I think it's really an amazing story but is sure went.
Normally if you are a tourist and go to visit a friend, he should give you information about your route trip for you have a good come back.
Kumiko friend's should has said her, that from London to Istanbul a direct fly takes 3 hours and 35 minuts
and by train the trip it's about 33 hours.
If you have a notion of time and space in 3 hours by train you can't reach Istanbul¡¡
Really in the world there are people for everything ¡¡