Clear tracks are provided in the US by this singer to intimidate jazz fan at the start (10)
I believe the answer is:
cowcatcher
'clear tracks are provided in the us by this' is the definition.
(a cowcatcher clears train tracks in the US)
'singer to intimidate jazz fan at the start' is the wordplay.
'singer' becomes 'cher' (American singer).
'to intimidate' becomes 'cow' (cow can mean to bully or intimidate).
'jazz fan' becomes 'cat' (slang term for a jazz fan).
'at the start' means one lot of letters go next to another.
'cow'+'cat'='cowcat'
'cher' after 'cowcat' is 'COWCATCHER'.
(Other definitions for cowcatcher that I've seen before include "Frame on front of locomotive" , "attached to front of Chattanooga choo-choo?" , "metal frame" , "Protective frame on the front of some trains" , "Device on old American trains to push aside obstructions" .)