I will have a several hours layover in Atlanta. Can someone recommend anything to see there or maybe some restaurants. I've heard hat the airport is not far away from downtown by train.

This might give you some ideas: http://www.frommers.com/destinations/atlanta/

Thanks!

Maybe someone can recommend something in particular?

How long is your layover? If it isn't at least 6 hours, you won't have enough time to go anywhere and spend enough time to make it worthwhile. Security lines are very long, the airport is huge (can take you 20+ minutes to get to some gates after security), and it can take 60 minutes or more to get to most attractions.

But if you do have that kind of time, I'd go to the aquarium. It's spectacular. Just make sure you buy tickets online in advance so you don't have to wait in line.