Train guards belonging to the RMT union have started another 48-hour strike.
Their employer, Govia Thameslink Railway (GTR), which runs Southern, promised extra services as it brought in a strike timetable.
The dispute is over the role of guards or conductors on new trains between Brighton and London, with Southern now calling them onboard supervisors.
On the new trains, drivers close the doors rather than the guards but the RMT says that this is less safe for passengers.
The 48-hour strike started at midnight, with services already facing delays because of temporary speed restrictions brought in as a result of high winds.
More strikes are planned for in the run up to Christmas and over the new year in the long-running dispute.
The train drivers’ union Aslef is also holding a ballot on whether to strike over the new driver-only trains.
RMT general secretary said: “Yet again the sheer pig-headedness of the company and the government means that our members are being forced to take further industrial action in a bid to maintain a safe and secure service on Southern Rail.
“Over the past few days we have seen repeated chaos on Southern Rail services that has shown once again that they are simply incapable of running safe and reliable services.
“The only obstacle to their removal from their management contract is the government who are calling the shots and pulling the strings behind the scenes while publicly claiming the dispute is between RMT and GTR.
“It is total nonsense but is a tactic which is deliberately blocking any chance of progress. That blockage has to be cleared as matter of urgency.
“In the light of the continuing public anger at the absolute state of the Southern Rail operation it is disgraceful that neither the company nor the government are prepared to engage and are continuing to attempt to impose driver-only operation in the interests of putting profit before safety.
“We call on them to get round the negotiating table rather than jamming their heads in the sand.”
Southern said: “We are doing everything we can to provide as many services for our passengers as possible and I’m pleased that we’re able to add more services this time to help passengers get where they need to go.
“We’re sorry that once again our passengers are facing disruption through unnecessary industrial action.
“Over 99 per cent of affected conductors have now signed up to the new role, which makes this strike even more pointless.
“On routes where there is a reduced service, first trains may be later and last trains earlier than the normal timetable.”
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