DL 3122 then DL 537 at Atlanta
Pittsburgh → Atlanta → Washington National
Timetable, Atlanta time
22:00DL 3122 from Pittsburgh at the gate
21:59DL 537 to Washington National leaves the gate
23 h 59 apart on the timetable, overnight
DL 537 leaves 23 h 59 after DL 3122 arrives on the timetable: more than half a day, so not a connection we count.