Startin' to modify conveyance of freight (7)

I believe the answer is:

transit

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'conveyance of freight' is the definition.
'transit' can be an answer for 'conveyance' (I've seen this in another clue). I am unsure of the 'of freight' bit.

'startin' to modify' is the wordplay.
'to modify' is an anagram indicator (I've seen 'modified' mean this).
'startin' is an anagram of 'TRANSIT'.

Can you help me to learn more?

(Other definitions for transit that I've seen before include "Crossing - passage" , "In migration" , "Passage of heavenly body" , "Shipment from A to B" , "Journey across" .)

I've seen this clue in The Irish Independent.

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