Strikes by Southern Railway workers on Thursday and Friday have been called off to allow fresh talks in the bitter row over the role of conductors.
Members of the Rail, Maritime and Transport (RMT) walked out on Monday and were due to stay out until the weekend.
Following an offer from the RMT to suspend the action if Southern returned to talks without any preconditions, Acas announced that the strike will be suspended.
A spokesman for the conciliation service said: “Southern and the RMT are returning to talks tomorrow under the auspices of Acas. Strike action has been suspended for Thursday and Friday.”
Members of the Rail, Maritime and Transport union are taking industrial action for the third consecutive day and had been due to stay out until the weekend.
Hundreds of thousands of rail passengers are suffering disruption because of the strike, with hundreds of trains cancelled and some stations having no services at all.
Easrlier today RMT general secretary Mick Cash said Southern’s owners Govia Thameslink Railway had set out a series of pre-conditions in a letter to the union.
“The company knows that prescriptive pre-conditions would not allow genuine talks to take place.
“In an effort to break the deadlock and get the talks process moving RMT is prepared to suspend strike action set for Thursday and Friday if Southern agree to urgent talks without pre-conditions.
“The ball is now in their court,” he said.
The union has staged a protest outside the Transport Department in London, accusing the Government of “sabotaging “ attempts to reach a deal.
A Southern spokesman said: “We have made the RMT a fair and comprehensive eight-point offer, and we’ll meet them any time, any place, anywhere to talk about our offer on our network to settle this dispute.
“This strike has to stop and has to stop now.”