“Mrs. Hubbard drew Poirot a little aside. ‘You know, I'm dead scared of that man…My daughter always says I'm very intuitive. “When Momma gets a hunch, she's dead right,” that's what my daughter says. And I've got a hunch about that man.’”

This quotation, which appears in Part One, Chapter Four, highlights the over-the-top and self-absorbed nature of Mrs. Hubbard’s character. As the end of the novel reveals, these traits prove essential to distancing her from the crime, but early on they work to establish her as a strong-willed woman who is unafraid to make her voice heard. Continually insisting that certain facts about the case are true, such as Ratchett’s evilness and the presence of a strange man in her compartment, gives Mrs. Hubbard the ability to shape how Poirot sees the case and aligns with the stereotypical American mother character she has chosen to play.

"Why, that's like what you said just now! He wouldn't have had a woman talking to him if he were dead, would he?"

At the end of her interview in Part Two, Chapter Four, Mrs. Hubbard offers this retort to Poirot after he asks her whether she heard a woman’s voice in Ratchett’s compartment before or after the strange man appeared in her room. The sassy, almost sarcastic attitude she expresses in this moment allows her to maintain a sense of power in her interaction with Poirot, a position which she uses to deflect suspicion away from herself. She also sets herself apart from all of the other women on the train who, by comparison, tend to be far quieter and more subdued.

“Then, in a soft rich dreamy voice, quite unlike the one she had used all the journey, Mrs. Hubbard said: ‘I always fancied myself in comedy parts.’” 

In the final chapter of the novel, Mrs. Hubbard owns up to her true identity as famed actress and Daisy Armstrong’s grandmother Linda Arden. This revelation, which occurs in response to Poirot’s solution to the crime, highlights her dedication to ensuring the success of their plot to kill Ratchett. Not only does she disguise her voice for the duration of the novel, she also chooses to play a comedic character and effectively maintains that character throughout despite her background being in dramatic acting. These choices render her completely unrecognizable as Linda Arden, thus making her involvement in the crime possible.