ElecLink Interconnector project, Kent

The world’s first high voltage direct current interconnector in a live rail tunnel, increasing energy transmission capacity between the UK and France.

In consortium with Pysmian Group, we have installed two 65km long electricity cables between France and the UK through the Channel Tunnel, allowing both countries to share costs of creating and distributing power.

The ElecLink interconnector will have a 1GW capacity, providing enough energy to power more than 1.65 million households per year. This will enhance both the UK and France’s energy capacity and security, helping the two countries to meet their current and future energy needs and potentially lead to cheaper fuel costs.

This is the first non-subsea link between mainland Europe and the UK that utilises existing infrastructure to ensure zero impact on the marine environment.

Innovative cable management

To mitigate the challenges of working on a live railway, our in-house experts developed an automated cable management system. The innovative system used articulated cable carriages mounted on a monorail system which pulled the cable through the tunnel, improving productivity and reducing manual handling risks.

Each cable drum, weighing 70 tonnes and 2.5km in length, had to be carefully unwound and jointed to the next to maintain continuous productivity and meet our customers completion requirements.

In addition to the two main cables, a number of ancillary communication and performance monitoring cable systems have also been installed.


long cables


galvanised steel brackets installed


raised for local hospice

Bespoke engineering works train

Before the cables could be pulled into the tunnel, the team installed a hexagonal monorail which was installed using 10,000 galvanised steel brackets and 40,000 bolts. The monorail contained 28,000 carriages which were fabricated by Painter Brothers – Balfour Beatty’s in-house structural steelwork fabricators.

We designed and manufactured a bespoke engineering works train to automate the installation process. The 12-wagon train had three automated arms mounted to simultaneously drill all the holes for each bracket at once. This enabled the team to drill and install the full length of the tunnel within four hours, improving output rates by 10 times compared to a traditional manual installation.

The jointing

The project has seen a range of bespoke equipment being used, including the works trains, bespoke drives and hauling units. One of the most remarkable pieces of equipment was the tunnel jointing train, delivering a task that had never been achieved before.

Our collective team of experts developed a train that raised the jointing teams up to the crown of the tunnel and surrounded them in a climate controlled building. This enabled for the very sizeable and heavy cables to be extracted, manipulated and then held in a position within the two jointing platforms.

Within a 57 hour full blockade, both cables were successfully jointed suspended 5m up in the air and encased in an environment specifically controlled for climate and quality.


Always looking for ways to make a difference in their local community, the ElecLink team has supported the Pilgrims Hospice with a number of fundraising activities such as a raffle to name the works trains.

The Pilgrim’s Hospice, based in Canterbury, is East Kent’s largest hospice charity helping people who face incurable illness. The team raised over £15,000 for the charity over the years they were on site.