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Big celebration: The Follo Line with double breakthrough in the tunnel

11 Sep 2018

The tunnel excavation in the Nordic region's longest rail tunnel has just reached its target towards Oslo city center. With the new minister of transport, Jon Georg Dale among the supporters, the tunnel boring machines named Dronning Eufemia and Queen Ellisiv fought for first place, but both broke through simultaneously.

In two years, the two queen machines heading northbound toward Oslo, have successfully drilled nine km each. The final launch for the tunnel is scheduled for spring 2019 when the last two tunnel boring machines (TBM) come out at Ski.

One of Norway's most important infrastructure projects

With today's breakthrough towards the center of Oslo, two giant tunnel boring machines (TBM) have completed the journey at the same time. It is probably the first time in history that two hard rock machines have bored closely after each other over such a long stretch and have come to the end at the same time. The two machines came out of the mountain and into a mountain hall where guests, 3D-mapping and festivities were waiting. When the dust had subsided, tunnel workers came crawling through the head of the large machines, with flags and cheers.

- Today's breakthrough with the first tunnel boring machines towards Oslo city center is the result of many years of planning and successful project implementation. The Follo Line project is one of the most important infrastructure projects in Norway, says Bane NOR's CEO Gorm Frimannslund.

Great milestone

Bane NOR chose this method for drilling most of the long tunnel (18.5 km of 20 km), and it is Entrepreneur Acciona Ghella Joint Venture (AGJV) who performs the tunnels on behalf of Bane NOR. The excavation started September 5th, 2016, and the boring in the north direction has been completed ahead of schedule.

- We understood early that tunnel boring machines could be a good choice. With this project we have documented that tunnel boring, in addition to explosives and more conventional methods, is a good choice for the production of waterproof, long tunnels, also in hard rock, as we have here in the country, says project manager for TBM, Anne Kathrine Kalager and add;

- Two years ago, we started the first machine. When we reach the goal two years later, not only with one, but two machines, it feels like reaching a big milestone, says Anne Kathrine Kalager.

Project Director at AGJV is proud of what they, together with Bane NOR, have achieved so far.

- We are proud of how AGJV, in cooperation with Bane NOR, has managed to handle this complex project. Together we continue to achieve goals, and through this cooperation over we solve the challenges together. The double breakthrough we experienced today, ahead of schedule, was emotionally strong and amazing, says Fernando Vara, Project Director, AGJV, who is also responsible for the corresponding tunnel towards Ski.

Railway technical work starts up

Well ahead of the Oslo Center, the two tunnel drills will be disassembled and transported out of the mountain. Equipment for this is already ready. Immediately, work on rail technology also begins to make the watertight tunnel a completed railway system.

- The Follo Line will provide a state-of-the-art infrastructure for this part of the Oslo region and further south to the towns we have on the eastern side of the Oslo Fjord and all the way to Sweden. It is designed for speed of up to 250 km/h and has at least 100 years of life expectancy, says Per David Borenstein, Project Director at Bane NOR.

Minister of Transport Jon Georg Dale emphasized in his speech that the Follo Line is an important part of the Intercity development. Bane NOR is expected to enter into 60 billion NOK of contracts for the next three years to ensure, among other things, a double track in Eastern Norway.

Facts about the Follo Line Project and tunnel boring

Two tunnel boring machines, each of 2400 tonnes, have bored from the Åsland area, south of Oslo, into a mountain hall at the center of Oslo, while another two machines have excavated and sealed the tunnel from the Åsland area towards Ski.

The 150 meter long machines have 9.96m diameter drill bits and are specially made for extra hard rock. These are the most powerful tunnel drills ever produced, according to the manufacturer Herrenknecht in Germany.

2/3 or just over 65% of the large Follo Line project has now been completed and the Follo Line will be completed in December 2021. Passengers can then take the train through the long tunnel on the journey between Oslo S and Ski - and the travel time will be halved relative to today's travel time with the fastest trains. Others may choose to take a local train on the Østfold Line, where the train service is significantly improved. The Østfold Line has been partially restructured and improved as part of the large Follo Line project.