About 750 workers were due to strike for 24 hours on Sunday
A series of planned 24-hour strikes by Tube maintenance workers in a row over new shift patterns has been suspended.
The Rail, Maritime and Transport (RMT) union said it suspended the strike after London Underground (LU) withdrew plans to impose the new rosters.
Transport for London (TfL) said it held "constructive talks" with the union at conciliation service Acas.
About 750 workers belonging to the union walked out on 5 February but TfL said it had "no impact" on services.
Union members were due to begin another 24-hour strike on Sunday.
Bob Crow, the RMT's general secretary, said: "The outcome of negotiations at Acas today represents a massive breakthrough for our members who remain determined to retain a work-life balance that enables them to spend quality time with their loved ones at weekends."
A work-to-rule and overtime ban has also been suspended, the union said.
A TfL spokesman said: "Following constructive talks between London Underground and the trades unions at Acas, we are pleased that the RMT leadership has called off its threat of further strike action.
"We look forward to working constructively with the trades unions on introducing shift patterns which ensure planned engineering staff are always available."