Extension of Line 3 from Legazpi to Villaverde Alto

From Legazpi, the line crosses the Manzanares River, to then turn south and take the alignment of Avda. de Córdoba, with stations that serve the Almendrales and Las Carolinas mudflats, as well as the Ciudad Sanitaria 12 de October, in the district of Usera.

Further to the south, the extension carried out has a station at the intersection with Avda. de San Martín de la Vega, which favors the neighborhoods of San Fermín and Orcasur and, beyond the M-40, within Avda. Andalucía, another in the neighborhoods of El Espinillo and Ciudad de los Ángeles. In the area of ​​"El Cruce", at the intersection with the highway from Villaverde to Vallecas, another station has been located that provides service to Villaverde Bajo and to the south of Los Angeles. After crossing the Gran Vía de Villaverde, another station is located in front of San Cristóbal de los Ángeles. Finally, the line reaches the Villaverde Alto station, with an interchange with the Cercanías lines C4 and C5.

Along the entire route, three construction methods are differentiated: tunnel executed with a tunnel boring machine, tunnel and stations between screens, and tunnel and galleries in the mine, by the traditional method of Madrid, which are described below:

Tunnel executed with tunnel boring machine

For the line tunnel, two EPB-type tunnel boring machines with closed shields have been used for most of its layout. They are from the manufacturers Herrrenknecht and Mitsubishi-NFM, which were baptized as Guster and La Adelantada respectively.

These machines basically consist of a large front drilling disk with a diameter equal to that of the excavation, on which, on the face that corresponds to the front, some spokes that carry the excavation blades stand out. In the space between them, some holes are left, through which the excavated soil is removed by turning the front disc on its axis, while pushing it against the ground. The aforementioned disc in turn drags a metallic shell, sheltered from which the final lining of the tunnel is assembled, consisting of prefabricated concrete pieces.

The machine has an excavation diameter of 9,38 m and the lining consists of prefabricated concrete segments arranged in 1,5 m rings. The thrust of the head of the shield, which in turn drags the armor, is generated by means of jacks supported on the last ring of the lining placed.

Simultaneously with the process of advancing the tunnel boring machines, mortar injections have been carried out to fill the annular space between the voussoirs and the ground (gap) and thus avoid settlements.

Tunnel and stations between screens

For part of the tunnel, about 225 m in its initial layout and 75 m in its final part, and for most of the stations, the screen method has been used.

For the tunnel, the execution process is as follows:

• Execution of the screens that will constitute the gables of the tunnel
• Heading of the screens to build a tie beam
• Execution of a roof slab
• Installation of a level of temporary or permanent metal or concrete bracing, which allows excavation under the slab
• Maximum excavation under the slab to the lower level. Cleaning concrete is spread over the maximum excavation platform to build the bottom slab.

All the stations present a very similar construction process, which consists of:

• Formation of work platforms, diversion of services, setting out and execution of guide walls
• Excavation and concreting of screens and pile-piles
• Preparation of the support surface and concreting of the roof slab
• Execution of the temporary access ramp at lobby level
• Internal excavation up to the support level of the vestibule slab and concreting it
• Progress of the excavation in the ramp and interior up to the elevation of the counter-vault (bottom slab on the ground) and its execution
• Construction of the internal structure. Substation slab in stations where it exists, emergency stairs and platforms
• Masonry, finishes and installations.

Tunnel and galleries in the mine using the traditional Madrid method

Using this method, 580 m of tunnel and various connecting galleries have been built. It basically consists of excavating the front of the tunnel section in phases, so as not to give rise to instabilities and collapses.

The execution process is as follows:

• A small gallery is opened in the key of the tunnel that gradually widens laterally until the entire section of the vault is excavated. The excavation is done by hand and it is supported with boards, props and metal longarinas
• Centering and concreting of the vault
• Excavation of the rubble with an excavator machine and with an offset with respect to the advance section
• Excavation and concreting of the gables by bataches counterpointed and located in such a way that they support two contiguous semi-rings of the vault
• Excavation and concreting of the vault.

In general, the excavation has been carried out in 2,5 m rings. However, it has been reduced to 1,25 m in a section of the line tunnel due to the presence of water on the ground.

