Gotthard base tunnel: Clear signal in the world’s longest tunnel
The new Gotthard base tunnel running through the heart of the Swiss Alps is 57 kilometres in length, making it the world’s longest tunnel. After eleven years of construction, breakthrough finally took place in the mountain just after 2:00 p.m. on 15 October 2010. This historic event was televised in a seven-hour live broadcast on Swiss television, which was made possible thanks to fiber optic cables from HUBER+SUHNER.
Europe is about to get smaller. When the new Gotthard base tunnel opens in 2017, rail passengers will be able to travel from Erstfeld on the northern side of the Alps to Bodio on the southern side in just 17 minutes compared to the hour it takes at present. Trains will be able to travel as fast as 250 km/h through the tunnel. Over the past eleven years, some 2,600 people have been employed in the construction of this historic structure, which runs up to 2,500 metres below the earth’s surface.
Seven-hour live broadcast from the mountain
The breakthrough in the 57-kilometre long tunnel took place on 15 October 2010. This historic event was televised in a marathon seven-hour live broadcast from the mountain by Swiss television. After months of preparation, 100 personnel from Swiss television took their positions on the big day. Ten presenters reported from all the key locations. They were live at the tunnel face, deep underneath the earth’s surface, where 200 specially invited guests awaited the breakthrough. They were also with the workers at the tunnel boring machine as this huge contraption was started up to break through the last few metres of rock from the southern side. The broadcast also included background information about the construction of this record-breaking tunnel as well as the political history of Neat and its finances. The event attracted a great deal of interest worldwide. In Luxembourg, EU transport ministers interrupted their meeting to watch the historic breakthrough live on Swiss television.
Extreme conditions for a cable
There was no margin for error during transmission. «The decision by Swiss television to broadcast high-quality HD video from deep inside the mountain was a huge technical feat and presented us with numerous challenges», says Kurt Schwaller, Project Manager with the production company TPC. The transmission of these huge data volumes in the humid, wet and rocky conditions underneath the mountain demanded the laying of many kilometres of robust and resilient fiber optic cables. A further challenge was the 800-metre access shaft in which the cables had to be freely suspended, thus subjecting them to extremely high tensile loads. Normal cables simply would not work under these conditions.
Over 16 kilometres of fiber optic cables
HUBER+SUHNER had the solution. Specially customized MASTERLINE fiber optic cable systems were used, combining extreme mechanical robustness and compliance with the stringent requirements with respect to tensile strength. The company produced over 16 kilometres of 24-fiber MASTERLINE fiber optic cable for the specialGotthard base tunnel broadcast. From the outside broadcast unit in Sedrun, a cable was routed over 1.2 kilometres along the ground to the access shaft. From there it was suspended vertically 800 metres into the tunnel and then ran a further 3.5 kilometres to the breakthrough point in the tunnel. Two cables were laid in parallel in the tunnel – the second acting as a backup in case the first failed during the broadcast. Fortunately this did not happen. Part of the HUBER+SUHNER cable systems was delivered on two-metre reels. Smaller reels were needed for laying in the shaft, as the bigger reels would not fit in the lift. The MASTERLINE cable systems were fully assembled and terminated with waterproof and dustproof E-2000 connectors. This meant that no splicing was required during installation and the cables simply had to be boxed.
Worldwide coverage thanks to HUBER+SUHNER
All of the Swiss television outside broadcast units depended solely on these fiber optic cables from HUBER+SUHNER for transmitting their reports. They reliably withstood the enormous loads and made it possible to broadcast the images of this historic event from deep inside the Gotthard base tunnel live all over the world