Whereas the bridge steals the headlines for its aesthetics and breathtaking views, its brother the tunnel is often unfairly overlooked. But however unglamorous it may be, the tunnel is still a hugely important way of transporting our cars and trains, and often takes on the jobs the bridge simply can’t handle. So as a sign of respect for their often uncelebrated achievements, we’ve put together a list of those tunnels which without doubt deserve your respect.
Eiksund Tunnel:Although still under construction the Eiksund Tunnel in Norway is already the deepest underwater tunnel in the world at 942ft below sea level. At 4.8 miles long, the tunnel will service the areas of Heroy, Sande, Ulstein and Hareid. The reinforcement of this mammoth tunnel has already consumed around 172,000 square foot of concrete. More than 1,300 tonnes of explosives and a staggering 5 million blast holes were used to blast out the route. The tunnel was originally intended to be opened to the public in July of 2007, but numerous delays have pushed the date back into 2008.
Guadarrama Tunnel:The Guadarrama Tunnel is part of the Spanish high speed rail network connecting Madrid and Valladolid and is one of the most important travel links in Spain.Crossing the Sierra de Guadarrama mountain peninsula, this double fornix tunnel is 16.5 miles long, with the widest of the two tunnels 33ft in diameter. The construction contract was signed in 2001, and work began soon after using a Tunnel Boring Machine, although progress was delayed by especially hard rock formations. The tunnel cost around $1.6 billion to build and upon completion, trains will be able to pass through at maximum speeds of 217mph.
Lotschberg Base Tunnel:Constructed to reduce heavy truck traffic on Swiss roads, the Lotschberg Base Tunnel allows vehicles to be loaded onto trains in Germany, carried through Switzerland and unloaded in Italy, as well as providing a quicker route for tourists skiing in the Alps. The world’s longest land tunnel was revealed in an opening ceremony in June 2007. It lies a further 400m under the existing Lotschberg Tunnel. The 21.5 mile tunnel aims to carry 110 trains a day, with tilt passenger trains able to pass through at a speed of 200mph.
Serpukhovsko-Timiryazevskaya Line:Often omitted from tunnel lists as it is in fact a metro line, the Serpukhovsko-Timiryazevskaya Line’s 25.5 mile length makes it the longest subway route in the world, so we feel it deserves some recognition. Originally opened in 1983, the line has been the subject of numerous expansions and lengthening until it achieved its well deserved title in 2007. It cuts the city of Moscow completely into two on a north-south axis, and has a total of 25 stops along an extensive journey through the Russian capital.
Gotthard Road Tunnel:It seems that in tunnel building the Swiss have found their calling (alongside chocolate and banks, of course), as the Gotthard Road Tunnel is one of the most heavily vehicle-travelled tunnels in the world. The Gotthard Road Tunnel comes in second behind its aforementioned compatriot the Lotschberg Base Tunnel in the list of the world’s longest land tunnels, with a total length of approximately 10.5 miles. As an important part of the Hamburg to Sicily transport route, estimates suggest the tunnel is used by at least 1.2 million trucks per annum, hence the chaos that ensued when two trucks collided in 2001 causing a fire within the tunnel, killing 11 people and closing the tunnel for the following two months. The tunnel now enforces a minimum 500ft distance between two lorries to avoid further catastrophe.
Cu Chi Tunnel:As far as tunnels go, none can have had more impact on one country that the Cu Chi Tunnel network in Ho Chi Minh City, Vietnam. This 46.5 mile long system of secret tunnels was an invaluable asset to the Vietnamese in their war against the USA that functioned as a military base of operations, planning and storage for the National Front for the Liberation of South Vietnam’s infamous Tet Offensive in 1968. The network was also an invaluable communications link for NLF troops, and as time went by, developed from being merely a set of underground tunnels to contain kitchens, medical facilities and sleeping quarters; poor air quality and insect infestation made conditions extremely harsh. The tunnels have been properly reinforced and are open to tourists today as a war museum. The Cu Chi tunnel network was never actually officially commissioned, but building commenced in 1948 to defend against the French.
Tokyo Bay Aqualine Tunnel:An integral part of the Tokyo Bay Aqualine, the Tokyo Bay Tunnel is a 5.9 mile long link between Kawasaki City and Kisarazu City that, along with a 2.75 mile long bridge and a completely artificial island, makes up the Trans-Tokyo Bay Highway. The Highway opened in 1997 and saves commuters a tedius 62 mile journey through the congested heart of Tokyo. The shield tunnel has the largest diameter of its kind in the world at 45.5ft for two lanes of traffic as well as vital protection and sturdiness in this highly earthquake prone area.
Seikan Tunnel:The 33.4 mile long Seikan Tunnel is the longest mixed use road / rail tunnel in the world to link the two Japanese islands of Honshu and Hokkaido. The track itself is sunk 747ft beneath the water, making it the deepest of its kind in the world. Commissioned in 1955 after turbulence on the Tsugaru Strait sunk a ferry and killed 1,430 passengers, usual tunnel boring machinery could not be used on unpredictable terrain underneath the water; workers used over 2,800 tonnes of explosives to painstakingly drill their way through a particularly earthquake prone area. The labourious process was eventually completed in 1983 at the expense of 34 lives and $5 billion. However, the recent advent of low fare air travel has made the tunnel almost redundant.
Laerdal Tunnel:The Laerdal Tunnel in Norway is a real feat of engineering that provides an invaluable link between the Bergen area and Eastern Norway, especially as winter conditions make the 6,000ft tall surrounding mountains simply too difficult to cross. At 15.2 miles long the Laerdal Tunnel is the longest road tunnel in the world. 200,000 16.5ft steel bolts hold it place and 376,736 square feet of concrete was poured to support the ceilings and walls. The monotonous 20 minute drive is purposely interrupted by 3 large caverns, which allow for a change of scenery for the driver and a chance to rest when tired. It is also the only tunnel in the world to have its own air treatment plant, situated 6 miles from Aurland, which removes dust and nitrogen oxide from the tunnel’s air supply!
North East MRT Line:Singapore’s North East MRT Line became the world’s first completely underground, automated and driver-less rapid transit line when completed at a cost $5 billion in 2002. The 12.5 mile long track connects central Singapore with the north-eastern part of the island. Each of the 16 stations were designed individually by the Art in Transit project, so each station has a unique style and identity. It takes approximately 30 minutes to complete the journey along the 4ft, 8inch gauge track operated by the SBS Transit Limited. Plans to expand the whole MRT network are currently in motion.
Channel Tunnel:One of the most celebrated engineering achievements of the modern era, the Channel Tunnel aka Chunnel holds the records for having the longest undersea tunnel section in the world (23.5 miles). It is also the longest international tunnel in the world and the second longest rail tunnel, its 31.5 mile length falling short of the Seikan Tunnel’s benchmark. Although the idea to build a permanent route across the channel dates back over 200 years, the tunnel wasn’t opened to the public until 1994. It consists of three parallel tunnels catering for freight trains and vehicle shuttles, as well as perhaps most importantly providing a Eurostar link between London,Paris and Brussels. At the deepest point the Channel Tunnel is 197ft beneath the seabed, which helps explain the reported £10 billion over-run on construction. The company that runs the trains through the tunnel, Euro Tunnel, have been in debt practically from the start. However, the tunnel has been gaining in popularity as track improvements made on the line to improve speeds into central London have come online.