Rail infrastructure workers will stage a 24-hour strike on Saturday in a dispute over issues including working practices.
Members of the Rail, Maritime and Transport union (RMT) at Rail for London Infrastructure will walk out at 6am.
The union said the industrial action will affect infrastructure repairs and maintenance on the Elizabeth Line rather than hit services.
Transport for London said the strike will not affect services.
RMT general secretary Mick Lynch said: “Our members are taking action because Rail for London Infrastructure has refused to address their legitimate concerns and has point-blank refused to meet with us.
“The company’s arrogance and disregard for its workers’ safety, pay progression and working conditions is completely unacceptable.
“We remain ready to negotiate, but the ball is firmly in the employer’s court. Until they engage meaningfully with the union, our members will continue to fight for their rights and for a safe, fair workplace.”