- Hercule Poirot: (Male, 30s–70s) Belgian detective. Fastidious, intelligent, and methodical. He is arrogant yet charming, observing psychology and behavior to solve the case.
- Monsieur Bouc: (Male, 30s–70s) Belgian. Owner of the Wagon Lit and old friend to Poirot. Gregarious and energetic, acting as a dramatic foil to Poirot.
- Mary Debenham: (Female, 20s–30s) British. A calm, cool, and determined governess with secrets and a hidden romantic past.
- Colonel Arbuthnot: (Male, 30s–50s) Arbuthnot is a rigid, polite, Scottish military man.
- Samuel Ratchett: (Male, 30s–50s) Ratchett is an aggressive, menacing American tycoon with a mysterious past. (Can be doubled)
- Helen Hubbard: (Female, 30s–60s) American. A gregarious, loud, and dramatic American passenger who is far more calculated than she appears.
- Princess Dragomiroff: (Female, 60s–70s) Russian. Elderly, imperious, and imposing nobility. A “formidable” presence.
- Greta Ohlsson: (Female, 30s–60s) Swedish. A timid, deeply religious, and compassionate missionary traveling with the Princess.
- Countess Andrenyi: (Female, 20s–30s) Hungarian. Beautiful and educated, she is a doctor and sharp-witted. She is close to the investigation.
- Hector MacQueen: (Male, 23–40s) American. Ratchett’s anxious, nervous secretary.
- Michel Conductor/Head Waiter: (Male, 40s–50s) French. The calm, polite train conductor who works closely with the passengers.
- Head Waiter: (Male 40s-50s) French, Very pompous. Works for the Tokatlian Hotel’s Cafe. (Can Double with Michael Conductor)