Metro Vancouver’s public transit authority says it is taking steps to reduce the level of noise emitted by the trains traveling on the SkyTrain’s Expo Line and Millennium Line.
In a report, TransLink says new measures are being considered after an increase in a number of noise complaints in recent years from residents living next to the elevated and ground-level tracks, with track condition and the growing number of residences clustered around the tracks being the leading factors.
Noise complaints tend to come from an area within half-a-block from the tracks, particularly residential buildings that are immediately fronting the system.
Measurements recorded by TransLink at 32 locations indicate noise levels can reach up to 90 decibels, which is higher than the maximum noise level of 75 decibels for residential building facades recommended by the World Health Organization.
Much of this noise is caused by the rolling contact of the steel wheels of the train on the steel rails; factors like temperature, weather condition, and wheel condition only had a “minor effect” on noise.
Even the type and age of train – Mark I, Mark II, and the new Mark III trains – all produced similar external noise levels. Newer trains, both the Mark II and Mark III, have significantly quieter interiors than the Expo-era Mark I trains.
The Canada Line does not have a high noise level issue due to factors such as the system’s younger age. Additionally, the Canada Line only runs above ground near Marine Drive in Vancouver and in Richmond.
In Richmond, building codes along the No. 3 Road Corridor already requires superior noise insulation to protect both commercial and residential buildings from low-flying aircraft noise from Vancouver International Airport.
According to TransLink’s analysis, officials with the public transit authority believe the main contributing factors to high noise levels are train speed, proximity and elevation of a residence, and track condition.
“The analysis concluded that track condition was the predominant, controllable factor that contributes to high noise levels, and which varies depending on the state of the asset,” reads the report.
“Rail roughness, corrugation, track defects and/or worn switches result in noise levels that can be upwards of 15 decibels greater than corresponding locations with track and/or switches in good condition.”
TransLink has already engaged in further rail grinding practices as one of its first noise mitigation measures.
It is now considering six new and improved measures, including improvements to its rail grinding practices, installing rail dampers, reintroducing top-of-rail friction modifiers, investigating head-hardened rail in place of current rail standard, and developing guidelines for new residential developments near SkyTrain.
These mitigation measure could have a “sizable” impact on TransLink’s budget for capital projects and operating and maintenance expenditures.
Another progress report that examines the feasibility of each option will be reported back to TransLink’s Board of Directors in March 2019.