(Bart picks up a Turkish newspaper, written in Arabic script)
Hakime: If you don't mind, that belongs to me.
Bart: Oh, by all means. I, uh, I was merely curious about the weather in Constantinople.
Bart's comment, and the Turkish man on the train, are references to Agatha Christie's Murder on the Orient Express (1934). In that classic mystery, detective Hercule Poirot boards a train in Istanbul, which was still named Constantinople at the time of Bart's adventure. In the novel, Poirot uncovers a murderous conspiracy. Here, Bart discovers that several passengers are trying to get rid of him, or rather, the man he's pretending to be - Cornelius Rensselaer.