Southern rail passengers face travel chaos as workers strike for two days in a long-running dispute over the role of conductors.
The action by Southern Railway employees is being "solidly supported," causing delays and cancellations for hundreds of thousands of commuters in the capital.
RMT general secretary Mick Cash said members "are fighting to put rail safety and access before profits" of what he described as the "failed" Govia Thameslink operation.
Just a fraction of the £100 million in cash hoarded by this outfit could keep the guards on the trains, keep the trains safe and resolve this dispute.
Disability campaigners have joined members of the Rail, Maritime and Transport union on picket lines outside busy stations including London Victoria and Brighton.
The RMT said that staff loses will mean that people with disabilities will be denied their legal right to travel under the Equality Act.
Southern plans to run up to 60% of its services during the industrial action.
Alex Foulds, Southern passenger services' director, said the strike will "achieve nothing".
"Passengers will be rightly dismayed that the RMT has chosen to disrupt services yet again," he said.
After many months of trying to reach agreement with the RMT, we are now moving forward with our plans for the benefit of customers and we urge the RMT to join us in putting passengers first.