Gotthard base tunnel, Switzerland – the world's longest railway tunnel

When it opens in 2016 the 57 km long Gotthard base tunnel under the Swiss Alps will be the world's longest. Together with the 15 km Ceneri base tunnel to the south, which will open 3 years later, it will provide a vritually flat railway across Switzerland. The tunnels aim to reduce significantly the amount of envrionmentally damaging lorry traffic crossing the country between Germany and Italy as well as cut north–south passenger train journeys by 1·5 h. This paper reports on the backround to the £7 billion project, describes the design and construction of the twin-bore tunnel and its sophisticated railway systems, and summarises lessons learned from over 10 years of tunnelling in hard rock up to 2·5 km underground.