MetaWindow: Noise protection on railroad tracks becomes transparent
Noise barriers along railroad tracks are set to become less of a "landmark" thanks to a new technology developed by Deutsche Bahn together with a start-up.
In a computer visualization, Deutsche Bahn shows the new noise protection (r.) in comparison to today's protective walls.
(Image: Deutsche Bahn, Phononic Vibes)
Deutsche Bahn has found a way to reduce noise from its tracks with transparent walls. The technology, which it developed together with the Italian start-up Phononic Vibes, will be used on the S4 suburban train line in Hamburg this year, according to a statement from Deutsche Bahn.
(Image: DB AG / Dominic Dupont)
There are already transparent noise barriers, but none that meet the legal requirements across the board. However, noise barriers are "characteristic of the location", especially on railroad lines in exposed urban locations, in tourist areas, near residential buildings and in spectacular or protected natural landscapes, explains the railroad company. That's why it worked with the start-up to find a solution.
They call it MetaWindow because the walls are made of "metamaterials". The special geometry of the noise protection system increases the acoustic efficiency compared to conventional noise protection systems. Certain frequency ranges are absorbed in a targeted manner, insulating 34 to 37 decibels of sound.
28 percent opaque
However, the walls are not completely transparent. The transparent material is combined with a classic absorption material. Ultimately, this leaves 72 percent of the surface transparent, making the MetaWindow walls look like airy fences.
The new noise barriers are also pricier than conventional ones, the railroad company also admits. This only applies to the pure material costs, not the costs for personnel and materials when the walls are installed. However, Deutsche Bahn expects that higher acceptance rates for these walls compared to conventional planning approval procedures will be completed more quickly, thus saving money. Deutsche Bahn did not specify how much the new and old walls will cost.
It plans to renovate around 3250 kilometers of track by 2030 and around 6500 kilometers by 2050. Added to this is the noise protection that is to be installed on new and expansion projects. To reduce noise, it not only wants to erect walls, but also work on the vehicles.
According to the Federal Environment Agency (UBA), there is no general regulation for protection against rail traffic noise in Germany. Only when a railroad line is newly built or significantly altered must the immission limits set out in the Traffic Noise Protection Ordinance be complied with. On noise barriers, the noise is typically reduced by 5 to 10 dB(A), in favorable cases up to 15 dB(A), the UBA continues. However, the noise-reducing effect can also deteriorate significantly in mid-wind and inversion weather conditions.
(anw)