Which Is The Longest Tunnel In The World?

From mountains to undersea crossings, tunnels have long pushed the boundaries of engineering and human ambition. But when it comes to sheer length and complexity, one tunnel stands above the rest. As of 2024, the longest tunnel in the world is the Gotthard Base Tunnel in Switzerland.

With a length of 57.1 kilometres (35.5 miles) through the Swiss Alps, the world's deepest and longest railway tunnel was finished in 2016. It took more than 17 years to build and was intended to improve freight transportation through one of Europe's most difficult terrains, ease traffic and shorten travel times.

Longest Tunnel In The World

The Gotthard Base Tunnel is the longest tunnel in the world. With a length of 57.1 kilometres (35.5 miles) through the Swiss Alps, the world's deepest and longest railway tunnel was finished in 2016.

Why It's an Engineering Marvel?

The Gotthard Base Tunnel is more than just a long passage through rock. Engineers had to overcome significant geological challenges, including high rock pressure, underground water and temperature differences deep below the surface. The tunnel was bored using massive tunnel boring machines and required extreme precision to meet in the middle from both ends.

Its design includes two single-track tubes with emergency escape routes, ventilation systems, and advanced safety technologies. Trains travel through it at speeds of up to 250 km/h (155 mph), making it a crucial link for both passengers and goods moving between Northern and Southern Europe.

Why Is the Gotthard Base Tunnel Important?

Better for Moving Goods (Freight)

Before the Gotthard Base Tunnel was built, trucks had to use mountain roads to move cargo across the Alps. Sometimes bad weather, like snow or rain, can cause delays in the transportation of goods by making the roads unsafe or closed. Goods can now be transported by train through the Gotthard Base Tunnel beneath the Alps. The tunnel is a straight and smooth path. 

Better for the Environment

Trucks use a lot of fuel, which results in high emissions of carbon dioxide (CO₂), a hazardous gas that contributes to climate change. Both the environment and human health are impacted by truck air pollution. Compared to trucks, trains emit less pollution and use less fuel per tonne of cargo, making them far more environmentally friendly. 

Better for Passengers

Before the tunnel, travelling by train through the Alps was slow and took a long time. The new tunnel connects Northern Europe to Southern Europe in a much faster and more comfortable way. For example, the train ride from Zurich to Milan used to take more than 4 hours. Now, it takes just under 3 hours. This faster travel also encourages more people to use trains instead of planes or cars. 

Safe and Fast

The Gotthard Base Tunnel allows high-speed trains to travel through the Alps at speeds of up to 250 km/h, making it one of the fastest train routes in the world. These include fire safety systems, ventilation systems, emergency exits and safe escape routes for passengers if needed. The tunnel also has 24/7 monitoring. This means there are always trained professionals keeping an eye on everything to make sure everything is running smoothly and safely. 

Why Was the Gotthard Base Tunnel Built?

To Make Travel Easier

Prior to the Gotthard Base Tunnel, passengers had to take slower, older rail lines that twisted around the Alps. These routes were slower and frequently bumpy, and they took longer. In order to provide a straight route beneath the mountains, the new tunnel was constructed. As a result, trains can move more quickly without having to climb hills or navigate complex tracks.

To Use More Trains, Fewer Trucks

To protect the environment and the Alps, Switzerland aimed to reduce the number of trucks that crossed the mountains. Trucks damage roads, cause traffic jams, and create a lot of pollution. The Gotthard Base Tunnel encourages more rail transport for goods so that fewer trucks need to use the mountain roads. This helps reduce pollution, traffic, and road damage.

To Save Time

The Gotthard Base Tunnel saves time for both passengers and freight. Before the tunnel, the journey from Zurich to Milan took over 4 hours. Now, it’s cut down to just under 3 hours. This time-saving is important for businesses because goods arrive faster, and for travellers, because it makes long-distance train travel more convenient.

To Connect Europe

The Gotthard Base Tunnel is part of a larger project called the Trans-European Transport Network (TEN-T). This is a plan to create better transport links across Europe, connecting countries and regions with fast and efficient rail and road networks. The tunnel connects Northern Europe (such as Germany and the Netherlands) to Southern Europe (like Italy). It plays a key role in the European economy by helping businesses move goods faster and people travel easily between countries. By linking different regions, the Gotthard Base Tunnel helps bring people closer together, promotes economic growth and strengthens European unity.

Some Other Notable Long Tunnels:

If you are simply curious about how trains cross entire mountains, the Gotthard Base Tunnel is a feat worth knowing.