A railway tunnel built under the English Channel at the Strait of Dover, Britain's gateway to the European continent, as it represents the only land corridor between them, linking Britain and France, and has become one of the main infrastructure assets for tourism, commercial and shipping transport in Europe.
One of the largest engineering projects of the 20th century, and the second longest undersea tunnel in the world, it was named one of the Seven Wonders of the Modern World in 1994.
Location & Design
The Channel Tunnel is a railway tunnel about 50 kilometers long, built under the Channel Sea at the Strait of Dover, linking the town of "Folkestone" in the county of "Kent" in southeastern England, and the city of "Coquill" located in the region of "Bad Calais" in northern France.
It consists of two double tunnels with a diameter of 7.6 meters, with a monorail for the movement of electric express trains, and a third tunnel with a diameter of 4.8 meters for service.
The tunnel is a road with its own mini-transport system, separating the two railway tunnels, used for ventilation, and used by narrow diesel vehicles for maintenance and emergency access.
The railway tunnels are connected to the central service tunnel by intersecting lanes every 375 meters, and the average depth of the tunnels is about 40 meters below the seabed, and they do not run straight, but bend up and down or left and right.
Shuttle trains require ample facilities, so two huge stations were built on both ends of the tunnel on the French and British sides, and the Folkestone station covers an area of 130 hectares.
The French Coccle station covers an area of approximately 700 hectares and at the time of its construction was the largest construction site in Europe.
About 15 kilometers from each tunnel gate, trains pass through large intersecting caves, the largest undersea caves in the world, measuring 158 meters long, 18 meters wide and 10.5 meters high.
Its purpose is to allow trains to pass from one tunnel to another, changing routes for periodic maintenance purposes or in emergency situations.
Nomenclature
It is called the "Channel Tunnel" because it was established under the English Channel, and it is also called the "Channel Tunnel" after the English Channel.
This is the name given to the English Channel by the English and is known as the "European Tunnel", because it is the only firm link between borderless Britain and the mainland in Europe.
Project Idea
The tunnel project was a dream that lasted for 250 years, and people were trying to get a better way than a boat to cross the English Channel, as the main reasons were related to trade and military activity.
In 1751, the Academy of Amiens launched a competition on how to cross the canal, and Nicolas de Smaritz won the proposal to build a tunnel.
Over the next 100 years, a series of mainly French proposals emerged with increasingly sophisticated ideas for a new link with Britain, the dominant idea being road tunnels, before the development of the railway system.
The Channel Tunnel project was cancelled in the 19th century after embarking on it due to British fears of invasion and then resumed (Reuters)
Although De Smaritz is the first documented proponent of a fixed link between Britain and France, the recognized "father of the tunnel" is the French engineer Aimé Thomé de Gamond, who proposed a railway tunnel, and his investigations on the seabed served as the basis for the final project.
With the French enthusiasm for a tunnel, the British viewed it with great suspicion, especially after Napoleon Bonaparte's campaigns, and were reluctant to end their isolation and disconnection from the European continent.
At the beginning of the 19th century, implementation began, and British Colonel and engineer Frederick Beaumont led a team that dug nearly two kilometers under the sea in the Strait of Dover.
A team of French engineers began work on a similar tunnel from the town of Sangat in Bad Calais, but the project was halted under pressure from senior members of the British defense establishment.
A new dialogue between France and the United Kingdom in 1972 led to the drafting of an agreement, the technical and financial feasibility was studied, construction work was prepared, and excavations began anew.
But by 1975, the British government had cancelled the project again, this time more about public spending than about the idea of an invasion.
Establishment of the project
The project resumed under British Prime Minister Margaret Thatcher and French President François Mitterrand, when a joint working group was formed to study technical and economic aspects in 1981.
After 4 years of studies and discussions, the initial procedures for the construction of the tunnel began, in 1985 a call for tenders was issued to finance the project by the private sector.
The Eurotunnel consortium, consisting of the channel tunnel group CTG, French Channel and FM, was awarded the project in January 1986.
On 12 February 1986, Queen Elizabeth II and President Mitterrand signed the Treaty of Canterbury, establishing and operating private franchise companies and authorizing the Intergovernmental Commission (IGC) to oversee the project.
