High Speed 1

High Speed 1 (HS1), officially known as the Channel Tunnel Rail Link (CTRL) and originally as the Union Railway or Continental Main Line (CML), is a 108-kilometre (67 mi) high-speed railway from London through Kent to the UK end of the Channel Tunnel.

The line was built to carry international passenger traffic from the United Kingdom to Continental Europe; additionally it carries domestic passenger traffic to and from towns and cities in Kent, and has the potential to carry Berne gauge freight traffic. The line, crossing over the River Medway and underneath the River Thames to London St Pancras railway station, opened in full on 14 November 2007. It allows speeds of 230 to 300 kilometres per hour (143 to 186 mph) and cost £5.8 billion to build. There are intermediate stations at Stratford International, Ebbsfleet International and Ashford International.

International passenger services are currently provided by Eurostar, with journey times of London St Pancras to Paris Gare du Nord in 2 hours 15 minutes, and St Pancras to Brussels-South in 1 hour 51 minutes, using a fleet of 27 Class 373/1 multi-system trains capable of 300 kilometres per hour (186 mph). Other, competing, passenger operators are expected to use the line in future.

Domestic high-speed commuter services serving the intermediate stations and beyond began on 13 December 2009. The fleet of 29 Class 395 passenger trains are permitted to reach speeds of 225 kilometres per hour (140 mph).

Following trials of a modified Class 92 locomotive hauling a loaded container train in July 2011, DB Schenker is running regular intermodal freight services on High Speed 1, enabling flat wagons carrying continental-size swap body containers to reach London for the first time.

The CTRL project was one of the United Kingdom's largest civil engineering projects, encompassing many new bridges and tunnels with a combined length nearly as long as the Channel Tunnel itself. During construction of the CTRL, significant archaeological research was undertaken. In 2002, the CTRL project was awarded the "Major Project Award" at the British Construction Industry Awards. The CTRL has seen periods of financial difficulty, and the line was transferred to government ownership in 2009, with a 30-year concession for its operation being put up for sale in June 2010. The concession was awarded to a consortium of Borealis Infrastructure (part of Ontario Municipal Employees Retirement System) and Ontario Teachers' Pension Plan in November 2010, but does not include the freehold or rights to any of the associated land.