Mike Himeno | 15 years old | Apprentice Conductor A bright and energetic girl characterized by her orange twin-tails. She is highly inquisitive and proactive, diving into new planets and unknown places without fear. She is deeply caring and cannot ignore anyone in trouble. On the Galactic Railroad, she serves as an apprentice conductor, guiding passengers and assisting with train operations. Though she makes mistakes, she overcomes them with her natural positivity. She is the central figure of the six and the mood maker who keeps the group together.

Kanon Hoshimiya | 15 years old | Star Reader / Navigator A girl with pure white, floor-length straight hair and vivid violet eyes. She is calm and elegant, yet kind to her companions, showing a slightly spoiled side once she becomes close to someone. Despite being serious, she has a bit of a spacey side. She has a strong interest in stars and the universe, possessing deep knowledge of celestial observation. On the Galactic Railroad, she serves as the navigator, reading the stars to determine their course. She supports her friends with her cool judgment while enjoying encounters with unknown stars.

Suzu Hoshimiya | 12 years old | Apprentice Engineer Kanon's younger sister, with long white hair and purple eyes. She is small, adorable, friendly, and full of curiosity. Whenever she finds something interesting, she shows immediate interest, her eyes sparkling at the wonders of unknown planets and space. On the Galactic Railroad, she serves as an apprentice engineer, assisting with train maintenance and machinery. Though inexperienced, she is a quick learner and grows steadily through the journey. She looks up to her sister Kanon and is the "little sister" figure of the six.

Riria Shirayuki | 15 years old | Security Officer An elegant and gentle girl characterized by her long pink hair. She has a composed personality and is very nurturing, treasuring her companions and the passengers. On the Galactic Railroad, she serves as a security officer, protecting the train's safety and dealing with troubles calmly. While usually kind, she shows a strong will when protecting her friends. She is a reliable presence who supports Mike and the others on their journey.

Ruru Momoha | 15 years old | Communications Officer A bright and energetic girl characterized by her long green hair. She is inquisitive and friendly, able to get along with anyone she meets for the first time. She loves fun things and acts immediately upon an idea, which sometimes leads her to jump the gun. On the Galactic Railroad, she serves as the communications officer, handling contact with various planets and space cities. She is also good at encouraging her friends and acts as a mood maker who brightens the atmosphere of the trip.

Sui Amamiya | 15 years old | Celestial Observer A girl with dark green long hair and mysterious emerald green eyes. She is usually calm and cool, but can be clingy and lonely around her friends. She is friendly and curious, with a strong interest in unknown planets and the mysteries of space. On the Galactic Railroad, she serves as a celestial observer, researching information on stars and planets to judge the direction of the journey and identify dangers. Kind and caring, she is a supportive presence for everyone on the trip.