Which is the longest railway platform in the world?

Question

In the "Harry Potter" books, students board the train to Hogwarts at Platform 9+3⁄4. Which London railway station has erected a sign at a wall between tracks 9 and 10 to commemorate this?

Answer 1

The longest railway platforms are:
1.Gorakhpur railway station, Uttar Pradesh, India:1,366.33 m (4,483 ft) (longest in the world)
2. Kollam Junction, Kerala, India:1,180.5 m (3,873 ft)
3. Kharagpur, West Bengal, India: 1,072.5 m (3,519 ft)
4. State Street subway, Chicago, Illinois, US: 1,067 m (3,501 ft) (longest in North America)