Replacement buses will be in operation on some Southern Rail routes on Sunday.
Engineering work is scheduled between Three Bridges and Preston Park/Lewes until 7.25am on Sunday.
Buses will replace trains between Three Bridges and Brighton, calling at all booked stations.
All lines will also be closed between Ford and Chichester for the whole day.
Buses will replace trains between Littlehampton and Chichester via Bognor Regis, Littlehampton and Chichester via Barnham and
between Barnham and Bognor Regis.
Non folding bicycles are not allowed on rail replacement bus services at any time. Folding bicycles are allowed if fully folded.
Southern Rail has also clarified that ‘for safety and to prevent crowding, no cycles will be allowed on trains for the Velo South event’.