I have taken the Stockholm and Gothenburg several time, both the black tin cans that are used as night trains and built somewhere around 1970, and the state of the art high speed train x2000 built during the 1990s. It takes me about a whole day to recover from the motion sickness, especially the x2000 which is well known for it lateral motion problem thanks to the non-straight rail and high speed.

The more rapid but shorter lateral movements on a plane does not trigger my motion sickness, and neither do turbulence. That could be a personal aspect. I have the same issue where if I am on a boat that goes up and down then I am usually fine, but not if the waves comes side to side.