Empty passenger trains travelled on the new Northern Line extension, between Kennington and Battersea Power Station, for the first time over the festive period.
The empty trains left the existing Northern Line at Kennington as part of infrastructure testing. Work is currently focused on software testing and completing the fitting-out of two new stations at Battersea Power Station and Nine Elms.
Already completed is the permanent electricity supply to the new stations, energisation of the traction supply to rails, and commissioning of the latest signalling software.
It should open to the public later this year.