After 17 years' construction time, the new Gotthard Base Tunnel was ceremonially opened on June 1, 2016. With a length of 57 kilometres it is not only the world's longest railway tunnel but also a unique masterpiece of engineering.
The Gotthard Base Tunnel extends from the north portal at Erstfeld, in the canton of Uri, to the south portal at Bodio, in the canton of Ticino. The main tunnel is 57 km long and consists of two singletrack tubes, which are 40 metres apart and connected to each other every 325 metres by a cross-passage. With the addition of all the connecting passages, access adits and shafts, the complete tunnel system measures around 152 km. With a rock overlay of up to 2,300 metres, the Gotthard Base Tunnel is the world's deepest railway tunnel; it also has virtually no gradients, with the highest point lying at 550 metres above sea level.
Two multifunction stations, beneath Faido and Sedrun, divide both tubes into three approximately equally long sections. In these multifunction stations the trains can cross over from one tube into the other and stop in an emergency.
The construction of the century was put into operation by Swiss Federal Railways with scheduled train services on December 11, 2016.
More informations about the Gotthard Base Tunnel: https://company.sbb.ch/en/media/background-information/gotthard-base-tunnel.html
For construction purposes, the Gotthard Base Tunnel was divided into five sections. To save time and costs, construction work on the individual sections was coordinated and, for some of the time, proceeded simultaneously.
To construct the Gotthard Base Tunnel, the miners had to cut through highly diverse rock strata: from hard granite to highly fragmented sediments. Eighty percent of the driving in the main tubes was performed by tunnel boring machines, twenty percent by conventional drilling and blasting. A total of 28.2 million tonnes of excavated rock was transported out of the tunnel. The underground temperature was up to 46 °C. At peak times, around 2,400 people worked on the tunnel construction sites. Construction work took place on a twenty-four-hour, three-shift basis.
On October 15, 2010, the world record under the Gotthard became reality: 30 kilometres from the south portal and 27 kilometres from the north portal, the final breakthrough of the world's longest railway tunnel took place. The surveyors also achieved a masterly performance: a deviation of only eight centimetres horizontally and one centimetre vertically. To excavate the entire tunnel, the miners took a total of around eleven years.
However, work operations in the Gotthard Base Tunnel did not end with the final breakthrough. They continued with fitting-out of the two tunnel tubes. The tunnel-infrastructure specialists equipped the tunnel with mechanical and electromechanical systems such as doors, ventilation and drainage. These ensure that the railway tunnel can be safely operated and maintained.
Installation of the railway infrastructure systems began in summer 2010. These comprised the track, catenary, electric power supply, cables, telecommunication and radio systems, safety and automation systems, and control systems.
Finally, the new tunnel also had to be connected with the existing railway network. For this purpose, in the north as well as in the south, auxiliary structures such as bridges and underpasses were built to provide a link from the existing SFR line to the tunnel.
Before the Gotthard Base Tunnel could be commissioned, in more than 3,500 test runs the interplay of all tunnel components and systems was thoroughly tested.
In November 2015 a train travelled for the first time at the maximum test speed of 275 km/h through the world's longest railway tunnel. In January 2016 the first goods train completed its journey through the new Gotthard Base Tunnel. At the start of June, 2016, the Gotthard Base Tunnel was opened with a largescale opening ceremony and a public festival for young and old. The construction of the century was put into operation by Swiss Federal Railways with scheduled train services on December 11, 2016.