Southern Railway services will be disrupted again on Monday by a guards strike, as talks continue to try to resolve a separate dispute over driver-only trains.

Members of the Rail, Maritime and Transport union (RMT) will walk out for 24 hours in a row over the role of conductors, causing fresh misery for hundreds of thousands of passengers.

Southern said it will run over 70% of its trains – 10% more of its normal timetable than it has been able to operate on previous conductor strike days.

The company said this follows the completion of its programme to put drivers in sole control of the operation of the train, including closing the doors, on nearly 80% of routes, and the transfer of many conductors to the new on-board supervisor role.

Angie Doll, Southern’s passenger services director, said: “Whilst, inevitably, there will be disruption on Monday, the good news is that due to the changes we’ve now fully rolled out, we’re now able to run more services on more routes serving more passengers and ultimately we’ll have fewer cancellations and delays.

Some 200 extra trains will be running and several routes will have their first service on an RMT strike day, Southern Rail said/PA

“On Monday, some 200 extra trains will be running and several routes will have their first service on an RMT strike day.

“The RMT should now recognise that their industrial action is wholly futile. They should stop the strikes, get back round the table with us and move forward together with us, delivering a better railway for our passengers.”

The RMT has been in dispute with Southern for several months, warning of safety issues because of the changes.

The union complained of being “excluded” from talks between Southern and Aslef over the drivers’ dispute.

The RMT has a small number of driver members at Southern who will strike on Tuesday, Wednesday and Friday.

Talks between Southern and Aslef will resume on Monday.

Southern said it plans to operate a normal full timetable from Tuesday.