Hogwarts needs not to be half a trainride north from London; considering the train starts from a platform hidden inside a pillar, it could be anywhere (that passage is obviously some dimensional gate or at least a "magic" beaming device )

Here's pretending not to have read the books

jokergirl

__________________
Si tacuisses, philosophus mansisses.

"Half of what I say is meaningless, but I say it so that the other half may reach you."