Journal of civil engineering and transport transEngin Volume 2, Issue 1 / 2020 ISSN 2658-1698 / e-ISSN 2658-2120 DOI: 10.24136/tren.2020.003 WAYS OF PROTECTION FROM NOISE POLLUTION IN RAILWAY AND TRAMWAY INFRASTRUCTURE Paulina Szabłowska 1, Maciej Rochel 2* 1 Cracow University of Technology, Faculty of Civil Engineering, Chair of Highway and Traffic Engineering, Poland, e-mail: paulinaszablowskaa@gmail 2 Cracow University of Technology, Faculty of Civil Engineering, Chair of Highway and Traffic Engineering, Poland, e-mail: maciek.rochel@gmail * Corresponding author Reviewed positively: 28.01.2020 Information about quoting an article: Szabłowska P., Rochel M. (2020). Ways of protection from noise pollution in railway and tramway infrastructure. Journal of civil engineering and transport. 2(1), 35-45, ISSN 2658-1698, e-ISSN 2658-2120, DOI: 10.24136/tren.2020.003 Abstract − The paper presents various ways of protection from traffic noise used in railway infrastructure in Poland. The sources of noise in rail and tram transport were discussed. Also commonly found solutions on the railway network were analyzed such as noise barriers and rail dampers. Modern tram surfaces have been presented as one of the noise protection methods in the tram infrastructure. In the tram infrastructure a noise protection method was presented in the form of tram track lubricators on sharp curves. In addition, the effectiveness of noise protection methods was assessed on the basis of tests and research. Key words − railway, tramway, infrastructure, noise pollution JEL Classification − R41 INTRODUCTION noise is harmful to people’s organism. Researchers say that between 20-30% of the children and young These days we are virtually overloaded by sounds. people have troubles with proper hearing [2]. Whenever we go to work or spend time with a family Traffic noise can be brought on by three basic sounds and music are present. It could be our favorite ways of transport: roads, railways or planes. That is music, sounds from commercials or traffic noise that why we differentiate: roadway noise, railway is mainly produced by vehicles. It wouldn’t be such /tramway noise and aircraft noise [1]. This paper a problem when these sounds weren’t noisy and hard focuses on railway/tramway noise. to bear for the average human being. Many studies have shown the damaging effect of SOURCES OF RAILWAY AND TRAMWAY NOISE environmental noise on people’s health. Prolonged As far as railways is concerned, one should exposure can cause hearing impairment, sleep realise that its causes are various (Fig. 1). They can disturbance and poor concentration. That is why it be divided into: can be regarded as one of the most important public ROLLING NOISE health issue. Rolling noise is the most important type of When it comes to the noise pollution, it can be railway noise that is mentioned above. It has the divided according to its source. We can distinguish: greatest impact on the overall rail noise level. This industrial noise, traffic noise, municipal noise, house is because it occurs at the largest and the most or work noise. It is said that traffic noise bears the common speed range which is between 50-300 km/h. greatest responsibility for noise pollution [2]. The The rolling noise is generated in a simple way. number of people estimated to be at risk of traffic Both the track and the wagons (above all the lateral noise in Europe is 100 million. surfaces of their wheels) are vibrated during rolling stock passing through [3]. Despite the small contact I. SOURCE OF NOISE IN RAILWAY AND TRAMWAY INFRASTRUCTURE area between the wheel and the rail (it is no more than 1,5cm2), this noise is the main reason for TRAFFIC NOISE railway noise [4]. Rolling noise depends mainly on As it was mentioned in the first paragraph traffic rail corrugation (unevenness occurring) within 35 Ways of protection from noise pollution in railway and tramway infrastructure wheel turning zones and railways. The surface connected with sound of current collector roughness during the journey contributes to the movement through contact wire of overhead vertical vibrations of both vehicles and rails. The contact line. There are also other factors that make material transmits vibrations that create sound ray up the traction noise such as sound of working in each of the elements. Finally this leads to the compressor or cooling process. It can be even creation of sound that causes noise [3]. connected with exhaust gas. AERODYNAMIC NOISE Vehicle’s speed contributes mostly to the Another source of noise is aerodynamic noise. It traction noise. However there are still some other can be mainly found in high speed trains. That’s factors as: type and power of engine and its speed because aerodynamic noise increases above the of rotation, type of used freezing system and type speed 250-300 km/h. It is caused by an aerodynamic of vehicle [3]. drag