There's a sort of swimming/breathing effect in the video that's nauseating to me in the same way that TV motion smoothing is. It looks like artifacts from trying to perfectly crop the video when the source film likely has become distorted over time, but it's hard to watch.
Rolling shutter is one possible explanation of "wavy" effects if they digitized cinematic footage improperly. However, in this case I think we see aliasing effects of static Gigapixel AI.
You can see the problems in the side-by-side clip at the end. A guy walks through the divide and the upscaled side of his body does not move with the un-enhanced side of his body.
For this very movie it would be presumeable quite trivial to correct the varying frame rate caused by the hand cranked camera with the help of the quite stable deceleration of the train and it's position to determine a corrected timestamp for each frame and then interpolate from there.
It's fair to assumem that at the time, a skilled presenter knowing the material was able to compensate for that too to some extent, since the Cinematograph was camera and projector in one, both manually operated. Stable frame rates were simply not a thing in earliest film.
