Background and overview
The extension of the Yamagata Shinkansen to Shinjo in 1999 created a requirement for additional rolling stock to operate ordinary services on the newly converted standard-gauge section of the Ōu Line. To meet this demand, JR East developed the 701 5500 series—a standard gauge suburban AC EMU—based on the 701-5000 series used on the Tazawako Line, incorporating several improvements tailored to the operating conditions of the Yamagata area.
The fleet consists of two-car sets, each formed of one motored car and one trailer car (1M1T). A total of nine two-car sets were delivered to the Yamagata Depot in 1999.
Car body
The carbody of the 701 5500 series measures 19,500 mm in length and 2,870 mm in width, with a bogie centre distance of 13,800 mm. The structure is primarily composed of stainless steel, except for the bolster beams, the end sections of the centre sill, and selected cross beams, which are fabricated from weather-resistant steel plate (Steel Plate Atmospheric).
The body employs Kawasaki’s two-sheet spot-welded stainless-steel structure, in which a pressed inner stainless steel sheet is spot-welded to an outer sheet. This double-skin construction provides the required rigidity without bead embossing. The exterior consists of unpainted flat stainless-steel panels, complemented by a green waistline band with a narrow orange accent band, and green bands applied below the windscreens.
The cab end is gangway-equipped, incorporating a gangway door finished in green and a low-profile driver’s cab. Flat windscreens are adopted to reduce manufacturing costs. Lighting equipment consists of two sealed-beam headlights mounted above the gangway door and two taillights positioned below the windscreens. An LED destination display is mounted above the co-driver’s-side windscreen.
Each car is fitted with three 1,300 mm-wide double-leaf automatic step-less sliding doors on each side. Door operation is controlled by TK113C units employing pneumatic direct-drive mechanisms mounted above the door headers. Manual operation is enabled via push-button controls located adjacent to each door.
Between the doors, the side panels are fitted with a horizontal band of four windows, including two double hung side windows with a height of 960 mm, except for a pair of fixed windows adjacent to the toilet compartment. Additional fixed windows are installed at each end of the carbody. All windows employ heat absorbent glass, eliminating the need for blinds.
LED destination indicators and external loudspeakers—used for platform side passenger announcements—are installed on each side of the carbody.
A roof mounted AU723 air-conditioning unit, rated at 38,000 kcal/h, is installed at the centre of the roof. No roof ventilators are provided.
End cars are equipped with an automatic jumper coupler to facilitate rapid turn-back operations.
Bogies
The powered bogies are designated DT63A, while the trailer bogies are classified as TR252. Both bogie types employ a bolsterless design with secondary air suspension, a trailing-arm journal box support system, and a single-link draw gear.
Power transmission utilizes Twin Disc (TD) flexible couplings with carbon-fiber-reinforced
plastic (CFRP) deflecting plates, with a gear ratio of 7.07. To improve
adhesion on the 33 ‰ gradients of the Itaya Pass, the outside powered axles
are equipped with a sandbox and delivery pipe.
The braking configuration differs between bogie types: powered bogies are equipped with single-tread brake rigging, while trailer bogies employ double-disc brake units.
Powertrain and ancillary equipment
Class Kumoha701-5500 cars are equipped with the CI10A traction system, which controls four MT65A three-phase AC asynchronous traction motors on a per-bogie basis, each rated at 125 kW.
The traction system comprises a three-level PWM converter utilizing IGBTs, paired with a two-level variable-frequency drive (VFD) employing power transistors, and incorporates field-oriented control and regenerative braking, eliminating the need for a roof-mounted braking resistor.
Class Kumoha701-5500 cars are also fitted with an SC49 auxiliary power supply unit (10 kVA) and a TM29 traction transformer, both mounted beneath the floor.
Current collection is provided by a PS105 lozenge-shaped pantograph, featuring a reduced folding height, mounted on the roof of the powered car.
Class Kuha700-5500 trailer end cars are equipped with an MH1112-C1600MF motor-driven air compressor mounted beneath the floor.
The braking system is an electrically commanded brake with regenerative braking.
Accommodation
Passenger accommodation features longitudinal bench-type bucket seating throughout. Each bench is fitted with end partition panels to reduce cold-air intrusion. The air-conditioning ductwork is installed above the ceiling, maintaining a clean interior profile, with slit-type vents providing evenly distributed airflow.
The cab is a left-side compartment-type design, optimized for conductor-less operation. Each car is equipped with ticket vending machines located near the doorways, as well as fare chart displays and fare boxes positioned behind the driver’s cab. A 1,200 mm-wide double-leaf sliding door is fitted at the gangway to facilitate movement between cars during conductor-less operation.
Class Kuha700-5500 trailer end cars are equipped with a universal-access
toilet incorporating a chemical holding tank. A wheelchair space is provided
across the aisle from the toilet..
Operations
Nine sets of 701-5500 series EMUs were assigned to the Yamagata Depot and entered revenue service on the Ōu Line between Yamagata and Shinjo in December 1999. The fleet is currently deployed on rural services of the Ōu Line between Yonezawa and Shinjo. |
|
| Technical Data |
| Items |
Data |
| Supply
Voltage |
20,000 V AC, 50 Hz |
| Service
speed, etc. |
Service speed: 110 km/h |
| Length |
19,500 mm |
| Width |
2,950 mm |
| Height |
3,670 mm |
| Bogie |
DT63A (motored) TR252 (trailer) |
| Collector |
PS105 |
| Traction
motor |
MT65A (125 kW) |
| Gear
ratio |
7.07 |
| Transformer |
TM29 |
| Traction system |
Converter and variable frequency drive on on a per-bogie basis: CI10A |
| Air
conditioner |
AU723 (38,000 kcal/h) |
| Designed
by |
JR East |
|
|
