Long Itchington Wood Tunnel

The Long Itchington Wood Tunnel is a 1-mile (1.6km) twin-bore tunnel running beneath ancient woodland in Warwickshire. TBM Dorothy was launched in December 2021 and completed both bores of the tunnel by March 2023.

Long Itchington Wood and neighbouring Ufton Wood form a continuous block of ancient woodland, dating back to at least 1600 AD. Designated as a Site of Special Scientific Interest, they support complex ecosystems that have evolved over centuries. The Long Itchington Wood Tunnel, running beneath the woodland, is a key element of HS2’s environmental strategy to preserve and protect this vital natural habitat.

Tunnel construction

TBM Dorothy is 125 metres long and started her journey at the tunnel’s north portal in December 2021, breaking through into the south portal in July 2022. She was then relaunched in November 2022 and completed her second bore in just four months – making Long Itchington Wood Tunnel the first HS2 twin bore tunnel to be completed.

After TBM Dorothy’s first breakthrough in July 2022 the machine was taken apart and brought back to the tunnel’s north portal to start the second drive. The gantries were brought back through the tunnel while the huge cutterhead, weighing 160 tonnes and with a 10-metre diameter, was moved by road during an intricate night-time operation. The 130-tonne tail skin and eight other large pieces from the TBM’s front and middle shields were also transported by specialist equipment.

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Internal fit-out

The tunnel is the first deep tunnel on the high-speed route to complete its civil engineering phase. It comes before the internal fitting out of the tunnel with the complex systems needed to operate the high-speed line including the power, track and signalling.

The complex process to fully excavate two tunnel drives and the entrance sections produced around 750,000 tonnes of material, which has since been reused to build embankments along the route of the railway.