More than a hundred workers are working at one time on one of the most important works of the legislative branch and one of the major debts to be settled with the North Capital. Turn on the machine at 7:00 AM. … In the morning and it stays like this for 12 days. Only during weekends is the shift reduced – from 9:00 am to 2:00 pm – to ensure the convenience of the neighborhood. Some massive artifacts come into view, under the watchful eye of the four towers (there are now five), the La Paz Hospital and, on the other side, the residents of the former colony of San Cristobal.
“They are like huge keys,” Javier Najera, the head of the structures service in the Works and Equipment District, tries to explain to ABC, in familiar language, while pointing with his index finger to the devices that fill the numerous cement piles already installed in the first section of the work. From the bowels of Castellana, the expert highlights the technology chosen to implement the aforementioned tunnel and how it attracted the curiosity of other countries that visited the intervention and seek to learn from this “reference model throughout Europe”. It also highlights the progress of the tasks, as in a short time hundreds of pillars, structures that will serve as pillars for the tunnel that will be covered, have been installed. But above all, it explains how north of Madrid was buried without cutting down supplies or trees.
Because although the majority of works of this size entail working to try to prevent the neighborhood from collapsing – whether through traffic diversions that irritate the vehicles that cross the area daily, or with supplies cut off to neighbors, who also endure the noise of machines, dust or scarcity of parking spaces – the case of the project on Paseo de la Castellana has its own specificity.
First, because the needs of the neighbors are added to the needs of large multinational corporations, which threaten with numerous complaints with every interruption of electricity and water, and the needs of the Hospital of La Paz, whose patients cannot be left without these basic supplies. And all this taking into account that the Isabel II Canal passes through there. In this way, Najera recounts the adjustment that the experts had to make in order to be able to implement the cuts without leaving any of the companies, which also operate on weekends, without supplies, not to mention the hospital that remains open 24 hours a day, seven days a week. “A temporary system has been installed while the reductions are implemented and until the final system is built.”
The second reason that makes these works special is that they are carried out on land where ancient trees live. Some of the specimens that the city council does not want to reduce, in addition, are in the same space where the large green park will later be built. Hence, a “huge effort” has been made to save the pine and cypress trees that have cast shadows over this place for more than 50 years. They are huge trees and have enormous ecological value, which is why the city council and the construction company made every effort to save them at any cost. They stress that all trees are large, and the goal is to save the vast majority of them.
In fact, the tunnel project was planned from the beginning so that the structures would not affect tree roots. In order to preserve them, some of them were replanted; Others are protected and intact, and some are very close to the excavations that have been done with great care so as not to damage their roots. As for the rest, its wide branches were trimmed so that the large machines passing by would not harm them. The five pine trees that were unable to remain in place were moved a few meters away from their original condition.
To do this, we relied on the most experienced Spanish company in this type of work. In order for the tree’s movement to be successful, a large portion of the ground beneath it is cut, the ground in which 90% of its roots are located, and by pushing some steel pipes horizontally, a base is formed that allows these large specimens to be lifted by a crane and carefully deposited in the new hole that awaits them. As if they were flying trees for a day. Once transplanted, each specimen is watered daily until it roots again. This is how they are now, with new buds, the five pines starting a new life near the place where they were born.
During these months, the City Council also had to deal with the complexity of traffic in the area, since it is the gateway to Madrid from the northern municipalities, reaching Castellana, La Paz, Plaza de Castilla and the Cuatro Torres financial district. Many of these residents choose to use public transportation, the well-known green buses, which connect Madrid with the cities in the mountains. Since the access point could not be changed because it was the only gate to the city in the north, Castellana had to continue accepting this entry and exit traffic. Thus, city council engineers and construction company technicians solved the problem by relocating as many as 18 bus stops serving fifty lines.
Once these setbacks are resolved, and without ruling out new quarrels, the works are progressing “very well” to open the tunnel in December 2026, as confirmed last Thursday by the delegate of the Works and Equipment Area, Paloma García, who confirmed that Castellana is proceeding on time and in the appropriate manner. In fact, the piles are now being built and the cover under which tunneling can begin “soon”.
Once the works are completed, the road will be buried for vehicular use and the surface will be designated for pedestrians who will be able to enjoy the new park. Its area will be 70,000 square meters, equivalent to approximately 10 football fields. Or what is the same, almost twice the size of the Bernabéu stadium or a 14,000-space parking lot. In addition, it will contain 787 newly planted trees that will be able to absorb between 7.8 and 19.7 tons of carbon dioxide per year when they reach maturity.
The tunnel will measure less than the park on the surface: 675 metres. Continuing the same comparison, its length would be equivalent to seven football fields, and a 10-storey office building would be as wide as a flat. Inside, 2,028 pile units will be buried distributed throughout the infrastructure, which, in comparative terms, is equivalent to about 2,983 truckloads of concrete. Also, for the most curious, if all these piles are placed linearly, they amount to 31,422 metres, which is equivalent to 31.4 kilometres, which is similar to going from the center of Madrid to Alcalá de Henares or from Barcelona to Mataró. Or also like swimming in 629 Olympic pools in a row.