Good Riddles

Question: An electric train is traveling south. Which way does the smoke go?

Question: A man drops an egg onto the cement. The egg doesn't break after falling 3 feet.

How could this be?

Question: Take my first and make it my last, now I happened in the past.

What am I?

Question: Which triangle will have a larger perimeter : 3,4,5 or 3,4,7 ?

Question: I smash but I never hurt you. Give me your unwanted items and I will eat them and take them so you can get more. Some people might not like me while others may but I still come around on certain days. What am I?