Riddle: Not far outside the town of Pottsville, a railroad track runs through a tunnel in a hillside. There's only one track, and the tunnel is wide enough for only one train. But one day, two trains went into the tunnel from opposite directions. Each train entered the tunnel exactly at eight o'clock. Three minutes later, each train came out at the opposite ends of the tunnel. Yet, there was no collision! How was this possible?
Answer: One train comes at 8am and the other train came at 8pm.