new queen st e & leslie st noise analysis toronto, ontario · 2020. 1. 4. · ttc / queen st e...

ASSESSMENT REPORT - Project: 15201.08

Queen St E & Leslie StNoise AnalysisToronto, Ontario

Prepared for:

Toronto Transit CommissionStreetcar Department1900 Yonge StreetToronto, ON M4S 1Z2

Prepared by:

Alexandra Davidson

Michael Medal, B.A.Sc., P.Eng.25 August 2017

TTC / Queen St E & Leslie St – Noise Analysis of 15

Table of Contents

1 Introduction 32 Descriptors 32.1 Frequency and Octave Bands.............................................................................. 3

2.2 Sound Pressure Levels ........................................................................................ 3

2.2.1 Leq .................................................................................................................... 3

2.2.2 Lmax ................................................................................................................. 3

2.2.3 L90 .................................................................................................................... 3

3 Site Description 44 Measurement Description 44.1 Instrumentation .................................................................................................... 4

4.2 Location ............................................................................................................... 5

4.3 Weather Conditions ............................................................................................. 5

4.4 Streetcar Pass-by Directions ............................................................................... 5

5 Analysis Procedures 55.1 Sound Analysis .................................................................................................... 6

6 Measurement Results and Discussion 76.1 Pass-by Sound Levels ......................................................................................... 7

6.2 Ambient Sound Levels ....................................................................................... 10

6.3 Comparison Between Different Intersections ..................................................... 10

6.4 Squeal Duration ................................................................................................. 11

7 Conclusion 12Appendix A 13


1 IntroductionAercoustics Engineering Limited (Aercoustics) has been retained by the Toronto TransitCommission (TTC) to evaluate the TTC streetcar sound levels from streetcar vehiclesturning through the intersection of Queen Street East and Leslie Street. The scope of theevaluation is to determine the sound levels from TTC streetcar turning pass-bys.

This report includes sound analysis conducted by Aercoustics on measurement datacollected from the Queen St E and Leslie St intersection on June 1st from approximately5AM – 9AM.

2 DescriptorsA brief description of the technical terms used in this report are summarized below.

2.1 Frequency and Octave BandsThe data in this report has been given in terms of its frequency distribution. The frequencyis the number of times in one second that a sound or vibration wave oscillates. Thefrequencies measured are expressed in terms of levels which are typically grouped intooctave bands with centre frequencies at 31.5, 63, 125, 250, 500, 1000, 2000, 4000 and 8000Hertz (Hz).

For more detailed analysis, results may also be divided into one-third octave bands, as hasbeen done in this report. For sound, the frequency range has been analysed from 20 Hz to20,000 Hz, which corresponds to the typical range of the human ear.

2.2 Sound Pressure LevelsThe sound pressure levels or simply “sound levels” used in this report are provided interms of decibels (dB) referenced to 20 micro Pascals. An “A-weighting” correction isapplied to the one-third octave band dB levels to capture the response of the human ear.

2.2.1 LeqLeq refers to the sound level equivalent of the total sound energy over a given period oftime, meaning the average sound level during a measurement period.

2.2.2 LmaxLmax refers to the maximum sound level during a measurement period.

2.2.3 L90L90 refers to the sound level exceeded for 90% of the measurement period, typically usedfor assessing background noise.


3 Site DescriptionThe track layout at the intersection includes straight eastbound and westbound tracksalong Queen St E and curved tracks from Leslie St to Queen St E. There are no tracksfrom Leslie St north of Queen St E. The streetcar traffic routes on the curves analysed inthe report are shown in Figure 1.

Figure 1: Site Plan and Streetcar Pass-by Directions

4 Measurement Description4.1 InstrumentationThe sound and vibration measurements at the Queen and Leslie intersection werecompleted using two (2) microphones. The measurement data was acquired using RION


data acquisition system with a sampling frequency of 51,200 Hz. All equipment wascalibrated prior to each site visit.

4.2 LocationThe sound measurements were completed on the north-east and south-west corners ofthe intersection. Both microphones were mounted at a height of approximately 1.3 m. Aplan view of the measurement locations is provided in Figure 5 located at the end of thereport in Appendix A.

4.3 Weather ConditionsThe weather conditions were favourable for all measurements, with negligible windspeeds, no precipitation, and dry track conditions. The temperature ranged from 11-13degrees Celsius throughout the measurement period of 05:00 – 09:00 and ranged from11-18 degrees throughout the day.

4.4 Streetcar Pass-by DirectionsBoth straight and turning streetcar pass-bys were observed during the measurementperiod from 05:00 – 09:00. The focus of the investigation is on the sound levels producedby turning streetcars pass-bys, which included Eastbound Queen to Southbound Leslieand Northbound Leslie to Westbound Queen. No streetcars were observed on theNorthbound to Eastbound and Westbound to Southbound curve.

