UA 6268 then UA 3263 at Houston
Tampico → Houston → Richmond
Timetable, Houston time
14:36UA 6268 from Tampico at the gate
07:00UA 3263 to Richmond leaves the gate
16 h 24 apart on the timetable, overnight
UA 3263 leaves 16 h 24 after UA 6268 arrives on the timetable: more than half a day, so not a connection we count.