Book 3, Question 24
Why Do Tunnels Go Through Mountains?
Going over a mountain costs time, fuel, and steep roads. A tunnel cuts a nearly flat path through the rock. A tunnel is a shortcut through the mountain, instead of over it!
From the book
Page from A Million Whys Book 3
More fun facts
- Switzerland's Gotthard Base Tunnel is the world's longest and deepest railway tunnel.
- Trains in the Gotthard tunnel run on a nearly flat course at up to 250 kilometers (155 miles) per hour.
- The Swiss built it mostly to move freight onto trains and cut the number of trucks on mountain roads.
- In 1980 a road tunnel opened through the Gotthard pass. At 16.9 kilometers (10.5 miles), it was then the world's longest road tunnel.
- The Blue Ridge Parkway in the United States uses 26 tunnels to pass through mountain ridges.
- Digging a 4,500 meter light rail tunnel through the Tualatin Mountains in Oregon gave geologists a rare look inside a mountain.
Sources: National Geographic, National Park Service, U.S. Geological Survey
Questions kids ask
What is the longest railway tunnel in the world?
Switzerland's Gotthard Base Tunnel, which runs deep under the Alps, is the world's longest and deepest railway tunnel.