Line 12 (Metrosur) of the Madrid Metro

Following are curiosities taken from the Topographical Relations of Felipe II, a survey consisting of two questionnaires, which the Monarch ordered to do in the 70s of the XNUMXth century to several towns of the Crown of Castile, this being the first survey of these characteristics that was made in Europe, as well as some data and names of the stations in each municipality.

Unlike the actions that have taken place in other Metro networks in other countries, Madrid has never supported author design and stations.

Metrosur provided the opportunity to reflect on the specific characteristics of underground transport and the opportunity to propose new design guidelines. Despite the apparent discontinuity that may exist between the outside world and the underground world of the Metro, it was wanted to provide an underground level, which should have an appropriate urban and architectural expression, linking outside and inside.

The main features that were adopted in the design of the stations were: a wide and generous geometry; designed as a great space where the traveler makes simple and easy itineraries; solid and resistant construction; easy maintenance materials; and generous lighting, with the aim of making the stations lively and pleasant spaces; equipped with escalators and elevators to resolve all level changes.

Functionality was enhanced, integrating practically all the needs of the station in a single volume that was executed and excavated between concrete screens.

In Metrosur, the route of the ring runs through five different municipalities, with their urban history and their peculiarities. The design of each station could have been customized according to the municipality in which it was located, however, the traditional construction that had been followed in Madrid was maintained, in which there is no difference in the design of the stations depending on the place where are located.

Access

A very important conditioning factor for everything that is done and built in Metro de Madrid, unlike what happens in other sectors, is that Metro designs and keeps the element it builds, taking care of its maintenance and replacement. This is a very present condition when developing idea projects, since in the final solutions it is intended to combine design, quality, ease of maintenance, durability and functionality as well as meeting the requirements of sufficient feasibility to be able to be repeated. as standard in future extensions.

When Metrosur began, an access that fulfilled all these characteristics was sought. We started from the model built for the Nuevos Ministerios and Cuatro Vientos stations, some modifications were incorporated and two models were finally proposed; one that incorporated escalators, fixed and elevator and another only with the package of stairs.

The main difference in operation with respect to the rest of the expansion projects was the definitive incorporation of the escalators to the surface in all accesses.

Faced with the need to close the subway at night, which meant leaving out the escalators (an easily vandalized element), a parallelepiped with a metal structure and glass walls was taken as a model. The transparency of these elements was very important, since since they were large volumes, like the elevators, it was necessary that they did not imply a visual interference in the urban fabric.

The main difference in operation with respect to the rest of the expansion projects was the definitive incorporation of the escalators to the surface in all accesses.

Faced with the need to close the subway at night, which meant leaving out the escalators (an easily vandalized element), a parallelepiped with a metal structure and glass walls was taken as a model. The transparency of these elements was very important, since since they were large volumes, like the elevators, it was necessary that they did not imply a visual interference in the urban fabric.

Functionality

In most stations, the vestibule slab becomes a viewpoint over the platform platform. The spatial richness that this situation generates provides a wide range of views, allowing the traveler to be immediately oriented.

On the sides of the hall, two vertical communication packages are born, equipped with two escalators and central fixed ones. Located near these nuclei, two elevators are being installed that connect the lobby level with each of the platforms.

Accessibility for People with Reduced Mobility is guaranteed with the installation of these vertical communication cores: escalators and elevators that overcome all differences in level.

The width of the platforms normally varies between 4 and 4,30 meters and their length is 115 metres, which allows greater range of movement and the use of the 8000 series trains.

Materials

Pavements:  Most of the floors of the station concourses and platforms are tiled with high-resistance Terastone-type tiles, laid with PA-350 cement mortar and 1/6 crumb sand. It is also easy to clean and has a wide range of colors.

At other stations, such as Getafe, the lobby and platform flooring is made of single-layer granite aggregate terrazzo, highly resistant to wear. Two centimeters thick and Berroqueño gray in color.

