The 570 and 1310 signals are now diplexed at the KTCK site; that happened about four years ago. I think the land for the previous 570 site (built in the early 1970s) was sold.If any DFW Cumulus AM goes dark, it would most likely be KTCK 1310 unless 570's tower array is in such disrepair that it's no longer viable.
The 1310 signal has been re-engineered a few times, though the night power has remained at 5kw. The current 1310 site was originally 5kw days, later raised to 9kw, and then to the current 25kw.Even 30 years ago, it didn't cover much of Tarrant County after dark, which is part of the reason Bonneville disposed of KAAM and led to the creation of The Ticket.
IIRC when the current 1310 array went on the air in the 1980s the initial night power was 1kw, which was bad for Tarrant County. That was a drop from the 5kw night power at the old White Rock Lake site which did make it into Fort Worth, but mediocre at best. The later increase to 5kw nights improved that situation.
The current 1310 facility would be a nice upgrade for another AM broadcaster in DFW. As mentioned elsewhere, plenty of bad AMs in the market.The programming on 1310 could be moved to the much better 570 signal. I'm a little surprised that hasn't already happened.