Moving back to one of the original questions, the Amfleet cars were built that way as the design already existed at the time Amtrak ordered them (it was the same body as the Metroliner fleet that the Pennsyvlania RR ordered, but first really ran as Penn Central).

That design was specifically built to look like an airplane, as at the time it was designed (1960s), trains were really perceived as old-fashioned and planes were modern. The thought was that be making a train look like a plane you could counteract that thought.