Channel Tunnel is a railway tunnel beneath the English Channel. The “Chunnel” links the United Kingdom and France. It opened in 1994. The tunnel was built and is run by the Eurotunnel Group, which operates in both France and the United Kingdom.
The tunnel carries three types of trains: (1) high-speed passenger trains; (2) shuttle trains for automobiles, trucks, buses, and their passengers; and (3) freight trains. Road vehicles are driven on and off the shuttles at terminals near the two entrances. One entrance is near Folkestone, England. The other is in Coquelles, a village near Calais, France. The trip through the tunnel takes about one-half hour. High-speed passenger trains using the tunnel can travel from London’s St. Pancras station to Gare du Nord (“North Station”) in Paris in about 2 hours 15 minutes.
The Channel Tunnel measures 31.4 miles (50.5 kilometers) from entrance to entrance, with 231/2 miles (37.8 kilometers) underwater. The structure consists of three parallel tubes. Two of them are rail tubes that are 25 feet (7.6 meters) in diameter. The third tube, a service tunnel, lies between the other two and has a diameter of 16 feet (4.8 meters). This tube supplies fresh air and maintenance access to the rail tubes, and could be used for emergency evacuation.
The three tubes generally lie about 130 feet (40 meters) beneath the seabed. Rings of concrete or iron form a continuous lining in the tubes. The rings measure about 5 feet (1.5 meters) wide and up to 2 feet (0.6 meter) thick. Passages connect the three tubes, and at two points the rail tubes merge to enable trains to cross from one track to the other.
Since the mid-1700’s, there had been interest in building a tunnel beneath the channel. Some digging occurred on both sides of the channel in the 1880’s, but the project was abandoned. In 1986, France and the United Kingdom announced that they would permit a tunnel to be built entirely with money from private investors. From 1987 to 1991, 11 boring machines dug the tunnels for the three tubes. They removed about 10 million cubic yards (7.6 million cubic meters) of chalk.
