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Part 2

An exercise in patience

Allianz Suisse | Zurich | Apr 15, 2013

Continued from April 8, 2013

Adding up all the crosscuts, access tunnels and shafts the entire tunnel system in the Gotthard stretches over 152 kilometers. More than 13 million cubic meters of rock were excavated – a volume five times greater than that of the Cheops Pyramid in Egypt.

 

Part 1 from April 8, 2013

A large amount of the spoil is used to make concrete at the construction sites and is returned to the mountain in the form of cladding. Millions of tons of it were also used to create artificial islands in Lake Urner for recreational and conservational purposes.

The Gotthard Base Tunnel is the centerpiece of the New Alpine Transversal (NEAT), which includes the Ceneri Tunnel (15 km) in the south, and the Lötschberg Tunnel (35 km), which was completed in 2007. The rail line should help shift a large portion of freight transport from the road to the railway. The number of trucks driving through Switzerland has been on the increase for many years.

As a result, the Gotthard road tunnel and the old Gotthard rail tunnel, which opened in 1882, are stretched to the limit of their capacities. Today 140 to 180 freight trains ply along the mountain railroad every day. The NEAT will accommodate up to 260 trains, which can be longer and heavier to boot. Rail capacity will double from the current 20 million tons to over 40 million tons annually.

A quarter of the tunnel length was excavated with explosive charges, the rest by tunnel boring machines.

A quarter of the tunnel length was excavated with explosive charges, the rest by tunnel boring machines. These monsters are up to 400 meters in length and weigh in at over 3000 tons. The drill heads, which are fitted with rotary cutters, are over nine meters in diameter.

Photo: AlpTransit Gotthard AG

Whereas the old Gotthard track has a gradient of 0.26%, the Gotthard Base Tunnel’s gradient is just 0.12%. With a maximum elevation of 550 meters (mountain section: 1,150 meters) the new route is also quite a bit lower. Freight trains will be able to travel at up to 160 km/h, passenger trains at 250 km/h. Travel time from Zurich to Milan will be shortened by an hour to two hours 40 minutes, making rail travel a real alternative to traveling by car or plane. The tunnel is to be handed over to the operator at the end of 2016.

 

When construction work began, it was assumed that the first high-speed trains could hurtle through the tunnel as early as 2012. But the Gotthard didn’t play ball. “Mountains can’t be x-rayed,” says Beat Guggisberg succinctly. “Despite all the structural test bores in the construction area, there’s always a risk that you’ll suddenly hit fault zones somewhere along the line.” And then the drilling process becomes an exercise in patience.

 

As was the case at the Faido construction site. Between 2005 and 2007, seismic disturbances triggered several micro-tremors measuring as much as 2.4 on the Richter scale. The mountain squeezed the tunnel profile a few times, and in some places the ceiling collapsed. The team needed two years to complete one 200-meter section. “That put paid to the schedule,” recalls Guggisberg. The costs for damage to the tunnel vault and the tunnel bore machine (which cost over ten million Swiss francs) were assumed by Allianz Suisse and Nationale Suisse, which each have a 50 percent share in the insurance program for the Gotthard Base Tunnel.

The safety concept
  The safety concept: The tunnel system consists of two separate single-track tunnels. The other tunnel will serve as a refuge in the event of an accident or fire. Crosscuts connect the two parallel tunnels every 325 meters. They serve as escape routes in an emergency. Emergency stations are located at Faido and Sedrun. From there passengers can reach six crosscuts in the parallel tunnel, which is under positive pressure and therefore smoke-free. Trains coming in the opposite direction will be automatically stopped. An evacuation train will pick up the passengers and transport them into the open air.
Masterpiece of engineering

Masterpiece of engineering

For many years the Alpine range was regarded as the greatest obstacle to traffic in Europe. Around 1870 a journey by coach from Basel to Milan took two full days. This only changed in 1882 when the first railroad tunnel through the Gotthard was opened. At the time it was the longest rail tunnel in the world. The engineer Louis Favre had estimated that construction would take eight years, but he didn’t live to see the tunnel’s completion ten years later: in 1879 he collapsed and died in the tunnel. Nevertheless, the old Gotthard tunnel – one 15 kilo-meter tube with two tracks – was a masterpiece of engineering.

The workers involved in the first Gotthard rail tunnel between Göschenen and Airolo had to contend with similar difficulties. 177 miners lost their lives during the ten-year construction period on the 15-kilometer stretch – the longest rail tunnel in the world at the time. That’s more than ten deaths per kilometer of tunnel. Nine workers have been killed so far during construction on the Gotthard Base Tunnel. The biggest risk to life and limb however isn’t collapsing ceilings or flooding. “The greatest hazards in modern tunnel construction are posed by machines and transport vehicles,” says Guggisberg.

Meanwhile, installation of the railroad bed, rails, power supply and telecommunication and safety systems is in full swing. In three years the work should be finished. Completion of the Ceneri Base Tunnel in 2019 will finally close the gap in the European high-speed network. When the last remaining open stretches have disappeared – plans are already in the offing – travelers will probably whizz through Switzerland without any view of the landscape. Actually, quite a shame.

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Part 1: "Cheops times five"