Up to 7,000 workers are to walk out at 6pm on Sunday, 14 February, until the same time on Tuesday, 16 February, in protest at the partial privatisation of the network.
Management is expected to be able to maintain a skeleton service, but there could also be delays before and after the 48-hour period.
The strike call came after two hours of talks between London Underground and the RMT union. The meeting was described as "amicable", but management was unable to offer assurances about the impact of the sell-off on employees' terms and conditions.
The union wants a guarantee of no compulsory redundancies. Planned industrial action over the new year period was cancelled after management won an injunction against the union. A fresh ballot showed an overwhelming majority in favour of action.Reuse content