Switzerland will open a record-setting tunnel this month: the Gotthard Base Tunnel, the longest and deepest railway tunnel ever built. Carved through the Alps, construction required 17 years and work through rock up to 7,500 feet deep. The project cost about $12 billion and, tragically, eight workers died during construction.
Beyond its engineering significance, the tunnel removes a major obstacle to trade and travel across a key European crossroads. At 35.5 miles long, the Gotthard Base Tunnel (GBT) was inaugurated on June 1. Test trains will run this month, with regular services planned to begin later in the year.
The twin-tube rail line allows trains to reach speeds of up to 155 miles per hour, cutting travel time between major cities. For example, journeys between Zurich and Milan are expected to fall from roughly four hours to about two and a half. The tunnel’s dual bores also more than double freight capacity on Switzerland’s north–south corridor, shifting a significant volume of goods from road to rail.
That modal shift has environmental as well as economic benefits. By enabling more freight to travel by train instead of by truck, the GBT will help reduce highway congestion and lower air pollution across the region. Increased rail capacity also supports more efficient passenger services and strengthens links between neighboring countries.
Engineering features of the Gotthard Base Tunnel include advanced tunnel-boring techniques, extensive safety systems, and parallel tubes connected by cross-passages for evacuation and maintenance. Those design elements reflect lessons learned from previous long tunnels and aim to ensure reliable, safe operations over decades of use.
Operational testing will verify track alignment, signaling, ventilation and emergency procedures before commercial timetables are introduced. Once fully operational, the tunnel is expected to change travel patterns in Central Europe by making rail a faster, more attractive option for both passengers and freight.