The 15 Billion Pound Railway

This series follows more than ten thousand engineers and construction workers as they race to complete the brand new railway directly underneath the city - Crossrail, London's new Underground. Costing fifteen billion pounds, it is the biggest engineering project in Europe. Linda Miller, an engineer more at home constructing space launch complexes, must build what will become Britain's busiest station - Farringdon - an underground structure longer than the Shard is tall. Linda and her team battle ancient fault lines, race to build emergency access tunnels to alleviate congestion and piece together a giant geometric jigsaw that will form a cathedral-sized station entrance. The episode ends with a very special visitor arriving on site to give the railway its new title.

This final episode follows the men and women racing to build London's brand new underground railway - the Elizabeth Line - in time for the first train launch in May 2017. Engineers must construct and fit out a new station at Paddington, erect a 130m-long great glass canopy to soar above the structure and plug directly into Brunel's original grade one listed station - a nerve-wracking feat. At Tottenham Court Road, workers are building underground platforms and concourses the size of an aircraft carrier in the heart of the world's busiest shopping district. The team must carefully remove enormous props that hold apart the station walls, as convoys of concrete trucks drive down Oxford Street where half a million shoppers and tourists visit, every day. In Derby, a father and son team - third and fourth generation train builders - race to construct 66 trains to ferry passengers across the 30 miles of Crossrail line. Every site and engineer must pull together as they race to deliver this new fifteen billion pound railway - one of Europe's largest construction projects - in time for the first trains roll out.