The school train

The Hogwarts Express is the term's moving corridor. Students are sorted into compartments before they are sorted into houses, which makes the train a social map: who shares sweets, who travels alone, who already knows the older pupils.

As a machine it is cheerfully out of date, a steam engine in a modern Britain. That anachronism is part of the charm and part of the politics. The hidden world prefers its own timetable.

The train is also one of the few places where the school story happens in transit, between the city and the castle, with no teacher officially in charge of the carriage.