TVANE – Train Vibration and Noise Effects: Presentation of a Swedish research project

Tomas Jersona, Mikael Ögrenb, Evy Öhrströmc

a Acoustic Department, WSP Environmental, Gothenburg, Sweden b Swedish National Road and Transport Institute, Linköping, Sweden

c Occupational and Environmental Medicine, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden

ABSTRACT For efficient planning of noise and vibration reducing measures, it is important to have knowledge of the health effects of noise and vibrations from railway traffic as well as from road traffic noise. Issues of relevance are “the railway bonus”, the effect of simultaneous exposure to railway and road traffic noise, the effect of vibrations from railway traffic per se as well as in combination with noise, and effects of high intensive railway traffic. The TVANE-project aims to investigate all these issues by socio-acoustic field surveys, noise and vibration measurements, and laboratory experiments.

1 INTRODUCTION Railway traffic causes both noise and vibrations in surrounding areas. To enable effective

planning of reduction measures it is important to gain a better knowledge about the relationship between noise and vibration exposures from railway traffic as well as noise from road traffic and how this effect human health. The exposures from railway may in fact increase in the future, due to increasing traffic intensity with both faster and heavier trains. To investigate this topic, a research project named TVANE (Train Vibration and Noise Effects) started in 2006 and will be carried out until 2010.

2 AIM OF THE PROJECT The research project addresses four aims. The first aim is whether a “railway bonus” can

be justified, i.e. whether noise from railway traffic is perceived as less annoying than road traffic noise at the same sound level. This research question is examined both in a field study (see Study 1b in Figure 1) and in a laboratory study and also in reanalyses of data obtained in an earlier investigation in Lerum municipality [1]. The second aim is to investigate the relationship between adverse health effects, including annoyance, and exposure to simultaneous noise and vibration from railway traffic (see Study 2). This question is examined both in a field study and in a laboratory study. The third aim is to investigate effects from simultaneous exposure to noise from train and road traffic by a field study (see Study 3b). The fourth aim is to investigate how high intensive railway traffic affects people in residential areas. This question will be examined in a field study (see Study 4). The four field studies are schematically illustrated in Figure 1. Before the field and laboratory studies started, a literature review was carried out [2].

a Email address: tomas.jerson@wspgroup.se b Email address: mikael.ogren@vti.se c Email address: evy.ohrstroem@envmed.gu.se

Figure 1: Schematic illustration of the four field studies

3 LITERATURE REVIEW

3.1 Studies of effects of railway noise compared with road traffic noise (“railway bonus”) According to the EU Position paper on noise annoyance [3], which includes European

studies published until 1993, a railway bonus of 5 dB relative to road traffic noise is motivated. However, studies in Europe carried out later than 1993 show contradictory results. French and German studies show results that do motivate a railway bonus, particularly at noise levels higher than LAeq, 24h 65 dB. In contrary, Japanese studies show that noise from high-speed trains and conventional trains are more annoying than noise from road traffic. An Austrian study supports the railway bonus at noise levels < Ldn 50 dB. The Swedish study in Lerum [1] and a Dutch experimental study that compared noise from maglev trains and road traffic give no evidence for a railway bonus.

The Japanese studies were carried out on railway lines with intense traffic, 500 – 800 trains per day corresponding to approximately one train per minute. This intensive traffic may to some extent explain the difference between the Japanese and European results. Taken together, most of the results indicate that a railway bonus might be justified for general noise annoyance and sleep disturbance, but not for speech interference.

3.2 Studies of effects of different vibration levels from railway traffic All field studies show that annoyance from railway traffic is larger in areas with

simultaneous vibrations. However experimental studies show conflicting results. For example, vibration levels were found to influence noise annoyance, but annoyance due to vibrations was influenced in a more complex way. Some studies reported that vibration annoyance was more pronounced at low noise levels, but in other studies, less vibration annoyance was observed at high vibration and high noise levels. A potentially explanation of the latter result is that noise masking reduced the perception of the vibrations.

3.3 Studies of effects of simultaneous exposure to noise from road and railway traffic Noise from two or more sources, for example railway and road traffic exists in many

environments. Therefore, for habitants or visitors the total effect of the combined noise environment is of vital importance. During expansion of new infrastructure, it is necessary to consider this fact to prevent and reduce the adverse effects of noise. Further research is needed for a more accurate estimation of the combined noise exposure and how it interacts with other disturbances (than noise). Intense and simultaneous railway and road traffic reduce

the amount of silent periods during day and night. The silent periods are essential to allow for rest and restoration.

4 PLANNED STUDIES WITHIN THE TVANE-PROJECT

4.1 Studies of effects of railway noise compared with road traffic noise (“railway bonus”) To determine whether a “railway bonus” is justified, the following studies were planned:

(i) A field study (Study 1b), has been carried out in four villages. In Falköping and Töreboda, situated at the railway called “Västra Stambanan”, railway noise from the railway up to a distance of 300 m was calculated by the Nordic Prediction Method for Railway Traffic Noise [3] (Figure 2 shows noise immission curves from railway traffic in Falköping). In Kungälv and Borås situated at two major roads (E6 and R40), the traffic noise from the main road up to a distance of 300 m was calculated by the Nordic Prediction Method for Road Traffic Noise [4]. Noise measurements were also carried out at a number of specific control points in all four villages. A socio-acoustic questionnaire on noise annoyance and other adverse health effects from railway and road traffic was sent to about 2000 inhabitants in the four villages.

Figure 2: Railway noise immission curves obtained for the centre of Falköping (predicted A-weighted

equivalent sound pressure levels) (ii) Experimental sleep studies with noise exposure from road and railway traffic have

been carried out in a newly built laboratory at the Department of Occupational and Environmental Medicine in Gothenburg. The laboratory has three bedrooms (see Photo 1), where in total eighteen test persons were sleeping during five consecutive nights.

