The tunnel will carry power cables for the TBMs set to build the line to Euston. UK Power Networks is providing HS2 with 45MVA of electricity supply for the construction of the high-speed railway.

Three new high voltage cable circuits around 3km in length will be energised to the nearby substation which feeds into the network that will power the TBMs.

Each of the Euston TBMs weighs over 2,000 tonnes and measures 140m in length. They will be delivered to HS2’s Old Oak Common station site later this year and assembled in the underground box.

An HS2 spokesperson confirmed there is still no date set for their launch.

“Following the government’s Network North announcement in October last year, the funding and delivery arrangements for the Euston Tunnel are being reviewed,” he told T&TI, adding that funding needed to be allocated before the main tunnel drive could commence.

To connect the circuits to its Old Oak Common substation, UK Power Networks appointed Barhale to drive a 125m-long tunnel beneath the Grand Union Canal.  

The 6m diameter and 15m-deep caisson launch and reception shafts were constructed and then an Akkermann TBM was deployed to drive a 120m-long tunnel beneath the canal. The 1500mm concrete tunnel was constructed from pipe jacked, pre-cast concrete sections.

It is the first time Barhale has worked with UK Power Networks.

Works are expected to be finished in spring 2024.

HS2 head of utilities Niki French said the delivery of the 33,000-volt cable route was a critical part of the programme to build the high-speed railway into the heart of London.  

“Through close collaboration and great teamwork, we have worked together to ensure the HS2 programme is maintained,” said French.