The 321 series is a DC commuter train that began operations in December 2005. It operates on the JR Kyoto Line and JR Kobe Line (Tokaido and Sanyo Main Lines), as well as the JR Fukuchiyama Line. With the opening of the JR Tozai Line in 2008, it also began through operations on the Gakkentoshi Line (Katamachi Line) and via the Osaka East Line to the Yamatoji Line (Kansai Main Line), serving a wide range of areas in the Kansai region.
- D15 formation belonging to Aboshi General Vehicle Center Akashi Branch has been produced
- Equipped with a Toshiba WAU708 cooler
- Reproduces the form where the front operating number display of the lead car has been removed
- Recreates the new type of arrester seen in recent JR West vehicles
- Pre-printed markings include the wheelchair and stroller marks on car No. 1, weak cooling car notation on cars No. 2 and No. 6, and ladies-only car notation on car No. 5
- Head/tail lights and front destination display are illuminated, with the color tone of the fog lights reproduced in yellow like the actual vehicle
- Employs a coreless motor for smooth and quiet running performance
- Front display "A Local Nishi-Akashi" is pre-installed. Comes with interchangeable front displays "A Local Kyoto" and "H Local Matsui Yamate"
- Uses a body-mounted KATO coupler dense connection type (with hook) for intermediate connections. The front is a dummy coupler
- Side display is printed in black. Comes with destination display stickers
- Compatible with interior lighting kit Kato 11-211 (11-212)