How we cite our quotes:
Quote #1
At the table opposite them were three men. They were, he guessed, single travelers graded and placed there by the unerring judgment of the restaurant attendants. A big, swarthy Italian was picking his teeth with gusto. Opposite him a spare, neat English-man had the expressionless disapproving face of the well-trained servant. Next to the Englishman was a big American in a loud suit – possibly a commercial traveler. (1.3.14)
The description of the three men plays on stereotypes about each nation.
Quote #2
Poirot, by now, knew all about Mrs. Hubbard's daughter. Everyone on the train who could understand English did! How she and her husband were on the staff of a big American college in Smyrna and how this was Mrs. Hubbard's first journey to the East, and what she thought of the Turks and their slipshod ways and the condition of their roads. (1.4.24)
Mrs. Hubbard personifies the loud, obnoxious American traveler. We were a little offended until we found out (many chapters later) that this is just an act.
Quote #3
"There isn't anybody knows a thing on this train. And nobody's trying to do anything. Just a pack of useless foreigners. Why, if this were at home, there'd be someone at least trying to do something." (1.5.42)
Mrs. Hubbard suggests that people are most loyal to their own countries and countrymen. Since they're all in a foreign land, she thinks they feel no responsibility to help solve the murder. Do you think that's a fair statement, even though "Mrs. Hubbard" is just Linda Arden putting on a show?