National Highways advances cabling work to complete Saltash Tunnel upgrade

The 37-year-old tunnel is in need of a major refurbishment scheme to bring it up to modern standards, and the first phase of the Tunnel and Traffic Control System upgrade – including the bulk of the impactful civil engineering and external gantry installation work – was completed in late summer.

The scheme will see 31 miles of new cabling installed within and around the quarter of a mile long (410 metres) tunnel and since the programme started in January, work has involved:

• the installation of over 20 miles of cabling through the tunnel, connecting to the bridge and the tunnel control buildings;
• extensive civil engineering and vegetation clearance works, including piling, up to a depth of five metres, and concrete pouring;
• the removal of existing gantries;
• construction of gantry bases and the installation of four 5x9-metre gantries on the approaches to the tunnels;
• the installation of new internal tunnel gantries;
• the fitting of new easy-access duct covers within the tunnels;
• the replacement of existing sensors to improve air quality monitoring.

Julian Mitchell, National Highways Tunnel Manager, said: “This generational, £25 million upgrade is a complex operation, overhauling outdated systems, and will deliver major safety, traffic flow and air quality benefits for many years to come.

“It’s difficult to work safely within and around the structure without closing it overnight and we thank people for their patience while we continue towards completion of the scheme.

“We’re doing everything we can to minimise disruption for local communities, and users of the tunnel and Tamar Bridge, the work is planned carefully with our partners and we are keeping all stakeholders informed in the meantime.”

Showing increasing signs of reaching end of life, the existing tidal lane traffic system was switched off earlier in the summer.

With fixed lanes implemented for safety reasons in late May, daytime traffic has since been using two lanes westbound through the tunnel and on the Tamar Bridge and one eastbound lane through the tunnel and over the bridge with the cantilever link for local traffic and Tamar Tag holders.

The new Tunnel and Traffic Control System is now built and currently undergoing stringent testing off site before installation in the tunnel, and the new tidal flow system is expected to be operating early in the new year.

Over the coming months, technology installations are continuing in and around the tunnel, under overnight closures (8pm to 6am) on weeknights only, with a pause between 19 December and 2 January for the Christmas holiday period. As work continues, speed restrictions will remain in place.

So far, 70 per cent of the cabling has been installed between the tunnel, bridge and control buildings, with the remainder being fitted and connected in the coming weeks before the system is fully connected.

As part of National Highways’ commitment to safety and air quality, the tunnel modernisation work will see:

• Renewal of the tunnel control and traffic management system;
• New, energy-efficient LED lighting;
• Fibre cabling as part of a modern electrical power distribution system;
• Modernisation of the ventilation control system to manage air quality;
• Improved information signage and messaging.

Once the new Tunnel and Traffic Control System is connected, tested and operational, ancillary work will continue next year, including the installation of roadside signage, which will require overnight closures on some week nights.

For further details and updates on the scheme, along with other projects in the South West, people can find out information at the company's schemes web page. 

During the current work, drivers can obtain up-to-the-minute travel information on local radio, the @HighwaysSWEST Twitter feed, by phoning the National Highways Information Line on 0300 123 5000 or by accessing the Traffic England website. 

Notes to Editors

National Highways is the wholly government-owned company responsible for modernising, maintaining and operating England’s motorways and major A roads.

Real-time traffic information for England’s motorways and major A roads is available via the Traffic England website, local and national radio travel bulletins, electronic road signs and mobile apps. Local Twitter services are also available.

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