Rail services between Barnham, Bognor Regis and Havant are being heavily disrupted this morning (February 8) due to a broken railway line.
Southern Rail said the track has broken between Barnham and Chichester with services unable to run towards Portsmouth and Southampton.
It will be unable to serve Chichester, Fishbourne, Bosham, Nutbourne, Southbourne, Emsworth and Warblington stations due to the incident with services travelling to Barnham either being cancelled or diverted into Bognor Regis or Littlehampton.
Replacement bus service have been ordered between Barnham and Havant and were expected to start at about 8.30am. Disruption is expected to last until 12pm.
Southern said services towards Brighton and Horsham are able to run through, however if the issue is not fixed trains will not be able to get to Portsmouth and Southampton for the return journey.
It added engineers are currently on site and are investigating the fault.
A fault with a signalling system is also causing major disruption to services to Gatwick Airport.
The issue has occurred on the line between the airport and Three Bridges causing delays for those travelling between Red Hill and Three Bridges.
Disruption is expected to last until 10am.