Car races on train track, creating a record (5,5)
I believe the answer is:
audit trail
'a record' is the definition.
(I have seen 'Record of transactions' mean 'audit trail' so perhaps 'record' could also mean 'audit trail')
'car races on train track' is the wordplay.
'car' becomes 'audi' (Audi is a German car brand).
'races' becomes 'tt' (Isle of Man Tourist Trophy races).
'on' means one lot of letters go next to another.
'train track' becomes 'rail' (I've seen this in another clue).
'audi'+'tt'+'rail'='AUDIT TRAIL'
'creating' acts as a link.
(Other definitions for audit trail that I've seen before include "Record of transactions" , "Record of changes" , "Administrative record" .)