Vertical enclosure: The vertical walls, both in the vestibule and in the platform platforms, receive the same treatment. It consists of a colored Vitrex panel cladding up to a height of 2,20 m (this solution is resistant, highly durable, vandal-resistant and easy to repeat). An installation gutter is placed on it and from it to the ceiling an openwork Italfilm-type metallic coating is used.

TRESPA panels

Trespa is a flat plate, produced from thermosetting resins homogeneously reinforced with wood fiber and manufactured under pressure and high temperatures. With the application of special techniques, it is possible to provide the plates with a decorative surface integrated with pigmented resins.

It has been used as an enclosing material on facades, cornices and eaves in the emerging buildings of interchange stations with Cercanías RENFE.

Stainless steel and glass carpentry

Pillars:  They have a plinth 1.5 mm thick and 30 cm high. They are also lined with curved stainless steel sheet with a frosted finish, with the horizontal joints welded and the vertical joints with beading of the same material attached to the joint with clips.

With the same finish, the mouth of the elevator, in stainless steel, composed of wall cladding and false ceiling if necessary.

pinion finial of the station with two plates 25 cm wide and 1,6 mm thick, welded at a 90º angle, keeping the shape of the tunnel entrance to the station and reinforcing its edges with a 10x10 mm square of the same material welded to The plate.

Front of the wind doors access, made with high quality stainless steel carpentry. Composed of a 2,10x0,82 pivoting leaf door, with double interior-exterior opening, with vertical handles made of 40 mm diameter stainless steel tube.

guardrail 1,00 high on a 30 cm granite plinth formed from stainless steel tubes and sheet metal; glazed with 6+6 mm safety glass.

Paintings

Two main colors have been used, red and blue. Normally, the low-slab ceilings, such as the Puerta del Sur on Line 10, have been painted silicate red.

On other occasions, the light gray color has been left under the vestibule slab and the Metro blue color under the roof slab.

Metrosur has three types of stations: ordinary stations; interchange stations with Renfe neighborhoods (there are 6 stations of this type); and a singular station for correspondence with the Metro network (this is the case of the Puerta del Sur station).

ordinary stations

Functionality was enhanced by integrating all the needs of the station in a single volume that was executed and excavated between concrete screens.

Interchange stations with Cercanías de RENFE

The location of the Metrosur stations next to the existing Cercanías stations made it necessary to proceed with the remodeling of the Renfe stations themselves to optimize and facilitate exchanges.

Correspondence station with Metro: Puerta del Sur

Located in Alcorcón, it is the communication link between the Metro (line 10) and Metrosur. At this station, a scheme with a cross-shaped plan layout was developed, following the model of the Colombia station.

Over the years, different cities around the world have been renewing and expanding their Metro networks. In some cases, the environmental quality of the stations has had the same importance as more technical aspects, such as the renewal of rolling stock and facilities. This new concern has become evident as a result of the conclusions of psychological studies, which have shown that the architecture of the interiors and exteriors of the Metro influences the perceptive improvement on the part of the user, motivating and promoting its use.

The new design criteria are based on the search for a rational integration between the three spaces that could be distinguished in the stations; functional, visual and environmental space.

With the new typology of stations embedded in an orthogonal volume, the result of construction with a screen system, the opportunity arose to treat the large vertical panels resulting from construction with slabs and screens.

The Ideas Competition for the execution of the ornamental motifs of the Metrosur stations was convened by Metro de Madrid, SA and was announced in June 2001, and published from the 13th to the 20th of the same month in the BOCM , La Razón, ABC, El Mundo and El País. In turn, letters were sent to the COAM, the COAAT of Madrid and the Royal Academy of Fine Arts of San Fernando indicating the phases and delivery dates of the Ornamental Ideas for ten Metrosur stations, two for each of the municipalities to which which serves your layout.

Móstoles Central

Coco Ortega's work "Allegory of a tunnel boring machine" was the winner for this season. It has been located in the main hall of the station, at the point where the addresses of all travelers who access from the street and from the connection with Renfe converge.

