The Gotthard Tunnel actually refers to a series of tunnels cutting through the Swiss Alps beneath the Gotthard Pass. The most famous is the Gotthard Base Tunnel, which opened in 2016 as the world’s longest railway tunnel at 57 kilometers (about 35.4 miles). But there’s also an older rail tunnel from 1882 and a road tunnel from 1980, all serving the same critical north-south route connecting German-speaking Switzerland to the Italian-speaking canton of Ticino and, beyond that, to Milan.
Three Tunnels, One Mountain
The Gotthard Pass has been a vital Alpine crossing for centuries, and engineers have punched through the mountains beneath it three separate times. The original rail tunnel, constructed between 1872 and 1880, stretches about 15 kilometers and sits at an elevation of roughly 1,150 meters. It opened in 1882 after a brutal decade of excavation that killed 167 workers and bankrupted contractors. At the time, it was the longest tunnel in the world and connected Lucerne to Milan by rail for the first time.
Nearly a century later, the Gotthard Road Tunnel opened in 1980, giving cars and trucks a direct route under the pass. It remains one of the longest road tunnels in the world and is notorious for heavy traffic and long queues during holiday periods.
Then came the Gotthard Base Tunnel, a project on an entirely different scale. Rather than climbing partway up the mountain like the 1882 tunnel, it bores through the base of the Alps at a much lower elevation, creating a nearly flat route. This is the tunnel most people mean when they search for “the Gotthard Tunnel” today.
How the Base Tunnel Was Built
The numbers behind the Gotthard Base Tunnel are staggering. Its two parallel tubes run 57 kilometers each, but when you count all connecting passages, shafts, and side tunnels, the total excavated tunnel length reaches 152 kilometers. Workers removed 28.2 million tonnes of rock during construction, with the mountain pressing down on the tunnel under as much as 2,300 meters of rock overhead at the deepest point.
Construction took nearly two decades. Planning and preliminary work began in the late 1990s, and the tunnel finally opened to regular traffic in December 2016. The project cost roughly 12 billion Swiss francs and required thousands of workers using massive tunnel boring machines that chewed through granite, gneiss, and unstable sedimentary rock zones deep inside the Alps.
What the Tunnel Does for Travel
The base tunnel’s low, flat profile is what makes it transformative. Older Alpine rail routes forced trains to climb steep grades using spiraling loops inside the mountains, which slowed travel considerably and limited the weight of freight trains. The Gotthard Base Tunnel eliminated that problem, allowing trains to pass through the Alps on a nearly level track at speeds up to 250 kilometers per hour for passenger services.
The result is significantly faster travel between northern and southern Switzerland. Trips between Zurich and Lugano, or Zurich and Milan, are noticeably shorter. Since opening, demand for the rail connection has been consistently strong and growing, with data suggesting the time savings attracted travelers who previously would have driven.
The tunnel’s daily capacity is enormous: up to 260 freight trains and 65 passenger trains can pass through every 24 hours. Switzerland built this capacity deliberately as part of its “modal shift policy,” a long-running national strategy to move freight off Alpine highways and onto rail. The goal is fewer heavy trucks grinding through mountain valleys, reducing pollution, road damage, and accident risk in sensitive Alpine communities.
Safety Systems Inside the Tunnel
Spending 20 minutes inside a mountain at high speed requires serious safety engineering. The tunnel’s two tubes run parallel to each other, connected by cross-passages every 325 meters. If something goes wrong in one tube, passengers and crew can quickly reach the adjacent tube, which acts as a safe evacuation corridor.
Two dedicated emergency stop stations are built into the tunnel for evacuations. Trains are equipped with onboard systems designed to keep them running to one of these stations even after a fire breaks out, rather than stopping in the middle of the tunnel. If a train does stop between stations, the adjacent tube can be pressurized to prevent smoke from entering.
Ventilation units at Sedrun and Faido, along with 24 jet fans at the tunnel entrances, supply fresh air and extract smoke during emergencies. A continuous water conduit system runs through each tube, feeding five liters per second into channels that can carry hazardous spills to retention basins outside the tunnel portals.
The 2023 Derailment and Recovery
In August 2023, a freight train derailed inside the tunnel, causing significant damage to the track and infrastructure. The incident forced partial closures and rerouted traffic for over a year. Swiss national rail operator SBB fully reopened both tubes on September 2, 2024, thirteen months after the derailment. During the closure, passenger and freight trains were diverted through the older, slower Gotthard rail tunnel and other Alpine routes, adding travel time and reducing capacity across the entire Swiss rail network.
Why It Matters Beyond Switzerland
The Gotthard Base Tunnel is a central piece of a broader European freight corridor running from the ports of Rotterdam and Genoa through the heart of the continent. By making it faster and cheaper to move goods by rail through the Alps, Switzerland positioned itself as a key link in Europe’s push toward lower-carbon logistics. The tunnel can handle double-stacked shipping containers and heavy freight loads that the older, steeper routes simply could not accommodate, making rail competitive with trucking on one of Europe’s busiest trade routes.