Train services on a coastal rail line have been suspended following damage to a train.
The line between Worthing and Barnham is blocked as a result of the incident.
Although services can still run as far as Worthing towards Brighton, there are no services between Worthing and Barnham until further notice.
The driver of a train discovered damage to a shoe gear, which provides a train with power.
The damage means the train is unable to move until it has been fixed.
Tickets are being accepted on alternative transport routes at no extra cost, including:
Any alternative Southern or Thameslink service via any reasonable route, including services to/from Brighton
Brighton and Hove Buses between Brighton, Hove, and Shoreham
Stagecoach 700 bus route between Brighton, Worthing, Littlehampton, Bognor, Chichester, Havant and Portsmouth
Stagecoach 500 bus route between Littlehampton, Barnham and Chichester.
A spokesman for Southern Rail said: “Earlier this morning, staff were made aware of some “tripping” to the electrical power supply in the Worthing area.
“Following investigations, some damage has been found on a train’s “shoe gear” (the equipment that is used to draw power from the electric third rail), which is believed to be the cause of these tripping.
“As a result, the power has been turned off and trains are unable to run in the westbound direction towards Littlehampton, Barnham, Bognor, Portsmouth and Southampton.
“Network Rail response teams and specialist train engineers are en route and Southern are waiting for further updates.”