It has a diameter of 550 cm and weighs about 1.000 Kg.

Fuenlabrada Central

The mural is called "Transport Ecosystem" and is the work of sculptor Luis Gil, graphic artist Gonzalo Mayoral and Sonia Perera.

Prior to its final printing, three test models were made on plain white canvas. The final assembly was carried out on a light support, which made additional lighting unnecessary.

Puerta del sur

Jorge Bernabeu's work, called "Landscapes of the South", is arranged in two panoramic murals. They reproduce panoramic photographs of two natural environments in the Community of Madrid. 

Both murals describe a semicircle of approximately 30 m in diameter. They are digital prints on fireproof canvas, completed with a backlight of white fluorescent tubes.

Julián Besteiro

The work of the team of architects Fernando VI, made up of Antonio Espejel Díez, Julio Iscar de Hoyos, Marcia Soto Téllez, Eduardo Navarro Pallarés and Marta Uriel Fernández, is located above the ticket office area raised to a height of four meters.

severo ochoa

Raúl Hermoso and Gonzalo Mayoral are the authors of "ADN y Lunas". It has been developed in two 9x8,50 m murals placed in front of the two escalators that access the Line 12 foothills from the main lobby.

Alonso de Mendoza

The work of Zoltan Espejel Enevold, "Demographic Explosion" symbolizes the expansion of the Madrid Metro and its outlying cities. Located in the lobby.

Juan de la Cierva

The authors of the award-winning mural were Carlos Alonso Pérez and Luis Sardá de Abreu.

The mural "Homage to de la Cierva" is located in front of the lobby, in the most privileged place in the station, in front of the viewpoint, suspended over the Line 12 tracks.

Parque oeste

"Con e de Europa", the work of Juan Carlos Melero, located on the lintel of the station hall that leads to the second entrance or service area.

Next, the different sections that make up the line are developed, with the stations that it includes and their constructive peculiarities. There are a total of twelve sections, awarded for execution according to six contracts, so that the tender would correspond, approximately, to each of the five municipalities affected by Metrosur.

The division by sections of the line follows an ascending order according to the anti-clockwise direction and its scheme is the one represented below:

• Section I, with a length of 4.374 m., comprises the Alcorcón 3 and Alcorcón 4 stations. It begins to the west of Alcorcón and runs between the NV highway and the railway, providing coverage for the Cercanías station and Rey Juan University. Carlos. The route leaves the municipality of Alcorcón to enter the municipality of Móstoles, through the Los Rosales industrial estate, where said section ends.

• Section II runs along 3.146 m. located in Móstoles, from the entrance pinion of Rey Juan Carlos University station (Móstoles 1) to the entrance screen of Hospital de Móstoles (Móstoles 4).

• Section III is somewhat special, since for its tender it was divided into two sub-sections executed in two different contracts.

Subsection III-A has a layout of about 2.845 m. It runs from the entrance pinion of the Móstoles 4 station and, along its route, crosses the Móstoles 5 station to exit in the municipal district of Fuenlabrada, some 1.400 meters from the tunnel boring machine used to excavate this section. .

Subsection III-B, belonging to another contract, begins 275 meters before the entrance pinion of the Fuenlabrada 1 station (Loranca) and ends at its exit. Its 407 meters are located in the Loranca urbanization, a satellite residential neighborhood of Fuenlabrada on the municipal border with Móstoles.

• Section IV runs from the exit of the Loranca station to the exit pinion of the Hospital de Fuenlabrada station (Fuenlabrada 2), where it connects with the exit shaft of the tunnel boring machine of the following section. In addition to this station, one more has been planned, which will come into operation in the future when this area is urbanized.

• Section V runs between the new hospital and the ring road, next to the Fuenlabrada 5 station exit. It is approximately 3.300 meters long and includes three stations within the municipality of Fuenlabrada.

• Section VI, 3.175 m. in length, it runs straddling Fuenlabrada and Getafe, from the ring road to the entrance of the Conservatory station (Getafe 2).

