The Harpy Express is a fictional setting, not true at all. All credits go to Doctor4t on YouTube. This is basically what if no murders happened on the Harpy Express

The Marquise

Is the daughter of the owner of La Sirene, the railroad company that owns the Harpy Express.

Albert and Eleanor Gray

Are the father and mother of the central family.

Tanaka Gray

Is a member of the central family.

Luxintrus

Is the Marquise's tailor.

Amy

Is the assistant to Luxintrus.

E.S. Square

Is a famous writer on the Harpy Express.

Quill

Is a famous and rich man on the Harpy Express.