Interior view of Channel Tunnel connecting UK and France
Connecting England with continental Europe

The Channel Tunnel is a 50.5-kilometer (31.3-mile) railway tunnel under the English Channel that links the United Kingdom and France. It is the third longest railway tunnel in the world, surpassed only by the Gotthard Base Tunnel in Switzerland and the Seikan Tunnel in Japan, and has the world’s longest undersea section — 37.9 kilometers (23.5 miles).

Challenge
Ideas for a tunnel connecting England and France have been around since the early 19th century, but it wasn’t until the 1980s that construction of an international, all-weather link using private funding was agreed upon by British and French leaders. Promoters were invited to submit proposals, and a submission by the Channel Tunnel Group/France-Manche (consisting of five banks and ten construction companies) to design and construct a tunnel system that could accommodate conventional trains as well as a vehicle shuttle service was selected. An infrastructure project of this scale and complexity, the largest in Europe to date, would require major engineering innovation and extensive private financing.

Solution
Louis Berger was retained by the Channel Tunnel Lending Consortium as Technical Advisor to the underwriting banks. The initial assignment was to analyze the proposed construction contract, cost estimates and other documents to identify potential risks and prepare an initial report used as the basis for negotiating the final contract documents.

With the raising of credit facilities and syndication of the loans, Louis Berger subsequently provided ongoing review of construction costs, analysis of the work in progress and technical advice to banks. This included ongoing evaluation of risks, assessment of funding requirements and high-level monitoring of project progress, particularly the terminal facilities, throughout the project duration.

Construction works comprised a rail link shuttle system including two 7.6 meter (24.9 feet) diameter bored tunnels and a separate service tunnel, each approximately 50 kilometers (31 miles) long, plus terminal complexes at each end.

Completed in 1994, the Channel Tunnel carries high-speed Eurostar passenger trains, the Eurotunnel Shuttle for road vehicles and trucks, and international freight trains. The journey between end points at Coquelles, Pas-de-Calais, France, and Folkestone, Kent, England takes about 20 minutes by passenger train and 35 minutes by vehicle shuttle. Over the course of 2015, it was recorded that 21 million passengers were accommodated through the tunnel, plus 1.5 million trucks.