• Section VII, 1.348 meters long, covers two stations, Getafe 2 and Getafe 3, which define the section from the entrance of the first, Conservatorio, to the exit of the second, Alonso de Mendoza.

• The layout of section VIII extends from the Getafe 3 station exit to the Getafe 6 input pinion. Its length is approximately 4.017 meters and, like the previous section, includes two stations.

• Section IX runs from the entrance to El Casar until after the N-401, where the mouth of the tunnel boring machine is. It is 1.996 meters long, includes two stations, and both this section and the previous two extend entirely through the municipality of Getafe.

• Section X begins north of Getafe, in the El Bercial area, accessing the municipality of Leganés and ending in the San Nicasio neighborhood, where it connects with the following section. It has a total length of 6.994 meters and includes six stations, one in Getafe and the rest in Leganés.

• Section XI runs from the input pinion of Leganés 6 station, San Nicasio, to the La Almudena attack shaft, a tunnel boring machine that excavated sections XII and I, in the municipality of Leganés; along 1.726 meters. On the route we only find one station.

• Section XII, 3.537 meters long, extends from the tunnel boring machine's access shaft to the connection with section I. It includes Alcorcón 1 and Alcorcón 2 stations.

THE LINE TUNNEL

Various methods were used to excavate the tunnels. The choice of one or the other depended above all on the characteristics of the terrain that was excavated, on the possible subsidence and settlements that could be reflected on the surface, especially in urban areas, with nearby buildings or structures, on the effect on existing services and traffic, and the performance of each of the methods.

Traditional method of Madrid

The traditional method of Madrid, widely experienced in the construction of the infrastructure already in service in the Madrid Metro network, was used for the execution of the line tunnel of subsection IV-A and the final part of section VI, the galleries of communication between it and the ventilation, pumping and emergency exit shafts, and the single-track tunnel that connects Line 10 with the Metrosur ring at the Puerta del Sur station in Alcorcón, for restricted use by the Metro.

The excavation and concreting phases are:

• Vault
• Center Shatter
• side gables
• vault

Vault

Excavation begins with a keystone advance gallery, 1 meter wide by 1,50 meters high, with continuous eucalyptus board shoring. The boards are placed as the excavation progresses, resting on the ground itself, lining the upper part of the gallery. Once the gallery has been completed in the length of the advance (between 1,25 and 2,5 m depending on the terrain), the longarinas are placed, which are TH metal profiles that will serve as support for the boards, arranged longitudinally to the tunnel and separated 1 meter.

Between the boards and the longarina, a continuous board is placed, acting as a false support and separating these with coves to leave enough space for the boards of the following lateral passes. This run table is called "false".

Once the advance gallery is finished, the excavation begins to be opened on both sides of it in passes, numbering these with first, second, etc., as they move away from it. The execution of the passes is carried out in an analogous way, passing the shoring boards through the false and wedged against the longarina already placed. In this way a partition of the section is configured, in sections of about 3 m² with a brace attached transversely.

Immediately after executing the excavation, the formwork and concreting of the vault section is carried out, thus preventing instantaneous deformation of the ground. The excavation is carried out with pneumatic hammers and the evacuation by means of conveyor belts to the hopper and truck. The supports of the vault on the ground must be inclined, for a better distribution of loads.

Center Shatter

Once the vault is concreted, and with a gap of about 5 or 6 rings, the destruction begins, consisting of excavating a central box, leaving a shelter of the order of 1 to 1,5 m in the gables, so that you can push them to vault transmits to the ground that serves as support do not form dangerous rupture planes, which could give rise to the settlement and rupture of the same. This operation is carried out with an excavating machine that is also used to remove the earth from the excavation of the vault, which is poured into the rubble through one or more conveyor belts.

side gables

Once the destruction is finished, the gables are executed by counterbalancing bataches. Its excavation is carried out with the same machine that destroys it and is later refined by hand. The shoring is usually light and little set. Modules of 2,5 m are excavated, as are the rings, with the following two precautions:

• The joint of the rings must fall approximately in the center of the batache in order not to completely undermine the vault.
• Two bataches facing each other are never excavated at the same time for the same reasons.

