UK-based company High Speed 2 (HS2) has begun construction of the Colne Valley Viaduct, the country’s longest railway bridge.

Located on the outskirts of London, the bridge will span 3.4km across a series of lakes and waterways between Hillingdon and the M25.

The project is designed to improve rail connections between London, Birmingham and the North of England.

A 700t, 160m bridge-building machine, referred to as the ‘launching girder’, has now started works on the bridge.

This will be used to lift 1,000 concrete deck segments, each weighing up to 140 tonnes, for the arched bridge into position.

In a statement, HS2 said: “56 piers, each weighing around 370t, are being constructed along the Colne Valley ahead of the girder, with the girder moving from one pier to the next, installing the deck segments as it goes.”

The 100m long viaduct pre-cast factory will cast nearly 12 segments a week using a match-casting technique. The factory has an internal volume of 105,000m³.

The Align joint venture between Bouygues Travaux Publics, Sir Robert McAlpine and VolkerFitzpatrick is the main contractor of the project, which aims to deliver a low carbon alternative to car and air travel.

Andrew Stephenson MP, minister for the HS2 project, said: “Today, HS2 began construction on what’s set to be Britain’s longest railway viaduct, a landmark moment for HS2 and a feat of British engineering, taking the HS2 line from London, and into Hertfordshire and Buckinghamshire.

“Infrastructure is the backbone of HS2 and this viaduct will be integral to delivering faster journeys and an increased capacity rail network.”

HS2 is the company responsible for building the UK’s high-speed rail network of the same name.

In April this year, the company revealed the final designs of the Thame Valley Viaduct, an 880m-long structure.