The whistle coming down the tracks is the sound of Europe’s rail renaissance. Coming round the bend is increased adoption of high-speed rail transportation which promises to reduce road traffic and to curb harmful emissions.
Prioritising sustainable rail transport promises significant benefits but unfortunately, it comes with unseen dangers of its own and not just for passengers. One of the lesser-known hazards of rail transport is the kind of noise pollution nobody can hear. Inaudible, low frequency ground vibrations emanate from the rolling stock on the railway as it passes. As well as affecting the structural integrity of nearby infrastructure, these vibrations can have a detrimental effect on people’s health, causing headaches, fatigue and even irritability in people experiencing them.
The BioMetaRail project is researching and developing special barriers deployed alongside the track to absorb the vibrations. The barrier walls rely on their shape for their noise reduction performance, rather than the properties of the material. Known as metamaterials, these synthetic composite materials have designer properties not found in nature. Their internal structures are engineered to interact with the low frequency sound waves of a passing train to trap and insulate against them.
“Basically, the idea is that we use shapes that have some resonant effects at frequencies that are typical for vibrations in the railway sector,” Capellari from Phononic Vibes, a company that specialises in noise and vibration technology said. In this context, the frequency of vibrations is typically between 30 and 60 Hertz. The result is a design for a two-by-three metre concrete structure that resembles a large window.
For ease of installation, there is no need to lift the railway line as these panels can be inserted into the ground alongside the track like a sunken fence, to protect clusters of homes or buildings.
Ultimately, these panels will be lining the ground alongside the track in residential areas, allowing rail networks to significantly boost their train traffic without adversely affecting the people and buildings nearby.
The European Union is committed to growing its rail transportation as part of the European Green Deal which aims to make Europe the first carbon-neutral continent by 2050.
By Sarah Wild for Horizon: The EU Research & Innovation Magazine, http://horizon-magazine.eu/