5 Analysis ProceduresThe collected measurement data was processed to isolate the sound from individualstreetcar pass-bys, which were further sorted by pass-by direction. This is important tonote, since this method of analysing the sound levels only during a streetcar pass-by helpseliminate other factors and focuses on quantifying the sound impact of each individualstreetcar pass-by.

Sound analysis was completed for the following turning pass-by directions:

· Eastbound (EB) Queen St turning to Southbound (SB) Leslie St· Northbound (NB) Leslie St turning to Westbound (WB) Queen St

Measurement data from simultaneous streetcar pass-bys was excluded to ensure soundlevels attributed to each pass-by direction were representative. Similarly, streetcarpass-bys during which other dominating noise sources were audible (e.g. road traffic) werealso omitted from analysis. The resulting number of pass-bys included in the analysis areshown in Table 1.


Table 1: Number of Pass-by Measurements

Pass-by Direction Total Number ofPass-bys

Total Number ofAnalysed Pass-bys

Eastbound to Southbound (EB to SB) 3 3

Northbound to Westbound (NB to WB) 27 13

Note that since only three (3) EB to SB pass-bys were observed during the measurementperiod, that was the only data which could be analysed for that pass-by direction. Typically,a sample size of five (5) to ten (10) pass-bys is preferred to give a more statistically certainresult, however analysis of the three observed pass-bys should still give a good indicationof pass-by sound levels.

5.1 Sound AnalysisProcessing of the sound data was conducted to obtain one-third octave band sound levelsin dB (ref. 20 µPa) in the range of 20 Hz to 20,000 Hz. An “A-weighting” correction wasalso applied to the sound levels to capture the response of the human ear.

· For each streetcar pass-by, the equivalent sound level (Leq) and maximum soundlevel (Lmax) for each one-third octave band frequency as well as an overall“A-weighted” broadband level was processed using a “fast” time constant(0.125 s).

· The individual pass-by sound levels for each pass-by direction were averagedtogether to indicate typical sound levels by direction.

· For a given pass-by direction, the maximum and minimum values in eachfrequency band were determined.

The data was further processed for FFT spectra with 0.5 second time increments and 2 Hzresolution up to 20,000 Hz.

· Periods of squeal were identified in the FFT spectra, verified by recorded WAV filelistening tests.

· Average squeal durations per pass-by, in seconds, were evaluated for top rail,flange, and total combined squeals. Periods where top rail squeal and flangesqueal occur simultaneously are only counted once towards the total combinedsqueal, which is the total duration for which squeal is audible.


Finally, the L90 was processed for the measurement, using data from periods betweenstreetcar pass-bys, which is indicative of the ambient sound level present during themeasurement period.

6 Measurement Results and DiscussionThere are two important factors which can influence the perception of noise from anindividual streetcar pass-by. The first is the perceived amplitude or sound level of thepass-by, part of which is influenced by the amount of wheel squeal. The second is thepresence and duration of any wheel-rail squeal throughout the pass-by, which can have asignificant influence on the annoyance on receptors. Analysis of both are presented below.

6.1 Pass-by Sound LevelsThe average sound levels of all the measured streetcar pass-bys in each pass-by directionare compiled in Table 2 for both the south-west and north-east corners of the intersection.

Table 2: Average Overall Sound Level for Curved Pass-by Directions

Meas. Pass-byDirection

Sound Level (dBA)

South-West Corner North-East Corner

LeqEB to SB 66 66

NB to WB 73 66

LmaxEB to SB 75 73

NB to WB 85 79

As seen in Table 2, the highest noise impact is on the south-west corner predominantlydue to the Northbound to Westbound pass-bys.

In general, the noise level from a streetcar pass-by depends on a number of factors,including the wheel locations relative to the microphone as the streetcar traverses thecurve. The point of the turn during which the any streetcar wheel squeal occurs can alsoaffect the results based on the orientation to the microphone locations. As a result, thelevels recorded at the measurement locations may differ.

Additionally, due to the small sample size of pass-bys, specifically for the Eastbound toSouthbound direction, there are variations in the data which may affect the average.However, the noise impact from these pass-bys was consistent across the dataset andfollows the same trend as the Northbound to Westbound pass-bys.


One-third octave analysis of the sound measurement data indicates the results have goodagreeance and display a fairly consistent trend between measurement locations andpass-by directions. Measurement data collected on the south-west corner is illustrated inFigure 2 and Figure 3 and on the north-east corner in Figure 4 and Figure 5.

Figure 2: A-Weighted Sound Level (Leq) at South-West Corner

Figure 3: A-Weighted Sound Level (Lmax) at South-West Corner

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Streetcar Passby Sound Level - LeqMeas. Location: SW Corner

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Figure 4: A-Weighted Sound Level (Leq) at North-East Corner

Figure 5: A-Weighted Sound Level (Lmax) at North-East Corner

The overall sound levels and trend across frequencies is comparable for both turningdirections. There are two noticeably higher peaks between 2500 Hz and 4000 Hz for theNorthbound to Westbound pass-bys measured from the north-east corner. These levelscan be attributed to high frequency wheel-rail squealing from the outside rail of the curve.

