In Harry Potter and the Philosopher’s Stone, the Hogwarts Express leaves from Platform 9¾.
Harry reaches the platform at King’s Cross station after Mrs Weasley explains that he must run directly at the barrier between platforms nine and ten. The magical platform is hidden from Muggle passengers and serves as the departure point for students travelling to Hogwarts.
The fraction is written as three-quarters, not as a conventional platform number. The film’s station scenes made Platform 9¾ one of the most recognisable pieces of Harry Potter imagery, and King’s Cross later installed a commemorative trolley at the location associated with it. The platform should not be confused with the train itself, which is called the Hogwarts Express.