The Channel Tunnel, (French: le tunnel sous la Manche; often nicknamed the Chunnel in English) is a rail tunnel beneath the English Channel at the Straits of Dover, connecting Cheriton in Kent, England and Sangatte in northern France. A long-standing and hugely expensive project that saw several false starts, it was finally completed in 1994. It is the second longest rail tunnel in the world, surpassed only by the Seikan Tunnel in Japan. It is operated by Eurotunnel plc .
A link between Britain and France had been proposed on many occasions.
- 1802 Albert Matthieu-Favier, a French engineer, put forward a proposal for a tunnel. Passengers would travel through the tunnel in horse-drawn coaches; the road would be lit by oil-lamps; and a mid-tunnel island would have provided a fresh-air respite for the horses. The cost would have been one million pounds even then.
- 1875 Peter Barlow, builder of London's first Underground railway suggested a floating steel tube across the Channel. Idea rejected
- also 1875 French & English Bills of Parliament passed to build the tunnel. Insufficient funds raised and concession ran out a year later.
- 1876 Extensive geological survey carried out; French sink two shafts.
- 1880 The South Eastern Railway (SER) arranges trial borings on English side
- 1881 Patented (Beaumont) boring machine drive a tunnel 897 yards (820 m) parallel to cliffs on English side
- also 1881 work begins on Channel Tunnel by (SER); again insufficient funds & Submarine Continental Railway Company set up.
- 1882 Rival Channel Tunnel Company causes a rift in proceedings; adverse comments by media and an influential group (including Robert Browning and Alfred Lord Tennyson). Eventually work was halted by the Board of Trade because of military objections: the ease with which invaders could attack from the Continent was cited.
- 1922 In 1922 workers started boring a tunnel from Folkestone: after 128 metres of tunnel had been completed, political objections again brought the project to an end.
The current tunnel
In 1957 the Channel Tunnel Study Group was formed. It reported in 1960 and recommended a railway tunnel of two main tunnels and a smaller service tunnel. The project was launched in 1973 but folded due to financial problems in 1975 after the construction of a 250 m test tunnel.
In 1984 the idea was relaunched with an Anglo-French government request for proposals to build a privately funded link. Of the four submissions received the one most closely resembling the 1973 plan was chosen and announced on January 20, 1986. The Fixed Link Treaty was signed by the two governments in Canterbury, Kent on February 12, 1986 and ratified in 1987.
The planned route of the tunnel took it from Calais to Folkestone (a route rather longer than the shortest possible crossing) and the tunnel was to follow a single chalk stratum (which meant the tunnel was deeper than the previous attempt). For much of its route, the tunnel is nearly 40 m under the seafloor, with the southern section being deeper than the northern.
Digging the tunnel took 15,000 workers over seven years, with tunnelling operations conducted simultaneously from both ends. The prime contractor for the construction was the Anglo-French Transmanche Link, a consortium of construction companies. Engineers used large tunnel boring machines (TBMs), mobile excavation factories that combined drilling, material removal, and the process of shoring up the soft and permeable tunnel walls with a concrete liner. After the British and French TBMs had met near the middle, the French TBM was dismantled while the British one was diverted into the rock and abandoned. Almost 4 million cubic metres of chalk were excavated on the English side, much of which was dumped below Shakespeare Cliff near Folkestone to reclaim 90 acres (360,000 m²) of land from the sea.
The Channel Tunnel consists of three parallel tunnels: two primary rail tunnels, which carry trains north and south, and a smaller access tunnel. This access tunnel, which is served by narrow wheeled vehicles, is interconnected, by means of transverse passages, to the main tunnels at regular intervals. It allows maintenance workers access to the tunnel complex, provides a safe route for escape during emergencies, and dissipates the aerodynamic shockwave that would otherwise accumulate in front of a train travelling through a main tunnel at full speed.
When the two tunnels met 40 m beneath the English Channel seabed on December 1, 1990, in what was to become one of the "crossover halls" that allow diversion of trains from one main tunnel to the other, it became possible to walk on dry land from Britain to mainland Europe for the first time since the end of the last ice age, over 13,000 years ago. The British and French efforts, which had been guided by laser surveying methods, met with less than 2 cm of error.
The Channel Tunnel is 50 km (31 mi) long, of which 39 km (24 mi) are undersea. The average depth is 45 m (150 ft) underneath the seabed. It opened for business in late 1994, offering two principal services: a shuttle run for vehicles, and the Eurostar passenger service linking London with Paris and Brussels. Nearly 7 million passengers take the 35 minute journey through the tunnel every year. At completion, it was estimated that the whole project cost around £10 billion.
The tunnel is operated by Eurotunnel plc. Four types of train services operate:
- Eurostar, a high speed passenger service. This connects London's Waterloo station (incidentally, named for the Napoleonic battle between the UK and France) with the Gare du Nord station in Paris and with Brussels Midi/Zuid station, with stops at Ashford, Calais-Frethun and Lille.
