The Challenge

HS1, running 109km between the Channel Tunnel and London’s St Pancras station, was the first major new railway line to be built in the UK for over 100 years and the UK’s first high speed line. Though most people see its role as decreasing journey times from London to the continent, HS1 serves other purposes: relieving congestion on existing lines in the South East; creating a faster, more reliable service for commuters in Kent; and encouraging regeneration around its stations.

HS1, then known as the Channel Tunnel Rail Link (CTRL) was delivered in two phases, between them costing £5.2bn. Phase 1 ran the 74km from the Channel Tunnel through Kent to the outskirts of London and opened in 2003. Phase 2 connected the first section to St Pancras and opened in 2007. In addition to stops at existing stations Ashford International and St Pancras, HS1 also saw the creation of new stations at Stratford in East London and Ebbsfleet in Kent.

The line was constructed under a public-private partnership between the UK government and concessionaire London & Continental Railway (LCR), a consortium of eight major shareholders which included SYSTRA and Arup. Rail Link Engineering, a consortium of Bechtel, Arup, Halcrow and SYSTRA, provided project design and engineering.

A quarter of HS1’s route lies underground. On phase 1, there is the 3.2km North Downs Tunnel and on phase 2, the line includes a 3km tunnel under the River Thames and runs 19km underground from Dagenham in the east to where it emerges close to King’s Cross. The 1.2km Medway Viaduct which carries the line over the River Medway in Kent, has a central span of 152.4m.


SYSTRA led the design and construction engineering structures, track and catenary, signalling, control-command and power supply. We also had overall supervision of the construction phase, design and implementation of the test programme, acceptance and commissioning and the preparation of the maintenance programme.