Switzerland may be famous for its snow‑capped peaks and punctual trains, but beneath its Alpine façade lies a sprawling subterranean world that rivals many surface cities. For almost three decades engineers have tunneled through solid rock, creating a hidden infrastructure that supports high‑speed rail, hydro‑electric storage, data centers, and emergency shelters. This article uncovers how the project began, the engineering feats that made it possible, the sheer scale of the network, its multi‑purpose functions, and what lies ahead as the nation pushes the limits of underground construction.
From alpine dreams to concrete reality
The vision emerged in the early 1990s when Switzerland faced mounting pressure to expand its transport capacity without compromising its pristine landscapes. The Swiss Federal Railways (SBB) proposed a series of deep‑level tunnels to divert traffic from congested valleys, while the federal government saw an opportunity to store renewable energy underground. Funding was secured through a mix of public‑private partnerships, and the first borehole was launched in 1994, marking the start of a relentless push through granite, gneiss, and limestone.
Engineering the impossible
Carving tunnels through some of Europe’s toughest rock demanded innovations that now set global standards. Tunnel Boring Machines (TBMs) equipped with real‑time seismic monitoring were deployed to anticipate fractures, while laser‑guided drilling ensured millimetre precision. Ventilation shafts, pumped water management systems, and automated safety protocols were integrated from day one. The project also pioneered the use of rock‑bolting techniques that allow sections of tunnel to self‑stabilise, dramatically reducing construction time and cost.
A network bigger than cities
Today the underground complex stretches over 1,200 kilometres, encompassing high‑speed rail corridors, freight passages, and utility tunnels. To put that in perspective, it surpasses the combined length of the road networks of many mid‑size European capitals. The table below summarises the most critical dimensions as of January 2026:
| Metric | Value | Comparison |
|---|---|---|
| Total tunnel length | 1,200 km | ≈ length of Switzerland’s surface road network |
| Rail capacity | 250 trains/day | Supports >10 million passenger journeys annually |
| Energy storage volume | 35 GWh (pumped‑hydro) | Enough to power the nation for 3 days |
| Data‑center space | 180 MW | Comparable to a small city’s IT load |
Beyond transit: multi‑purpose uses
While high‑speed trains dominate headlines, the underground arteries serve a host of secondary functions. Pumped‑hydro reservoirs, hidden within the mountain basins, store excess wind and solar power, smoothing out supply fluctuations. Climate‑controlled chambers host data centers that benefit from the natural cooling of the rock, reducing energy consumption by up to 40 %. Additionally, the network doubles as a civil‑defence shelter capable of housing 30,000 citizens for up to three weeks, complete with food supplies and medical facilities.
Future horizons and sustainability
Looking ahead, Switzerland plans to extend the system by another 300 km, linking the Jura region to the Alpine passes. The next phase will incorporate green hydrogen production sites directly adjacent to the tunnels, creating a seamless loop of generation, storage, and distribution. Continuous monitoring using AI‑driven sensors aims to predict rock movement and optimise maintenance, ensuring the underground megacity remains safe and efficient for generations.
In conclusion, Switzerland’s subterranean network demonstrates how visionary planning, cutting‑edge engineering, and a commitment to sustainability can transform a country’s geography into an asset rather than a constraint. The tunnels not only alleviate surface congestion but also provide critical infrastructure for energy, digital services, and emergency resilience, positioning the nation as a global benchmark for underground urbanism.
Image by: Roberto Nickson
https://www.pexels.com/@rpnickson