To improve the accessibility of the stations, as a general rule, they have been located at the lowest possible depth. Only the San Fermín station does not meet this premise. The nearby existence of a collector at a depth of 18 m made it necessary to reach a depth of 26 m at the intersection of both infrastructures.

The configuration of the new stations allows the immediate orientation of the traveller. The hall is situated in the center of the floor. A large opening visually connects the two levels, turning the lobby slab into a wide viewpoint over the platforms. The technical and service rooms are grouped at the ends. The communication with the platforms is carried out by means of sets of stairs made up of two mechanics and one fixed. There are lifts nearby to guarantee accessibility for people with reduced mobility.

The width of the platforms is 5 m and the length is 90 m. At the end of each platform are the emergency exits.

The accesses from the street are resolved with a steel and glass pavilion equipped with two escalators and one fixed. All of them have at least one elevator which, in some cases, is integrated into the pavilion.

Almendrales Station

Located under Avda. de Córdoba, 400 m from Glorieta de Cádiz and 1000 from the confluence of Avda. de Córdoba and Avda. de Andalucía. It has two entrances, provided with a fixed staircase and two mechanical ones. The access towards Glorieta de Cádiz is resolved with a steel and glass pavilion.

On the opposite access, Avda. de Córdoba is 4,60 m below the adjacent building. This difference in levels materializes in a landscaped embankment. To give shape to this access, the integration of the pavilion into the slope was determined, with a glass front facing the street and walls clad in blue vitrified brick with gray impost lines. The roof is landscaped and is at the height of the residential area. It has an elevator with a stop at the lobby level and the deck level.

The plant is rectangular, 151,90 m long and 25 wide. The station was designed with a central platform.

The lobby is rectangular in shape. On the larger sides the accesses from the street are located, one is direct and the opposite one has a 15 m cannon. A large opening in the slab visually communicates this level with the platform floor. The hole is moved towards one of the side screens to allow access to the changing room and substation area. The technical rooms are grouped behind the passenger service post. Communication with the platform is via a wide staircase, an elevator and two escalators.

The development of the platforms follows a curved guideline, which is also reflected in the cladding of the side screens. At the ends are the rooms for drivers. The Legazpi address pinion has a mezzanine for changing rooms and offices.

Hospital Station October 12

Located in the Glorieta de Málaga, next to the Hospital 12 de Octubre. A part of the site where the station has been built belongs to the Hospital and was intended for surface parking. The area affected by the works has been redeveloped following the Hospital's management plan, which provided for the construction of a garden area for public use.

An area of ​​2100 m has been paved² with prefabricated concrete tiles of different colors forming a checkerboard. Shade trees have been arranged at the vertices of the squares. The remaining surface, about 1200 m² It has been landscaped with trees and shrubs.

The plant is rectangular in shape, with two different widths. The largest, measuring 33,42 m, corresponds to the central space, and contains the lobby and vertical communication elements. Two bodies of escalators and fixed stairs are arranged laterally, in the center the viewpoint opens on the platform floor. Elevators are installed nearby to ensure accessibility.

In front of the stairs that descend to the platforms there is a cylindrical wall that serves as a support for the mural, which consists of a large holography, with a plan development of 41 m and a height of 5 m.

The lateral bodies have a width of 18,34 m. In one of them the technical and service rooms are housed, in the other the station's ventilation rooms.

The total length of the station is 110,20 m. As in all Metro stations, the emergency exits are located at the end of each platform, where they join at a higher level reaching the street in a single staircase. At the opposite end are the station's ventilation shafts.

San Fermín-Orcasur Station

Located on Avda. de Andalucía, in the San Fermín neighbourhood, near the intersection with Avda. de San Martín de la Vega.

It has two twin entrances on the sides of the avenue. Communication with the lobby is direct. They are equipped with two escalators and one fixed, one of them with an elevator. The accesses are architecturally defined by pavilions.

The environment was restored until reaching the initial urbanization conditions.

The difference in level to overcome from the street accesses to the platform floor is 25,40 m. This depth determined that the station was developed in three levels.

The vestibule slab has a large opening with an oval geometric shape. The italfim cladding accompanies the edge of the slab, completing three quarters of the oval. On the minor axis are the stairs that descend to the mezzanine. At this level the stairs unfold to reach the platforms. In front of these, the enclosure repeats the curved shape. This arrangement of elements creates a cylindrical envelope over 25 m high, emphasized by two free-standing piers of equal length.

