In the past, the Astral Express was first bestowed by Akivili. Shortly after the fall of the Aeon, the Nameless took upon Akivili's trailblazing legacy. When the Stellaron began to spread, the Star Rail also fell victim under its influence to the point where the train could barely function at all. As a result, the Nameless faction decided to abandon it after the rails have long been obstructed.
The Astral Express was later discovered by Himeko during her childhood, during which she became fascinated about the stories of the engine. She would repair the train years later to begin her journey across the universe.