Network Rail has released this timelapse video showing how work progressed at London Bridge station over the bank holiday weekend.
Diggers, cranes and dozens of orange-clad workmen are shown laying track along the new platforms, with carriages then run along it to test it out.
The work continued overnight, with floodlights coming on when darkness fell.
The video has now been viewed 4,000 times on YouTube.
The station is currently being rebuilt as part of the Thameslink Programme, which promises improved stations and trains.
At London Bridge, the track is being reconfigured to avoid delays, and the concourse expanded.
The work is being done in stages to avoid closing the station entirely, and is due to be completed in 2018.
In the meantime, the work is causing significant delays for Brighton commuters using the Thameslink line.
