# E721 series

The E721 series (E721系) is an AC electric multiple unit (EMU) train type operated by East Japan Railway Company (JR East) on services in the Sendai area of Japan since February 2007.

## Variants

* E721-0 series 2-car sets, since February 2007
* E721-500 series 2-car sets, since March 2007
* E721-1000 series 4-car sets, since November 2016
* SAT721 series 2-car sets, since March 2007 (owned by Sendai Airport Transit)
* AB900 series 2-car sets, since July 2019
* E721-0 series set P-4 in March 2007
* E721-500 series set P-502 in November 2007
* E721-1000 series set P4-14 in January 2017
* SAT721 series set SA102 in March 2008
* AB900 series set AB-1 on delivery at Zushi Station in February 2019

## Operations

* ■ Banetsu West Line (since March 2017)
* ■ Joban Line
* ■ Senzan Line
* ■ Sendai Airport Line (E721-500 series and SAT721 series only)
* ■ Tohoku Main Line
* ■ Abukuma Express Line (AB900 series)

## Formations

As of 1 October 2015, the fleet consists of 42 two-car E721-0 series sets (P-2 to P-44), four E721-500 series two-car sets (P-501 to P-504), and three SAT721 series two-car sets (SA101 to SA103), formed as follows with one motored (Mc) and one trailer (Tc') car.

### E721-0 series

| Designation | Mc | Tc' |
| Numbering | KuMoHa E721-xx | KuHa E720-xx |
The KuMoHa cars have one PS109 single-arm pantograph. The KuHa cars have a toilet.

### E721-500 series

| Designation | Mc | Tc' |
| Numbering | KuMoHa E721-50x | KuHa E720-50x |
The KuMoHa cars have one PS109 single-arm pantograph. The KuHa cars have a toilet.

### E721-1000 series

The 19 four-car E721-1000 series sets (P4-1 to P4-19) are formed as follows, with two motored ("M") cars and two non-powered trailer ("T") cars. The KuHa E720 is located at the southern end.
| Designation | Tc' | M | T | Mc |
| Numbering | KuHa E720-10xx | MoHa E721-10xx | SaHa E721-10xx | KuMoHa E7210-10xx |
| Weight (t) | 34.3 | 32.0 | 37.2 | 39.1 |
| Capacity (seated/total) | 50/132 | 62/152 | 62/152 | 56/138 |
The two motored cars (KuMoHa and MoHa) each have one PS109 single-arm pantograph. The KuHa cars have a toilet.
* The interior of car KuMoHa E721-1005 of set P4-5 in January 2017
* An LED passenger information panel above the doorway in car KuMoHa E721-1005 of set P4-5 in January 2017

### SAT721 series

The two-car SAT721 series sets are formed as follows.
| Designation | Mc | Tc' |
| Numbering | SAT721-10x | SAT720-10x |
The KuMoHa cars have one PS109 single-arm pantograph. The KuHa cars have a toilet.
* The interior of car SAT721-101 in April 2017
* Priority seating and luggage space in car SAT721-101 in April 2017

### AB900 series

The Abukuma Express AB900 series are derived from the E721-500 and SAT721 series used for JR East.
Sets are formed as follows.
| Set | Numbering | Numbering |
| AB-1 | AB901-1 | AB900-1 |
| AB-2 | AB901-2 | AB900-2 |
| AB-3 | AB901-3 | AB900-3 |
| AB-4 | AB901-4 | AB900-4 |
| AB-5 | AB901-5 | AB900-5 |

## History

The first E721-0 series sets were delivered from December 2006, and entered service on 1 February 2007 on Tohoku Main Line services. The first E721-500 and SAT721 series sets were delivered from February 2006 and entered service on Sendai Airport services on 18 March 2007.
Two sets, P-1 and P-19, were derailed and badly damaged by the 2011 Tōhoku earthquake and tsunami on 11 March 2011 while at Shinchi Station. Both sets were written off and scrapped.
* The remains of sets P-1 and P-19 at Shinchi Station after the tsunami in 2011
The first of a fleet of 19 new four-car E721-1000 sets (76 vehicles in total) was introduced on 30 November 2016 on Tohoku Main Line, Joban Line, and Senzan Line services, replacing older 719 series units. The new trains are built by J-TREC, with construction shared between the company's Yokohama and Niitsu factories. These trains feature LED interior lighting.
The first four E721-1000 series intermediate cars were delivered from J-TREC's Niitsu factory to its Yokohama factory in September 2016 to be combined with driving cars built there.
In order to replace their 8100 series trains, Abukuma Express announced the order of new AB900 series trains in summer 2018. They are based on the E721 series, and are the first new trains for Abukuma Express since 1988. The first AB900 series set was delivered in February 2019. It entered service on 1 July 2019.

## Fleet/build details

The manufacturers and delivery dates for the fleet are as shown below.

