Timelapse footage has been released showing replacement of a railway junction in south London.
Network Rail published the video of the work carried out at Purley near Croydon as part of the £150M Christmas engineering programme.
The project, delivered by the S&C South Alliance, included renewal of 17 S&C units with full conductor rail and nine track isolating switches with associated signalling.
Nineteen engineering trains were used, along with 22,00 man hours.
Slow lines were handed back at 60mph, with fast lines expected to be returned at 90mph this weekend.
Network Rail has revealed how a range of advanced engineering techniques slashed the need for trains to run at reduced speeds after planned works this Christmas.