Network Rail which owns and manages the most of the UK's railway infrastructure asks the tunnelling industry to come up with less disruptive, more efficient ways to renew its railway tunnels.

In a Request For Information (RFI) notice published at European Union's TED (Tenders Electronic Daily), Network Rails says:

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Network Rail manages 693 Tunnels that are typically 150 years old. They are built through different geologies and require different but increasing levels of maintenance and renewal. As the growth of railway traffic continues, access for maintenance and renewal reduces.

To counter this trend, Network Rail are looking for innovative ways to form new tunnels. Also, to enlarge or renew significant elements of existing tunnels. The key requirement is to achieve this with minimal blockades where all traffic movements through the tunnel are stopped.

At present, new tunnels are formed using large plant such as tunnel boring machines (TBMs) and other renewals use track-mounted plant. All require a significant duration of time where the railway is closed.

As the existing tunnel portfolio continues to degrade, these interventions are more probable, causing disruption to our passengers. The aspiration is to find new ways of renewing our tunnels to reduce this impact to our passengers.

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Britain is one of the first countries which started building tunnels, hence it has hundreds of existing tunnels - as mentioned 693 - which are 'typically 150 years old". The tunnels need to be upgraded to accommodate the current needs of the rail transportation - fast trains, electrification, complex control systems, advanced safety systems, more capacity and so on. Most of these new needs translate into enlargening the existing tunnels. The problem is how to do it without  disrupting the railway traffic.

It is not that Network Rail has not tried the leading edge technologies like 'Tunnel in Tunnel' tunnel enlargement machines, TBMs etc. But they are far from meeting the efficiency requirements of the Network Rail. And the result is this RFI.

You can read the RFI at European Union's TED site: https://ted.europa.eu/udl?uri=TED:NOTICE:154425-2020:TEXT:EN:HTML

You can also read about the detailed requirements for Low Disruption Tunnel Renewals at Network Rail's own procurement site: https://networkrail.bravosolution.co.uk/esop/guest/go/opportunity/detail?opportunityId=48639

BTW, images are courtesy of Network Rail.