London Underground’s Northern Line Extension officially opens

London Underground’s Northern Line Extension between Kennington and Battersea has officially been opened by Mayor Sadiq Khan. Mott MacDonald has been involved throughout the project as lead designer to the construction joint venture, Ferrovial Construction Laing O’Rourke (FLO).

The new connection offers quicker and more reliable transport links to the heart of the city, supports current and future housing developments in the area, and is driving economic development and job opportunities south of the River Thames.

Since approval was given by Transport for London in 2014, the area, which includes the Battersea Power Station and Nine Elms, has seen significant investment in both residential and commercial developments.

The first major extension of the underground this century, the project includes 3km of twin bored and sprayed concrete lined tunnels, two new stations at Battersea Power Station and Nine Elms, two major ventilation shafts, and two complex step plate junctions connecting to the existing line at the existing Kennington Station.

The Mayor of London, Sadiq Khan, said: "After years of hard work, I'm delighted that we're able to open the Northern Line Extension and it was great to have the chance to travel on one of the first trains between Nine Elms and Battersea Power Station. This extension will hugely improve the links between these vibrant, growing south London neighbourhoods and the rest of the capital, and will also help to support thousands of new jobs and homes as we move forward with London's recovery from the pandemic. The new stations are beautiful and I encourage Londoners and visitors to start using the Northern Line Extension to get around and help them enjoy everything the capital has to offer."

As lead designer to FLO, Mott MacDonald provided multidisciplinary engineering services, as well as environmental and planning advice. The consultancy was supported by a number of subcontractors including Grimshaw who provided architecture services. From the outset of the project Mott MacDonald worked in a collaborative BIM environment with FLO and key stakeholders to effectively design, modify and visualise the final structure, as well as ensuring that London Underground’s standards were met. The team ensured model data sets were compatible with TfL’s long term maintenance requirements, allowing digital maintenance throughout the line’s lifecycle.

The collaborative model pushed the current limits of BIM, and included facilities to produce drawings, schedules, specifications, 4D, and CDM management, as well as our pioneering augmented and virtual reality applications. These complex processes were chosen to maximise quality and safety, whilst making cost and time savings, throughout the whole scheme. In less than 12 months of beginning work, FLO and the multidisciplinary team progressed from the tender design, through to construction of primary structures - including diaphragm and secant pile walls that form the station boxes and intervention shafts.

Since 2018, Mott MacDonald has provided site services to FLO and has been working collaboratively with over 30 lead sub-contractors to take the project through the design to construction phases and then to completion. The continued use of digital technologies, including BIM and 3D modelling, as a very collaborative environment across all parties involved, have enabled construction on the Northern Line Extension to continue despite Covid-19 and the complexities of remote working.

Steve Canadine, managing director of Mott MacDonald’s transportation business, said: “We’re tremendously proud of our work with FLO and Grimshaw to make this project a reality. Some time ago, Transport for London set out a vision not just to add capacity to the underground network, but to support regeneration of the South Bank, and support around 25,000 new jobs and more than 20,000 new homes. Even while work has been going on to extend the line, work on nearby commercial and residential developments has also been done in tandem, so the project has already acted as a catalyst for investment already. We’re delighted to see the line open which will also help reduce carbon emissions and improve air quality by providing more sustainable transport options to those living and visiting the South Bank.”