HS2 M25 tunnel work under way

NEW RAILWAY SET TO RUN UNDER MOTORWAY

IF you live around the area or perhaps drive past it on your way to work, you may be wondering what is the massive wall that has gone up just inside the M25 near west London.

The 17-metre high headwall that has just been built is located just inside the M25 near West Hyde and not far from Gerrards Cross.

It sits alongside Chalfont Lane, just outside of north-west London, quite close to Harefield and Northwood, in Hillingdon.

It is the site of the south portal of the Chiltern tunnel, which will take HS2 underneath the M25 and onwards towards Birmingham.

The tunnel will be 10 miles long. This wall marks the site of the excavation, at which the tunnel boring machine will soon start digging early next year and it is expected to take around three years to finish the tunnelling project.

At its height, around 1,200 people are expected to be employed to work on the Chiltern tunnels project, according to London blog Ian Visits.

Two tunnels will be built next to each other, one for northbound services and one for southbound.

The site will not stay looking like it does now.

When the tunnels have been dug out and ventilation shafts put in, the material dug out from the tunnels will be used to fill in the site and trees will be planted on top so that it looks, once more, like the surrounding countryside.

For now, people will see this huge wall and excavation site when driving that way on the M25.

David Bennett, delivery director at HS2, told Global Railway Review: “The south portal site will have one of the most important parts to play in the story of HS2.

“From here, we’ll manage the construction of the Chiltern tunnels and the iconic Colne Valley viaduct.

“It’s great to see how much progress has been made on site – and I look forward to working with the team to deliver what will be two of the most exciting and ambitious engineering challenges on the project.”