that comes from the unequal air flow during OTHERS the train run. As it was mentioned above there are also some The difference between this kind of railway other sources of railway/tramway noise. Among noise and others is that it doesn’t come from solid them we can distinguish an acceleration noise. This vibrations but arises due to the movement of type of noise occurs due to the friction of the brake elements in the air. In addition to speed, the main blocks on the wheel. This is a key noise factor in physical factors such as a shape and a height have areas near railway stations. In the same area there an impact on an aerodynamic drag [5]. is also braking noise that is connected with working TRACTION NOISE engine sound [6]. Traction noise can be described as a kind of In other cases there is also a noise, which comes noise that is associated with the operation of an from train wheels squeak on track arch. It occurs electric or internal combustion engine. It is also mainly on small radius arch, so this is the dominant Fig. 1. Sources of railway noise - based on [3] 36 transEngin Volume 2, Issue 1 / 2020 factor source of noise in the tram infrastructure. It efficient because modern vehicles have strictly is also worth paying attention to the noise defined acceptable noise emission parameters. In generated in the area of engineering structures, comparison to vehicles from the 1960s-1980s they such as bridges. There are also occasional types of should emit a noise lower by a minimum of 10 dB [7]. noise, e.g. accidental/collision noise. Other method of protection is modernization of II. WAYS OF PROTECTION FROM NOISE rolling stock. It is slightly cheaper way yet still POLLUTION IN RAILWAY effective. It can reduce noise up to 8 dB. This can be achieved mainly due to the replacement of steel Nowadays, due to the increasing people’s brake blocks with composite ones and the awareness about the harmful effects of noise on installation of wheel springs or sound shields for health, more and more solutions reducing noise traction devices [7-9]. are emerging. Both the effectiveness and the way they are used are different and give various effects. METHODS OF PROTECTION DUE TO THE PLACE OF ACTION When we talk about railway noise pollution protection we need to realize that two solutions can be found and applied (Fig. 2). They are recognized by the place in which noise pollution is being solved. Fig. 3. Types of reducing noise at the place of origin The former is connected with methods of - based on [7] reducing noise at the place of origin. It is mainly related to works on the railway surface or rolling INFRASTRUCTURE SOLUTIONS stock elements. It usually requires direct works The second group of noise reduction solutions is related to railway infrastructure. directly related to the railway surface. The first The latter consists of solutions that are used at involves modernization of old, damaged the place of spread. This method involves infrastructure with outdated technology. As in application/implementation the construction of rolling stock case, it is also expensive and it cannot protective elements outside railway infrastructure. be made too often [7]. At this point, another It can be easily used on existing railways. positive aspect of railway infrastructure modernization based on changing the type of railway traffic-control devices should also be seen. The new devices allow the flow of traffic, which reduces the number of brakes and train starts. It also helps to reduce noise. The idea that gives measurable benefits is to keep the railway infrastructure in good condition. This can be ensured mainly by grinding the running Fig. 2. Types of noise protection - based on [9] surface of the rails and the use of rail shock absorber systems (to ensure better elasticity). It is REDUCING NOISE AT THE PLACE OF ORIGIN also important to replace the old rail crossings with This type of protection can be split into three new ones and to abandon the classic track for parts (Fig. 3). The first of them is related to activities a Continuously Welded Rail [7]. based on rolling stock. Next is related to the Both modernization and renovation have operation and maintenance of the railway a noticeable effect in terms of absorption and infrastructure and last is about introducing new suppression of acoustic nuisance, which also has devices into the existing railway infrastructure, in a positive translation to reduce noise emissions particular railway surface. This devices are installed [10]. Just grinding the rails is able to compress noise to reduce friction between rail and wheel. by 3 dB. Modernization or renovation involving at ROLLING STOCK SOLUTIONS least the replacement of the surface leads to The simplest and the most effective method of absorption and damping of sound at even 10dB reducing noise is the replacement of rolling stock (depending on the speed) [9].