Low noise barrier
A low noise barrier , also a low noise barrier or mini noise barrier, represents a measure to reduce rail traffic noise. Based on the assumption that a large part of the noise emissions of a rail vehicle is caused by the contact between the wheelset and the rail , the low noise barrier is attached as close as possible to the track , in order to reduce these emissions. Individual sections of the route are currently being equipped with low-noise barriers on a trial basis.
Mode of action
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Low noise protection walls are 30 to 80 centimeters high and are set up in the immediate vicinity of the track. Since the standard light space according to the railway building and operating regulations is not a rectangle, but rather tapers downwards, low-noise barriers up to a height of 36 centimeters can even be installed below the side walls of a rail vehicle. Due to this proximity to the noise source, a low- noise barrier has a higher airborne sound insulation effect than a conventional, two to three meter high noise barrier .
The effect of a low-noise barrier is based on two physical principles: absorption and reflection . By choosing suitable materials such as plastic and an appropriate insulating material, sound waves are absorbed by the low-noise barrier and thus no longer get into the environment. In addition, some of the sound waves are reflected into the track bed , where they are in turn absorbed by the ballast . Therefore, inclined constructions are more effective than box-shaped ones. Theoretically, noise reductions of up to 5 dB for slab tracks and up to 7 dB for gravel superstructures can be achieved for a receiver at a distance of 10 meters .
Comparison with conventional noise barriers
advantages
The advantages of low noise barriers compared to conventional noise barriers are:
- Universal applicability: Due to their low construction height, low noise barriers can also be erected in places where high noise barriers cannot be integrated into the cityscape or would violate monument protection regulations.
- If there is another source of noise between conventional noise barriers and the receiver, for example a street, the street noise is often amplified by the noise barriers. This effect does not apply to low noise barriers.
- Due to the proximity to the track and the possibility of installation between two tracks, the angle at which sound waves can pass through a low noise protection wall is often lower than the comparable angle with a conventional noise protection wall. This means that fewer sound waves get into the environment. This effect is particularly important when there are many adjacent tracks: In order to be able to shield the noise from tracks that are further away, conventional noise barriers at the edge of the route must be up to six meters high.
disadvantage
Low noise barriers also have disadvantages:
- A low-noise barrier merely dampens the rolling noise of a train. Aerodynamic noises and drive noises, for example from the engine of a locomotive , continue to get into the environment. The effectiveness of low noise barriers is therefore lower in practice than that of high noise barriers, especially when used only on one side on double-track lines.
- If it is necessary to leave the track area quickly after a possible railway accident , low-noise barriers can represent obstacles. To prevent this, the accident prevention regulations stipulate emergency crossings. These emergency crossings hinder the function of the low-noise barrier.
- Low noise barriers can only develop their effect if their position closely approximates the clearance profile. This makes them an obstacle to repairs. Trains that have exceeded the loading gauge may no longer be able to use the route. One solution are low-noise barriers that can be folded away hydraulically if required.
- Diffraction effects occur at each top edge of a noise barrier . In the case of low noise barriers, this upper edge is at a lower height than with conventional noise barriers.
application
In March 2007, the Karlsruhe Institute of Technology carried out a three-day series of measurements in which the noise emissions from trains on the Karlsruhe urban railway with and without low-noise barriers were compared in Rheinstetten . The measurements showed a reduction in volume of 5 dB. However, the train on which the measurement was carried out with a low noise protection wall was 5.2 km / h slower than the train whose noise emissions were measured without noise protection.
In 2011 and 2012, various manufacturers installed low-noise barriers of various types on various sections of the route in the Rhine Valley . It is not possible to erect conventional noise barriers in the historic villages , some of which are protected by UNESCO World Heritage . The funds for the financing were made available from the economic stimulus package II . Low-noise barriers were also installed on the BASF premises in Ludwigshafen and in Garßen near Celle . In November 2012, measurements of a low-noise protection wall in Oberwesel on the left-hand side of the Rhine showed only minor effects. The situation could be improved by increasing the height from 55 cm to 74 cm above the top edge of the rails and building a center wall between the two main tracks.
In some cases, low-noise barriers were also erected for test purposes in places without buildings, in order to be able to carry out measurements from different distances and thus gain knowledge of effectiveness.
In the early summer of 2014, 1.6 kilometers of low-noise protection wall was installed on the Mühldorf – Burghausen railway line in the urban area of Burghausen , after a prior acoustic report predicted a reduction in noise emissions as a result of this measure. The installation of the noise protection elements took 18 hours on the closed route.
In summer 2019, a combination of rail dampers, low-noise walls and soundproofing panels was installed on bridge railings on the Gronau – Coevorden line of the Bentheimer Eisenbahn in Nordhorn in order to shield a new building area planned below the line. According to the noise report prepared for this, the alternative would have been a 6 meter high (conventional) noise protection wall.
Web links
- Investigation of ways to avoid railway noise by the Karlsruhe Institute of Technology (PDF; 3.4 MB)
- dvlv.de (German Association for Noise Protection on Traffic Routes eV)
Individual evidence
- ↑ a b c d e Dr.-Ing. Eberhard Hohnecker: Reduction of rail traffic noise through mini noise barriers . In: Engineer mirror . No. 2, 2012, pp. 10-14.
- ↑ a b c d e David Ohrndorf: World premiere in Rhöndorf: Railway tests new noise protection wall ( Memento from May 30, 2012 in the Internet Archive ) on wdr.de , accessed on December 23, 2013.
- ↑ a b c d e f Page no longer available , search in web archives: Suzanne Breitbach: Noise barriers bring almost nothing (PDF; 819 kB), excerpt from the Rhein-Zeitung from November 15, 2012 on bahnlärm-Mittelrhein.de , Retrieved December 23, 2013.
- ↑ a b page no longer available , search in web archives: Pro Rheintal: Ruhe im Rheintal (PDF; 3.4 MB), accessed on December 23, 2013.
- ↑ Technische Universität Berlin: Statement on noise protection measures in the course of the complete renovation of S7 Berlin West ( memento of the original from December 26, 2013 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. on wir-in-nikolassee.de , accessed on December 25, 2013.
- ↑ Katja Auer: Fear of the Bamberg Wall being built (requires ad blocker or JavaScript) on sueddeutsche.de , accessed on December 25, 2013.
- ↑ a b c For the sake of the environment: Low noise barriers on train tracks tested on heringinternational.de , accessed on November 6, 2017.
- ↑ Announcement: 8th rail symposium of the German Association for Noise Protection e. V. In: Eisenbahntechnische Rundschau 9/2014, p. 192.
- ↑ Rieder 360 ° - the low noise barrier. In: Eisenbahntechnische Rundschau 9/2014, p. 138.
- ↑ Citizens' Initiative Transport Concept ( Memento from November 1, 2014 in the Internet Archive )
- ↑ Göschl, Andreas: "It's all in the mix! - Combination of noise protection measures". In: Verkehr und Technik 2/2020, page 61 ff.
