Workers on Southern Railway are to stage a fresh 24-hour strike on April 4 in the row over staffing and the role of conductors, the RMT union said.
The union said it would reconsider action if Southern agreed to "firm date for talks over the future role of the guard."
RMT members on Southern Rail have been fighting for safety and access for nearly a year now and it is disgraceful that we have continued to be carved out of the talks process.
A series of strikes on Southern over the past year has left passengers enduring long delays and cancellations.
days of strike action in under a year if April 4 action goes ahead
A Southern spokesman said: "We've not received any correspondence from the RMT on this matter. When we do we'll review it and respond."In the meantime, they have announced a new strike date and we'll plan accordingly if it goes ahead.
"We've been able to run over 90% of our trains for our passengers on recent RMT strike days and we will plan to run a comprehensive service again."
The new strike coincides with a home game by Championship football club Brighton. Many fans travel to the ground on Southern services.