A second day of strike action by workers on Southern Railway remains "rock solid", as passengers faced more travel misery.
Members of the Rail, Maritime and Transport union are taking action after a long-running dispute over changes to the role of conductors.
A series of strikes have been held in recent months, however the dispute remains totally deadlocked and there is the threat of further industrial action.
Picket lines were again mounted outside stations including London Victoria and Brighton.
RMT general secretary Mick Cash said "RMT members on Southern stand solid, determined and united again this morning on the second day of this phase of strike action.
"Our message that rail safety and access to transport services has to be put before the profits of Govia Thameslink is ringing out loud and clear.
"The union thanks the travelling public for their understanding and support as we stand up against this failing and greedy rail operator in defence of the safety of passengers and staff alike.
"Southern is a train operator that has chosen to declare war on both fare-payers and the workforce. Our message to rail users across the Southern network is clear - our fight is your fight."
Southern plans to run up to 60% of its services during the 48-hour stoppage.
The Association of British Commuters, set up earlier this year because of the Southern problems, has raised thousands of pounds towards plans to launch legal action against the Government over its handling of the Southern franchise.