HS2 in Hertfordshire
The Colne Valley Viaduct carries the new high-speed railway from Harefield in Hillingdon across the Colne Valley into Buckinghamshire. The route enters the 10-mile Chiltern Tunnel at its southern portal, just inside the M25 in Hertfordshire.
Key infrastructure in Hertfordshire includes the Colne Valley Viaduct, the Chiltern Tunnel South Portal, and the Chilterns South Portal Chalk Grassland Project.
Find out more about our works in the area
Management of construction noise at the South Portal
Residents may hear our works activity from viaduct fabrication plant at HS2’s South Portal works site near West Hyde, Rickmansworth.
This Frequently Asked Questions (FAQs) may be useful to find out how we plan to manage construction noise at our South Portal site.
What we're delivering in Hertforshire
Colne Valley Viaduct
Stretching for more than 3.4km (2 miles) across a series of lakes and waterways between Hillingdon and the M25.
Chilterns South Portal Chalk Grassland Project
A new chalk grassland project in the Chiltern Hills is being constructed as part of our Green Corridor Programme.
Chiltern Tunnel
The Chiltern Tunnel is 16km (10 miles) long and will carry passengers under the Chiltern Hills.
Keeping you informed
Stay informed by the works
Find information about HS2 works and activities taking place in your area.
Managing impacts of construction
Find out information about how we manage construction impacts.
Construction look ahead and newsletters
Read our three-month look ahead and newsletters for associated work in Hertfordshire