ASSESSMENT REPORT - Project: 151.08 Queen St E & Leslie St Noise Analysis Toronto, Ontario Prepared for: Toronto Transit Commission Streetcar Department 1900 Yonge Street Toronto, ON M4S 1Z2 Prepared by: Alexandra Davidson Michael Medal, B.A.Sc., P.Eng. 25 August 17
TTC / Queen St E & Leslie St Noise Analysis Page 2 of 15 Table of Contents 1 Introduction 3 2 Descriptors 3 2.1 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 4 4 Measurement Description 4 4.1 Instrumentation... 4 4.2 Location... 5 4.3 Weather Conditions... 5 4.4 Streetcar Pass-by Directions... 5 5 Analysis Procedures 5 5.1 Sound Analysis... 6 6 Measurement Results and Discussion 7 6.1 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 12 Appendix A 13
TTC / Queen St E & Leslie St Noise Analysis Page 3 of 15 1 Introduction Aercoustics Engineering Limited (Aercoustics) has been retained by the Toronto Transit Commission (TTC) to evaluate the TTC streetcar sound levels from streetcar vehicles turning through the intersection of Queen Street East and Leslie Street. The scope of the evaluation is to determine the sound levels from TTC streetcar turning pass-bys. This report includes sound analysis conducted by Aercoustics on measurement data collected from the Queen St E and Leslie St intersection on June 1 st from approximately 5AM 9AM. 2 Descriptors A brief description of the technical terms used in this report are summarized below. 2.1 Frequency and Octave Bands The data in this report has been given in terms of its frequency distribution. The frequency is the number of times in one second that a sound or vibration wave oscillates. The frequencies measured are expressed in terms of levels which are typically grouped into octave bands with centre frequencies at 31.5, 63, 125, 2, 0, 0, 00, 00 and 00 Hertz (Hz). For more detailed analysis, results may also be divided into one-third octave bands, as has been done in this report. For sound, the frequency range has been analysed from Hz to,000 Hz, which corresponds to the typical range of the human ear. 2.2 Sound Pressure Levels The sound pressure levels or simply sound levels used in this report are provided in terms of decibels (db) referenced to micro Pascals. An A-weighting correction is applied to the one-third octave band db levels to capture the response of the human ear. 2.2.1 Leq Leq refers to the sound level equivalent of the total sound energy over a given period of time, meaning the average sound level during a measurement period. 2.2.2 Lmax Lmax refers to the maximum sound level during a measurement period. 2.2.3 L90 L90 refers to the sound level exceeded for 90% of the measurement period, typically used for assessing background noise.
TTC / Queen St E & Leslie St Noise Analysis Page 4 of 15 3 Site Description The track layout at the intersection includes straight eastbound and westbound tracks along Queen St E and curved tracks from Leslie St to Queen St E. There are no tracks from Leslie St north of Queen St E. The streetcar traffic routes on the curves analysed in the report are shown in Figure 1. Figure 1: Site Plan and Streetcar Pass-by Directions 4 Measurement Description 4.1 Instrumentation The sound and vibration measurements at the Queen and Leslie intersection were completed using two (2) microphones. The measurement data was acquired using RION
TTC / Queen St E & Leslie St Noise Analysis Page 5 of 15 data acquisition system with a sampling frequency of 51,0 Hz. All equipment was calibrated prior to each site visit. 4.2 Location The sound measurements were completed on the north-east and south-west corners of the intersection. Both microphones were mounted at a height of approximately 1.3 m. A plan view of the measurement locations is provided in Figure 5 located at the end of the report in Appendix A. 4.3 Weather Conditions The weather conditions were favourable for all measurements, with negligible wind speeds, no precipitation, and dry track conditions. The temperature ranged from 11-13 degrees Celsius throughout the measurement period of 05:00 09:00 and ranged from 11-18 degrees throughout the day. 4.4 Streetcar Pass-by Directions Both straight and turning streetcar pass-bys were observed during the measurement period from 05:00 09:00. The focus of the investigation is on the sound levels produced by turning streetcars pass-bys, which included Eastbound Queen to Southbound Leslie and Northbound Leslie to Westbound Queen. No streetcars were observed on the Northbound to Eastbound and Westbound to Southbound curve. 5 Analysis Procedures The collected measurement data was processed to isolate the sound from individual streetcar pass-bys, which were further sorted by pass-by direction. This is important to note, since this method of analysing the sound levels only during a streetcar pass-by helps eliminate other factors and focuses on quantifying the sound impact of each individual streetcar 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 sound levels attributed to each pass-by direction were representative. Similarly, streetcar pass-bys during which other dominating noise sources were audible (e.g. road traffic) were also omitted from analysis. The resulting number of pass-bys included in the analysis are shown in Table 1.