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6.2 Ambient Sound LevelsThe ambient sound level at the intersection during the measurement period, betweenstreetcar pass-bys, was 51 dBA on the south-west corner and 58 dBA on the north-eastcorner. The ambient sound level is sufficiently below the measured pass-by sound levelsthat they did not affect the analysis and results.

6.3 Comparison Between Different IntersectionsThe measurements at the Queen & Leslie intersection were compared to measurementsfrom three other intersections with similar track curve geometry, including King & Sumach,Queen & Broadview, and Bathurst & Fleet. It must be noted that due to differences in themeasurement environment and conditions between the observed intersections, the resultswill not reflect exactly comparable sound levels for the subject track sections, but ratherprovide a rough representation of the general noise impact at the measurement locations.

Measurement data from the three additional intersections was collected the morning ofMay 4, 2017. Measurements at Queen & Broadview and Bathurst & Fleet were taken onthe inside of the track curve, approximately 8 m away from the streetcars as they traversedthe curve. The measurements at King & Sumach were taken at the same distance of 8m,but located on the outside of the curve. As the streetcar was travelling away from theposition for the outside of the curve measurement rather than roughly maintaining themeasurement distance for the inside of the curve locations, the outside of the curvemeasurement is expected to result in lower measured sound levels; we estimate atapproximately 2-3 dB lower. Levels were compared to the measurements of theNorthbound to Westbound curve at Queen & Leslie, which were also taken approximately8 m from the inside of the track curve.

The comparative overall sound levels are summarized in Table 3 and the average Leqvalues by one-third octave band frequency are plotted in Figure 6. The noise levelrecorded at Queen & Leslie is comparable to the levels measured at Queen & Broadviewand Bathurst & Fleet, with Queen & Leslie measuring slightly higher levels atapproximately 1600 Hz. As expected due to the measurement location on the outside ofthe track curve, the levels recorded at King & Sumach are slightly lower but stillcomparable to the other intersections. After allowing for the differences in measurementposition and the typical variations expected from field measurements, the differences instreetcar pass-by sound level recorded at each of the intersections are consideredgenerally insignificant.


Table 3: Average Pass-by Sound Level at Different Intersections

MeasurementQueen &

Leslie(1 Jun 2017)

King &Sumach

(4 May 2017)

Queen &Broadview

(4 May 2017)

Bathurst &Fleet

(4 May 2017)

Average Leq (dBA) 73 67 74 72

Figure 6: Comparison of Average A-Weighted Leq at Different Intersections

6.4 Squeal DurationThe average squeal durations for top rail squeal, flange squeal, and total combined squealwere calculated for the curve pass-bys and are summarized in Table 4 below. Periodswhere top rail squeal and flange squeal occur simultaneously are only counted oncetowards the total combined squeal, which is the total duration for which squeal is audible.

The squeal duration for the turning pass-bys was 2 seconds on average for both top railsqueal and flange squeal, with approximately 1 second of simultaneous squeal. Thesqueal duration measured at Queen & Leslie was comparable to measurements ofstreetcar pass-by squeal at similar intersections, conducted the morning of May 4, 2017.The comparison is shown in Table 4.


Table 4: Pass-by Squeal Durations for Different Intersections

IntersectionAverage Squeal Duration (s)

Top Rail Flange Total Combined*

Queen & Leslie (NB to WB) 2 2 3King & Sumach (EB to SB) <1 1 1

Queen & Broadview 1 4 5Bathurst & Fleet <1 3 3

*Note: Total combined squeal duration does not double count periods where top of rail and flange squealoccurred simultaneously

7 ConclusionAercoustics has completed sound measurements for the track curve at the Queen St Eand Leslie St intersection. Additional measurements at similar intersections used forcomparison were completed at an earlier date.

It is noted that due to the limited sample size and the effect that variable weatherconditions can have on streetcar wheel-rail squeal, the results presented are not a fullrepresentation of the full range of pass-by sound levels possible at the intersection, butrather they are an indication of the levels present on the particular measurement day. Inorder to better understand the effect of environmental factors on the streetcar pass-bysound levels and squeal durations, continuous measurements for an extended periodwould be required. Additionally, variations exist in the conditions between the Queen &Leslie measurements on June 1, 2017 and the measurements used for comparison onMay 4, 2017, meaning these comparisons are not absolute but rather a general indication.

Based on the data collected, the sound levels and squeal duration from the turningstreetcar pass-bys at Queen & Leslie are comparable to similar turning curves at otherintersections. After allowing for the differences in measurement position and the typicalvariations expected from field measurements, the differences in streetcar pass-by soundlevel recorded at each of the intersections are considered generally insignificant.


Appendix A

SITE PLAN


Figure 7: Measurement Locations


Figure 8: South-West Corner Measurement Set-Up

new queen st e & leslie st noise analysis toronto, ontario · 2020. 1. 4. · ttc / queen st e...

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