Background and overview
JR Kyushu developed 815 series rural AC electric multiple unit (EMU) trains
for the start of the regional services on newly electrified Chikuhi line
between Kumamoto and Higo-Ohzu in 1999. 26 two-car sets consisting of 1
powered vehicle and 1 trailer vehicle were delivered in 1999.
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 unpainted with hairline finish with various logos splashed everywhere. The gangwayed front cab section is constructed by steel for the protection against the level crossing accident and is employed unit assembled construction fitted with the control desk, a gangway door, windshields, wipers, headlights, and taillights beforehand. This cab section is fitted to their main body by bolts. An automatic jumper coupler and an automatic gangway connection device are fitted at the front to ease rush-up operations. A destination rollsign is fitted above the gangway door. Two headlights applied sealed beam light bulbs are horizontally fitted each side of the gangway and two LED trail lights below headlights. Their floor level is 1115mm which is 10mm lower than 813 series to eliminate the level difference between low platforms and the floor for accessibility. They are equipped with three 1300mm wide double-leaf automatic sliding doors on each side of the vehicles. A 3000 mm wide and 1000 mm high large fixed window is fitted between sliding doors. Class kuha814 vehicles are equipped with a destination rollsign on each side of the body. Loudspeakers, providing guidance broadcast for passengers waiting at a station, are also fitted on each side of the body. They are equipped with an air conditioner, AU407K rated at 42,000kcal/h on their roof.
Bogies
Motored bogies are DT404K and trailer bogies are TR404K, featuring bolster-less secondary air suspension, corn-shaped multilayered rubber spring journal supporting system, and the single link traction device. 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 6.53. Both motored and trailer bogies employ the single tread brake device.
Traction unit and ancillary equipments
Class kumoha815 vehicles are equipped with a traction system, PC402K, consisting of a 3-level PWM converter, a 2-level Variable-frequency drive (VFD) employing Insulated Gate Bipolar Transistor (IGBT), and a brake chopper reactor. This traction system controls 4 AC asynchronous traction motors, MT401KA, with a power output of 150kW. Class kumoha815 vehicles are also equipped with a traction transformer, TM406K, featuring natural air cooling under their floor and a single-arm current pickup, PS401K, on their roof. Trailer end vehicles, class kuha814, are equipped with a motor-driven reciprocating air compressor, MH410K-C1000ML, and an ancillary power supply unit, SC405K, with a power output of 5kVA under their floor. They feature the electric commanding brake with regenerative brake and holding brake, featuring brake control of trailer priority.
Accommodation
Seating accommodation is longitudinal bench seating which consists of aluminum plate integrating seat and back-rest, and having independent seats and seat backs. The unit assembled cab, unit assembled toilet, and sliding doors are painted in yellow, and the decorative plate used for the other parts is satin finished and clear painted aluminum plate. Each window features green tinted heat ray absorbing tempered glass to leave out the roller blinds. The width of the gangway having no door is 1000mm. Class kuha814 vehicles are equipped with a universal access toilet and a wheel chair space. The ticket machine, which put the ticket indicating the boarding station, is located beside doorways at the end of their body. The fare chart seven segment display and the fare box are located behind the driver's cab. The fare box is storable inside the driver's cab while the gangways of the front are opened. Their cab is a compartment type located at the left side of the train 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 at the opposite side of the driver's cab.
Modification
Their headlights were changed into the LED light. Vehicles used in Kumamoto are additionally equipped with external security cameras.
Operations
Seventeen 2-car sets were delivered to Kumamoto depot and entered rural revenue services on Kagoshima line between Ginsui and Yatsushiro and Houhi line between Kumamoto and Higo-Ohtsu in 1999. Coluctor-less operation between Tosu and Ginsui started in 2005. Two 2-car sets were relocated to Ohita depot in 2005 and another in 2016. Sixteen 2-car sets are now used on rural services in Kumamoto area.
On the other hand, nine 2-car sets were delivered to Ohita depot and entered the revenue services on Nippo line between Nakatsu and Saeki, and twelve 2-car sets are now used. |
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