The Knight Bus is the magical bus that rescues stranded wizards in the Harry Potter book series.
Harry encounters the Knight Bus in Harry Potter and the Prisoner of Azkaban after leaving the Dursleys’ home. He accidentally causes the bus to appear by holding out his wand arm. The conductor, Stan Shunpike, and the driver, Ernie Prang, take him to the Leaky Cauldron for a fare of eleven Sickles.
The bus travels through Britain at extraordinary speed, shrinking between ordinary vehicles and making sudden movements that would be impossible for a normal coach. Passengers sleep in beds rather than sitting in conventional seats. Its name is a pun on “night bus,” while “Knight” reflects its role as a rescue service for witches and wizards in trouble. It is not the train used by Hogwarts students.