19 May 2016
Press release: Gotthard Base Tunnel – World's longest railway tunnel - a masterpiece of engineering
For over 20 years, Pöyry has been involved in the realisation of the Gotthard Base Tunnel with numerous specialists contributing to the successful conclusion of this 'project of the century'.
Pöyry unites different disciplines under one roof, offering a broad range of services from a single source in the specialised fields of tunnel construction, tunnel equipment, railway technology as well as special topics, such as surveying and the environment. Among those benefiting from this is Alp Transit Gotthard AG, the builder of the new transalpine rail route.
Pöyry was already involved in the project from early on and worked on the alignment studies as far back as the mid-1980s. Pöyry was active in the IG GBTS (Ingenieurgemeinschaft Gotthard Basistunnel Süd) framework in the planning and construction management of the geologically ambitious Sedrun tunnel section. In addition, Pöyry collaborated significantly in the tunnel equipment and the traction power supply for the railway in the entire tunnel.
Due to the high speed of the trains, the overhead lines presented the team with special challenges. With site supervision of the Sedrun emergency stop as well as planning the safety systems in the whole tunnel, e.g. the ventilation system, Pöyry made an important contribution to operational safety and reliability in the tunnel.
Studies on the environmental impact and the proposal for mitigation and recovery measures were likewise among the duties of Pöyry. For Transtec, the total railway equipment contractor, Pöyry coordinated the implementation planning, supervised the fulfilment of requirements, led the risk management and provided support in various other aspects.
Smart solutions for complex challenges
With the realisation of the Gotthard Base Tunnel Pöyry mastered the diverse challenges, which were due to the tunnel length, the large depth of tunnel cover, the high rock temperatures as well as the difficult geological conditions. The engineers were challenged to rethink previously used methods of tunnel construction and develop new solutions. Hence, special measures were taken in the Sedrun segment to counteract the high pressure in the mountain. The same segment posed additional major logistical challenges for Pöyry, as the only access for the tunnel builders was a 800 metre deep shaft.
The numerous exploration bores required major planning and the surveying, as the most important basis for the correct alignment and successful construction of the tunnel, had to satisfy stringent requirements. During the planning of the tunnel equipment, particular attention was paid to the air pressure fluctuations in the tunnel, generated by railway traffic.
Demonstration of Swiss engineering skill
Pöyry is proud to have contributed to the successful conclusion of this ‘project of the century’ – the world’s longest railway tunnel. In every respect this is a pioneering achievement, which gives proof of the innovative strength of the Swiss construction industry. The realisation of the Gotthard Base Tunnel once again demonstrates the capability of Swiss engineering skill.