### E721-0 series

| Set No. | Manufacturer | Date delivered | Date withdrawn |
| P-1 | Kawasaki Heavy Industries | 28 November 2006 | 12 March 2011 |
| P-2 | Kawasaki Heavy Industries | 17 January 2007 | |
| P-3 | Kawasaki Heavy Industries | 17 January 2007 | |
| P-4 | Kawasaki Heavy Industries | 17 January 2007 | |
| P-5 | Tokyu Car | 18 December 2006 | |
| P-6 | Tokyu Car | 18 December 2006 | |
| P-7 | Kawasaki Heavy Industries | 15 January 2007 | |
| P-8 | Kawasaki Heavy Industries | 6 February 2007 | |
| P-9 | Kawasaki Heavy Industries | 6 February 2007 | |
| P-10 | Kawasaki Heavy Industries | 23 February 2007 | |
| P-11 | Kawasaki Heavy Industries | 23 February 2007 | |
| P-12 | Tokyu Car | 15 January 2007 | |
| P-13 | Tokyu Car | 15 January 2007 | |
| P-14 | Kawasaki Heavy Industries | 28 February 2007 | |
| P-15 | Kawasaki Heavy Industries | 28 February 2007 | |
| P-16 | Kawasaki Heavy Industries | 8 March 2007 | |
| P-17 | Kawasaki Heavy Industries | 8 March 2007 | |
| P-18 | Kawasaki Heavy Industries | 23 March 2007 | |
| P-19 | Kawasaki Heavy Industries | 23 March 2007 | 12 March 2011 |
| P-20 | Kawasaki Heavy Industries | 23 March 2007 | |
| P-21 | Kawasaki Heavy Industries | 23 March 2007 | |
| P-22 | Kawasaki Heavy Industries | 17 April 2007 | |
| P-23 | Kawasaki Heavy Industries | 17 April 2007 | |
| P-24 | Kawasaki Heavy Industries | 27 April 2007 | |
| P-25 | Kawasaki Heavy Industries | 27 April 2007 | |
| P-26 | Kawasaki Heavy Industries | 27 April 2007 | |
| P-27 | Kawasaki Heavy Industries | 27 April 2007 | |
| P-28 | Kawasaki Heavy Industries | 31 May 2007 | |
| P-29 | Kawasaki Heavy Industries | 31 May 2007 | |
| P-30 | Kawasaki Heavy Industries | 31 May 2007 | |
| P-31 | Kawasaki Heavy Industries | 31 May 2007 | |
| P-32 | Kawasaki Heavy Industries | 6 July 2007 | |
| P-33 | Kawasaki Heavy Industries | 6 July 2007 | |
| P-34 | Tokyu Car | 30 August 2007 | |
| P-35 | Tokyu Car | 30 August 2007 | |
| P-36 | Tokyu Car | 26 September 2007 | |
| P-37 | Tokyu Car | 26 September 2007 | |
| P-38 | Kawasaki Heavy Industries | 2 November 2007 | |
| P-39 | Kawasaki Heavy Industries | 2 November 2007 | |
| P-40 | Kawasaki Heavy Industries | 13 September 2010 | |
| P-41 | Kawasaki Heavy Industries | 13 September 2010 | |
| P-42 | Kawasaki Heavy Industries | 13 September 2010 | |
| P-43 | Kawasaki Heavy Industries | 13 September 2010 | |
| P-44 | Kawasaki Heavy Industries | 13 September 2010 | |
* 1 2 Destroyed by tsunami on 11 March 2011.

### E721-500 series

The delivery of E721-500 series cars are as follows:
| Set No. | Manufacturer | Date delivered |
| P-501 | Kawasaki Heavy Industries | 17 February 2006 |
| P-502 | Kawasaki Heavy Industries | 30 September 2006 |
| P-503 | Kawasaki Heavy Industries | 30 September 2006 |
| P-504 | Tokyu Car | 25 October 2006 |

### E721-1000 series

All manufactured by J-TREC.
| Set No. | Date delivered |
| P4-1 | 21 October 2016 |
| P4-2 | 26 October 2016 |
| P4-3 | 11 November 2016 |
| P4-4 | 16 November 2016 |
| P4-5 | 28 November 2016 |
| P4-6 | 1 December 2016 |
| P4-7 | 6 December 2016 |
| P4-8 | 14 December 2016 |
| P4-9 | 27 December 2016 |
| P4-10 | 26 December 2016 |
| P4-11 | |
| P4-12 | |
| P4-13 | |
| P4-14 | |
| P4-15 | |
| P4-16 | |
| P4-17 | |
| P4-18 | |
| P4-19 | |

### SAT721 series

All sets are manufactured by Kawasaki and delivered as of 20 November 2006.
* Set No.
* SA101
* SA102
* SA103

### AB900 series

All sets are manufactured by J-TREC.
| Set No. | Date delivered |
| AB-1 | 21 February 2019 |
| AB-2 | February 2020 |
| AB-3 | 25 January 2022 |
| AB-4 | |
| AB-5 | |