High-Speed Lines

León - Asturias High-Speed Line


A way of making Europe.

During the period 2000-2006 co-financing was provided as follows:

  • By the European Regional Development Fund (ERDF) through the Castile-León Integrated Operational Programme and the Asturias Integrated Operational Programme, the track bed works for the Pajares Tunnels, with financing amounting to 284.0 and 107.9 million euros, respectively.
  • By RTE-T (Trans-European Transport Networks), funding for the studies and projects, amounting to 3.2 million euros.

During the period 2007-2013 co-financing will be provided as follows.

  • By the Cohesion Fund as part of the Operational Programme of the ERDF Cohesion Fund, the track bed works for the La Robla – Pajares Tunnels and Pajares Tunnels – Pola de Lena subsections, the supply and assembly of tracks and facilities, and various additional actions inside the Pajares tunnels, with estimated funding of 389 millions of euros.

(Information valid at 31 December 2012)



León-Asturias Map

Construction of the new railway line will link León and Asturias with a modern high-speed line, permitting both passenger and freight trains to run. Because of this, the line is highly important socioeconomically for the territorial structure of Spain.

The works to overcome the Cantabria Mountain Range are a great challenge for engineering, in Europe and globally, because of the geological and morphological diversity of these mountains.  

The current Puerto de Pajares Railway Pass

From time immemorial the Cantabria Mountain Range has been an almost impassable obstacle between the plateau and the north of the peninsula, and has historically represented a natural barrier for communications between the principality and the Castile-León plateau. Opening a railway pass to and from Asturias became a priority during the second half of the 19th century.

More than 120 years have gone by since the official opening of the Puerto de Pajares railway on 15 August 1884 by King Alfonso XII and Queen María Cristina, but the track route has hardly changed, with several distinctive aspects such as the continuous series of tunnels, the winding route, with some curves with a radius of less than 300 metres, and the steep ramps and slopes.

Train in the winter of 1940

Present conventional line data, La Robla (León) - Pola de Lena (Asturias) section

  • Distance 83 km
  • Average cruising speed: 60 km/h
  • Tunnels: 79
  • Maximum permitted speed (depending on the type of train): 105 km/h

The Pajares New Line

Pajares tunnel interior

The Pajares New Line is part of the León–Asturias Line, belonging to the High-Speed North-Northwest Corridor. It is specifically located in the section between La Robla (León) and Pola de Lena (Asturias), in the central hub of this line, between the León - La Robla and Pola de Lena - Oviedo sections.

It is 49.7 km long and, in addition to the construction of two main Pajares tunnels, between Pola de Gordón (León) and Telledo (Asturias), includes the outer stretches in the direction of La Robla and Pola de Lena.

The Pajares Tunnels, approximately 25 km in length, will be the sixth longest in Europe and the seventh in the world. Another important tunnel to be built is Pontones, 6 km long.

The construction of these Tunnels allows the natural wall that the Puerto de Pajares mountainous massif has represented historically to be crossed, while ensuring a high-speed connection between Madrid, Castile-León and Asturias.

The distance between Asturias and Castile-León will be shortened by 33 km in relation to the current railway route, with a new route designed with high-speed parameters, where trains will be able to reach speeds of over 250 km/h.

The time taken to travel along the new line will be approximately 15 minutes.

The project includes the links with the current León-Gijón conventional gauge line, near La Robla and in Pola de Lena station.

Track gauge

Line with three tracks

The Pajares New Line will be suitable for passenger and freight trains. In the first phase, the tracks on the New Line will be installed in Iberian gauge on multi-service sleepers.

Operating initially in Iberian gauge will avoid the Pajares New Line being isolated from the rest of the railway infrastructures currently in service.

Installing this type of sleeper – suitable for both international and Iberian gauge – will allow for a quick and simple adaptation to switch the gauge, once works to connect the New Line with the rest of the high-speed network have been completed.

Thus, not only the citizens, but also Asturian companies will benefit from the advantages offered by the new railway access to Asturias.

Thanks to this solution, freight trains will also be able to use the new infrastructure, thus avoiding the winding and slow route of the current conventional network. Railway traffic from the Asturian ports of Gijón and Avilés bound for the central plateau will be boosted with this measure.


Geological profile

Due to geological and morphological complications to be overcome in the mountain massif, the Pajares Tunnels represent a great engineering challenge.

Tunnelling machines in the tunnel mouth

Another characteristic element in this type of work is the use of tunnel boring machines (TBMs).

Five TBMs were used to excavate the Pajares tunnels.

Safety is the fundamental and main advantage offered by this type of machines, since the tunnel excavation and propping take place inside the machine's protective shield. They also allow the tunnel's final lining to be put in place. In this way, with the placement of the prefabricated, reinforced concrete key segments, the tunnel structure is left totally finished as the tunnelling machine progresses.

Exit towards the emergency gallery

To maintain the highest level of safety, the tunnels are interconnecting galleries every 400 metres, which will facilitate maintenance tasks and evacuation, if necessary. 

There is a preferred stopping point halfway along its 25 km, prepared for evacuations in case of any emergencies. If a train suffers an incident (breakdown, supply fault, etc.) it can stop so that passengers can be transferred to another train or be evacuated to the exterior through the Buiza access gallery.

Basic tunnel data

  • 2 single-track tunnels
  • Distance: 25 km
  • Continuous longitudinal gradient of 16.8 thousandths, downward direction towards Asturias
  • Circular section: 8.5 m diameter
  • Surface area: 52 m2
  • Connecting galleries: every 400 m
  • Distance between the axes of both passages: 50 metres in the interior of the massif

Commitment to the Environment

Environmental protection actions are carried out throughout the work in order to ensure railway integration into the environment.

In this regard, and in order to safeguard the natural richness of the territory crossed by the Pajares New Line, an environmental protection policy has been applied as one of the strategic priorities of the Administrator of Railway Infrastructures (ADIF).

Planning and building a base tunnel 25 km long involves a clear commitment to minimising the environmental impact that can be caused by a high-speed railway line. In this case, the impact is limited to the tunnel mouths, the material resulting from excavation and the implementation of auxiliary worksite systems.

The most significant environmental actions include:

  • Waste control.
  • The material is carried on a conveyor belt to the controlled landfill for inert waste (DCRI) to avoid heavy lorry traffic in the area.
  • Protection of the River Huerna according to Northern Water Authority parameters.
  • Treatment and protection of hydrological systems: water purification, waste water treatment, industrial water treatment facility, flood containment tanks.
  • Reduction of pollutant emissions into the atmosphere.
  • Regeneration and environmental enhancement in tunnel mouth areas and DCRI.
  • Environmental integration and compensation measures in accordance with the Environmental Impact Statement: laying out of topsoil, hydrosowing, sowing.
  • Planting of indigenous species: hazel nut trees, chestnut trees, oak trees, poplar, willow, birch, lime trees, rowan trees, holly (main sustenance for capercaillies) and cherry trees (main sustenance for brown bears).
  • Fauna protection: partnership agreement between ADIF and the Brown Bear Foundation for the monitoring, control of conservation measures and protection of the natural habitat of the Iberian brown bear (ursus arctos) in the construction area of the Pajares Tunnels.
  • Environmentally-friendly geological surveys with capercaillie leks.

Western tunnel view

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