Franks and Wieners get their names from the cities of Frankfurt, Germany and Vienna, Austria (Wien, in the local language). Each had a particular type of sausage. Frankfurt’s were all pork, Vienna’s were a mix of pork and beef. Hot sausages in bread were served during royal coronations in Germany back to the 13th century, so it’s an old fast-food.
Fast-forward to late 1800s America. Lunch wagons become popular on college campuses, called “dog wagons” since they looked like the dog-catcher’s wagon. The Kennel Club lunch wagon at Yale gets its own bit in the Yale Record humor magazine about biting a “dog” in a bun. Boola Boola!