An ancient Earth method of transportation, the Orient Express, a steam-propelled locomotive train, connected Paris to Istanbul from the late 19th century to the 1970s. At its peak, the train carried over ten thousand passengers a year.
In later centuries, it was still held to be a romantic and mysterious method of transportation, since one never knew who one would meet on the Orient Express. Sigmund Freud met Gertrude Stein on the Orient Express, and had dinner with her every evening.
Beverly Crusher was particularly fond of this train, and had a holodeck recreation of it. This program merged with an active program occupied by Lieutenant Commander Data and Captain Jean-Luc Picard, almost killing them both, due to a malfunction in the holodeck safety protocols. (TNG: "Emergence")