Photo 1: A bedroom in the laboratory used for sleeping experiment under controlled noise exposure

The objectives of the experimental study were, firstly, to study the effects on sleep quality from railway noise in comparison with road traffic noise with the same equivalent sound level (Lnight 31 dB) and in comparison with road traffic noise with the same maximum sound level (LAFmax 54 dB) and, secondly, to compare perceived disturbance during night from the three type of sound exposures. The test persons were exposed to recorded railway and road traffic noise according to a well-defined scheme during three of those nights (the two first nights were for habituation). Every morning each person filled in questionnaires about their observed sleeping quality. At every evening, each person also answered questionnaires about their day, if they felt tired or stressed. In Figure 3 results from the experimental sleep study is presented. The results from the study have been presented elsewhere [5].

Figure 3: Number of test persons reporting awakenings in different two hour periods during the three exposure nights

Photo 2: Railway and road traffic passing Lerum community

(iii) A reanalysis of sub-samples within the Lerum-study [1, 6] have been done (see Photo 2). In these sub-samples, individuals exposed to either railway noise or road traffic noise (LAeq 24h, 45 - ≥ 65 dB) were included.

4.2 Studies of effects of vibrations and noise from railway To gain more knowledge of annoyance and other effects from railway vibration in

dwellings and the importance of interaction with railway noise, two studies have been planned.

(iv) Annoyances from railway vibrations and the interactions between railway noise and vibrations are investigated in different residential areas. In field study 2, two types of areas have been chosen; one with expected low vibration levels (< 0.4 mm/s in Töreboda and Falköping) and one with expected high levels (> 1.4 mm/s in Kungsbacka and Alingsås, see photo 3). Theoretical calculations will be carried out to predict vibrations levels in discrete houses. A questionnaire has been sent to about 2000 people in the two areas. A number of vibration measurements have been conducted in houses where the people answered that they were highly annoyed by train vibrations and also in houses were people answered that they were not annoyed at all.

(v) Experimental sleep studies with vibration and noise exposure from railway traffic have been carried out in a laboratory study. Three beds were equipped with vibrators, which generated realistic vibrations from recorded train passages. The design of test facilities has been reported elsewhere [7]. The subjects in the study were exposed to train vibrations and noise according to a well-defined scheme. Every morning each person filled in questionnaires about their observed sleeping quality. At every evening, each person also answered questionnaires about their day, if they felt tired or stressed.

Photo 3: A freight train with heavy load passing by on its way through Sweden

4.3 Studies of effects of combined exposure to road and railway noise (vi) A reanalysis of sub-samples within the Lerum-study [1, 6] have been done. In these

sub-samples, individuals exposed to combined railway noise and road traffic noise (LAeq 24h, 45 - ≥ 65 dB) were included.

(vii) A new field study is planned to investigate how train and road traffic noise interacts. The same questionnaire concerning adverse noise health effects from train and road traffic that were used in the Lerum-study will be sent to about 1000 inhabitants in the selected municipalities.

4.4 Studies of noise disturbance from intensive train traffic (viii) A field study (Study 4) is currently conducted in a suburb to Stockholm with very

intensive railway traffic, approximately 480 train passages per day. A socio-acoustic questionnaire on noise annoyance and other adverse health effects from train and road traffic have been sent to about 1500 people in the suburb.

5 COMMENTS AND CONCLUSIONS Information about the project can be found at the web-site www.tvane.se. At present,

most data collection from the field studies is finished and analyses of the data are currently carried out. The final results are planned to be presented at forthcoming conferences and as peer-reviewed articles.

6 ACKNOWLEDGEMENTS This paper is based on research grants from the Swedish Rail Administration (Banverket).

7 REFERENCES [1] Öhrström E., Barregård B., Andersson E., Skånberg A., Svensson H., and Ängerheim P.

(2007). Annoyance due to single and combined exposure from railway and road traffic noise. J Acoust. Soc. Am.122 (5): 2642-2652 Part 1, Nov 2007.

[2] Öhrström E. and Skånberg S. (2006). Litteraturstudie avseende effekter av buller och vibrationer från tåg- och vägtrafik (in Swedish). (Literature review on the effects of noise

and vibrations from railway and road traffic noise). Rapport 112, Göteborgs universitet. ISSN 1650-4321,ISBN 91-7876-111-5

[3] Railway Traffic Noise – Nordic Prediction Method, Nordic Council of Ministers, TemaNord 1996:524, ISBN 92-9120-837-X.

[4] Jonasson H., and Nielsen H., Road Traffic Noise – Nordic Prediction Method, Nordic Council of Ministers, TemaNord 1996:525, ISBN 92-9120-836-1.

[5] Öhrström E., Ögren M., Jerson T. and Gidlöf-Gunnarsson A. (2008). Experimental studies on sleep disturbances due to railway and road traffic noise. Proceedings of the 9th Congress of the International Commission on the Biological Effects of Noise (ICBEN) 2008, July 21-25, Foxwoods CT, USA. (Invited paper) (Available on CD, ISBN 978-3-9808342-5-4).

[6] Öhrström, E., Andersson, E., Skånberg, A., Barregård, L. (2007). Relationships between annoyance and exposure to single and combined noise from railway and road traffic. Inter Noise 2007, Istanbul 28-31 August, Paper no IN07_242 (Available on CD.)

[7] Ögren M., Öhrström E., Jerson T. (2008). Noise and vibration generation for laboratory studies on sleep disturbances. Proceedings of the 9th Congress of the International Commission on the Biological Effects of Noise (ICBEN) 2008, July 21-25, Foxwoods CT, USA. (Available on CD, ISBN 978-3-9808342-5-4).