The Hogwarts Express
Platform Nine and Three-Quarters
Interesting facts and notes
The Hogwarts Express was originally a Muggle train which some railway workers in Crewe "mislaid," thanks to 167 Memory Charms and a huge Concealment Charm. This happened sometime before 1849, when Evangeline Orpington became Minister for Magic and came up with the idea for Platform Nine and Three-Quarters.
There are other magical platforms in King's Cross.
"Over time, as the Ministry of Magic introduced legislation regarding animal cruelty (sub-sections 13-29 inclusive relate to potion ingredients and their production) such practices were gradually outlawed. "
Trevor, Neville's toad, eventually went to live in the Hogwarts lake.