journal supporting system, and the single link draw gear. Conical roller bearings are adopted and yaw dampers are prepared to ensure smooth ride characteristics even at 120km/h. Their bogie employing smaller 810mm diameter wheels realizes to lower their floor level. 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 6.5. Both motored and trailer bogies employ the single tread brake device.
Traction unit and ancillary equipments
BEC819 series have two modes: on electrified sections, it runs from the
overhead AC power and on unelectrified sections in runs in battery mode.
In the overhead AC power mode, the train runs on the electrified sections
with the current collector raised and the battery is charged with low current
until a certain charge rate is reached. On the other hand, in battery mode,
the train runs on the unelectrified sections with the current collector
lowered and the train runs with battery power. The electricity generated
with regenerative braking is stored into the battery.
Powered end vehicles, class kumohaBEC819 are equipped with a traction system,
PC407K, consisting of a 2-level PWM converter and a 3-level Variable-frequency
drive (VFD) employing Insulated Gate Bipolar Transistor (IGBT). This traction
system controls 4 AC closed internal fan cooling asynchronous traction
motors, MT404KA, on truck basis with a power output of 95kW. They are also
equipped with a traction transformer, TM410K, beneath the floor and a single-arm
current pickup, PSB401K, on their roof with 4 slide plates for current
suppression in quick charge. On the contrary, trailer end vehicles, class
kuhaBEC818, are equipped with a traction battery, CH75-6, connecting three
battery packs in parallel employing 72 series modules of lithium-ion secondary
batteries. This traction battery provides a total capacity of 383.6kWh
and a voltage of 1598VDC. In case of failures on a battery pack, a contactor
connected with the input of failed battery pack is opened to allow to continue
travelling using only the remaining healthy battery packs. Since the underfloor
of class kuhaBEC818 is occupied with this traction battery alone, an auxiliary
power supply and an air compressor are installed beneath the floor of class
kumohaBEC819 vehicles. An auxiliary power supply is able to convert 1598VDC
to 440V 3-phase AC with power output of 80kVA. An auxiliary power supply
connected between the converter of the traction system and the traction
battery is powered by the converter of the traction system on electrified
sections or the traction battery on unelectrified sections to supply auxiliary
power at all time even though power mode switchover. At the time the train
stops at the electrified station after traveling on an unelectrified section,
the traction battery can be charged with a high-power electricity in a
short period of time to reduce charging time. BEC819 series employ the
train control and management system, Synaptra developed by Hitachi Ltd.,
which provides information on remaining battery, train condition, fault,
and travelable distance estimation, and notice electrified/unelectrified
sections switchover, using ethernet transmission. An oil-free reciprocating
air compressor, VV120-T, made by Knorr-Bremse of Germany is featured for
them to reduce the work time for maintenance. They feature the electric
commanding brake with regenerative brake and holding brake, featuring brake
control of trailer priority.
Accommodation
Passenger accommodation consists of longitudinal bench seating with two stanchions to divide seating into three-four-three-seater having 440 mm wide per person throughout to provide increased overall capacity and relieve overcrowding. The seat and backrest are made of fire-resistant wood and have cushions covered with fabric. Seats located next to the stanchions have a headrest. 17-inch LCD displays for providing passenger information are fitted above the door header of sliding doors in zigzags. Straps were fitted throughout their body. The passenger saloons employ LED interior lighting arranged in 2 rows. Class kuhaBEC818 vehicles are equipped with a universal access toilet employing flush fresh water toilet system and a wheelchair space located across the aisle from the toilet. 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. A rubbish bin is fitted beside the doorway.
Additional delivery
Six mass-production 2-car sets were delivered to the Chikuho line in February 2017. Furthermore, additional eleven sets classified into -300 subseries were delivered to the Kashii line over the period from January 2019 until February of the same year. BCE819-300 series feature the capacity increased traction battery to fulfill the longer travel distance required for the Kashii line. They are also equipped with body-mounted cameras to monitor passengers boarding and alighting the train for conductor-less operations. For this reason, the automatic jumper coupler involves additional ethernet couplers. They also employ a body vibration detector applying accelerometers installed near their bogies to prevent damage caused by derailment and collision to name a few from spreading.
Modifications
A 2-car set of BEC819-0 series received the modification to install body-mounted
cameras in 2018 to monitor passengers boarding and alighting the train
for conductor-less operations and was classified into -100 subseries. Another
2-car set also received the same modification in 2019. JR Kyushu had been
testing automatic train operation on a 2-car set BCE819 series over the
period from 2019 until 2020. As the result, all sets of BCE819-300 series
received modification to install an ATO equipment over the period from
January 2022 until February 2024 and were classified into -5300 subseries.
Furthermore, 2 sets of BCE819-100 series received modification to install
an ATO equipment over the period from March 2024 until July of the same
year and were classified into -5100 subseries.
Operations
BCE819 series entered the rural services on the Chikuho line between Wakamatsu and Orio in December 2016. Mass production sets were delivered in 2017 to enter revenue services on the Chikuho line between Wakamatsu and Keisen, and the Sasaguri line along with 817 series EMU. In addition, BCE819-300 series entered the rural services on the Kashii line March 2019. They started the Kashii and Kagoshima lines interrunning services in March 2020 and extended interrunning services to Futsuka-ichi in 2024.They are now used on rural services on the Chikuho, Sasaguri, Kashii, and Kagoshima lines. |
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