The Mystery of the Blue Train characters

First appears in chapter 12

A retired Belgian detective travelling to the Riviera on the Blue Train. He has no official position in the case, but Rufus Van Aldin asks for his help and the French police are willing to work with him. He studies the passengers' relationships and prepared stories as closely as the physical evidence.

First appears in chapter 4

A sensible young Englishwoman who has spent years as the paid companion of an exacting old lady in St Mary Mead. A legacy unexpectedly makes her wealthy and independent, leaving her free to travel and decide what kind of life she wants after years spent arranging someone else's.

Appears from the start

An American financier who built a vast fortune through force, calculation, and a refusal to lose. He is devoted to his daughter Ruth and deeply distrustful of both her estranged husband and the French aristocrat she has been seeing. He gives her a celebrated ruby called the Heart of Fire before she leaves for the Riviera.

First appears in chapter 2

Rufus Van Aldin's daughter, rich, unhappy, and separated from her husband Derek. She has resumed an entanglement with the Comte de la Roche despite her father's warnings, and boards the Blue Train intending to meet the count in Paris while carrying the Heart of Fire among her jewels.

First appears in chapter 2

Ruth's estranged English husband, handsome, charming, and chronically short of money. Van Aldin regards him as an adventurer and is pressing Ruth to divorce him. Derek is also involved with the dancer Mirelle, though neither money nor affection has made that relationship simple.

First appears in chapter 2

Van Aldin's British secretary, a former army major whose war wound ended his service. Quiet, capable, and trusted with his employer's most private business, he manages sensitive arrangements with tact and efficiency.

First appears in chapter 12

Ruth Kettering's personal maid, travelling in the adjoining compartment. She reports that her mistress dismissed her for the night in Paris and that a man was present in Ruth's compartment, though she says she could not see his face.

First appears in chapter 2

A polished French aristocrat with a taste for wealthy women and valuable objects. Ruth has been drawn back to him while separated from Derek, and her father believes the count is interested chiefly in the ruby she carries.

First appears in chapter 9

A celebrated dancer and Derek Kettering's lover, passionate, possessive, and accustomed to turning every entrance into a performance. She is certain Derek will soon be free to marry her and speaks of their future as settled.

First appears in chapter 8

Katherine's wealthy cousin, an invalid who presides over a fashionable and financially strained household on the Riviera. She invites Katherine to stay at the Villa Marguerite and watches the investigation with lively curiosity.

First appears in chapter 8

Rosalie Tamplin's forthright daughter, much younger in manner and considerably more perceptive than the rest of the villa's social circle. She takes a protective interest in Katherine and is candid about Derek Kettering.

First appears in chapter 21

A Paris dealer whose knowledge extends beyond respectable antiques. Poirot has dealt with him before and consults him about the history of the Heart of Fire and the international jewel thief known as the Marquis.