I can not speak on the assistance part, you might look HERE for that. It appears you should handle that with Delta when making reservations.

The train system works very efficiently and is underground so there will be escalators you will be taking and some walking involved. If Delta allowed the booking with that connection time, they must think it will work. Anything less than an hour would concern me some but there seems to be a 20 minutes or so of extra time built into schedules. If everything happens on time, you should be fine.

I prefer ATL over CLT of late, although it is a much bigger airport.