Despite Prime Minister Margaret Thatcher's enthusiasm for the project, it did not meet with consensus among ministers and was met with outrage within Parliament, with great fear of a military invasion, illegal immigration or even an attack by rabid rats.
A large protest movement took place on the British street, and an angry crowd harassed President Mitterrand when he attended the signing of the Treaty of Canterbury, holding banners unusually decorated with messages such as "Britain remains an island".
However, these loud voices did not hinder the implementation of the project, and the concession agreement was signed on March 14, 1986, defining the rights and roles of the concessionaires, the British and French governments and the Intergovernmental Commission (IGC).
The agreement stipulates that concessionaires have the right to implement the project, finance, build and operate during the concession period, which was restricted to 55 years, and later extended to 99 years, that is, until 2086.
According to the terms of the agreement, the concessionaires had to finance, design, construct and operate the project entirely at their own risk, without resorting to government funds, and were given the freedom to determine their tariffs, trade policies, and the type of service they would provide.
The Intergovernmental Committee, which is composed of an equal group of representatives of the French Government and the United Kingdom, is the body responsible for the overall application of the treaty, overseeing the construction and operation of the tunnel, and adopting and implementing the rules on behalf of both countries.
The committee ensures that all safety standards are followed and developed, and the safety aspects of the project have been placed under the management of the Channel Tunnel Safety Authority (CTSA).
The Channel project required 15,<> workers and working conditions on the French and British sides were different (Reuters)
Stages of construction
The Eurotunnel consortium entrusted the construction company Transmanche-Link with responsibility for the implementation of the project, forming two separate companies to carry out the work on both sides of the canal, each consisting of 5 companies.
The five French companies were known as Transmanche, while the British companies were called Translink.
The work began with the collection of data on the marine and geological environment beneath the English Channel, with hundreds of wells drilled on the seabed, and hundreds of kilometers of geophysical transit lines constructed, to help engineers build a three-dimensional picture of the terrain.
In 1988 excavation began on both sides of the canal using tunnel boring machines (TBMs), then caves were built and prefabricated tunnel liner was laid, followed by water pipes, ventilation ducts, power and communication cables, then railways, lighting and emergency equipment were installed.
The project required an army of 15,<> workers at its peak, which led to the creation of a temporary village in Farthingloe on the British side.
The procedures for work on both sides of the canal were different, as the conditions of the natural and cultural environment of the two countries were not on the same line. For example, the ground conditions on the French side were wetter than on the British side, meaning that French machines were moving slowly, and there was a difference in work habits on both sides.
This difference and discrepancy between the two ends of the tunnel did not affect the two teams completing the task with equal professionalism and commitment, with attention to quality, safety and the use of the most appropriate technologies and work practices.
The tunnel was officially opened on May 1994, 6, six years after drilling began, and became the only land communication route between Britain and the European continent.
The first Eurostar high-speed train connection between Paris, Lille and London was established in 1994, Brussels was added in 1997, and in 2015 a line was extended from London to Avignon, Lyon and Marseille, and then to Amsterdam in 2018.
Funding & Cost
Although the French government had no concerns about allocating public funds to the tunnel, it accepted the British insistence on private funding.
The project was fully financed by private sector capital, including 5 banks that were part of the Transmanche Consortium, and financed from shareholder investments, as well as £8 billion in debt, equivalent to US$12.2 billion as of 1994.
The project faced many financial difficulties during construction and operation, resulting in numerous restructuring and significant losses to the private sector, resulting in construction costs reaching more than double initial expectations.
However, the financial situation has been resolved thanks to several restructuring and refinancing plans, the participation of several individual shareholders, and the canal tunnel operating model based on the terms of the railway contract.
When it opened in 1994, the project cost £9.5 billion, and the tunnel was then considered the largest privately funded construction project in the world, with no government funding at all.
All materials used in the Channel tunnel are highly fire-resistant (AP)
Mechanical Tunnel Systems
The tunnel has main mechanical systems: ventilation, cooling, drainage, lighting and firefighting.