- Eurotunnel shuttle , a rail ferry service. These carry cars, coaches and vans between Sangatte (Calais/Coquelles) and Folkestone. Enclosed railcars with minor amenities, some double-decker, permit drive-on and drive-off operation; passengers stay with their vehicle. (Formerly marketed as Le Shuttle.)
- Eurotunnel freight shuttle trains. These carry lorries on open railcars, with the lorry drivers travelling in separate passenger coaches.
- Eurotunnel rail freight service. These trains carry conventional rail freight or container loads between a special transfer yard in France to destinations in England.
Although Eurostar trains travel at high speeds in France (where the tracks are modern and custom-made for the standard TGV cruising speed of 300 km/h (186 mph), and within the tunnel at up to 160 km/h (100 mph), their speed in Kent is limited by the relatively low-speed tracks over which they must run. The Channel Tunnel Rail Link project, a partly government-funded scheme to build a dedicated high-speed line from London to the tunnel entrance, is expected to be completed in 2007. A first stage of the link, running from the tunnel to North Kent, was opened in 2003.
There have been proposals for local passenger rail services linking Kent with towns in the Pas de Calais, along the lines of the local trains that run between Zealand and southern Sweden across the Oresund Bridge, but the prospect of such a service remains uncertain.
The Channel Tunnel's only serious operational incident as of 2004 was the November 18, 1996 fire aboard a shuttle train carrying truck trailers. With rescue crews already alerted, the Folkestone-bound train came to an emergency stop halfway through the tunnel. Amid acrid smoke, passengers were evacuated to a train headed the other way. Fire crews managed to extinguish the superheated fire in a number of hours, battling low water pressure, high-velocity wind from the emergency actions of the ventilation fans, and intense heat. 200 meters of the tunnel lining were seriously damaged, and another 200 meters were significantly damaged. In some areas the concrete liner was thinned due to spalling from the heat to within only 5 centimeters of its original 45 centimeters thickness. The rear cars and rear locomotive of the train were destroyed. No lives were lost, due in large part to the safety of the tunnel design and the response of safety crews from both France and the UK.
The tunnel was re-opened for limited use on November 21 1996, only three days after the fire. With only one main tunnel in operation, safety rules prohibited passenger services from using the tunnel. Freight services operated in half-duplex fashion until the tunnel was repaired. Passenger services resumed on December 4 1996, and full service was restored on January 6 1997.
The Tunnel's operators faced criticism for mishandling the incident. The train had been observed to be on fire when entering the tunnel, and much of the incident's complexity could have been avoided if the train had stayed above ground. Once it was decided to have the train proceed to Folkestone, much of the trouble could again have been avoided if this plan had been completed. (The train driver decided to stop in the tunnel due to concern about a possible derailment.) There were also miscommunications in the fire-fighting response. 
The tunnel has become a popular means by which asylum seekers, hoping that their chances of receiving asylum are better in the UK than in France, illegally enter the UK. A few attempt to walk through the tunnel or to cling to the trains themselves, but most try to hide in freight containers or trucks using the tunnel. In 2002, British immigration authorities added sophisticated listening and imaging equipment to their post in Kent, hoping to hear the heartbeats or sense the breathing of such stowaways. In early 2003 the British government persuaded French authorities to close the controversial centre for asylum seekers at Sangatte , which they felt encouraged such clandestine travel. In an unusual move, the British and French governments agreed to provide immigration staff at opposite ends of the tunnel; thus the French immigration control posts are located in England while the British ones are in France.
Appearances in film
Given its status as one of the 20th century's most significant feats of engineering, it is perhaps surprising that the Channel Tunnel has not become more of a cultural icon (although admittedly other "modern wonders of the world" such as the Golden Gate Bridge and Empire State Building are more photogenic).
The Channel Tunnel features in the climax of the film Mission: Impossible (Brian De Palma, 1996), in which Tom Cruise, clinging on to a high-speed train, is chased by a helicopter into what is supposedly the Channel Tunnel. The largely CGI sequence contains many factual errors in addition to the physical impossibility of such a feat. In the film the tunnel is shown as a single rectangular twin-track tunnel, and the trains shown are standard French TGVs without overhead wires. In reality the Channel Tunnel uses two physically separated single-track tunnels for the two directions of travel, while SNCF passenger trains do not operate in the tunnel. The sequence showing the train going into the tunnel was reportedly filmed in the Upper Nithsdale valley on the Kilmarnock to Dumfries railway line in Scotland.
- Channel Tunnel History
- Channel Tunnel Facts - a selection of historical and geological facts about the tunnel
- Channel Tunnel Fire - detailed technical summary of the emergency response
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