Application | Tunnel Machinery

with highly flexible control wires. The outer sheath also has to withstand the mechanical stresses. Stephan Gabler, Director of Customized Products at Lapp: “We are very proud of the fact that we were able to deliver this cable for this fascinating project for Herrenknecht for years without complaint.” INSIDE LAPP SOLUTIONS Stefan Jäke also stressed the importance of expert suppliers and high- quality components: “Without good suppliers, we would not be able to manage the volume that we process here every day.” Streb, which is now a company employing 500 staff in 16 locations, was one of the first electrical machine building companies in Germany and is now one of the country’s ten biggest SMEs in electrical wholesale. “Streb, LAPP, and Herrenknecht make an efficient team,” said Streb General Manager Michael Ufheil on a joint tour. Which exact components are used in all control cabinets, transformers, and supply lines in a 100 meter machine? That’s a company secret. But the reason why is no secret: in the Herrenknecht-Streb-LAPP constellation, quality is key. When it comes to collaboration, Stefan Jäke also knows that: “The most important aspect nowadays is open communication, and that requires built-up trust.”

various boulders along the way. Everything is moving, “This creates tremendous vibrations, especially when drilling through hard stone, but even in “normal” conditions.” “All the components we use have to withstand this,” said Stefan Jäke. “Our big aim is that both the machines we use and the components inside them survive the drilling sections in one piece.” The common denominator for everything is reliability. This also applies to the components. This is why companies depend on suppliers being reliable partners and shipping reliable products. The electrical wholesaler Friedrich Streb supplies components for these extreme applications to Herrenknecht, including LAPP connection solutions like ÖLFLEX ® power and control cables, UNITRONIC ® and ETHERLINE ® data network cables, SKINTOP ® and SKINDICHT ® cable glands and EPIC ® connectors. EPIC ® industrial connectors, for example, were used during construction of the Gotthard tunnel as extension connectors. This was because the further the tunnel boring machine was driven into the mountain, the longer the cable for the power supply and controls had to be. To ensure that everything worked reliably, EPIC ® HBE connectors were interconnected with housings and inserts every 50 meters. These connectors are particularly suitable for higher voltages as well as currents and boast a high level of reliability. This is especially important deep in the tunnel. Should the LAPP product range ever not have the right cable for the job, they simply develop one. For Herrenknecht, LAPP developed a special cable for a crane system located at the rear of the tunnel boring machine. In normal operation, this crane is controlled via wireless remote control. If this fails, the crane must be operated via an emergency control cable. The crane operator carries a portable control panel with a six-meter connection cable, which can be connected to the provided sockets when necessary. The cable is used to transmit bus signals and to stop the crane in an emergency. It must be designed to withstand constant movement. The designers at LAPP developed a combined Profibus cable

THE WORLD’S LONGEST RAILWAY TUNNEL Four Herrenknecht tunnel boring machines drilled through more than 85 km to create the Gotthard Base Tunnel. The total volume of drilled-out material is five times the volume of the Great Pyramid of Giza: 13.5 million m 3 .

Final breakthrough in the Gotthard Base Tunnel in October 2010. Photo source: Herrenknecht

View inside one of the tunnel boring machines. The machines can measure up to 18 meters in diameter. Photo source: LAPP/Maiwolf

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