Captain Nemo

the fact the train is moving at 250mph is insignificant, if the fly managed to get through the window it would be ok, and lucky, if however it flew into the side then it would fly into something at "fly" speed an hit something very fast ikely it will just bounce off, if the fly is capable of hitting something at "fly" speed and surving then its ok, likely though it gets its head sanded off by nature of the train moving very fast past it as it collides.

somebodys gonna say ..what train???

this is a similar thing to what happens if you drop something out of a car window at 100mph (naughty naughty), the thing doesnt carry on from 100mph and decelerate due to gravity its stays where it is, as the item dropped doesnt actually have any kinetic energy to carry on its journey, same thing if you threw it out at 20mph, it doesnt suddenly travel at 120mph, just the 20mph that it had the energy to sustain in the first place.

sounds right anyway, im not good with ll this science stuff, dont know enough big words, all my favourite words are small, like tit, thats a good word................