Transport making final journey to catch Southeastern (6)
I believe the answer is:
hearse
'transport making final journey' is the definition.
(vehicle used in a funeral)
'catch southeastern' is the wordplay.
'catch' becomes 'hear' (to catch something is to hear it being spoken).
'southeastern' becomes 'se'.
'hear'+'se'='HEARSE'
'to' is the link.
(Other definitions for hearse that I've seen before include "Coffin conveyance" , "Vehicle for carrying the dead" , "Funeral car" , "Undertaker's car" , "Vehicle for one's last journey" .)