Friday Puzzler -- Trestle Crossing
Alex Y
You and a friend are walking across a 700-yard long train trestle, and after walking 400 yards, you hear the whistle of a train approaching. You make a snap decision and run toward the train and the closer end of the trestle, and clear the tracks just before the train would have hit you. Your friend makes the opposite decision and runs away from the train, toward the more distant end of the trestle, but also clears the tracks just before the train would have hit him.
Because of the treacherous footing on the trestle, the best speed you had your fiend could both make is 10 mph.
How fast was the train moving?