Madrid never sleeps, and neither does the hidden city that lives beneath its ground. More than 170 kilometers of underground tunnels transport the capital’s most important supply system: electricity, fiber optics, and water. 237 entrances and exits are hidden on the city’s sidewalks or in tunnels, and even some large buildings like the Cuatro Torres, the Palacio de Congresos de la Castellana, or the Torre Picasso have direct access. They are classified as critical areas because “imagine leaving these towers, the city council, theaters or commercial areas without electricity,” says Carlos Rubio, Deputy General Director of Urban Facilities for the Works and Equipment Department of the Madrid City Council.
This network is constantly evolving, albeit with the limitations that a city with so much underground life like Madrid entails. Galleries integrate new services and new technologies that guarantee control and security. In the new developments in the southeast, “another 20 kilometers of galleries have been completed, into which treated water pipes have been installed,” to be used in parks, for cleaning, and other services. New power lines are also being laid for electric vehicle charging stations. They run through the city’s main streets, and from this labyrinth, you can get anywhere by metro: “Through one of the entrances near the Santiago Bernabéu stadium, we could reach Puerta del Sol or the Manuel Becerra neighborhood.” In the main and longer streets like Príncipe de Vergara or Paseo de Recoletos, there is one on each side of the sidewalk. In total, there are 105 passages. While these largely unknown passages are key to ensuring basic services, they also have advantages. Working on them creates no impact, as sidewalks do not have to be dug up: “At the moment, pipes with a diameter of more than one meter are being renewed on Paseo del Prado, and nobody finds out,” explains Rubio. Since they are large, “they also allow new installations to be carried out very quickly, as the thickness of the pipes is more limited with surface pipes.” Normally, these corridors are about 15 meters underground, but “there are some that reach up to 25 meters deep.” Due to the importance of this infrastructure, security measures are crucial. In the urban facilities control center in the Azca district, about twenty workers guard the interior of the galleries 24 hours a day, every day of the year. Night vision cameras provide real-time information on the entire interior to control access or if an accident occurs. And there are smoke detectors “every 50 meters” and gas sensors “every 100 meters.” In fact, no one enters without a gas detector to know the levels of oxygen and other gases. The center’s staff are in direct dialogue with the emergency services, to whom they send the specific location. The National Police’s Underground Special Unit supports the permanent monitoring of the galleries and intensifies it in the face of extraordinary events such as the NATO Summit.
Control of Tunnels, Fountains, and Public Lighting
In this center full of screens, the 40 urban tunnels (except those on Calle 30), the public lighting (more than 264,000 lampposts), and 436 ornamental fountains are also controlled. The most complex task, Carlos Rubio admits, are the tunnels, because “vehicles of all kinds constantly enter and a multitude of accidents occur.” However, there are many alternative actions: “The most drastic is to close the tunnel; but there are also traffic lights, barriers to cut off access, activation of ventilation systems, increasing lighting, or informing about possible cut lanes on blackboards.” All this is immediately activated from the control center, viewed through the images of the “860 tunnel cameras.” Technological progress has improved the management of public lighting from this type of headquarters. “Not only do the streetlights no longer turn on, we also control their operation.” The Deputy General Director of Urban Installations explains that they adjust the luminosity through 2,500 sensors distributed throughout Madrid. “Before businesses close, it’s at maximum, then it’s reduced by 80% until in the early morning it has 60% less lighting than at the beginning of the evening.” With the centralized systems, the command center, in the event of an event ending at three in the morning, would increase the intensity of the lights when the public leaves the venue. In the case of ornamental fountains, a clock used to be activated and deactivated in each of them. Now “a small automaton does this work and controls many other things.” For example, the quality of the water or the wind, to reduce the height of the nozzles if necessary and thus not wet the street. If the color of the Cibeles fountain changes, the color of this control center also changes. For unforeseen events such as power outages, the center has an uninterruptible power supply system that operates for 45 minutes. Then the generators supply power to the equipment with diesel. In the galleries, monitoring at the entrances was done “the old way, with teams distributed throughout the city.” In any case, there is a replica center that can be used if an incident occurs in the main center, so that Madrid and its basic services do not stop functioning.
