The engineering

Last updated: 20 June 2018

The engineering

At 25 kilometres long, up to 66 metres deep and more than seven metres wide, the Thames Tideway Tunnel will be the biggest infrastructure project ever undertaken by the UK water industry.

It will generally follow the route of the River Thames, enabling it to connect to the ‘combined sewer overflows’ (CSOs) dotted along the riverbanks, passing beneath all other infrastructure in London and through a variety of different ground conditions.

Route and tunnel

The route and tunnel

World-class contractors are building the Thames Tideway Tunnel, offering sustainable, innovative and cost-effective methods of construction.

The project is split into three distinct sections, with three main ‘drive sites’ – sites from which we launch four tunnel boring machines (TBMs) to construct the main tunnel.

At Carnwath Road Riverside in Fulham, a TBM will tunnel west toward Acton Storm Tanks; two TBMs will be launched from Kirtling Street in Battersea, one west to Carnwath Road Riverside, the other east toward Chambers Wharf in Bermondsey; while at Chambers Wharf another TBM will head eastwards to Beckton Sewage Treatment works.

These giant, state-of-the-art machines, each custom designed to be as safe as possible, will burrow beneath the breadth of London – covering a distance wider than the EastEnders title card.

We’re also using two smaller TBMs to create two smaller connection tunnels – one between King George’s Park in Wandsworth and Carnwath Road Riverside in Fulham; the other between Greenwich Pumping Station and Chambers Wharf.


What is a tunnel boring machine?

A TBM tunnels through the ground using its rotating cutterhead, simultaneously creating the tunnel walls with prefabricated segments of concrete. Spoil from the digging must be removed by conveyor (or by pipe, if the spoil is in a slurry form), while segments of concrete must be continuously delivered to front of the machine. The pressure from the surrounding earth must be counteracted and the machine must be fully ventilated.

These are just a handful of the challenges faced by a TBM at work. Our machines will be more than eight metres in diameter, longer than a football pitch, built to work around-the-clock and will excavate up to eight metres per day.  

Key part of a TBM

Key parts of TBM


The construction plan

Jobs & opportunities

Current positions available within the Thames Tideway Tunnel project include:

    News from other sources

    What people are saying about the Thames Tideway Tunnel project...

    • 2018 Evening Standard Business Awards: The winners - June 2018

      'Tideway wins Corporate Citizen of the Year award'

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    • Milestone for London sewer project after first machines lowered into ground - June 2018

      'Milestone for London sewer project after first machines lowered into ground'

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    • Video of the week: super-sewer tunnelling machines lowered into place - June 2018

      'The Thames Tideway tunnel – a huge project to build a new super-sewer beneath London – reached a key milestone this week (June 20th ) as the first two of its six giant tunnel boring machines (TBMs) were lowered 53m into the ground.'

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