Good Riddles

Question: There were 2 trains heading the opposite directions on the same track.1 was going North, and one was going south, There was a 100m gap between them, avoiding the collision, 2 men saved the trains from colliding on time, Who were they and how did they save them?

Question: What do you call a retired vegetable?

Question: Why should you take a pencil to bed?

Question: What runs but doesn't get anywhere?

Question: What does a shark like to eat with peanut butter?