Background and overview
JR Hokkaido considered introducing trains incorporating the double-skinned
aluminum alloy construction to reduce weight and cost. However, this type
of vehicle had not been used in Hokkaido which is extremely cold region.
Thus, JR Hokkaido built 735 series suburban AC electric multiple unit pre-production
trains sets in 2010.
Car body
The double-skinned aluminum alloy construction is incorporated into the vehicle design. This construction 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. They have 2800mm wide bodies. Their cross-section profile is changed from that of 731 series due to not incorporating pneumatic tilt system. Their floor level is 100mm lower than 731 series to get rid of the step at the doorway for better accessibility. Bodies are painted in metallic silver with olive-green waistline bands below the windscreens. The cab end has a gangway with the gangway connection base and features the higher mounted driver's cab, reinforced gangway connection base column, reinforced framework around the driver's seat, and the shock absorbing construction for the protection against obstacles at the level crossing. A 3-colour LED destination indicator is fitted above the gangway door@and clusters of a headlight employing shieled-beam light bulb and a taillight employing LED are fitted at the left and right sides of the destination indicator. Additional clusters consisting of headlights employing a shielded-beam light bulb and a high intensity discharge (HID) lamp are also fitted on each side of the gangway door. They are equipped with three 1200mm wide single-leaf automatic sliding doors which can be operated manually by pushing the buttons fitted beside the door and two fixed windows having 990mm height and 1990mm width are fitted between the sliding doors. The door operating equipment is TK103A having flashing alarm lamps while door opening/closing, fitted above the door header of the sliding doors. A 3-colour LED destination indicator is fitted on each side of the body and the louver of the snow separator employing the cyclone to remove airborne snow from intake for cooling the traction motor is also fitted on each side of the powered vehicles. An air conditioner, N-AU735, rated at 30,000kcal/h is fitted on the centre of the roof and 1mm thick stainless cover plates are fitted between equipments under the floor to reduce the waving for preventing snow and ice from sticking thereon.
Bogies
Motored bogies are N-DT735, trailer bogies of end vehicles and trailer bogies are N-TR735 featuring bolster-less secondary air suspension, trailing arm link journal box supporting system, and the single link traction gear. The wheel diameter is reduced to 810mm, and bow-shaped bogie frame is employed to lower their floor level. These bogies feature 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 4.89 to get high acceleration performance and the maximum service speed at 130km/h. Both motored and trailered bogies employ the double tread unit assembled brake device with high adhesive alloy cast iron shoes.
Traction unit and ancillary equipments
Class moha735-100 vehicles are equipped with a traction system, N-CI735, which controls 4 AC induction motors, N-MT735, with a power output of 230kW on truck basis, a travelling wind self-cooling shell type traction transformer, N-TM735-AN, beneath the floor, and a single arm current pickup, N-PS785 on the roof. This traction system consists of a 3-level PWM converter employing Insulated Bipolar Transistor (IGBT) and a 2-level Variable-frequency drive (VFD) employing IGBT. Class kuha735-200 vehicles are equipped with a motor-driven air compressor, N-MH1785-C2000ML and two auxiliary power supplies, N-APS-735, for AC and DC power supply which consist of the converter employing both the diode bridge and the chopper circuit featuring IGBT powered by the third winding of the traction transformer, and inverter. The brake system is an electric commanding brake with regenerative brake to zero speed, featuring brake control of trailer priority.
Accommodation
Passenger accommodation consists of longitudinal bench seating throughout, with an individual seat width of 455 mm per person and three stanchions to divide seating into four sections. Since they don't have the vestibule areas used on the earlier 721 series trains, they are equipped with air curtains mounted above the doorway, and electric blow heaters located beside the doorway to reduce the penetration of outside cold air into the heated passengers' cabin. LED displays for providing passenger information are fitted in zigzags and door chimes are fitted above the door header of the sliding doors. Roller blinds are gotten rid of. Class kuha735-100 vehicles are equipped with a universal access toilet featuring vacuum toilet system and a wheelchair space. As for the device for driving cab, one handle master controller operated by the left hand is employed. The gangway door window and the co-driver's side windshield adopt the polycarbonate with effect of heating up by energization on the surface for snow-melting and anti-condensation effect.
Operations
735 series EMU trains were delivered to Sapporo depot in March 2010 and entered extensive test running to examine the thermal insulation performance of the car body during low temperatures and snowfall. Subsequently, they entered revenue services. They are now used on the regional services on the Hakodate, Chitose, and Sassho lines. |
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