TTC / Queen St E & Leslie St Noise Analysis Page 6 of 15 Table 1: Number of Pass-by Measurements Pass-by Direction Total Number of Pass-bys Total Number of Analysed 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 measurement period, 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 certain result, however analysis of the three observed pass-bys should still give a good indication of pass-by sound levels. 5.1 Sound Analysis Processing of the sound data was conducted to obtain one-third octave band sound levels in db (ref. µpa) in the range of Hz to,000 Hz. An A-weighting correction was also 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 sound level (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 averaged together to indicate typical sound levels by direction. For a given pass-by direction, the maximum and minimum values in each frequency band were determined. The data was further processed for FFT spectra with 0.5 second time increments and 2 Hz resolution up to,000 Hz. Periods of squeal were identified in the FFT spectra, verified by recorded WAV file listening 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 flange squeal occur simultaneously are only counted once towards the total combined squeal, which is the total duration for which squeal is audible.
TTC / Queen St E & Leslie St Noise Analysis Page 7 of 15 Finally, the L90 was processed for the measurement, using data from periods between streetcar pass-bys, which is indicative of the ambient sound level present during the measurement period. 6 Measurement Results and Discussion There are two important factors which can influence the perception of noise from an individual streetcar pass-by. The first is the perceived amplitude or sound level of the pass-by, part of which is influenced by the amount of wheel squeal. The second is the presence and duration of any wheel-rail squeal throughout the pass-by, which can have a significant influence on the annoyance on receptors. Analysis of both are presented below. 6.1 Pass-by Sound Levels The average sound levels of all the measured streetcar pass-bys in each pass-by direction are 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-by Direction South-West Corner Sound Level (dba) North-East Corner Leq Lmax EB to SB 66 66 NB to WB 73 66 EB to SB 75 73 NB to WB 85 79 As seen in Table 2, the highest noise impact is on the south-west corner predominantly due 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 the curve. The point of the turn during which the any streetcar wheel squeal occurs can also affect the results based on the orientation to the microphone locations. As a result, the levels recorded at the measurement locations may differ. Additionally, due to the small sample size of pass-bys, specifically for the Eastbound to Southbound 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 and follows the same trend as the Northbound to Westbound pass-bys.
TTC / Queen St E & Leslie St Noise Analysis Page 8 of 15 One-third octave analysis of the sound measurement data indicates the results have good agreeance and display a fairly consistent trend between measurement locations and pass-by directions. Measurement data collected on the south-west corner is illustrated in Figure 2 and Figure 3 and on the north-east corner in Figure 4 and Figure 5. A-Weighted Sound Level (db, ref. upa) A-Weighted Sound Level (db, ref. upa) 90 70 60 30 10 0 90 70 60 30 10 0 25 31.5 63 Streetcar Passby Sound Level - Leq Meas. Location: SW Corner EB to SB - Minimum EB to SB - Maximum 125 160 0 2 315 0 0 630 0 0 12 NB to WB - Minimum NB to WB - Maximum 1600 00 31 1/3 Octave-band Centre Frequency (Hz) 00 00 6300 00 00 Figure 2: A-Weighted Sound Level (Leq) at South-West Corner 25 31.5 63 Streetcar Passby Sound Level - Lmax Meas. Location: SW Corner EB to SB - Minimum EB to SB - Maximum 125 160 0 2 315 0 0 630 0 NB to WB - Minimum NB to WB - Maximum 0 12 1600 00 31 1/3 Octave-band Centre Frequency (Hz) 00 00 6300 00 00 Figure 3: A-Weighted Sound Level (Lmax) at South-West Corner 1 16000 1 16000 000 000
TTC / Queen St E & Leslie St Noise Analysis Page 9 of 15 A-Weighted Sound Level (db, ref. upa) 90 70 60 30 10 0 25 31.5 63 Streetcar Passby Sound Level - Leq Meas. Location: NE Corner EB to SB - Minimum EB to SB - Maximum 125 160 0 2 315 0 0 630 0 0 12 NB to WB - Minimum NB to WB - Maximum 1600 00 31 1/3 Octave-band Centre Frequency (Hz) 00 00 6300 00 00 Figure 4: A-Weighted Sound Level (Leq) at North-East Corner 1 16000 000 A-Weighted Sound Level (db, ref. upa) 90 70 60 30 10 0 25 31.5 63 Streetcar Passby Sound Level - Lmax Meas. Location: NE Corner EB to SB - Minimum EB to SB - Maximum 125 160 0 2 315 0 0 Figure 5: A-Weighted Sound Level (Lmax) at North-East Corner The overall sound levels and trend across frequencies is comparable for both turning directions. There are two noticeably higher peaks between Hz and 00 Hz for the Northbound to Westbound pass-bys measured from the north-east corner. These levels can be attributed to high frequency wheel-rail squealing from the outside rail of the curve. 630 0 NB to WB - Minimum NB to WB - Maximum 0 12 1600 00 31 1/3 Octave-band Centre Frequency (Hz) 00 00 6300 00 00 1 16000 000
