Tetsuyuki Shinbashi stands as a central human figure in the franchise, first portrayed as a train enthusiast who partners with sentient bullet train robots to repel alien threats. His alliance with Minayo Kanda forms a partnership vital to planetary defense, marked by tightly coordinated teamwork. Proposed localization suggests the name "Terry" for English audiences, though official adaptations have not confirmed this. His narrative role deepens through an innate ability to communicate directly with robotic entities, enabling seamless coordination during critical missions. This skill proves indispensable in scenarios demanding human-machine collaboration. Later installments reintroduce him as an adult, reflecting the story’s temporal progression. His sequel appearances emphasize evolved responsibilities, including a confrontation with protagonist robot Nozomi that hints at shifting loyalties or internal strife. Expanded lore ties him to factions like the Evolution Railway Development Agency and the Astral Express following events involving the character Vina, suggesting arcs exploring institutional ties and personal stakes. Interactions with teammates such as Taisei, Akane, Ryota, Morito, and Ten contextualize his place within team dynamics, though specifics remain undefined. His trajectory shifts from a secondary support role to an autonomous operative across the series, underscored by episodic missions alongside robotic allies and battles against antagonistic forces. While explicit milestones are scarce, his gradual rise underscores adaptability central to his character.