Update on Noise Analyses for the Deux-Montagnes and Anse-à-l’Orme Branches 

In the summer of 2024, our team created opportunities to meet and engage with the public to explain how we were going to take advantage of the initial circulation of REM cars on the Deux-Montagnes and Anse-à-l’Orme branches to conduct additional analyses of REM operational noise.

Findings have now been drawn from this additional noise measurement campaign carried out over the past few months. Here is a summary of the findings. 

Overview of the process

The overall noise analysis process for the REM project has had several stages that began in 2018.

However, when REM service was launched on the South Shore in 2023, it became necessary to validate the data considered at the start of the process through complementary field analyses. This is the approach we have taken for the rest of the network.  

Led by SYSTRA, a firm specializing in railway engineering and acoustics, the objectives of this complementary noise measurement campaign were to measure the actual noise of the REM passage to identify if additional mitigation measures were to be considered.

Two findings emerged from this campaign:  

• First, the prior mitigation measures, such as the prefabricated panel noise barriers and the track grinding done in 2024, were shown to be effective.  
• Second, SYSTRA identified some sectors where noise mitigation measures need to be improved.   

Additional mitigation measures

Our objective remains to reduce the impact of REM noise by implementing the right measures in the right places. That is why, in addition to the noise measurements, SYSTRA used this testing period to test several kinds of equipment that could be used to reduce the noise impact of the REM, in order to validate their effectiveness on the Deux-Montagnes and Anse-à-l’Orme branches.

Finally, as was the case on the South Shore, two mitigation measures were selected: 

Dynamic absorbers: As with the absorbers installed on the South Shore, testing has confirmed that when installed directly on the rail, where appropriate, this equipment is highly effective in absorbing track vibrations and reducing rolling noise on bridges and overhead structures.  

Noise barriers: A noise barrier is a physical structure installed along the tracks that limits the spread of noise. Several barriers have already been installed on the network at the locations identified during the initial modelling. However, adjustments will be made in certain locations, including Île-Bigras, Deux-Montagnes, the Saint-Laurent borough, and in Town of Mount Royal.

Photo of dynamic absorbers © Poly Corp INC

Our teams are already working to have these measures, which are currently being implemented, finalized in the coming months.

Once the REM is in operation, the noise monitoring process will be established to confirm the effectiveness over time of all the mitigation measures implemented on the REM network.