FR 4584 then FR 58 at Barcelona
Porto → Barcelona → Napoli
Timetable, Barcelona time
18:55FR 4584 from Porto at the gate
13:25FR 58 to Napoli leaves the gate
18 h 30 apart on the timetable, overnight
FR 58 leaves 18 h 30 after FR 4584 arrives on the timetable: more than half a day, so not a connection we count.