Elasticity for the track in the Gotthard Base Tunnel

Vibration protection from Getzner in the world's longest railway tunnel

23.10.14

Bürs, Austria. Getzner Werkstoffe has equipped the track in the Gotthard Base Tunnel with an anti-vibration system. The measure will extend the life of all components in the track superstructure and improve ride comfort for passengers. At 57 km, the Gotthard Base Tunnel will be the longest railway tunnel in the world and is scheduled to open in 2016.

The Gotthard Base Tunnel is part of the New Rail Link through the Alps (NRLA), currently the largest construction project in Switzerland. Passenger and freight trains will travel the whole 57 km length at speeds of up to 250 km/h, taking just 15 minutes to do so. This places heavy demands in terms of the availability, load capacity and service life of the tunnel track.

To ensure that the track remains usable for a long time to come and prevent undue stress, it has been necessary to equip the track with elastic components. It was decided to employ the LVT (Low Vibration Track) system, whereby the track is made up of single-block concrete sleepers. The sleepers have elastic inserts made from Getzner's Sylodyn® material in a rubber boot. "The main advantage of the LVT system is that it's easy to replace individual elements, because there is no rigid connection between the rails and the slab. It also provides favourable characteristics such as high track accuracy, durability, reliability and low maintenance costs," explains Helmut Bertsch, project manager at Getzner. All the turnouts in the tunnel have also been laid on the highly elastic polyurethane material Sylodyn®. On the ballasted track leading to the tunnel portals, many of the track and turnout sleepers feature elastic sleeper pads from Getzner. They protect the ballast and prolong the tamping intervals, thereby reducing maintenance work and expense.

The measures inside the tunnel are aimed at reducing the vibrations that occur when a train passes through, resulting in a longer track life and a more comfortable ride. "The Gotthard Base Tunnel is a flagship project that surpasses anything that has gone before, anywhere in the world, in terms of tunnel length, technology and logistics. The fact that we were awarded the contract is mainly thanks to the excellent properties of the materials, our technical know-how and our big-name references," concludes Helmut Bertsch.

Toughest demands in terms of quality and ability to deliver

This project imposed very heavy demands on the railway technology in the tunnel, because all the materials had to deliver excellent performance over the entire planned service life of the tunnel. Similarly, the extremely frequent use of the track, with up to 250 trains per day, also puts the line under above-average stress. The materials therefore had to undergo prior testing under high permanent loads as well as artificial ageing tests. The client also imposed strict requirements, as Helmut Bertsch explains: "Getzner had to guarantee high delivery capability and a high level of quality for the entire project period."

Optimum choice of material

Dedicated high-speed turnouts were developed especially for the Gotthard Base Tunnel using the latest technology. It was particularly important that all components should meet the toughest requirements. The various highly elastic Sylodyn® inserts from Getzner ensure even deflection as the train passes over, along the entire length of the turnout and in the transition area between the straight line and the turnout. Getzner calculated the optimum choice of materials and the resulting rail deflection. "Long-term references from all over the world and real track measurements prove that our railway superstructure solutions have been used successfully for decades. Our highly elastic materials effectively isolate vibrations in the track area – very much to the satisfaction of passengers," sums up Helmut Bertsch.

Gotthard Base Tunnel fact box

Construction time for rail engineering: 2009 - 2016
Getzner solution: 394,000 elastic insertion pads for sleeper boots made from Sylodyn®, 30,000 track and turnout sleeper pads, 5,000 m² of under-ballast mats
Project support: Model and forecast calculations, installation plans, quality assurance
Planned opening: End of 2016