The ventilation system has two types: the normal ventilation system (NVS) and works at all times, and the supplementary ventilation system "SVS" which only works in times of emergency.
The cooling system consists of a set of pipes, which carry chilled water from a special station on each coast, and its usefulness is to remove any excess heat caused by the movement of the train in the tunnels.
The drainage system relies on collecting water through drainage lines in the tunnel floor, then directing it to the storage basins, before discharging it to the surface treatment plant through one of the three pumping stations.
The tunnel lighting system consists of high-level lighting, supported by an emergency generation system, and 20,<> luminaires have been installed in the tunnels alone.
All materials used in construction and the rest of the works were chosen to be very fire-resistant, and the tunnel contains a wide range of fire detection and protection devices.
Water tanks and pumping stations are available at 4 locations, with a pipe network under the service tunnel fed at the intersecting passages, as well as foam forming devices and fire extinguishers.
However, three large fires broke out in 3, 1996 and 2006, forcing the authorities to close the tunnel and carry out repairs.
Trolleys & Transportation Services
Trains are equipped in four types: intercity express passenger trains, shuttle passenger trains for cars and buses, shuttle trains for transporting trucks, and freight trains.
The shuttle trains are designed to operate at top speed, and each shuttle consists of 12 double-decker cars for cars, 12 single-decker coaches for bus cars, and other high-sided vehicles.
The passenger train is 776 meters long and its vehicles are the largest in the railway world, and Eurotunnel operates two to three passenger shuttles per hour in each direction, rising to 3 at peak times.
The journey takes about two and a half hours from London to Paris, and about two hours and 25 minutes from London to Brussels, and high-speed routes have been established on French and Belgian routes, reducing flight times, making them very competitive with air transport.
Eurostar shuttle trains run at 160 km/h, but when they reach high-speed lines in Belgium and France they reach speeds of up to 300 km/h.
There are around 30 Eurostar services every day between London, Paris or Brussels, with Eurostar accounting for 60% of the transport service.
The main work of passenger shuttles is leisure travel, and the largest flows are recorded in the summer vacation period.
The freight shuttles were originally 28 wagons long, then extended to 32 vehicles due to increased demand. Unlike passenger trains, freight cars are almost open, and truck drivers don't stay with their cars, but instead take them to the front of the train where they are served a meal.
Features and importance
One of the largest engineering projects of the 20th century, the tunnel was elected in 1994 by the American Society of Civil Engineers as one of the Seven Wonders of the Modern World.
Although not the longest in the world, it is about 4 kilometers shorter than the Seikan Tunnel in Japan, but the 37-kilometer subsea section is the longest in the world.
Digging a tunnel under the seabed also reduces health risks caused by pollution and reduces vulnerability to environmental disasters.
The project had significant economic and political implications in terms of trade and tourism, in particular strengthening relations between the United Kingdom and France, and then between the United Kingdom and the rest of the European Union, as the tunnel was Britain's gateway to Europe.
The tunnel's primary purpose was to join the main road and rail networks in Britain and France, but it has been a pillar in connecting Europe's transport systems as a whole, connecting Britain's 16,150-kilometre railway network with more than <>,<> kilometres of tracks on the continent, among other road networks.
The use of the tunnel is important in reducing travel time between Britain and Europe dramatically, as the time it took to travel between London and Paris was 6 to 7 hours, while trains could make the same journey through the tunnel in as little as two and a half hours.
The tunnel has become one of the basic infrastructure assets for tourist, commercial and trans-European transport, allows fast travel in all weather conditions, and provides a faster transport option than ferry and more affordable than air travel.
The tunnel is one of the busiest rail lines in the world, and when it reaches its maximum capacity, it handles 30 train movements per hour in each direction.
Before the tunnel opened, international rail freight between Britain and France was limited to around 1994 million tonnes a year, all of which had to cross the English Channel on ferries, and freight volumes have grown slowly but steadily since freight services began in <>.
The speed and efficiency of transport provided by the Channel Tunnel has dramatically increased trade connectivity between Britain and the EU, with consumers having access to products at a low cost.
The commercial value of commercial transport through the tunnel is estimated to be equivalent to 26% of total trade between the UK and the EU as of 2016.