Comprehensive renovation of Line 3

Line 3 is one of the oldest of the Madrid Metro. It represents an enormous contribution to mobility in Madrid due to its route, which runs through the center of Madrid, with multiple connections to the rest of the network, since 7 of its stations correspond to lines 1, 2, 4, 5, 6 and 10, as well as with the Moncloa transport interchange and with Line C5 of Cercanías.

The demand for the line grew uninterruptedly, to the point that it presented saturation problems in the section from Lavapiés to Sol. The densely populated districts of Usera and Villaverde had the opportunity to become one of the best communicated, by connecting with the center by extending the line from Legazpi to Villaverde Alto, where it would be possible to connect with Cercanías.

Thus arose the need to undertake a major performance consisting of two parts. On the one hand, the comprehensive renovation of the existing line, and on the other hand, its extension to the south, extending its layout with the most up-to-date construction methods and design criteria. The renovation provided the line with the same characteristics as those of new construction. In this way, it was possible to equip Line 3 with the most advanced facilities and rolling stock, so that it works in a completely unitary manner.

To increase the capacity of the line, two essential actions were carried out:

• Extend the length of the platforms that were 60 meters to the current 90. This has allowed the trains on the line to go from being made up of 4 cars to 6 cars at present.
• Change of railway signalling. Installation of the DTG (Distance to go) system already implemented on line 10 and Metrosur, which allows trains to circulate with 90-second intervals.

The result of both actions has made it possible in practice to double the supply of the line, going from 14.000 passengers/hour to 22.500 passengers/hour.

This capacity increase entailed other actions that have completely changed the line and are described below:

• Construction of a new station in Moncloa, under Calle Princesa, fully integrated into the transport interchange, parallel to the current line 6 and with a shunting sack bottom that extends towards Avda. de los Reyes Católicos, with a layout that will allow in the future the extension of the line towards Cuatro Caminos.
• Construction of a new connection tunnel between the Argüelles station and the new Moncloa station.
• Creation of new halls in all stations, as well as new spaces and itineraries in them, to ensure the mobility of travellers. To highlight the technical difficulty to carry out these works without excessively disturbing the service and minimizing the occupation of the road. It is important to mention the expansion of the Embajadores station interchange, an action financed in equal parts between Metro de Madrid and Adif.

• Structural reinforcement of the tunnel and waterproofing throughout its length.
• Change of track on ballast to track on concrete.
• Change of the railway signaling system from fixed block to Target Distance.
• Change of tram suspension system in the electrical supply to rigid catenary throughout the line.
• Changing the traction power supply voltage from 600 Vdc to 1500 Vdc
• Construction of 3 new electrical substations.

• Mechanization of all vertical movements through stairs and elevators.
• Total conditioning of the line for people with reduced mobility, including correspondence with other Metro lines and with Cercanías. With this action it will become the first underground metro line in the world of those built in the first half of the last century that is fully accessible.
• Remodeling of the architecture of all the stations, including their waterproofing.
• Implementation of the TETRA communications system.
• Replacement of the four-car 2000 series trains with 36 3000 series boa-type trains.
• Installation of new ticket vending machines.
• Implementation of the commercial supervisor system on the line, similar to that of Metrosur.

The construction procedure was carried out in different phases:

• Phase 0: Initial state
• Phase 1: Metallic protection of the tunnel and diversion of services
• Phase 2: Screen and roof slab. First half

• Phase 3: Screen and roof slab, 2nd half
• Phase 4: Excavation under the cover slab and demolition of the tunnel
• Phase 5: Removal of the metallic protection of the tunnel

• Phase 6: Completion of civil works.
• Phase 7: Completion of architecture and equipment.
• Final state.

This process was executed in different phases:

• Initial state. track on ballast
• Phase 1. Dismantling of track and storage of rails
• Phase 2. Ballast removal

• Phase 3: Assembly of track and formwork
• Phase 4: Concrete track and assembly of the other track
• Final state: Concrete track.

This process was executed in different phases:

• Phase 1: Preliminary work, clearance check and ballast protection
• Phase 2: Cleaning of the intrados
• Phase 3: Chopping of damaged areas of the intrados
• Phase 4: Drilling
• Phase 5: Injection of cement mortar
• Phase 6: Drilling of Californian drains

• Phase 7. Placement of waterproofing sealing sheets
• Phase 8. Placement of steel mesh
• Phase 9. Wet or semi-wet waterproofed shotcrete
• Phase 10: Removal of footings and spraying of concrete manually
• Phase 11: Verification of gauges
• Phase 12: Finishing and cleaning.

In the following images you can see the state of the tunnel before and after its consolidation.

The stations are the spaces that the public perceives and in which the greatest architectural effort has been put, combining simplicity, functionality, comfort, aesthetics and accessibility, 

The stations of the renovated line are affected by the constraints of their construction with old criteria, which gave rise to long access and connection corridors, which formed a complex knot of galleries and canyons, necessary to guarantee all movements. This situation caused great lengths to travel by travelers, orientation difficulties and inexorable dependence on signage.

Interventions have been carried out in all the renovated stations to open up the space to facilitate its understanding and its luminosity. In this way, multilevel spaces arise, which allow the simultaneous vision of the different connecting circulations, endowed with a strong spatial richness, due to the confluence of stairs and levels around large empty spaces. Thus, all the stations on the line (renovated and new) are the result of a common approach, although each of them is its own reality with certain determining factors. All this putting civil works at the service of functionality and the traveller.

Accessibility for people with reduced mobility is guaranteed by the installation of elevators that connect all levels. As an alternative, all the differences in level can be saved by means of escalators.

The finishing materials are the same in the part of the renovation and extension and similar to those used in other lines, guaranteeing its maintenance, as well as its image of modern architecture.