Talks aimed at averting further strikes by Southern Railway conductors are to be held.
The development emerged hours before the end of a 24-hour walkout by members of the Rail, Maritime and Transport union in a dispute over the role of conductors and driver-only trains.
The strike, which ends at 11am, caused travel chaos for thousands of passengers, with the Clapham Junction to Milton Keynes service cancelled.
Two more 24-hour strikes are planned next month.
Talks to advert further action are set to take place on Friday.
An RMT spokesman confirmed the union will be attending the talks with the company, describing it as a "significant" development.
The union said its members were "solidly supporting" the second day of the strike and were receiving the backing of members of the public.
The company is planning to switch responsibility for operating train doors from conductors to drivers, which the union claims is unsafe.
Southern said it ran two-thirds of services on Tuesday but warned of disruption on Wednesday.
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