I was talking about real life, but I think factorio calculates damage in more than one physics iteration. If that's the case, your odds increase a very small bit by going faster, but a bit that is way more significant than the "indistinguishable from zero" you get in real life.

Oh, and just to add, your hits of being hit by a meteor on any single trip reduce the faster you move. But the trains are always out there, so their odds of being hit in a game-play don't change (or change very little).