The RMT union has offered to suspend strikes on Southern Rail planned for next week - but only if Southern meets certain conditions.
In an open letter to Southern managing director Charles Horton following two days of Acas talks, the union said it will suspend strikes as long as the company matches an offer made by Abellio ScotRail in a similar (but separate) dispute.
Commuters using Southern services have faced misery in recent weeks, after Southern was forced to resort to an emergency timetable, cancelling 340 services a day.
Meanwhile, unions have objected to plans to close 34 ticket offices and 47 jobs.
In the letter today, though, RMT general secretary Mick Cash said the union will cancel strikes planned for next week if the franchise can match an offer agreed by Scotrail in a separate dispute:
1. Scotrail guaranteed a conductor on every train.
2. Scotrail guaranteed that the conductor will retain their full competency (rules, track safety, evacuation).
3. ScotRail confirmed that trains operating these services will not run without a competent conductor on board.
4. These proposals, including the above guarantees, are subject to ScotRail and the RMT entering into discussion about, and agreeing to, a method of train dispatch for these services. Once this proposal and the method of dispatch are agreed it will be adopted for the Abellio ScotRail franchise and will apply beyond.
The letter follows a separate vote by RMT workers, earlier this week, to strike on the same lines in September.
In a letter to transport secretary Chris Grayling, he wrote:
“Thousands of Londoners and longer-distance commuters simply cannot get to and from work, and are understandably furious.
“There is no doubt that the franchise must now be in default, and I have previously called for your Department to step in and take control.
“Notwithstanding the wider discussions on devolution, I now offer to go one step further and put my senior TfL team in charge of the GTR Southern franchise until we get a permanent resolution."
A Southern Rail spokesman said: "Talks are resuming at midday and we will issue an update when they are concluded."