This operation, which seems to be of little importance when the terrain is relatively good, can become complicated and become one of the most demanding phases when there is an abundance of water and the terrain has little cohesion.

Slab or vault

The corresponding excavation is carried out with a machine, in a length of 10 to 15 m (five rings), which is usually carried out on weekends, subsequently concreting with templates to achieve the shape of the type section. It can be done in the whole light or in halves. When the land has a lot of water, ditches or drainage wells are used.

This method, used since 1917 to build 87,6 km of tunnel, as well as canyons, galleries, etc., is well calibrated on the land of Madrid. The average performance is around 50 m/month per work front. It presents as main advantages:

• Minimum initial investment in facilities, as it is a method that only requires hand tools and traditional excavation machinery.
• Possibility of advancing on several fronts, provided that several attack ramps and sufficient specialized personnel are available.
• Stability of the front as it is a method of attacking a split section and having the possibility of shoring it.
• Adaptability to almost any type of terrain, which allows to execute without previous treatments, in areas where it would not be possible with other methods.
• Great flexibility of action against unforeseen events, shortening the passes, increasing the shoring, or treating the terrain.
• Good settlement control, due to the execution system itself with little open face, with the pre-support placed immediately after excavation and with the final support glued to the excavation face.
• Competitive price with more mechanized methods.
• Reduces deadline uncertainties by requiring fewer treatments than other systems.

On the contrary, the following can be cited as main drawbacks:

• Dependence on specialized labor for the execution of the method. The method implies a high proportion between labor and materials.
• It causes many construction joints, with the consequent impact on the surface finish and the long-term duration of the work.

Earth pressure shields. Tunnel boring machines

Execution of the line tunnels using EPB earth pressure shields or tunnel boring machines was the most representative and spectacular method used in the excavation of the METROSUR ring. This method meant the maximum mechanization of the excavation and subsequent lining of the cavity created.

In general, EPB earth pressure shields have been used in all Metrosur tunnel sections, except in sections III-B, IV-A and IV-B, which were built entirely without a tunnel boring machine.

The tunnel boring machine basically consists of a large frontal drilling disc with a diameter equal to that of the excavation, in which the excavation blades stand out on the radii of the face corresponding to the front. The excavated soil is removed through holes left in the space between the spokes, by turning the front disk on its axis while pushing on the ground.

This disc in turn drags a metal crown, sheltered by which the definitive lining of the tunnel is mounted, consisting of rings with an internal diameter of 8,43 m formed by seven Madrid-type voussoirs. These are prefabricated concrete, with a trapezoidal shape, thickness of 32 cm, average length of 1,50 m and can describe minimum radii of 250 m. Each ring is made up of seven voussoirs: a frustoconical key voussoir and six with an angle to the center, the union between these being made by means of 13 equidistant galvanized steel bolts: two per voussoir with only one in the key voussoir. Impermeability is achieved by means of watertight joints between voussoirs (radial joints) and rings (circumferential joints), which are made of neoprene.

The thrust of the head of the shield, which drags the armor, is carried out by means of jacks that rest on the last ring of the lining placed. These machines can compensate for the thrust of the ground and the filtered water at the front, creating a pressure chamber in the excavation material supply area and using different systems to compensate for differences in thrust. The stability of the front is achieved by balancing the rate of soil excavation in the aforementioned pressure chamber.

EPB (Earth Pressure Balance) machines arose from the closed shield of slurry tunnel boring machines. The cutter chamber uses the excavated soil to exert pressure on the excavation face that balances it to the full section, leaving it stable. To control this pressure, a worm screw is used that regulates the exit speed of the excavated soil from the excavation chamber. The land is dumped onto a belt that unloads onto wagons, which in turn transport it abroad to be finally taken to landfill. With the injection of water mixed with tensoactive materials, foams or polymers, in the chamber that contains excavated soil, its consistency is modified to make it suitable for extraction by screw. These conditioning agents convert the excavated soil into a paste that very effectively supports the effective pressure of the excavation face, creating a plug of dense and impermeable sludge in the waste outlet screw, which prevents the more humid soil from escaping when opening. the exit gate.

