# 121 series

The 121 series (121系) is an electric multiple unit (EMU) train type introduced in March 1987 by Japanese National Railways (JNR), and currently operated by Shikoku Railway Company (JR Shikoku) on local services in Shikoku, Japan as the 7200 series.

## Design

The 121 series design was based on the earlier 105 series, with lightweight stainless steel bodies.
The motor bogies were the same DT33A bogies as used on the JNR-era 103 series EMUs, and the trailer cars used DT21T bogies recovered from withdrawn 101 series EMUs. The pantographs were also recovered from withdrawn 101 series EMUs.
* A DT21T trailer bogie

## Operations

The sets are based at Takamatsu Depot and operate on the Yosan Line and Dosan Line in 2-, 4-, or 6-car formations.

## Formations

As of February 2019, the fleet consisted of 18 two-car 121 series sets and one 7200 series formed of one motored "Mc" car and one non-powered "Tc" trailer car as shown below with the motored "Mc" cars at the Takamatsu end.

### 121 series

| Designation | Mc | Tc |
| Numbering | KuMoHa 121 | KuHa 120 |
| Weight (t) | 42.0 | 28.0 |
| Capacity (total/seated) | 118/62 | 118/62 |
The "Mc" cars are each fitted with one S-PS58 lozenge-type pantograph.
* KuMoHa 121-14 in December 2007
* KuHa 120-14 in December 2007

### 7200 series

| Designation | Mc | Tc |
| Numbering | KuMoHa 7200 | KuHa 7300 |
| Weight (t) | 37.6 | 28.5 |
| Capacity (total/seated) | 132/52 | 132/52 |
The "Mc" cars are each fitted with one S-PS58 lozenge-type pantograph.
* 7218 in January 2019
* 7318 in January 2019

## Interiors

Seating is arranged as a mix of transverse seating bays and longitudinal bench seats. The sets are not equipped with toilets.
* An interior view in September 2007

## History

The 121 series sets were introduced on 23 March 1987, just nine days before JNR was privatised on 1 April, following which the 121 series fleet came under control of JR Shikoku. The sets were originally delivered with magenta "Red No. 20" bodyside stripes, but were repainted with JR Shikoku corporate light blue ("Blue No. 26") bodyside stripes during September and October 1987.
In 1992, the original pantographs were replaced with the same S-PS58 type pantographs also used on the JR Shikoku 7000 series EMUs to ensure adequate clearance through tunnels on newly electrified sections of the Yosan Line.
In 2011, two sets (numbers 001 and 002) were modified for wanman driver only operation. These sets were repainted with their original JNR-style magenta bodyside stripes.
* 121 series sets in original JNR livery, circa 1987
* Set 009 with a front-end red warning stripe added for a short period during the 1990s
* A pair of 121 series sets in May 2009
* Modified driver-only set 001 in April 2012

## Refurbishment and conversion

From 2016, the entire fleet of 19 two-car trainsets was scheduled to undergo refurbishment, and at the same time reclassified "7200 series". Refurbishment included replacement of the DC motors with 140 kW AC motors and VVVF control, new side windows, new "efWing" CFRP bogies (S-DT67ef motor bogies and S-TR67ef trailer bogies), and a new livery based on the original style with a thin green line added to the magenta bodyside stripe. Internally, the refurbished trains have fixed four-person seating bays on one side with longitudinal bench seating on the other.
The first trainset to be treated, set 3, departed the JR Shikoku's Tadotsu Works in February 2016, and entered service from 13 June 2016.
* An S-DT67ef motor bogie on car KuMoHa 7203
* An S-TR67ef trailer bogie on car KuHa 7303
* Inside the car
* Wheelchair space
* Driver's cab

## Fleet history

The individual build histories for the fleet are as follows.
| Set No. | Manufacturer | Date delivered | 7200 series conversion date |
| 001 | Hitachi | 17 November 1986 | 12 October 2018 |
| 002 | Kinki Sharyo | 20 November 1986 | 18 February 2019 |
| 003 | Kawasaki Heavy Industries | 13 December 1986 | 15 March 2016 |
| 004 | Kawasaki Heavy Industries | 13 December 1986 | 9 September 2016 |
| 005 | Kinki Sharyo | 27 December 1986 | 28 March 2017 |
| 006 | Kinki Sharyo | 27 December 1986 | 20 February 2018 |
| 007 | Kinki Sharyo | 27 December 1986 | 7 November 2017 |
| 008 | Tokyu Car | 27 January 1987 | 5 June 2017 |
| 009 | Tokyu Car | 27 January 1987 | 28 February 2017 |
| 010 | Tokyu Car | 27 January 1987 | 22 August 2018 |
| 011 | Tokyu Car | 27 January 1987 | 28 December 2017 |
| 012 | Hitachi | 13 January 1987 | 2 July 2018 |
| 013 | Hitachi | 27 January 1987 | 28 October 2016 |
| 014 | Hitachi | 27 January 1987 | 6 December 2016 |
| 015 | Kawasaki Heavy Industries | 16 January 1987 | 13 September 2017 |
| 016 | Kawasaki Heavy Industries | 16 January 1987 | 18 January 2017 |
| 017 | Kawasaki Heavy Industries | 16 January 1987 | 20 July 2017 |
| 018 | Kinki Sharyo | 20 January 1987 | 11 December 2018 |
| 019 | Kinki Sharyo | 20 January 1987 | 28 March 2018 |