Carrie Anne Gardner, a 17-year-old who has been banned from using the train because of her yobbish behaviour.
The teenager has been told she faces jail if she is caught travelling on a train between Cardiff and Barry alone, anytime within the next two years.
Gardner, of Columbus Close, Barry, was slapped with the Asbo (Anti-social behaviour order) banning her from taking the train, after she was convicted of a string of 'anti-social offences'.
The order means she is:
Banned from travelling on any train between Barry Island Railway Station and Cardiff Queen Street Station, without an adult of 18 or over with her.
She cannot go into Barry Island Railway Station and Cardiff Queen Street Station, unless she is travelling with an adult.
Banned from harassing or causing 'alarm or distress' to anyone who lives in the Vale of Glamorgan or in Cardiff.
The youngster has been warned that if she breaks the order, made on July 26, at Barry Magistrates' Court, she will face jail, a fine of £5,000, or both.
Pc Steve Lawrence of British Transport Police, said: 'British Transport Police, South Wales Police and the Vale of Glamorgan Council have all worked in partnership to secure this anti-social behaviour order against Carrie Anne Gardner.
'This was due to her continuing offending and we felt that it was necessary to protect the wider community from her behaviour.'
If you are aware of Gardner, or any other person, breaking their Asbo, police in the Vale of Glamorgan are asking you to contact them on 01656 655555 or call Crimestoppers on 0800 555 111.