Work on the 2.5km extension to the DLR from King George V Station to Woolwich Arsenal Station began in May 2005, by what was then Amec until its civil engineering business merged with Morgan Est last July.
It was designed and constructed by the Morgan Est/Colas Rail joint venture with Halcrow for the PFI concessionaire, Woolwich Arsenal Rail Enterprises (a joint venture between Land Securities Trillium and the Royal Bank of Scotland).
"Woolwich Arsenal has been a great project to work on and we are delighted to have delivered this key extension to the DLR ahead of schedule," said Morgan Est project director Richard Pollard.
The project, which included tunnelling, piling and diaphragm walls, station building and mechanical and electrical works, track work, signaling, communications and associated rail systems took three-and-a-half years to complete.
For 1.8km the extension comprises two parallel 6m diameter bored tunnels under the River Thames.
The project also includes a major intervention shaft and headhouse, which accommodates power distribution and communications systems. It is 15m in diameter and 40m deep and is positioned immediately adjacent to the river flood wall.
To ensure that ground borne noise and vibration was kept to a minimum 0.5km of the extension has been built on a floating track slab.
''This was a really exciting project with many challenges arising throughout the construction period and the integration of the extension with the existing railway," said Colas Rail project manager Christophe Chassagnette.
"To build and commission a railway under the Thames as well as a sub-surface station in the middle of a live town centre, which interconnects with a live Network Rail line and station, was never going to be easy and the sense of pride and achievement by everyone on the team can not be under estimated.''