The weak point of these EPB machines is the main bearing. The enormous horizontal thrust of the jacks with which the head is pushing against the ground when digging passes to the head, where the bearing is the transmitting element.

The space between the excavated cylindrical surface and the extrados of the concrete ring is filled by injecting cement mortar, whose function is twofold, one is to balance pressures by transmitting the loads of the ground to the annular structure of the ring concrete and the other is to contribute to the waterproofing of the tunnel. 

Briefly, the excavation process is as follows:

• Assembly of the head and shell of the shield in a well between screens created for this purpose or taking advantage of the excavation for a station or infrastructure well.
• Creation of a thrust structure to which the effort of some shield advancement jacks is transmitted, until the friction between the placed rings and the ground is sufficient so that it is no longer needed.
• Excavation of the land by means of the front rotating disc blades, transmitting the thrust force against the ground from the last placed ring through hydraulic jacks.
• When the excavation has advanced the length corresponding to a ring, the thrust jacks retract sequentially while the lining voussoirs are placed.
• It is excavated again, transmitting the load to the head through the jacks that have been supported by the successive voussoirs placed in the last ring.
• Injection between the ground and the annular voussoir lining, between the last injected section and the final part of the shell, where the sealing brushes are located.
• Repetition of the excavation sequence and placement of the ring that forms the definitive lining of the tunnel.

SEASONS

In general terms, the stations are configured by a large area made up of screens and reinforced concrete slabs, with a widening at one end, corresponding to the lobby and the stairway blocks that give access to the platforms; in the rest of the enclosure the width is limited to that necessary to house the track box and the platforms.
 

"cut and cover" method

This construction method has been used in almost all the stations on the line. It has three variants, which are described below:

In the first of them, after the removal of the affected services and diversion of traffic in the affected area, the work surface is prepared. Next, after making the corresponding guide walls, the perimeter screens that confine the station enclosure are excavated and concreted using batches. In stations with lights between screens of a certain entity, these are distributed, using intermediate pile-piles, which are executed before concreting the cover. Once the screens and pile-piles have been cut off, the roof slab is built and subsequently waterproofed. At this point, you can begin to fill in with earth on the roof and replenish services and traffic, while excavating under the slab until you reach the vestibule level, where the vestibule slab is executed. Next, the excavation continues until the lower level of the inverted vault, which is carried out next. Finally, once the tunnel boring machine has finished its work, the platforms and finishes are made.

The second variant differs, basically, in the moment and way of executing the roof slab. Once the screens and pile-piles have been executed, excavation is carried out to the vestibule level and the vestibule slab is concreted. Next, prefabricated beams are placed and the roof is concreted. Excavation under the vestibule is then restarted up to the lower level of the counter-vault. The other steps are similar to the previous method. 

In the third variant, after the execution of the roof slab, excavation is carried out to the lower level of the inverted vault and, after concreting, the vestibule slab is built supported by pillars founded on the inverted vault. This is the case of Los Espartales station, in Getafe.

In the stations where there was no time to carry out the excavation before the passage of the tunnel boring machine, mainly because it was very close to the respective attack shaft, the tunnel was excavated first, and the lining had to be demolished later, when the emptying was carried out. from the station enclosure.

Open pit execution

In areas where land availability has allowed it, such as the Manuela Malasaña station in Móstoles, located on unscheduled developable land and free of nearby buildings, the open-air station is built, with a trolley inside a trench previously executed and cemented the vault in situ.

