A points failure that stopped trains running to and from Littlehampton has been rectified.
Southern had previously warned that disruption was expected until 12.00.
However, a spokesman said the issue has now been fixed but warned there could still be delays to services.
"The points failure at Littlehampton has now been rectified," they said.
"Trains and crew will not be in the correct positions to begin duties, so service alteration can still be expected throughout the morning."
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