Bachelor travels on motorway to help girl taking train (10)
I believe the answer is:
bridesmaid
'girl taking train' is the definition.
I can't judge whether this defines the answer.
'bachelor travels on motorway to help' is the wordplay.
'bachelor' becomes 'B' (abbreviation e.g. BA=Bachelor of Arts).
'travels on' becomes 'rides' (I've seen this in another clue).
'motorway' becomes 'M' (as in motorway names - Ma, M4 etc).
'to help' becomes 'aid' (synonyms).
'b'+'rides'+'m'+'aid'='BRIDESMAID'
Can you help me to learn more?
(Other definitions for bridesmaid that I've seen before include "one's holding up train perhaps" , "match participant" , "Attendant at wedding" .)