Cajon driven into Metrosur-Renfe interchanges. Particular case: Alcorcón Central

To ensure the connection and connectivity between METROSUR and RENFE, it was necessary to build caissons under the railway tracks, creating corridors and vestibules, except in the two stations located in Getafe, which have a direct interchange with the Cercanías network.

In order to observe the different phases of the execution and driving processes of a caisson, the particular case of the Alcorcón Central station will be studied below.

A transport interchange was built between the C-5 Cercanías line of RENFE and METROSUR, for which the demolition of the old station was necessary. The new railway station, much larger and more modern, is located in the same place as the old one and next to the new METROSUR station, Alcorcón Central.

To enable the passage of passengers from one platform to another and to access the METROSUR station from Berlin Street, which is under the railway platform, a reinforced concrete box was built, which was pushed by hydraulic jacks from the side from Calle Berlín towards the side of Avenida de Móstoles.

Before the on-site construction of the box, with a rectangular section and external dimensions of 10,80 m wide, 8,68 m high and 20,43 m long, a series of concrete piles were built to form and protect the excavation site.

Once the excavation was carried out, a concrete floor was built that was covered with a plastic sheet to facilitate the push of the caisson that was going to be built on it. Next, the bottom slab of the box and the gables were made, with their corresponding waiting reinforcement, to later go on to execute the upper slab of the box, using a falsework to support the formwork.

Once the necessary resistance was acquired, the upper slab was dismantled and the railway tracks were lowered in order to start the caisson thrust.

Next, the horizontal pushing or jacking system was installed, consisting of a series of 12 hydraulic jacks with a diameter of 20 cm and a maximum pushing capacity of 350 t, arranged in two groups of three pairs. The reaction of these jacks is transmitted to a rigid metal structure, which in turn rests on a concrete wall against the ground.

The pushing process was carried out for ten days, in sections of just over 2 m, in order to be able to excavate the ground of the open front of the caisson without risk of detachment of the sides.

The attached table shows how the pressures reached by the jacks increase and their total thrust is indicated as the advancement to the origin of the caisson increases, due to the beginning of the friction of the base of the caisson on the ground, already outside of the plastic sheet.

Pressures reached in cats

The friction increases progressively and with it the pressure exerted by the jacks, up to a maximum of 5.000 t of total thrust. The weight of the caisson is approximately 1.400 t, and the total distance is 20,79 m.

The attached drawings indicate the longitudinal profiles and the cross section, in the initial and final positions of the pushing process.

THE SUPERSTRUCTURE

It is slab track with a naturally hard rail of 54 Kg/m, of the UIC-54 type in 18 m long bars, supported on reinforced concrete pads coated with elastomer. This solution optimizes track maintenance throughout its useful life. The studs have to withstand a load of 12,5 tons per axle and the fastenings with the rail are of the SKL-1 or Pandrol type, depending on the required vibration and noise attenuation, and the Vossloh fastening system, with Corkelast-type elastomer. In addition, track devices, aluminothermic rail welding and concrete were used for the execution of the superstructure.

In general, the superstructure was concreted either in sections of single track, approximately 100 m long, to then build the other, or in a complete section, that is, double track.

In the sections executed with a tunnel boring machine, once the provisional tracks had been removed, the inner zone of the ring was filled with a layer of approximately 1 meter of gravel-cement, in order to reach the level of concreting necessary for the installation of the via. Next, the track was laid with its blocks, supported by temporary frames supported by the gravel-cement, with its legs embedded in plastic tubes to be able to recover them after the platform was concreted.

Metrosur is a line that can be considered a pilot in terms of innovations and in which we discover today many of the solutions that became widespread in the Metro.

New and sophisticated furniture designs have replaced the old ones, complementing this renewal and modernization of image while meeting its functional requirements. The turnstiles incorporate renewed software, which allows different applications, optimizing their performance. Likewise, the vending machines are incorporated into this modernization and the aesthetic set of the station.

Electrification

The traction system, which allows the circulation of the trains, is fed through 12 electrical substations located in as many stations, located in intermediate slabs of the underground structure of each station.

