Tunnel Vision

This past December, a giant construction project finally paid off. Officials opened the Gotthard Base Tunnel, a new train route beneath the Swiss Alps. At 57 kilometers (35 miles) from end to end, it’s the longest train tunnel in the world. 

About 2,600 people worked on the tunnel, which took 20 years to complete. More than half of that time was spent digging through the mountains. The Alps are made of hard rocks and minerals, solid materials that form in Earth’s crust. Engineers used explosives and massive drills to cut through 30 million tons of these materials.

A giant construction project finally paid off this past December. Officials opened the Gotthard Base Tunnel. The new train route runs beneath the Swiss Alps. It’s the longest train tunnel in the world! It stretches 57 kilometers (35 miles) from end to end.

About 2,600 people worked on the tunnel. It took 20 years to complete. More than half of that time was spent digging through the mountains. The Alps are made of hard rocks and minerals. These solid materials form in Earth’s crust, or outer layer. Engineers cut through 30 million tons of these materials. They used explosives and massive drills.

Intense temperatures made construction tricky. Pressure from the rocks above heats the inside of the mountains up to 50°C (122°F). To stay safe, engineers built cooling systems into the tunnel as they worked. 

Why dig through the mountains? Vehicles used to take a long, winding path over the Alps. Cutting straight through saves time and fuel. “Many people had doubts we could finish,” says Kalman Kovari, an engineer on the project. “But we did it.”

High temperatures made construction tricky. Pressure from the rocks above heats the inside of the mountains. Temperatures reach up to 50°C (122°F). Engineers built cooling systems into the tunnel to stay safe. 

Why dig through the mountains? Cars and trucks used to take a long, winding path over the Alps. Cutting straight through saves time and fuel. “Many people had doubts we could finish,” says Kalman Kovari. He’s an engineer on the project. “But we did it.”