Pioneering Achievement 2,200 Meters under the Alpine Peaks

With the Gotthard tunnel Switzerland is making history – and ContiTech is in on the action

January 2011 Switzerland has notched up another superlative. In October 2010, the tunnel boring machine “Gabi I” drilled through the final centimeters of the 57-kilometer-long Gotthard base tunnel. Switzerland can now claim the world’s longest tunnel. Hoses and conveyor belts from ContiTech are also involved in the construction work.

In the forefront of the action are German companies like Schwanau, Germany-based Herrenknecht AG, a specialist for tunnel boring machines. The Swabians supply tunnel boring machines and specially developed operating platforms for the most diverse projects all around the world. Several ContiTech business units have a role to play in all of this. As an expert in the design of special-purpose hoses, Eddelbüttel + Schneider has been a partner to Herrenknecht for many years. It has designed hoses for the tunnel boring machines and installation devices employed in tunnel construction.

The sharp-edged granite blocks generated in the course of boring operations have to be transported over long stretches. Both steel cord and fabric-reinforced belts made by the ContiTech Conveyor Belt Group are used to do the job. The conveyor belt specialist has been supplying products for this huge project for ten years now. In the meantime, more than 140 kilometers are reliably in service, both outside the tunnel leading up to access points as well as inside the tunnel. As the construction of the tunnel advances, the conveyor belts grow kilometer by kilometer as well. Together with a partner company, Agom Technica S.A. of Switzerland, ContiTech ensures that the conveyor belts on the Gabi I guarantee – day in, day out – uninterrupted removal of overburden

But why are the residents of the Alps building this huge tunnel? The main reason is that the country has become a bottleneck of sorts for the constantly expanding goods transport on the roads between central and southern Europe. Every year the Swiss are forced to cope with a higher volume of traffic. The consequences for both people and the environment are immense. Under the motto "Off-road, on track", this prompted the Swiss in the mid-90s to launch the NRLA project. NRLA stands for “New Railway Link through the Alps” and stands for the construction of a new state-of-the-art high-speed train connection along the country’s north-south axis. Three new train tunnels of enormous proportions are at the heart of the project. The largest of these is the new base tunnel at Gotthard. Commencement of service – planned for 2017 – is expected to effect an improvement in many respects: The route will be much shorter than via the old railway tunnel; it will be able to handle greater loads and higher speeds; and it will enhance safety and, above all, achieve drive energy savings of roughly 50  percent. It is hoped it will provide a strong incentive to transport heavy goods by rail.

The connection is designed as a flat-level rail line. Devoid of gradients of any note, the tunnel maintains a fairly consistent altitude of 550 meters above sea level. And it does so no less than twice over a distance of 57 kilometers, for the construction consists of two separate tubes running parallel to one another: the east and the west tunnel. Counting all the access and connection tunnels as well, the whole system has a length of 156 kilometers – that's 156,000 meters that have to be hewn or blasted out of the mountain, piece by piece. Each tunnel being ten meters in diameter, that works out to 30 million metric tons of stone. Around a third of the overburden is reused in the concrete employed for completion of the interior.

The core component in tunnel construction is Gabi I, one of Herrenknecht AG’s four tunnel boring machines providing service in the Gotthard. It is a truly humongous unit, measuring 450 meters in all. The forward eight meters are used for the drilling operation, while the remaining length forms a kind of mobile scaffolding, from which the bore hole walls are secured with anchors and shotcrete. Propelled by a hydraulic device, the entire unit moves on trackage with a width of seven meters, at a speed corresponding to headway boring progress.

With its 62 chisels, Gabi I's cutter head has a diameter of 9.58 meters. It is powered by ten electric motors with an aggregate output of 4,700 HP. That’s enough to propel Gabi I through up to 40 meters of hard rock each day. Just behind the cutter head, a vacuum is generated that helps to neatly conduct the hewn material through a massive ContiTech rubber hose to a steel-reinforced conveyor belt.

Working from an operations platform called "the worm", the team completes the job of fortifying the walls. The worm is a structure developed specifically for the Gotthard project. It keeps Gabi I constantly supplied with electric power and water while the tube walls to the rear are being clad with foil and concrete. Here the worm bridges a gap in the otherwise unbroken chain of permanently installed supply lines. Equipped with a hose reel about four meters in diameter and a rubber hose up to 150 meters in length, the hydraulically powered front end of the worm moves forward on the trackage as work on the tunnel walls progresses.

After a week at the most, the rear end of the worm is then dragged forward, the hose rolled up again and, in this way, the requisite hose length for a further week’s work provided. When Marcus Prinz, general manager of Eddelbüttel + Schneider, off-handedly points out that this isn’t sorcery of any kind but actually just a “Gardena garden hose system”, that can only be understood as pure understatement, even coming from an amiable North German. The ContiTech hose used in the Gotthard is, after all, 40 centimeters in diameter and weighs 70 kilograms – per running meter. That's hardly what you'd call a garden hose!

In 2017 – after 18 years of construction work – the first trains will roll through the AlpTransit, connecting Zurich and Milan by train in just 160 minutes.

Pioneering Achievement 2,200 Meters under the Alpine Peaks>

Pioneering Achievement 2,200 Meters under the Alpine Peaks>

Pioneering Achievement 2,200 Meters under the Alpine Peaks>

Pioneering Achievement 2,200 Meters under the Alpine Peaks>

Pioneering Achievement 2,200 Meters under the Alpine Peaks>