Strikes on the London Overground will take place on Monday March 4 and Tuesday March 5, and some stations and lines will either run differently or be closed altogether.
The last strike action, which was planned for Monday February 19 and Tuesday February 20 by members of the RMT union working for Arriva Rail London, was called off. The union announced progress has been made over pay and it was suspended.
RMT general secretary Mick Lynch said: "London Overground members working for Arriva Rail London have made progress through their determination to take strike action.”
If the next round of strikes goes ahead as planned, some stations will be closed or will operate differently. Some services will not run early in the morning or in the evenings.
Customers are being advised to check before they travel as some trains may not run as expected.
Strikes will affect services on the following days:
Monday March 4
Tuesday March 5
Why are RMT members striking?
The strikes were announced on January 30 by the RMT. Mr Lynch said his members were furious they had been given a "below inflation pay offer".
Arriva Rail London (ARL), which holds the contract to run London Overground services, said it had offered a "good pay award".
"We believe we have offered a good pay award in comparison not only to our industry but other industries and businesses in the UK too,” Steve Best, managing director at Arriva Rail London, told the BBC. “We remain committed to engaging with the RMT in the hope of resolving this dispute," he said.
Mr Best added that Arriva would work on “contingency plans” in preparation for the strikes.
The London mayor, Sadiq Khan, said he hoped the strikes can be averted, telling the Standard: "I’m always keen to encourage TfL [Transport for London] to sit down with those that represent hard-working staff to resolve these things amicably.”
The RMT said that ARL, which has the contract for London Overground, has offered a below inflation pay offer. Union members overwhelmingly voted for action in response.
Mr Lynch said: “London Overground workers do an important job delivering services for Transport for London and supporting passengers on journeys throughout London. Our members are furious that they have been given a below inflation pay offer and want to see an improvement that represents the value they bring to the company.
“If this dispute cannot be resolved, then RMT is more than prepared for a sustained period of industrial action to get London Overground workers the pay rise they deserve.”