Madrid - Barcelona - French Border line

Tarragona - Barcelona Sants section

The access works to the city of Barcelona on its passage through the municipalities of Sant Joan Despí, Sant Boi, El Prat de Llobregat, L'Hospitalet and Barcelona are the most outstanding actions in the section between Tarragona and Barcelona

The effort centred on integrating this new infrastructure in the urban setting, reducing insofar as possible disturbances to the normal daily life of the inhabitants and paying special attention to the environmental and mobility conditioning factors.

  • Sant Joan Despí - L´Hospitalet section
  • L´Hospitalet - Sants section
  • Sants - La Sagrera section

Urban integrations

We can highlight the covering of the conventional and international gauge tracks in their passage through Vilafranca del Penedès at a length of 1,318 m and a total surface area of 42,373 m2, and the burying of the infrastructure in El Prat de Llobregat. In this last municipality, 1.3 km of the conventional gauge line has been buried by a cut and cover tunnel between walls, with a surface area of 30,000 m2 and close to 2 km of high speed tracks, which involves a surface area of 38,000 m2.


Sant Joan Despí - L' Hospitalet section
Section Start Finish Length
I Sant Joan Despí Sant Boi 4,096 m.
II Sant Boi L´Hospitalet 3,737 m.

Main elements of the Sant Boi-L´Hospitalet section

  • Basic infrastructure of the new intermodal station of El Prat de Llobregat, which will house conventional and high speed trains. It also foresees the integration of the Metro de Barcelona line
  • Burying of the Iberian (1,668 mm) and UIC (1,435 mm) gauge tracks in their passage through the town of El Prat
  • Construction of a 210 m length viaduct which will replace the existing bridge
  • Location of two new tracks, which will be increased to four in the new station.

The viaducts constitute the main singular infrastructures of this section. The first has a length of 870 m. It is located opposite Sant Boi and makes it possible to cross River Llobregat, the C-245 road from Castelldefels to Barcelona, the access branch lines to the Ronda Litoral and the Ferrocarrils de la Generalitat rail line. The second, double, for conventional and high speed train lines, is located between El Prat and L'Hospitalet, over River Llobregat and has a length of 212 m

The viaduct over the River Llobregat at Sant Boi

The viaduct over River Llobregat at Sant Boi has two sections. The first is formed by a mixed structure of steel and concrete of 340 m, which rests on 5 intermediate supports. It has a steel structure, with the form of straps, which connects the viaduct deck to the upper end of the support. To build the deck, the metal structure is mounted on one of the ends and, later, the already mounted section is pushed to its final location. Once the metal part is positioned, the concrete elements will be constructed.

The second section has a concrete structure, with a length of 530 m, resting on 10 intermediate supports. The deck will be built by an auxiliary structure (self-formwork), which will serve as a provisional support in the concreting process.

El Prat viaduct

El Prat viaduct also has a concrete structure. It has a length of 212 m and rests on 4 intermediate supports. The deck is built by manufacturing dowels (parts into which the panel is separated) at one of the ends and, then, the pushing and displacement of the already manufactured section until its final location.


L' Hospitalet - Sants section
Section Start Finish Length
III L´Hospitalet La Torrassa 2,724 m.
IV La Torrassa Sants 2,069 m.


Section III completely runs through the municipality of L'Hospitalet de Llobregat. It has a completion deadline of 20 months

In the La Torrassa-Sants section the remodeling of the current railway corridor stands out at a length of 1,300 metres, which will enable the covering of the tracks in the area of action. The completion period is 23 months

Cut and cover tunnel construction process

Adif carries out thorough geotechnical studies in the construction works of all rail tunnels in urban environments, both in the project phase and during their construction.

In these sections, in the greater part of the route, the cut and cover tunnel construction method using walls has been adopted, which should not be confused with the conventional tunnel. The process consists of making two side walls with reinforced concrete within the ground before starting the excavation. This guarantees the integrity of the surrounding constructions.

A slab is then placed which joins two walls by their upper part, after which the street works of street on the cut and cover tunnel will visually disappear. They then excavate below the slab until building the vault (roof) and the inverted arch (floor) of the cut and cover tunnel.

This method guarantees stability of the ground at all times, maximizing safety with respect to streets and buildings.