I've had experiences reasonably similar to yours, and the reasons seem to be one of three factors (obviously, combining factors makes this even more likely): 1: I'm overtired 2: I'm stressed out 3: Overstimulation. The causes are in no particular order. Any one of them can do it. Specifically - if I'm overtired, even a little stressed, and in a moving vehicle (train, car, whatever) so that images and sounds flash past quickly, this is absolutely certain to happen. If I'm not in control (for example, I'm stuck on a train, or in a car with someone who is racing along, refusing to slow down or stop) that's the worst of all. This can happen even if I'm running or walking fast, but then it is much easier to make it go away; I just slow down immediately.
It sounds to me as if this is what happened to you, although obviously I can't be certain you work exactly the way I do. But the fact this happened on a train suggests at least that part of the reaction is similar.
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AQ Test = 44 Aspie Quiz = 169 Aspie 33 NT EQ / SQ-R = Extreme Systematising
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Not all those who wander are lost.
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In the country of the blind, the one eyed man - would be diagnosed with a psychological disorder