They are back. Shakes, vibrations, oscillations that torment the residents of some buildings along the subway lines. I am caused by the comings and goings of underground trains: in particular circumstances it causes roars and tremors capable of reaching street level and the highest floors of apartment buildings. The phenomenon was already emerged in 2019. Atm, Municipality and Mm with the Polytechnic had set up a technical table to understand the causes and seek solutions. Extraordinary maintenance activities had been planned and started to reduce or cancel the inconveniences. But, after two years, the problem arises again.
The vibrations started again from the end of August tells Paolo Talenti with a house in piazzale Piola, right above one of the curves of the M2. They are a little different than before. There was a period of high frequency of the tremors, then they decreased but the intensity increased. And let’s consider that my apartment is 30 meters high. A report has been sent to ATM through the condominium administrator. From via Giotto, above the Pagano-Buonarroti section della rossa, since last spring some citizens have complained about the roars and the daily earthquakes. like having operated a pneumatic hammer at home with each passage of the metro, one of them writes. Their voices are joined by those of other Milanese they have contacted Noise mission, a non-profit association founded twenty years ago and led by Giorgio Campolongo, engineer specialized in acoustics and vibrations. Just take a look at the map on the online portal to see which neighborhoods are most affected. From January to today, Mission Noise has collected 16 reports from residents along the Sesto Marelli-Sesto Rond section, five between Gorla and Pasteur, six in Loreto. Other alerts come from the stops between Cadorna and Lotto, always along the M1 which has 35 alarm bells. Five related to the green line, concentrated between Caiazzo and Loreto and between Moscova and Lanza. In addition to these are two requests for intervention for the M5, the last made in the city network.
Campolongo underlines: I believe that there are many more cases, we have only intercepted a few. But you can still add your own situation, in complete safety. The engineer, on the strength of his past work experience in ATM, explains that one of the causes of the vibrations is marbling of the rails. To remedy this, an intense maintenance activity with special grinding trains is required. There is another variable – he adds -: the aquifer which in recent years has risen. It has created problems in some sections, for example along the green line, and ATM has started work to waterproof the tunnels. But I think it also plays a role in the shocks. However, this is a complex problem.
The multiplicity of causes had also emerged in the table created by the institutions two years ago, when the question of the jolts caused by the metr had landed in Mobilit commission at Palazzo Marino. The technicians at the time had talked about rigidity rigidity, anomalous wear of the tracks, curves of the track and water in the tunnel. There are also various remedies: shock absorber bearings under the rails which in some places would have been smoothed more frequently, slowing down the running of the trains. The shock treatment was effective immediately. Now the effect seems to have ended, at least in some neighborhoods. Atm specifies that in the Piola area, as well as on the whole network, ordinary grinding operations continue, while the extraordinary ones are scheduled on the recommendation of Mm, appointed by the Municipality to carry out the surveys. Observations that citizens are asking to repeat.
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September 27, 2021 | 07:32
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