FR 4546 then FR 3108 at Barcelona
Porto → Barcelona → Luxembourg
Timetable, Barcelona time
23:25FR 4546 from Porto at the gate
15:40FR 3108 to Luxembourg leaves the gate
16 h 15 apart on the timetable, overnight
FR 3108 leaves 16 h 15 after FR 4546 arrives on the timetable: more than half a day, so not a connection we count.