The main rolling stock of Shinkawa Railway. A 2-car commuter train with a stainless steel body and blue stripes. He has a bright and outgoing personality, but can be overconfident and sometimes ignores the opinions of others. He feels restless unless he is the center of attention and has a bit of a self-important hero complex. First person: I (soft, polite). His favorite color is blue, the color of his own body. Built in 2023.

A small 1-car train. Though the body is short at 17m, she has a strong core and says what needs to be said. While she looks like a train from a previous era, she is actually a contemporary of the 3100 Series. She speaks in an androgynous manner, making her gender identity ambiguous. First person: I (soft, polite).

An old-fashioned 2-car train. The body is rigid, painted in a two-tone color scheme of bright blue and white. He tries to act like a youth, but his actual age is over 40 years, and he extremely dislikes having that pointed out. First person: I (rough, casual). Built in 1970.

The younger brother of the 3100 Series, with a significant age gap. A 2-car commuter train. He lacks self-confidence and is easily influenced by the opinions of others, but his performance is actually better than his brother's. His body is almost identical to the 3100 Series, but because he was manufactured at a different factory, his face (front end) has a different design. First person: I (soft, polite). Built in 2025.

A veteran, old-fashioned electric locomotive. It has a so-called convex body with the driver's cab in the center (looking like a protruding shape from the side). He has a foul mouth but is quite kind at heart. The body is painted blue. He usually hauls freight trains. He is a representative figure among the trains and holds considerable authority within Shinkawa Railway. First person: I (rough, casual). Built in 1946.

A sister unit of the same model as the 3100 Series. A 2-car commuter train. Unlike her brother, she wears a red and cream paint scheme. According to her, it is a revival livery of a vehicle that used to run on Shinkawa Railway in the past. She is more reliable than her brother and has never lost a verbal argument. Because she handles her duties perfectly, she is highly trusted by the crew. First person: I (polite, feminine). Built in 2023.