Slow train that follows one that is late (7)

I believe the answer is:

cortege

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'slow train' is the definition.
'cortege' can be an answer for 'train' (thesaurus). I'm not sure about the 'slow' bit.

I don't 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 "Solemn funeral procession" , "train" , "Entourage, retinue" , "Processing figures" .)

I've seen this clue in The Globe and Mail.

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