Switzerland is often described by what rises above the surface. Mountains, passes, lakes and rail lines are part of that picture. Less visible is what runs beneath. Over decades, the country has invested heavily in tunnels to move people, goods, water and power through difficult terrain. This work has not followed a single plan or era. It has grown gradually, shaped by geography, postwar rebuilding, and pressure on transport networks. Today, Switzerland has thousands of tunnels, stretching for thousands of kilometres. Some are short and local. Others run for tens of kilometres through solid rock. Together, they form a system that supports daily life while remaining mostly unseen.
Beneath Switzerland’s mountains lies one of the world’s largest tunnel networks
The landscape leaves little choice. Much of the country is mountainous, with sharp changes in height over short distances. Building roads or railways on the surface is often slow, costly, or disruptive. Tunnels offer a way through without constant exposure to weather, steep gradients, or fragile slopes. Mobility also plays a role. Switzerland has high levels of daily travel, both within the country and across borders. Infrastructure is expected to work reliably and reach even remote areas. Over time, tunnelling became a practical response rather than an engineering exception.
One of the largest tunnel networks in the world
According to the Swiss Tunnelling Society, Switzerland has built around 1,852 tunnels. Together, they stretch for about 2,544 kilometres. These include road tunnels, railway tunnels, and older structures linked to water and power systems. The scale is difficult to picture from the surface. In length alone, the underground network rivals that of major urban transport systems. In some regions, travel underground accounts for a significant share of all movement.
What role do highways play underground
Switzerland’s highway network is among the densest in the world. Around 1,840 kilometres of national highways are currently in operation. About 250 tunnels are part of that network. When planned sections are completed, the total length is expected to reach nearly 1,893 kilometres, with more than 270 tunnels spanning roughly 290 kilometres. Many highways run through tunnels to limit noise, reduce land use, or pass beneath towns. At least three-quarters of the network consists of four-lane divided roads, many of them carrying international traffic.
The tunnel boom began in 1950
According to the Swiss community, the major expansion began after the Second World War. From around 1950, Switzerland started large-scale drainage tunnelling for hydroelectric power. Road tunnel construction followed in the 1980s. Railway tunnels became the main focus from around 2000. Today, more than a tenth of both the motorway and railway networks run underground. This proportion is considered a global record. Around 50 railway tunnels and 55 road tunnels are longer than two kilometres, and their total length continues to increase.
Gotthard Base Tunnel : Longest tunnel in the world
The Gotthard Base Tunnel is often cited as the symbol of this approach. Opened in June 2016, it runs for 57 kilometres, making it the longest tunnel in the world. It allows trains to cross the Alps at low altitude, reducing travel time and energy use. While it stands out, it is part of a broader pattern. Long base tunnels now form the backbone of Swiss rail transport, shifting traffic from roads to rail.
Are tunnels constructed exclusively in the Alps
Much of the recent work has taken place away from the high mountains. The Central Plateau has become a focus due to congestion and urban growth. Plans include a 30-kilometre railway tunnel between Zurich and Rupperswil to ease a major bottleneck. Other projects around Zurich include the Brüttener tunnel and a second Zimmerberg tunnel. Road projects also favour underground routes, particularly in cities like Basel, Lucerne, Berne and St Gallen.
What lies beneath Swiss cities
Major cities are building entire tunnel systems around their stations. Zurich opened a new underground station in 2015 to handle east-west traffic. Further underground expansions are planned in Basel, Berne, Geneva and Lucerne. These spaces are functional rather than grand. Platforms, service corridors, ventilation shafts and emergency routes form a quiet layer below the streets. They are designed to cope with daily pressure, then fade back into routine.
About the Author
