Red Kimono (Symbol)
A number of witnesses claim to have seen a woman wearing a red kimono make her way down the train's corridor. We know they're not fabricating this entirely, because Poirot himself sees such a woman from behind. Not only that but, at a pivotal moment in the case, Poirot discovers the very same kimono neatly folded on top of his own luggage. It later transpires that the entire kimono episode was staged in order to confuse Poirot. Therefore, as the mystery drags on and the kimono in particular remains inexplicable to Poirot, it comes to symbolize the entangled, contradictory, and teasing nature of the case itself. By the end of the book, when it has been revealed as an elaborate prank, it comes to seem like a symbol of the passengers' ingenuity.
Jury (Motif)
At least two juries appear in this novel, paralleling one another. The first is the official, legal jury assembled to judge Cassetti, which determines that he is not guilty of the murder of Daisy Armstrong. The second is a makeshift, motley crew of jurors: the train passengers themselves. As a matter of fact, the passengers have decided to form a jury of their own in response to the failures of the first, official jury. At the book's end, one may discern the formation of another jury, comprised of Constantine and Bouc. This micro-jury determines that the passengers on the train should not be punished for Cassetti's death. In the context of the book, these latter two unofficial juries are more just and reasonable than the legally valid jury that acquits Ratchett.
The Armstrongs (Symbol)
The Armstrongs, especially Daisy, symbolize everything that is innocent, good, and hopeful. While many of the book's characters are good people, they're no longer innocent, because they've all been corrupted due to their links to the Armstrongs. In order to avenge their loved ones' deaths, the passengers must become comfortable committing acts of violence. However, the Armstrongs themselves remain innocent, simply because they're dead: they don't have the agency to become perpetrators of violence themselves and will forever be innocent victims of it. Daisy herself is an especially strong symbol of innocence because of her youth. In this sense she is a reflection of America itself, which can be understood here as a younger, more hopeful alternative to Europe—though this hopefulness is exposed as a farce after America becomes the site of Daisy Armstrong's death.
Travel and Tourism (Motif)
A certain tension animates the setting of Murder on the Orient Express. The train on which the book is set is both an expansive, diverse place and a contained, restrictive one. It stops in cities all over the world and contains people from all walks of life. (Although in this particular case the people on the train all happen to know one another, M. Bouc himself notes that even in normal circumstances the train is a place where people from all backgrounds are thrust together.) At the same time, the train is set apart from the various cities it passes through, and it keeps its passengers separate from the unknown places outside its walls. None of the passengers on the Orient Express come from the Turkish or Yugoslavian cities the train passes through, either. In this book, travel does not bring people into contact with new places and cultures. It's more complex than that—travel, here, is instead a mechanism that creates a micro-society of travelers, neither fully integrated with the places they visit nor fully separate from them.
Servitude (Motif)
The Orient Express, at first glance, contains a variety of servant/employer relationships. MacQueen and Masterman each serve Ratchett in subtly different ways. Hildegarde Schmidt massages the Princess, reads to her, and prioritizes her protection at all costs. Of course, these dutiful servants are all eventually revealed to be false personas. Schmidt's relationship to Dragomiroff is that of an equal, not a maid. Meanwhile, MacQueen and Masterman are both actively spying on and plotting against their employer. But this doesn't mean that the servants in the book are rebellious. As a matter of fact, they're deeply dutiful: many of the passengers, from Foscarelli to Arbuthnot, are revealed to have been devoted servants of the Armstrong family, and they feel such a strong attachment to their old masters that they are willing to literally kill for them. The novel, then, portrays two types of servitude. There is an on-paper servant-employer relationship, in which one individual is officially employed by another to perform certain transactional duties. But there is also a deeper form of devotion, only partially expressed by official terms of employment, according to which servants are defenders of and advocates for those they serve.
The Number 12 (Motif)
The number twelve crops up constantly in this book. Ratchett is stabbed twelve times. The coach has twelve passengers. Ratchett has twelve killers. Finally, a jury, like the one that acquitted Ratchett, has twelve members. It's this last instance of the number twelve that all of the others are based on: Ratchett's killers have consciously chosen to act as a group of twelve, in an instance of the drama and near-artistry they bring to their crime. They have consciously incorporated a motif, in other words, weaving it into their actions to emphasize the significance of the murder. For this reason, the count stabs Ratchett in his wife's place—it's more important to have exactly twelve people stab Ratchett than it is for any individual to do so.