The hall has a width of 33,42 m. The ground floor is completed by two lateral bodies 18,35 m wide. The scheme is repeated on the mezzanine. The station's ventilation rooms are located on this level.

Los Angeles City Station

It is aligned with Avda. de Andalucía, between C/ de Bohemios and Avda. de la Verbena de la Paloma in the Los Ángeles neighbourhood.

It has two entrances on both sides of the avenue. The pavilion scheme with a fixed staircase and two escalators is repeated. The elevator that connects the street with the lobby floor is located on the side towards Villaverde.

As the station was displaced with respect to the axis of Avda. de Andalucía, it was necessary to build a 15 m long canyon to connect the access in the Legazpi direction with the lobby. The dimensions of the corridor, 6 m wide and a height equal to that of the lobby, mean that it is perceived as part of the lobby itself and not as a connecting element.

The volume of the station is divided into three bodies of rectangular geometry. In the central one, the lobby with a balcony over the platform floor is developed. On the sides are the packages of stairs. Opposite the italfim enclosure curves until it connects with the side screens. Behind are the ventilation rooms. The adjoining side body houses the cable plant and the substation on two different levels. At the opposite end are the technical and service rooms.

The total length of the station is 110,20 m. There are emergency exits at the end of each platform.

Villaverde Bajo-Cruce Station

Located at the intersection of Avda. de Andalucía with the road from Villaverde to Vallecas.

On the surface, an interchange station for urban and intercity buses has been created. One of the two entrances that make up the station has been located in the central area of ​​the docks. From the other side of the avenue, the station is accessed through a 35 m long canyon. 

The access bandstands are provided with a fixed staircase and two mechanical ones each. The exchanger also has an elevator that connects the street with the lobby.

In terms of geometry, it is made up of a central volume with a rectangular floor plan 33,40 m wide, which houses the lobby, the sets of stairs that communicate with the platform floor and the ventilation rooms, these located behind the front curved that delimits the central double-height space. Adjacent to the rooms, an unused space communicates with the emergency stairs. The technical and service rooms are grouped in a third body.

San Cristobal Station

Located in the neighborhood of San Cristóbal, adjacent to Avenida de Andalucía, it occupies a vacant area within a military zone.

The tunnel route turns west away from Avda. de Andalucía before reaching the station. This fact conditioned the layout of the station floor plan, and especially that of the access canyon.

Access from Avda. de Andalucía is through a 68 m long canyon. The difference in level between the vestibule and the canyon caused the latter to increase in width to accommodate a set of stairs and a ramp at the point of union between both elements. The two accesses are covered by steel and glass temples.

The station was used as an attack pit. The need for space to house the tunnel boring machines conditioned the shape and size of the plant. Two bodies form the volume of the station. The main one is 37,30 m wide and 99,40 m long. It includes the lobby, the communication cores, the cable gallery and the substation on the upper floor. The technical rooms and the ventilation rooms are located on the platform floor. The smaller body contains the technical and service rooms at the lobby level. The total length of the station is 117,90 m.

The construction system used, unlike the other stations, was ascending. The roof made is based on prestressed beams and board.

Villaverde Alto Station

It is located aligned with the track beach of the Renfe suburban station and with Valle de Tobalina street. The limited space available between both infrastructures conditioned the shape of the access plan.

Access to the station is on the surface through a large bandstand. It is located centered on the roof of the hall, with a skylight that allows natural light to enter. The scarcity of space makes it necessary to have a mezzanine level between the hall and the roof.

The floor plan is rectangular in shape, 19,20 m wide and 155,40 m long. The station is developed on two levels. The upper level houses the lobby, the technical and service rooms, as well as the cable gallery and substation, and the lower level is made up of a single platform with a curved guideline.

To house the exchange between the two modes of transport, the solution of a box sunk below the level of the existing tracks was developed. In this way, the box serves the two central suburban platforms, allowing a set of escalators and fixed stairs and a lift to be housed in each of them. Following this box, the Renfe lobby is developed, to which a new access with a pavilion on the side of the Renfe station is incorporated.