Ep 5. Gotthard Tunnel

In Extreme Engineering season 3 episode 5, titled "Gotthard Tunnel," viewers are taken on a journey through the Swiss Alps as they follow the construction of one of the world's most impressive engineering feats: the Gotthard Base Tunnel.

The Gotthard Base Tunnel is a railway tunnel that spans a length of 57 kilometers (35.4 miles) through the heart of the Swiss Alps. The aim of the project was to create a more efficient rail connection between Switzerland and Italy that would allow for faster travel times and increased trade.

The episode begins by introducing the project's chief engineer, Heinz Ehrbar, who explains the numerous challenges faced during the tunnel's construction. The Swiss Alps posed a significant obstacle to the project due to their unstable geology, unpredictable weather patterns, and difficult terrain.

To overcome these challenges, the construction team used a range of cutting-edge technology and innovative engineering techniques. One such method involved the use of a massive drilling machine known as a tunnel boring machine (TBM), which was able to dig through the mountain at a rate of 25 meters (82 feet) per day.

However, even with the advanced technology at their disposal, the construction team still faced numerous hurdles during the project. One notable challenge was the need to drill through rock that was over 2,000 meters (6,500 feet) thick, which required the use of specially designed drilling heads and high-powered machinery.

Throughout the episode, viewers are taken through the different stages of the construction process, from the initial excavation work to the installation of the track and the final testing phase. The crew also highlights some of the unique features of the tunnel, including its state-of-the-art ventilation and cooling systems, which help to maintain a safe and comfortable environment for passengers.

Overall, the episode is a fascinating look at one of the most impressive engineering projects in recent history. From the ambitious goals of the project to the innovative techniques used to overcome the challenges encountered along the way, "Gotthard Tunnel" showcases the incredible skill and determination of the construction team behind this monumental achievement.