Naoto’s fascination with railways began during his childhood. As a young boy, he collapsed in the snow from hunger and was rescued by a passing train, which carried him to the nearest hospital. The railway worker who saved his life left a lasting impression on him, inspiring Naoto to pursue a future as a train driver. From that point forward, he developed a strong passion for trains and the Japanese National Railways, which shaped both his career ambitions and his dedication to the railway system.

Naoto is depicted as a young man with short black hair that reaches the nape of his neck and black eyes. His attire typically reflects his role with the railway security force: he is most often seen wearing a smart uniform complete with a captain’s hat, white gloves, and an armband denoting his position. His appearance is often described as approachable and friendly, accentuated by his bright smile, which reflects his earnest personality.

Naoto is characterized as a gentle and kind-hearted individual, treating others with respect and consideration. His selfless nature often drives him to put himself in harm’s way when he believes it is necessary, reflecting both his courage and sense of responsibility. Despite his generally polite demeanor, he occasionally displays moments of awkwardness, particularly around Haruka Kōmi, toward whom he develops romantic feelings.

Naoto is also highly knowledgeable about trains, demonstrating enthusiasm for their types, models, and operations. His deep passion for railways is one of his defining traits and serves as both his motivation and source of confidence throughout the series.

Haruka Kōmi
Naoto first meets Haruka when he accidentally embarrasses her, though they quickly become friends after beginning their railway training classes together. Haruka is the first person he befriends, and despite occasional awkward moments, she consistently treats him with kindness. Over time, she develops romantic feelings for him and shows jealousy when other girls vie for his attention. It is later revealed that Haruka’s affection may have originated years earlier, when Naoto saved her during their childhood.

Aoi Sakurai
Aoi is the first person Naoto encounters upon joining the program, leaping onto his back to retrieve a child’s balloon. Initially, she treats him coldly and dismisses him as a pervert after catching him looking at Haruka. However, as the story progresses, Aoi grows to understand and respect Naoto, eventually developing feelings for him. Their bond strengthens into mutual trust, with Aoi vowing to protect both him and the train he dreams of driving. By the conclusion of the light novel, the two confess their feelings to one another, though Aoi departs for America for several years. They promise to wait for each other during her absence.

Shō Iwaizumi
Shō is Naoto’s first male friend and a fellow student in the railway program. Known for his athleticism and passion, he shares a mutual respect with Naoto. In missions, Shō frequently addresses him as “Deputy Leader” and seeks his approval before taking action, reflecting their professional camaraderie and Naoto’s trusted position within the squad.

Nana Iida
Nana serves as the leader of Naoto’s squad and holds him in high regard, both as a subordinate and as a person. Naoto often turns to her for advice or reassurance when faced with difficult decisions. She consistently expresses her trust in him, encouraging him by affirming that he always makes the right choices. On several occasions, she assures him that she will take responsibility for his decisions, underscoring her confidence in his judgment and leadership potential.

Mari Sasshō
Mari is a childhood acquaintance of Naoto’s whom he reconnects with during his time at Japan National Railways. Their renewed relationship suggests that Mari harbors feelings for him, adding another layer of romantic tension to Naoto’s personal life.

The given name Naoto (直人) combines the kanji 直 (nao), meaning “straight” or “direct,” with 人 (to), meaning “person.” His surname, Takayama (高山), is formed from 高 (taka), meaning “tall” or “high,” and 山 (yama), meaning “mountain” or “hill.” Together, the name can be interpreted as “a straightforward person from the tall mountain.”