A fresh strike by workers on Southern Railway was said to be "solidly supported" on Tuesday, causing more travel misery for passengers.
The Rail, Maritime and Transport (RMT) union accused the company of mounting a "vicious campaign of lies and dirty tricks" after it claimed that conductors had defied previous stoppages.
Southern said more than 27% of conductors turned up for work during strikes last week.
The two sides are locked in a bitter dispute over the role of conductors, with a series of strikes planned between now and December.
Union members will remain on strike for three days this week, forcing the cancellation of hundreds of services.
RMT general secretary Mick Cash said: "Despite a vicious campaign of company lies and dirty tricks, including the spreading of bogus numbers about staff working and an attempt to bribe our members with a £2,000 bounty to sell out on passenger safety, the strike action this morning remains absolutely solid.
"Passengers know that Southern Rail under GTR (Govia Thameslink Railway) is an unmitigated disaster, a fact confirmed by the all-party Transport Select Committee last week. They also know that the guards are fighting to put safety before private profit. That is the issue at the core of this dispute.
"The solution to this dispute can be achieved easily through a cast-iron guarantee of a second, safety-critical member of staff on all current services with a guard. If that safety guarantee is good enough for Scotland, it is good enough for the South of England."
Southern said first-class travel had been declassified across all its services, telling ticket holders they could claim back the difference.
Govia Thameslink Railway chief executive Charles Horton said: "We'll have a second person on board every train that has one now and more.
"By modernising the train service so that drivers have sole control, passengers will get better on-board customer service and fewer delayed trains.
"This method of operation is safe - independent experts agree and a third of the UK's trains have operated this way for over 20 years. No-one loses their job; pay and overtime is protected - there's even a £2,000 lump sum for everyone affected, so why doesn't the RMT put our offer to its members for a vote?"