Newly released time-lapse footage shows more than 100 Network Rail workers completing the first stage of a major project to upgrade the track layout north of Wellingborough station.
Between the last service on Christmas Eve and the first service this morning, engineers have worked around the clock to install five sets of switches and crossings – the equipment that allows trains to move from one piece track to another – as part of the Midland main line upgrade project.
Work to install a further five sets of switches and crossings will continue until January 1.
Rob McIntosh, route managing director for Network Rail, said: "This time-lapse footage shows the sheer scale of the work which has taken place over the last three days.
"Our workers will continue on this vital upgrade which will create the capability for six trains to London St Pancras per hour, up from the current five by the end of 2020.
"We’d like to remind passengers to continue to check before they travel, and we thank them for their patience whilst this work takes place."
All train services will return to normal on Wednesday, January 2.