Since 711 series currently used for commuter train in suburbs of Sapporo
were superannuated, JR Hokkaido developed 731 series in 1996. 731 series
are equipped with three doors and all seats are the long seats. Moreover,
the partition door of the doorway was discontinued for the first time among
suburban trains in Hokkaido. For this reason, the air curtains for preventing
from open-air coming in are fitted on doorways. Bolster-less bogies are
used and their journal box supporting system is axle arm type like 721-1000
series. The diameter of wheels is reduced to 810mm compared with 860mm
on other vehicles, in order to make the floor level lower. The maximum
service speed is 130km/h. The traction motors rated at 230kW are controlled
by AVAF inverter traction systems. 1 out of the 3 cars are motored. Moreover,
731 series have adopted regenerative brake for the first time among the
electric trains of JR Hokkaido, and the brake resistor was discontinued.
In addition, cooperation operation with Kiha201 series diesel train is
available.
Now 731 series are used on the commuter trains in the suburbs of Sapporo. |
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