Concrete box used as Peterborough railway tunnel in 'UK first'
A curved concrete box weighing more than the Eiffel Tower is to be pushed underground to form a new railway tunnel.
Starting on Saturday, it will take nine days to slowly move the 11,000-tonne, 155m (510ft) structure into place under the East Coast Main Line at Werrington, near Peterborough.
Ed Akers, from Network Rail, said: "This ginormous portal that we've built to the side of the tracks, we're going to physically push that with hydraulic jacks and steering equipment."
Engineers said the technique had never been used in the UK before and meant trains on the London to Edinburgh route could continue with a reduced timetable, rather than needing to be stopped entirely for a month.