Lists of tunnels facts for kids

A tunnel is an underground passage built by people. Tunnels allow us to travel through mountains, under rivers, or beneath busy cities. They are important for cars, trains, and even water pipes.

What are Tunnels For?

Tunnels help us get from one place to another when there are obstacles in the way.

Moving People and Goods

Tunnels are often used for transportation.

• Road Tunnels: These tunnels let cars and trucks drive through mountains or under water. They help shorten travel times and avoid difficult terrain.
• Railway Tunnels: Trains use tunnels to cross long distances, especially through hills or under cities. Some of the longest tunnels in the world are for trains.
• Subway Tunnels: In big cities, subways run underground in tunnels. This helps millions of people travel quickly without adding to traffic on the streets above.

Carrying Water and Utilities

Tunnels are not just for transport.

• Water Tunnels: Many cities get their drinking water through long tunnels from distant reservoirs. These tunnels are like giant underground pipes.
• Utility Tunnels: Some tunnels carry important services like electricity cables, gas pipes, or communication lines. This keeps them safe and out of sight.

How are Tunnels Built?

Building a tunnel is a huge engineering challenge. It takes a lot of planning and special equipment.

Digging Through Rock

When building through hard rock, engineers use powerful machines.

• Drill and Blast: This method involves drilling holes into the rock, placing explosives, and then blasting the rock away. The broken rock is then removed.
• Tunnel Boring Machines (TBMs): These are giant machines that can slowly chew through rock or soil. They have a rotating cutting head that grinds away the material. TBMs are very efficient and can build tunnels quickly and safely.

Building in Soft Ground

When the ground is soft, like clay or sand, different methods are used.

• Cut-and-Cover: This method involves digging a trench from the surface, building the tunnel structure inside it, and then covering it back up with soil. This is common for shallow tunnels, like some subway lines.
• Shield Tunneling: A large metal shield is pushed forward, creating a safe space for workers to dig and install tunnel segments behind it. This helps prevent the ground from collapsing.

Famous Tunnels Around the World

Many tunnels are famous for their length or the challenges faced during their construction.

Longest Tunnels

Some tunnels are incredibly long.

• Gotthard Base Tunnel: Located in Switzerland, this is the longest railway tunnel in the world. It is about 57 kilometers (35 miles) long and helps trains travel faster through the Alps.
• Seikan Tunnel: This Japanese railway tunnel is one of the longest in the world, connecting the islands of Honshu and Hokkaido. A large part of it runs under the sea.

Tunnels Under Water

Building tunnels under water is very difficult.

• Channel Tunnel: Also known as the "Chunnel," this tunnel connects England and France under the English Channel. It allows trains to carry passengers and vehicles between the two countries.

Safety in Tunnels

Safety is very important in tunnels. Tunnels have special ventilation systems to bring in fresh air and remove exhaust fumes. They also have emergency exits and fire safety equipment to keep everyone safe.