One is late for this train (7)
I believe the answer is:
cortege
'for this train' is the definition.
(both can mean a procession following behind)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for cortege that I've seen before include "train" , "Processing figures" , "Solemn funeral procession" , "Entourage, retinue" .)