train motion sickness

after spending 3 and a half hours on a fast train, you get used to the subtle movements. but after spending 3 and a half hours off the train, walking around and sitting to eat lunch, and you still move?

well that's train motion sickness.
it's as if you're still on the train, and you pretty much only notice it if you're sitting down.
it's a pretty weird sensation that i have had the great pleasure of experiencing.