Mobile phone shooting at last thanks to 80 km cable

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Engadin is a hiking and skiing paradise. Every year 1.15 million people find their way to this enchanting valley through the Rhaetian Railway and the Albula Tunnel.

But the tube running through the mountain, which was put into service in 1903 after four years of construction, is now showing its age. Therefore, the Albula Tunnel II has been under construction since 2015. It will be put into service between 3-9 June 2024. From then on, Albula Tunnel I will only serve as a safety tunnel where passengers can be evacuated in case of emergency.

First stage completed

The shell of the new tunnel was completed in early December 2022. Curea Elektro AG, which was recently owned by Arnold AG and thus BKW Infra Services, has completed the first phase of its work. Group companies of BKW together with Baumelereitungsbau AG and Elbatech AG.

“We ensure that electricity flows and communication is possible in both tunnels. We also undertake the laying of cables for safety measures,” explains Roger Küng tasks. He is chairman and board member of the energy and railway technology division at Curea Elektro AG. In the first phase, 68.7 kilometers of copper cable, approximately 12.7 kilometers of fiber optic cables and around 24 kilometers of cable protection pipes were laid.

The project at an altitude of about 1800 meters is challenging. “The short timeframe from late January to mid-March 2023 was a big challenge,” Küng says. “All materials, including personnel, had to be brought to the construction site in Preda by train. Because Albula Pass is closed in winter and is used for tobogganing.»

Equipment such as diesel or heating oil also had to be delivered by Rhaetian Railway, RhB for short. “A mobile gas station was set up on site to refuel our vehicles,” Küng explains.

Cable difficulties

Temperatures were also a factor that was difficult to assess. “We had nights where the outside temperature dropped to almost -20°C.” Although the lowest laying temperature for cables is -5 °C, temperatures below 0 °C are not recommended. “The colder the weather, the tougher the cable jacket. This makes cables significantly more susceptible to tensile and bending loads. Our condition to ensure quality was at least +5 °C.»

To achieve this goal, a heatable storage tent was set up where the material was brought to the right temperature. “Getting the necessary cable reels in the tent at the right time has always been a logistical challenge. We had to move 90 reels from 100 kilos to 7000 kilos.” ​​A total of 220 tons of weight was transported in three months.

Navigation in the tunnel is impossible

Another difficulty was that you could not pass through the 5.8 kilometer long tunnel. The vehicles are 2.5 meters wide, and the track is only 3 meters. “Therefore, all vehicles had to go all the way to the end of the tunnel in Spinas to return to Preda, one after the other, in one convoy,” explains Roger Küng. From a logistical standpoint, it was acrobatics: “The 20 workers had to be coordinated every day to be in the right place with the right cable.”

When asked exactly where the staff were staying, Küng said, “Some of them slept in overnight containers at the hotel in Preda and at the construction site. Some of them stayed in a hotel in Filisur. Then there were a few people who were able to go home in the evenings because they lived nearby.”

Employees are now busy with other projects. However, in the fall, the second phase of the Albula Tunnel II will begin for Curea Elektro AG and other companies in the BKW network. We haven’t been able to do that yet, as it’s currently under construction.” Then the new tunnel was procured. “Then everything can be checked and put into operation.” A year later comes the third and final phase. “During his trip, we are equipping the old tunnel which is being expanded into a safety tunnel. “

Roger Küng emphasizes that employees can be proud of what they have already achieved. Emin: “This project will be remembered especially later when you get on the train through the tunnel.” He is pleased that it will be possible to send phone calls or text messages here in the future, thanks to the cooperation between the four BKW Group companies. “Expanding digital communication and supply networks and enabling public transport are helping to make living spaces more livable. Good infrastructure is very important for people’s quality of life.»

Source : Blick