731 series

731 series
731 series set G116 in August 2009
In service	1996–Present
Replaced	711 series
Constructed	1996–2006
Number built	63 vehicles (21 sets)
Number in service	63 vehicles (21 sets)
Formation	3 cars per trainset
Fleet numbers	G-101–121
Operator(s)	JR Hokkaido
Depot(s)	Sapporo
Line(s) served	Hakodate Main Line, Chitose Line
Specifications
Car body construction	Stainless steel
Car length	21,670 mm (71 ft 1 in) (end cars), 21,300 mm (69 ft 11 in) (intermediate cars)
Width	2,800 mm (9 ft 2 in)
Height	3,620 mm (11 ft 11 in)
Doors	3 per side
Maximum speed	130 km/h (80 mph)
Electric system(s)	20 kV AC (50 Hz)
Current collection method	Overhead line
Multiple working	721 series, 733 series, 735 series, KiHa 201 series
Track gauge	1,067 mm (3 ft 6 in)

The 731 series (731系^?) is an AC electric multiple unit (EMU) train type operated by Hokkaido Railway Company (JR Hokkaido) on Sapporo area suburban services in Hokkaido, Japan since 1996.

As of 1 October 2016^[update], 21 three-car sets are in service, numbered G-101 to G121, and based at Sapporo Depot. The trainsets are formed as follows, with one motored intermediate car and two non-powered driving trailer cars.

Car 2 is fitted with one N-PS785 single-arm pantograph.

Seating consists of longitudinal bench seating throughout, without the vestibule areas used on the earlier 721 series trains.

Interior view, February 2010

A total of 63 vehicles (21 sets) were delivered to Sapporo Depot between 1996 and 2006. The first units entered service from 24 December 1996.

From the start of 22 March 1997 timetable revision, 731 series EMUs were operated in multiple with KiHa 201 series DMU sets over certain routes.

Polycarbonate window protectors were added in 2002, and the original pantographs were replaced with single-arm pantographs between 2004 and 2005.

The individual build histories of the fleet are as follows.