I can't imagine making that connection in Atlanta. It's not like you can shove people out of the way on that very long escalator to the train. Then when you get to your terminal, you have to take the very long escalator up again before you can run to your gate.
Besides the stress, and if you make it, it's doubtful your luggage will make the connection with you. Be prepared to see it at a later time.
I had a 25 minute connection in Charlotte last year and although I made it right before they closed the door (no escalators or trains, but went from end of one terminal to middle of another, running), my luggage didn't make it in time.
Good luck if you try it. I really hope it works out for you!