{"id":1804,"date":"2021-08-31T11:01:56","date_gmt":"2021-08-31T11:01:56","guid":{"rendered":"https:\/\/horizon.peachpuff-wolverine-566518.hostingersite.com\/?p=1804"},"modified":"2021-08-31T11:10:08","modified_gmt":"2021-08-31T11:10:08","slug":"how-future-trains-could-be-less-noisy","status":"publish","type":"post","link":"https:\/\/scienceblog.com\/horizon\/1804\/how-future-trains-could-be-less-noisy\/","title":{"rendered":"How future trains could be less noisy"},"content":{"rendered":"
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by <\/strong>Sarah Wild<\/p>\n

Rail transportation is core to Europe\u2019s plans to become carbon neutral by 2050, but noisy trains are an obstacle that will need to be first overcome.<\/strong><\/p>\n<\/div>\n<\/div>\n

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\u2018We have a lot of resistance from people (living) beside the tracks who are against all construction and upgrades of the lines,\u2019 said Rudiger Garburg, senior consultant for noise and vibrations technology at German railway company Deutsche Bahn AG. \u2018It really is a bottleneck, (when) we speak about transforming transport and transferring traffic from road to rail.\u2019<\/p>\n

Greenhouse gas emissions from transport in Europe increased in 2018 and 2019, according to the\u00a0European Environment Agency<\/a>, and road transport was responsible for almost three-quarters of those emissions. In its\u00a0\u2018Sustainable and Smart Mobility Strategy\u2019<\/a>, the European Commission aims to shift traffic from road to rail and double its high-speed passenger rail traffic across Europe by 2030 and double rail freight by 2050.<\/p>\n

To get community buy-in, however, governments and rail companies need to reduce rail noise. \u2018Noise is always a problem of the system, not just the train,\u2019 said Garburg,\u00a0who is\u00a0a member of Shift2Rail’s\u00a0FINE 1<\/a>\u00a0and\u00a0FINE 2<\/a>\u00a0projects to reduce noise, vibrations and energy use. A railway system includes the trains, their wheels, the rails, and the tracks that support them.<\/p>\n

For passenger and freight trains, which move at between 60km and 200km per hour, the noise is mainly generated between the wheels and the rail. However, it is very difficult to determine which part of the system is making the noise.<\/p>\n

FINE 1<\/a>, which involved partners in rail, mobility and automation, was a broad project to curb excess noise and energy from trains. It looked to model and predict noise sources, among other objectives. This information is vital for both regulators and for train manufacturers.<\/p>\n

The project, for example, was able to simulate the noise both inside and outside the train made by cast iron wheels compared to composite-material wheels. \u2018In the past, trains used a cast-iron braking system for the wheels,\u2019 Garburg explained. While good for braking, the iron sheared over time, making the wheels very rough \u2013 and noisy. \u2018In past years, we\u2019ve worked very hard to find more braking blocks (made out of) composite materials, not cast iron.\u2019<\/p>\n

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In\u00a02019<\/a>, Europe\u2019s revised train noise standards, part of a larger suite of\u00a0rail specifications<\/a>, came into force. Unlike cars,\u00a0where manufacturers produce thousands of vehicles, train manufacturers only produce a limited number. \u2018You cannot build a prototype, test it, and work on it,\u2019 explained Garburg. \u2018If you build a new train, you have to guarantee that your train adheres to this limit of noise, similar to air pollution and so on.\u2019<\/p>\n

As part of FINE 1, project members developed verifiable, realistic requirements to characterise noise sources. These specifications are important to create standards for manufacturers to follow, and ultimately make trains quieter. Its successor, FINE 2, plans to take this research even further and fine-tune its noise source prediction models.<\/p>\n

\u2018In FINE 2, we have special measurement procedures,\u2019 Garburg said. The team uses an \u2018acoustic camera\u2019, an array of 30-40 microphones, to capture the sound of the rail system. He likens it to a thermal camera, in which \u2018you see yellow, red and green parts of a building\u2019 to create a heat map. \u2018We will use such procedures for the noise to get pictures that show you clearly where the main noise sources are,\u2019 he said.<\/p>\n

Better models could also enable train manufacturers to possibly obtain virtual certification for their trains to show that they adhere to the EU standards. All trains need to be certified by regulatory authorities before they are allowed on the track, but this process can be expensive and time-consuming.<\/p>\n

In Shift2Rail’s\u00a0partner project\u00a0TRANSIT<\/a>, virtual certification is the \u2018dream on the horizon\u2019, says Ines Lopez Arteaga, a professor of mechanical engineering at Eindhoven University of Technology in the Netherlands. \u2018It would save a lot of money and time and resources to be able to do it based on calculations.\u2019<\/p>\n

But there are many research milestones to reach first, said Prof. Lopez Arteaga, who is\u00a0TRANSIT<\/a>\u00a0project leader. We have tools to predict where train noise originates, but they could be improved, she says.<\/p>\n

\u2018Noise is always a problem of the system, not just the train.\u2019<\/p>\n