The SR1 series 100 series was the first new car on the Shinano Railway to replace the 115 series, and started commercial operation in July 2020 for the purpose of reinstatting liner trains.

The vehicle is 6 trains of S101-S103, and the body is the same Sustina series body as the E129 series, and the coating color is held, and based on a dark royal blue that imagined the wind of the plateau. On the side is a design that draws a green and light blue line inspired by the clear stream of the Shinshu and the clear stream of the Chikuma River, and a champagne gold that follows the 115 series design.

In addition to the entire section of the operation of the railway, it is operated on the Shin-Etsu Main Line (Shinonoi-Nagano), which is a direct operating destination, and 3 trains (6 cars) connected to 3 trains (6 cars), and 2. Active in the formation (4 cars) "Shinano Sunset".

It is operated on all sections of the Shinano Railway and on the Shinetsu Main Line (between Shinonoi Station and Nagano Station), which is a direct operation destination, and in rapid train operation, "Shinano Sunrise" and 100 It is used and active in the "Shinano Sunset" where 4 cars of 2 trains are connected.

• Dimensions: 10.1 x 20.2 x 3.1 cm
• Weight: 129g