Poles involved in characteristic movement of goods (7)
I believe the answer is:
Here is my best explanation:
'movement of goods' is the definition.
'poles involved in characteristic' is the wordplay.
'poles' becomes 'ns' (North and South poles).
'involved in' indicates putting letters inside.
'characteristic' becomes 'trait' (I've seen this before).
'ns' put inside 'trait' is 'TRANSIT'.
(Other definitions for transit that I've seen before include "To pass through/across", "In passing", "A passing across", "Moving", "Passage of planet across the disc of the sun", "Crossing - passage", "Journey across", "Change", "Pass through; van" and "Act of passing across".)