# 521 series

The 521 series (521系, 521-kei) is a dual-voltage AC/DC outer-suburban electric multiple unit (EMU) train type operated by West Japan Railway Company (JR West) and third-sector railway operators IR Ishikawa Railway and Ainokaze Toyama Railway on local services in the Fukui and Kanazawa areas since November 2006. In March 2024, Hapi-line Fukui acquired some sets after taking over the section of the Hokuriku Main Line within Fukui Prefecture from JR West.

## Design

The 521 series was the first dual-voltage suburban EMU type to be built for JR West. The body of the first two batches was based on the 223-5000 series suburban EMU design, with the same WMT102C 230 kW (308 hp) traction motors. The sets are able to be used on wanman driver-only operation services.

## Operations
### JR West

* 521-0 series
** Hokuriku Main Line (Maibara – Toyama)
** Kosei Line (Ōmi-Imazu – Ōmi-Shiotsu)
** Obama Line (Tsuruga – Higashi-Maizuru, sometimes substituted for 125 series)
* 521-100 series
** Nanao Line (from 3 October 2020)

### Third-sector lines

* Hapi-line Fukui
* IR Ishikawa Railway Line
* Ainokaze Toyama Railway Line
* Echigo Tokimeki Railway Nihonkai Hisui Line

## Fleet

As of 1 April 2021, JR West operates 50 two-car sets (E01-E05, G14-G15, G17, G20-G24, G28-G30, J01-J19, U01-U15), allocated to Kanazawa depot and Tsuruga depot. The Ainokaze Toyama Railway operates 22 two-car sets (AK01-AK22), and the IR Ishikawa Railway operates eight two-car sets (IR01-IR08).
15 additional two-car sets were transferred to Hapi-line Fukui in March 2024 following JR West's forefeiture of the Hokuriku Main Line within Fukui prefecture.

## Formations

Sets consist of one motored and one non-powered trailer car, and are formed as follows.
| Designation | Mc | Tpc' |
| Numbering | KuMoHa 521 | KuHa 520 |
| Capacity (total/seated) | 129/48 | 129/40 |
| Weight | 43.2 t | 44.3 t |
The KuHa 520 cars are each fitted with one WPD28D single-arm pantograph.

## Interior

Seating is arranged as 2+2 abreast transverse flip-over seats. The KuHa 520 cars include a toilet.
* Interior of a 2nd-batch set in April 2022
* Interior of a 3rd-batch set in July 2022
* Priority seating in July 2022
* Toilet in July 2022
* LED passenger information display in July 2022
* Fare indicator board for driver-only operated services
* Driver's cab in April 2022

## History

The first five sets, E01 to E05, were built by Kawasaki Heavy Industries and Kinki Sharyo, and were delivered to Fukui depot between September and October 2006. These entered revenue service from 30 November 2006. The fleet was reallocated to Tsuruga Depot from 1 June 2010.
Ten more sets, G01 to G10, built by Kinki Sharyo, were delivered to Kanazawa depot between October 2009 and March 2010, entering revenue service from 13 March 2010. A further five sets, G11 to G15, were delivered from Kawasaki Heavy Industries in December 2010 and January 2011. 15 more sets, M01 to M15, were delivered from Kawasaki Heavy Industries to Tsuruga Depot between January and March 2011.
Nineteen third-batch two-car sets (J01 to J19) were delivered to Tsuruga Depot in fiscal 2013. The third-batch sets have cab ends based on the JR West 225 series EMUs, with improved crash resistance, and use LED lighting for interior lighting. These sets entered revenue service in spring 2014.
In December 2019, the first three two-car 521-100 series sets (U01 to U03) for the Nanao Line were built by Kinki Sharyo. Unlike older JR West 521 series sets, the 521-100 series sets feature red waistline striping, reminiscent of the body colour used by older 413 and 415 series trains operated on the line. By October 2020, a total of fifteen two-car sets were built for JR West. Three more sets for the IR Ishikawa Railway (IR06 to IR08) were delivered on 3 December 2020. The 521-100 series fleet entered service on the Nanao Line from 3 October 2020.
Two more 521-0 series two-car sets (J22 and J23) were built by Kawasaki Heavy Industries and delivered to Kanazawa Depot in March 2021.

