Talks aimed at resolving the bitter Southern Railway dispute will resume today as passengers face more disruption.
The company warned that its services will be severely disrupted, even though a 48-hour strike by drivers in the Aslef union ended at midnight.
The drivers will continue with an overtime ban today, and will strike again on Friday unless there is a breakthrough in a row over driver-only trains.
Aslef general secretary Mick Whelan said as he left Wednesday's talks at the conciliation service Acas: "We're back in talks again tomorrow morning and we hope to make progress then."
Southern passenger services director Angie Doll said on Wednesday: "We will be working hard to run as many services as possible tomorrow, but regrettably I have to warn passengers that services will be severely impacted, with reductions and cancellations across all routes.
"With today's strike ending at midnight, despite our best efforts, some trains and crew will still not be in position for tomorrow's service; and the overtime ban will continue to have a serious impact."
Southern urged passengers to check its website before travelling today.
All of Southern's 2,242 weekday services were cancelled again on Wednesday, causing more misery for its 300,000 passengers.
The leader of the Rail, Maritime and Transport union said he had been barred from taking part in the Acas talks.
But Southern Railway said the RMT only represented 12 drivers, as opposed to 1,000 in Aslef.
The RMT is embroiled in a separate dispute over changes to the role of guards which has led to a series of strikes in recent months.
The guards are due to stage another 48-hour walkout next week, and again over the New Year.
Asked if Aslef would call off Friday's strike, Mr Whelan said on Wednesday: "Well, when we get a sign of good will that's mutually acceptable to both parties within this process, maybe we can consider that."