First AVE to Asturias arrives in Oviedo in three hours and ten minutes
Pajares represents nearly twenty years of effort aimed at a colossal challenge: boring through the Cantabrian mountain range to install a high‑speed line that lets trains glide at 275 km/h. It stands as a milestone in Spanish engineering, elevating the project to global prestige thanks to the prestige of the Pajares variant.
The Pajares section spans roughly 50 kilometers between La Robla in León and Pola de Lena. About 80 percent of the route is tunnel, with several sections plunging more than 1000 meters underground. In total, 11 viaducts and 13 twin‑tube tunnels were required; one of them, the Pajares base tunnel, stretches 24.6 kilometers, placing it among the longest in Spain, Europe, and the world.
Experts describe this as one of the most intricate railway projects ever undertaken, a feat of complexity not only for Spain but on a global scale. The Guadarrama high‑speed tunnel, at 28.4 kilometers, is the longest in Spain and ranks among the longest globally, built over five years from 2002 to 2007 despite favorable geological conditions. The investment was substantial yet modest by comparison: about 1.219 billion dollars, a fraction of the several‑billion price tag seen in other major projects.
Welcomed as the first AVE to Asturias, Oviedo in three hours and ten minutes
But how does Pajares compare with other tunnels worldwide? The closest parallel is the Gotthard tunnel in the Swiss Alps, the longest railway tunnel globally at 57.1 kilometers, with a broader network totaling 151.84 kilometers when account is taken for all tunnels and galleries. The Gotthard project required decades of research, began excavations in 2003, and spanned 13 years. The investment reached about 8.3 billion euros, more than twice Pajares, and it opened in 2016. By August of that year, freight trains moved at roughly 100 km/h and passenger services shared speeds around 250 km/h on the new route.
Incidents have tested the system. On a notable day at Gotthard, a freight train derailment led to temporary shutdowns and rerouting that affected both freight and passenger services. The old line was preserved as a scenic route afterward, illustrating how major tunnel projects can reshape transport networks and local economies alike.
The engineering story continues with other long tunnels on the same scale. Seikan, connecting Japan’s main islands, measures 53.85 kilometers with part of its length beneath the seabed. Construction spanned 17 years, ending in 1988, and cost about 3.6 billion dollars. It includes two underwater stations, a first in railway history.
Another remarkable undersea passage is the European Tunnel, linking France and the United Kingdom under the English Channel. It holds the record for the longest underwater section, about 39 kilometers, with a total length of 50.45 kilometers and an average depth near 50 meters. It is a twin‑tube design, one line for conventional trains and another for shuttle trains carrying road vehicles. It opened in 1994 and has faced fires in 1996 and 2008 that temporarily closed sections, with a disruption in 2015 as well.
The list of the world’s longest tunnels also includes Lotschberg in Switzerland, the Coralm in Austria, New Guanjiao in China, Guadarrama’s high‑speed alternative in Spain, Taihang in China, Hakkoda in Japan, and Iwate‑Ichinohe in South Korea. Plans are already in motion for projects that could change the ranking: the Lyon–Turin main tunnel between France and Italy at about 57.5 kilometers, the Brenner base tunnel around 55 kilometers, and a proposed 52‑kilometer Chile–Argentina corridor named Aconcagua Bio‑ocean.
Of course, tunnels serve many purposes beyond rail. The world’s longest tunnels are often aqueducts for water transport, surpassing railway tunnels. Notable examples include Delaware in the United States, Päijänne in Finland, Dahuofang in China, Orange‑Fish River in South Africa, and Bolmen in Sweden, all extending well beyond the 50–140 kilometer range in various cases.
When it comes to road tunnels, the Laerdal tunnel in Norway stands out at 24.5 kilometers. Its construction was carried out over five years at a cost of about 125 million euros, underscoring how road infrastructure can achieve remarkable milestones with careful planning and execution.
At the heart of these achievements lies a persistent push to connect regions, shorten travel times, and strengthen economic links. Pajares, Gotthard, Seikan, and the Channel Tunnel each reflect a broader story: how modern tunnels reshape geography, logistics, and the daily lives of millions of travelers and workers across continents. Attribution: project histories and official transport records provide the basis for these comparisons and rankings, illustrating the ongoing evolution of rail and road infrastructure around the world.