## Other operators

16 two-car 521 series sets were transferred to the third-sector railway operating company Ainokaze Toyama Railway for use from 14 March 2015 when JR West handed over ownership of the sections of the Hokuriku Main Line in Toyama Prefecture running parallel to the new Hokuriku Shinkansen. Likewise, three two-car sets were transferred to the IR Ishikawa Railway, which took over control of the section of the Hokuriku Main Line in Ishikawa Prefecture from 14 March 2015. Two more sets were newly built for the IR Ishikawa Railway.

### Ainokaze Toyama Railway

As of 1 October 2017, the Ainokaze Toyama Railway 521 series fleet is as follows.
| Set No. | Former set No. | Manufacturer | Delivery date |
| AK01 | G06 | Kinki Sharyo | 27 October 2009 |
| AK02 | G07 | Kinki Sharyo | 27 October 2009 |
| AK03 | G08 | Kinki Sharyo | 22 December 2009 |
| AK04 | G09 | Kinki Sharyo | 22 December 2009 |
| AK05 | G11 | Kinki Sharyo | 15 February 2010 |
| AK06 | G12 | Kinki Sharyo | 15 February 2010 |
| AK07 | G13 | Kinki Sharyo | 2 March 2010 |
| AK08 | G15 | Kinki Sharyo | 2 March 2010 |
| AK09 | G16 | Kawasaki Heavy Industries | 18 December 2010 |
| AK10 | G17 | Kawasaki Heavy Industries | 18 December 2010 |
| AK11 | G18 | Kawasaki Heavy Industries | 18 December 2010 |
| AK12 | G21 | Kawasaki Heavy Industries | 12 January 2011 |
| AK13 | G23 | Kawasaki Heavy Industries | 26 January 2011 |
| AK14 | G24 | Kawasaki Heavy Industries | 26 January 2011 |
| AK15 | G31 | Kawasaki Heavy Industries | 24 February 2011 |
| AK16 | G32 | Kawasaki Heavy Industries | 24 February 2011 |
| AK17 | – | Kawasaki Heavy Industries | 12 December 2017 |
| AK21 | – | Kawasaki Heavy Industries | 14 February 2023 |
| AK22 | – | Kawasaki Heavy Industries | 14 February 2023 |
Five new two-car 521-1000 series sets are scheduled to be introduced over a period of six years, with the first set delivered in December 2017. These sets are based on the JR West 3rd-batch design, and are intended to replace the operator's ageing 413 series EMUs. On 22 June 2023, it was announced that some of the two-car sets would be lengthened to three cars each in the future after fiscal 2025 to increase transportation capacity on the Ainokaze Toyama Railway Line.
Sets AK21 and AK22 were delivered in February 2023.

### Hapi-line Fukui

15 more two-car 521 series sets were transferred to the third-sector railway operating company Hapi-line Fukui for use from 16 March 2024 when JR West handed over ownership of the sections of the Hokuriku Main Line in Fukui Prefecture running parallel to the extension of the Hokuriku Shinkansen from Kanazawa to Tsuruga.

### IR Ishikawa Railway

As of 4 December 2020, the IR Ishikawa Railway 521 series fleet is as follows.
| Set No. | Former set No. | Manufacturer | Delivery date | Livery accent colour |
| IR01 | G10 | Kinki Sharyo | 22 December 2009 | ■ Light green |
| IR02 | G14 | Kinki Sharyo | 2 March 2010 | ■ Purple |
| IR03 | G30 | Kawasaki Heavy Industries | 15 February 2011 | ■ Indigo |
| IR04 | J20 | Kinki Sharyo | 6 February 2015 | ■ Ochre |
| IR05 | J21 | Kinki Sharyo | 6 February 2015 | ■ Maroon |
| IR06 | – | Kinki Sharyo | 3 December 2020 | – |
| IR07 | – | Kinki Sharyo | 3 December 2020 | – |
| IR08 | – | Kinki Sharyo | 3 December 2020 | – |