TTC / Queen St E & Leslie St Noise Analysis Page 10 of 15 6.2 Ambient Sound Levels The ambient sound level at the intersection during the measurement period, between streetcar pass-bys, was 51 dba on the south-west corner and 58 dba on the north-east corner. The ambient sound level is sufficiently below the measured pass-by sound levels that they did not affect the analysis and results. 6.3 Comparison Between Different Intersections The measurements at the Queen & Leslie intersection were compared to measurements from 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 the measurement environment and conditions between the observed intersections, the results will not reflect exactly comparable sound levels for the subject track sections, but rather provide a rough representation of the general noise impact at the measurement locations. Measurement data from the three additional intersections was collected the morning of May 4, 17. Measurements at Queen & Broadview and Bathurst & Fleet were taken on the inside of the track curve, approximately 8 m away from the streetcars as they traversed the 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 the position for the outside of the curve measurement rather than roughly maintaining the measurement distance for the inside of the curve locations, the outside of the curve measurement is expected to result in lower measured sound levels; we estimate at approximately 2-3 db lower. Levels were compared to the measurements of the Northbound to Westbound curve at Queen & Leslie, which were also taken approximately 8 m from the inside of the track curve. The comparative overall sound levels are summarized in Table 3 and the average Leq values by one-third octave band frequency are plotted in Figure 6. The noise level recorded at Queen & Leslie is comparable to the levels measured at Queen & Broadview and Bathurst & Fleet, with Queen & Leslie measuring slightly higher levels at approximately 1600 Hz. As expected due to the measurement location on the outside of the track curve, the levels recorded at King & Sumach are slightly lower but still comparable to the other intersections. After allowing for the differences in measurement position and the typical variations expected from field measurements, the differences in streetcar pass-by sound level recorded at each of the intersections are considered generally insignificant.
TTC / Queen St E & Leslie St Noise Analysis Page 11 of 15 Table 3: Average Pass-by Sound Level at Different Intersections Measurement Queen & Leslie (1 Jun 17) King & Sumach (4 May 17) Queen & Broadview (4 May 17) Bathurst & Fleet (4 May 17) Average Leq (dba) 73 67 74 72 Figure 6: Comparison of Average A-Weighted Leq at Different Intersections 6.4 Squeal Duration The average squeal durations for top rail squeal, flange squeal, and total combined squeal were calculated for the curve pass-bys and are summarized in Table 4 below. Periods where top rail squeal and flange squeal occur simultaneously are only counted once towards 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 rail squeal and flange squeal, with approximately 1 second of simultaneous squeal. The squeal duration measured at Queen & Leslie was comparable to measurements of streetcar pass-by squeal at similar intersections, conducted the morning of May 4, 17. The comparison is shown in Table 4.
TTC / Queen St E & Leslie St Noise Analysis Page 12 of 15 Table 4: Pass-by Squeal Durations for Different Intersections Intersection Average Squeal Duration (s) Top Rail Flange Total Combined* Queen & Leslie (NB to WB) 2 2 3 King & Sumach (EB to SB) <1 1 1 Queen & Broadview 1 4 5 *Note: Bathurst & Fleet <1 3 3 Total combined squeal duration does not double count periods where top of rail and flange squeal occurred simultaneously 7 Conclusion Aercoustics has completed sound measurements for the track curve at the Queen St E and Leslie St intersection. Additional measurements at similar intersections used for comparison were completed at an earlier date. It is noted that due to the limited sample size and the effect that variable weather conditions can have on streetcar wheel-rail squeal, the results presented are not a full representation of the full range of pass-by sound levels possible at the intersection, but rather they are an indication of the levels present on the particular measurement day. In order to better understand the effect of environmental factors on the streetcar pass-by sound levels and squeal durations, continuous measurements for an extended period would be required. Additionally, variations exist in the conditions between the Queen & Leslie measurements on June 1, 17 and the measurements used for comparison on May 4, 17, meaning these comparisons are not absolute but rather a general indication. Based on the data collected, the sound levels and squeal duration from the turning streetcar pass-bys at Queen & Leslie are comparable to similar turning curves at other intersections. After allowing for the differences in measurement position and the typical variations expected from field measurements, the differences in streetcar pass-by sound level recorded at each of the intersections are considered generally insignificant.
TTC / Queen St E & Leslie St Noise Analysis Page 13 of 15 Appendix A SITE PLAN
TTC / Queen St E & Leslie St Noise Analysis Page 14 of 15 Figure 7: Measurement Locations
TTC / Queen St E & Leslie St Noise Analysis Page 15 of 15 Figure 8: South-West Corner Measurement Set-Up