The Pajares variant ranks among the most expensive high-speed sections per kilometer anywhere. According to the Ministry of Transport, the project will approach 4,000 euros per kilometer for a route of 49.7 kilometers, resulting in a total around 80 million euros for each kilometer of distance. This figure surpasses five times the typical high-speed cost in Spain, which seldom reaches 15 million euros per kilometer.
Bypass figures stand apart from other high-speed sections built on the Peninsula. The most costly per kilometer opened to date is the Atocha-Chamartín tunnel in Madrid, extending about 7,000 meters and costing 338 million euros, or 48 million euros per kilometer.
The last two high-speed sections inaugurated in Spain also show lower costs per kilometer when compared to the Bypass. Antequera-Granada, opened to commercial traffic in 2019, required 1.675 billion euros for an 86-kilometer journey, equating to about 20 million euros per kilometer. Pedralba-Orense, the most recent open segment of the AVE to Galicia, spent 2.965 billion euros on a 119.4-kilometer route in 2021, close to 25 million euros per kilometer.
If the entire AVE corridor to Galicia is considered—from Olmedo to Santiago and La Coruña—the disparities become even larger. Official data from the Ministry show that the AVE investment in Galicia together with the Atlantic Axis totals 10.95 billion dollars. When including the 4.18 billion euro investment between Olmedo and Madrid to bring high-speed service to Galicia’s major cities, the total rises to about 15.13 billion. With the full route spanning 418 kilometers, the cost is just under 36 million euros per kilometer, roughly half the Pajares variant cost.
The contrast grows starker when the bypass is compared with sections through regions with more favorable terrain. Take the 166-kilometer stretch from Valladolid to Leon, which cost 1.62 billion euros in 2015, or under 10 million per kilometer—about one-eighth the cost of moving from Asturias to the Meseta. Even updated, the price would not surpass 12 million per kilometer. Other examples include Monforte del Cid-Murcia (23 million per kilometer), Madrid-Valladolid (25), Córdoba-Málaga (17), Madrid-Barcelona-Figueras (16), and Madrid-Albacete/Valencia (14).
One of the lines with the lowest unit cost per kilometer is the Madrid-Seville route, opened in Spain in 1992. If updated to current euros, the cost stands at roughly 11 million euros per kilometer.
outside of Spain
What about other countries? The pattern is similar: high-speed mileage sits slightly above average, with around 60 million euros per kilometer in Italy, more than 50 in Japan, around 40 in Korea, Germany, and Taiwan, about 20 in France, and roughly 10 in China. Notable examples include Stuttgart-Munich, Milan-Venice (43), Frankfurt-Cologne (33), Turin-Salerno (32), Berlin-Munich (50), and Ren-Rhone (19).
Researchers attribute these vast differences primarily to terrain. A study by the Foundation for Applied Economics Studies (Fedea) notes that construction costs depend on terrain features and decisions about the project’s design and functions. Costs escalate in urban and densely populated areas and in hilly zones that necessitate viaducts and tunnels, such as the Pajares Bypass, which required 11 viaducts and 13 tunnels.
In a study by the Independent Financial Responsibility Authority (AIREF) on transportation infrastructure from 2020, it is stated that the global average cost per kilometer for a high-speed line ranges from 10 to 40 million euros. It also notes costs of 5 to 25 million euros per kilometer in Spain and France, while costs for existing European lines tend to be even lower.
The report details unit costs for sections ranging from 5 million euros per kilometer on relatively flat terrain to 40 million euros per kilometer on more complex surfaces. For tunnels, per-kilometer costs can range from 25 to 35 million euros for cross-section single-track or double-track tunnels, rising to 50 to 70 million euros for tunnels with two or more tubes. Additional factors such as road bed type, siding, baffling, electrification, signaling, and security systems all push costs higher.
In the Pajares variant, the high price reflects its status as the most intricate public works project undertaken in Spain. A massive engineering effort unfolded over more than 1,000 meters of depth, pressing engineers to devise unprecedented solutions for unstable terrain and potential flooding.
The scale is striking: over 200 kilometers of rails, thousands of sleepers weighing 400 kilograms each, hundreds of concrete slabs tipping the scales at 4,000 kilograms, vast lengths of cables and pipes, and hundreds of fans weighing more than a meter in diameter. Slopes reach up to 45 meters, requiring a gauge changer with numerous sensors and a component weighing more than 45 tons. Seven retaining walls with two million cubic meters of earth moved and secured with steel cables. In total, 5.2 million cubic meters of earth were excavated in the Pajares tunnels alone, along with tens of thousands of voussoirs reinforced with steel, and hundreds of thousands of cubic meters of concrete used in the main tunnels. Conveyor belts to move materials, a treatment plant capable of handling 1,234 cubic meters of water per day, and a landfill with a capacity of two million cubic meters all feature in the grand scope.
Construction of La Variante began in February 2004 with plans to open to commercial traffic in 2010, but it has accumulated a delay of 13 years. Ministry representatives will meet with Principality leaders to discuss when the Variant will finally open, where circulation tests have taken place since September 2021.
Among ongoing works, the winning bidders have completed fire protection, detection, energy, communication, and ventilation systems for the tunnels, and assembly of galleries and technical rooms continues. Fixed telecommunication facilities, protection and security systems for the Galicia-Pajares bifurcation, and the fiber optic link between Pajares and the Pola de Lena bifurcation via the West tunnel are undergoing internal testing for validation and system integration.
Adaptation to the third lane and to the European traffic management system (ERTMS level 2) is nearing completion, while testing across the full scope of the variant continues. Access, evacuation routes, and protection and security installations in tunnels await completion. Three evacuation galleries from the Vega de Ciego and Pico de Siero tunnels are under construction, and work is progressing on the Campomanes “argayón” tunnel, though this latest step does not guarantee the Bypass will begin.
External construction activity is also advancing: the southern helipads for the Bypass are finished, and the northern helipad in Asturias is completed. Studies continue to replace the existing treatment plant with a new facility, though this work does not require the line to be commissioned.