言葉にする必要はない

Astral Express Crew Members are: MC, March 7th, Dan Heng, Welt and Himeko.

This achievement has no cultural references in the English and Chinese versions. It is likely specific to the game. The name of the train that serves as the headquarters for the Trailblazers is the Astral Express. The "-ions" in "Express-ions" is a clever wordplay, signifying the stickers associated with the Astral Express crew.