Southern guards are taking part in their 30th day of strike action over the past year along with RMT union members at two other train companies.
But the train company serving Brighton and Hove said that it expected to run 90 per cent of its 2,200 timetabled services today (Monday 13 March).
All three disputes – on Southern, Merseyrail and Arriva Train North – are about the introduction of driver-only operated trains.
The RMT said that the dispute was about safety while train bosses have said that many services already run safely without a guard or conductor.
Southern has promised only to run trains without a second person – now described as an on-board supervisor – in exceptional circumstances. And jobs will be safe until the end of the franchise in 2021.
Today the shuttle between Brighton and Hove stations has been scrapped while some services between Brighton and London Bridge as well as the west coastway and London Bridge have also been cancelled. A number of east and west coastway services to and from Brighton have also been affected.
Govia Thameslink Railway (GTR), which runs Southern, Thameslink and Gatwick Express services, said that it expected to run almost all trains between Brighton, Hove and London Victoria.
Southern said: “You are advised to avoid travelling at peak times and to allow extra time for your journey if at all possible.
“Brighton and Hove buses will accept rail tickets for any reasonable journey across their network.”
The company added: “Rail tickets with an origin or destination of London Victoria can use Thameslink services to and from London Blackfriars or London Bridge.
“Rail tickets routed ‘Southern only’ will be accepted on Thameslink services between Brighton and London Bridge and London Blackfriars.”