These substations, in addition to supplying the line's traction, serve the transformation centers installed in all the stations to supply all the other facilities: escalators and lifts, ventilation and pumping systems, lighting, etc.

Signaling

All the safety systems that control the circulation of trains (ATP) and automatic driving (ATO) are incorporated, which allow the interval between trains to be reduced to the maximum, with the consequent increase in line capacity.

Communications

A multiservice transmission network is included: voice, data and video by ATM/IP over fiber optic support for the line and the stations. The TETRA digital trunking radio system is also incorporated to streamline communications with rolling stock and security and emergency services.

Escalators and elevators

All the stations are equipped with escalators and lifts that bridge the differences in level from the street to the lobby and from the lobby to the platforms and allow access for passengers with reduced mobility.

Fire protection

Is incorporated:

• Early detection by aspiration, facilitating continuous surveillance of risks
• Fire extinguishing through centralized water mist systems
• Dry column extinguishing in stations, ventilation shafts and emergency exits

Ventilation

The ventilation system in tunnels and environmental conditioning of the stations is based on the construction of a series of wells (extraction, compensation and inmission) where the mechanical equipment (fans, silencers, etc.) are located.

Emergency exits

An emergency exit was provided at all stations, as an alternative to exiting through the hall, and inside the tunnel, so that there is one at least every 1000 metres.

The Metro network is a transport system in which it is necessary to have facilities and services that, although they are not perceived by the user, are vital for the development of the activity.

Among them, the rolling stock depots stand out for their importance. Maintenance work is carried out on them and trains are parked when they are not in service.

Metrosur has two modern garages. One at El Bercial station, between the towns of Getafe and Leganés, and it is the only underground one. It is mainly dedicated to train parking. It has a capacity of 8 lanes of 115 meters in length.

The other is located in Loranca, between Fuenlabrada and Móstoles, built on the surface and intended for both parking and first-level maintenance. It has a capacity of 18 tracks of 115 meters, and 7 more tracks were also arranged to accommodate the auxiliary vehicles necessary for the maintenance of the catenary track.

The design of first level maintenance facilities is conditioned by studies of the number of trains that must be accommodated simultaneously. They are divided into specific modules according to the operation to be carried out on the rolling stock: parking, maintenance or washing.

The preventive and corrective maintenance area is more difficult to design due to its peculiarities. The tracks are usually mounted on concrete or metal pillars to allow the existence of pits to work under the racks of the trains.

Second level maintenance facilities are designed and built not so much as pure railway workshops, but as true industrial manufacturing facilities.

In addition to the depots, 4 siding tracks have been built at the Rey Juan Carlos University station, which are used to regulate the number of trains in circulation.

Facilities for maintenance. First level

• Parking Spaces
• Short Cycle Scheduled Maintenance
• Cleaning
• Breakdown repair

Facilities for maintenance. Second level

• Review and repair of equipment
• big mods
• Repainted
• accident repair

The rolling stock used in Metrosur is type 8000. Each train carries 609 passengers (two seats for PRM), it takes 58 minutes to travel completely around the ring. The average frequency between trains is around three minutes.

Its design and manufacture was carried out entirely in Spain. The motorization of these trains allows a maximum acceleration of 1,2 m/s2 and they run at a top speed of 110 km/hour. They have a computerized driving and maintenance assistance system, a black box, an automatic train protection system (ATO), an underrun protection system, a radiotelephone, a public address system and air conditioning.

The main quality of these trains is their operation at 1.500 Vdc, which allows their speed and equipment performance to be increased. In addition, the construction of the boxes has used a light aluminum alloy that reduces the weight of the vehicles and their energy consumption.

In terms of safety, they are the first rail vehicles, together with those of the 7000 series, to be equipped with water mist fire extinguishing systems on board. Side stairs have also been incorporated for the evacuation of passengers in case of fire and interior photoluminescence and video surveillance systems.

The compositions of the 8000 series trains are made up of three cars, with a total length of 55,5. The configuration is continuous train.