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Gibraltar bridge
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Gibraltar Tunnel is envisioned as a rail tunnel that would link Africa and Europe. The idea of a link via a bridge or a tunnel across the Strait of Gibraltar has existed since the 1980s.
The Spanish and Moroccan governments had been jointly investigating the feasibility of a tunnel underneath the strait, similar to the Channel Tunnel between the UK and France. However, 2008 geological studies cast doubt on its practicality.
The idea of a tunnel for petrol/diesel powered road vehicles has been discounted due to the currently insurmountable engineering challenge of ventilation to remove exhaust gases from automobiles from a tunnel some 14 kilometres (8.7 miles) long.
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Gibraltar Tunnel is envisioned as a rail tunnel that would link Africa and Europe. The idea of a link via a bridge or a tunnel across the Strait of Gibraltar has existed since the 1980s.
The Spanish and Moroccan governments had been jointly investigating the feasibility of a tunnel underneath the strait, similar to the Channel Tunnel between the UK and France. However, 2008 geological studies cast doubt on its practicality.
The idea of a tunnel for petrol/diesel powered road vehicles has been discounted due to the currently insurmountable engineering challenge of ventilation to remove exhaust gases from automobiles from a tunnel some 14 kilometres (8.7 miles) long. A three-year study for a railway tunnel was announced in 2003.
The strait depth extends to 900 metres (3000 ft), and is about 14 kilometres (8.7 miles) wide at its narrowest point.
The project would be financed by two publicly owned companies in Spain and Morocco, with the assistance of the European Union.
A report on the feasibility of the tunnel is due to be presented to the EU in 2009.
Original proposals
A group of American and British engineers have studied the feasibility of building a bridge to span the Strait. Such a bridge would have been of a combination suspension-truss design and its height, over 900 metres (3000 ft), would dwarf any existing bridge.
A bridge was ruled out because of the depth of the strait (900 metres, 3000 feet).
A floating bridge was not an option either because of the number of ships passing through the Gibraltar corridor and the strong currents of the strait.
Planning
In December 2003, Spain and Morocco agreed to explore the construction of an undersea rail tunnel to connect their rail systems. In late 2006, Lombardi Engineering Ltd, a Swiss engineering and design company, was retained to draft a design for a railway tunnel. According to the company, the main differences between the construction of this tunnel and that of the Channel Tunnel, linking France and Great Britain, are the depth of the sea and the geological conditions. The area under the Strait is less stable than that under the English Channel as an active major geologic fault, the Azores-Gibraltar Transform Fault bisects the Strait, and severe earthquakes have been known to occur in the area. The presences of two very deep Quaternary clay channels in the middle of the Strait also makes construction complex, causing doubts about the feasibility of the project and proposals for a exploratory tunnel.
It is projected to carry 9 million passengers in its first year of operation, which is expected to start in 2025. No official figures about the cost of the project have been announced as of 2007, but previous estimates were at least five billion Euros.
Technical aspect
The twin rail tunnel would be long, deep, and its construction could take 15 years. Initally a single rail tunnel and a smaller service tunnel is envisaged. A second tunnel would be built if required.
The rail gauge of the tunnel would be standard gauge , to match the proposed construction and conversion of significant parts of the existing Iberian gauge to standard gauge. The line is likely to be electrified at 25 kV AC, the same as Spanish AVE lines, despite both countries having 3kVDC electrification systems, as the 25kV AC is more modern and requires less infrastructure.
The tunnel would have linked Cape Malabata near Tangier with Punta Paloma 40km west of Gibraltar. This link will be 300 metres (around 900 feet) deep. The original link was planned to link the two continents via the narrowest part of the strait but this idea was dismissed as it is 900 metres (around 2700 feet) deep. Even 300 m is deep since today's deepest undersea tunnel, the Eiksund tunnel is 287 m (942 ft) below sea level.
Aside from the actual tunnel itself, it is likely that a branch from the Madrid-Seville AVE line would connect to the tunnel at the north end. There were also proposals to develop a high speed network in Morocco. Similarly, terminals would need to be constructed for trans-shipment of road vehicles like those at Cheriton and Frethun.
See also
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