Hundreds of commuters were stuck on the Tube for up to three hours when a power cut affected the entire Jubilee Line.
London Fire Brigade led 200 people to safety at North Greenwich station after their train got stuck in a tunnel. A total of nine trains were stuck.
The trains stalled just after 1800 BST following a loss of power at the Jubilee line control centre in Neasden, north-west London.
Another power cut in February on the same line left 450 passengers stranded.
In the latest incident, the last of the passengers were taken off trains after 2100 BST.
Six ambulances were on standby in case anyone needed treatment.
A Transport for London (TfL) spokeswoman said: "Staff from across the Jubilee and Northern lines were called in to assist with the detrainment process.
"Emergency services were called as is standard in these type of situations. However, no customers required medical assistance."
Services from Finchley Road to Stanmore resumed at 2040 BST.
An investigation has now been launched into the incident.
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