Originally Posted by
Gadget freak
Eckhard's post doesn't really explain the basic physics because the train isn't accelerating.
Neither is the wind. The Downwind theory myth is that an airplane in a steady, un-accelerated wind, (no gust, no turbulence, no wind shear) turning downwind will lose airspeed. A railroad train traveling at a constant velocity on a straight track is perfectly analogous to a steady, gust-less, shear-less wind.