REM noise during operations: Implementation of mitigation measures
- In the spring, a rigorous analysis process was carried out in partnership with international experts to gain a better understanding of the sources of noise.
- The resulting diagnosis confirmed an unsatisfactory noise impact in certain areas between Île-des-Sœurs and Central Station.
- Two proven solutions will be rolled out: carrying out acoustic grinding along the entire segment and installing dynamic dampers on major sections of the route near residential areas.
- A significant reduction in total noise intensity of 5 to 10 dB at the source is anticipated. In general, such a reduction is equivalent to a 3 to 10-fold decrease in the level of noise emitted compared to the current situation
Media representatives were invited to a technical presentation of the results of an analysis carried out by acoustics experts on the REM segment in service, as well as on the mitigation measures to be rolled out in Griffintown, Pointe-Saint-Charles and Île-des-Sœurs.
“As we have said before, we are not happy about the noise caused by REM operations in certain areas. Over the last few months, we have adopted a strategic approach, with the support of international experts, to establish a diagnosis that will now enable us to implement proven solutions. These will be closely monitored to ensure that our noise reduction targets are met,” said Jean-Marc Arbaud, President and Chief Executive Officer of CDPQ Infra.
Noise impact taken into account and monitored from the outset of the project
Beginning in the design phase, noise impact modelling and the subsequent planning for necessary mitigation measures was carried out for the REM. In addition, at the project’s inception, a program was implemented to monitor noise levels during operations.
However, following discussions with residents in certain areas, Projet REM s.e.c. launched a new noise measurement initiative to gain a clear understanding of the current situation and determine the measures to be taken based on the results. SYSTRA was commissioned to carry out the assessment.
A total of seven sound level meters were installed in residential areas in Île-des-Sœurs, Pointe-Saint-Charles and Griffintown to continuously measure the impact of the REM. The data collected shows that the situation varies from one area to another. Griffintown and Île-des-Soeurs show higher levels than those indicated by initial modelling.
REM operations are carried out in compliance with the regulatory framework set by the Québec government, including the Politique sur le bruit routier by the Ministère des Transports du Québec et de la Mobilité durable (MTQMD), according to the criteria applicable to the project.
At-source mitigation measures with proven results around the world
International experts from SYSTRA concluded that the main sources of noise are:
- The transmission of vibrations from the track to the elevated structure, which creates a rumbling noise
- Contact between car wheels and the track, which generates a rolling noise
Based on its worldwide experience in transit systems, the team of experts recommended proven noise reduction measures that can be applied directly at the source: carrying out acoustic rail grinding and installing dynamic absorbers on major sections of the route near residential areas.
Following the implementation of these two measures, a reduction in total noise intensity of 5 to 10 dB at the source is anticipated. Generally speaking, such a reduction is equivalent to a 3- to 10-fold decrease in the level of noise emitted compared to the current situation.
Rapid rollout of identified measures
In early November, acoustic rail grinding will be carried out on the entire segment between Île-des-Sœurs and Central Station, continuing as far as Brossard station. Dynamic absorbers will be installed gradually from mid-October to December.
REM users and local residents will receive more specific information about these measures in the coming weeks.
The possibility of adding additional noise barriers was also examined. However, given the height of the built environment, this measure is not considered to result in significant acoustic improvements.
Projet REM s.e.c. will continue to monitor noise to ensure that noise reduction targets are met, and will share the results publicly.
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