The Gotthard Base Tunnel below the Swiss Alps will be the longest, deepest tunnel in the world. It will allow both passenger trains and shuttles carrying lorries to cross the Alps using far less energy, reducing congestion on the roads above. The tunnel is being built in phases and electronic systems are used to ensure the sections meet up to within 25cm. The engineers explain how they have developed a way to use the rubble from the excavations to produce high quality concrete to line the tunnel walls.

First broadcast:
11 June 2009

Could be used to illustrate electronics and control systems in civil engineering. It could also be used as an example of new developments in materials, and to contribute to discussions on recycling of waste material. It could be used to highlight the variety of career paths open to engineering students.