The first of Sydney Metro's new generation of trains emerges from the tunnel at Bella Vista Station as it undergoes testing on the Northwest alignment.

On 26 May, the first stage of Australia‘s largest public transport project was opened: the Sydney Metro Northwest. The immense project demanded unique specifications for noise minimisation, particularly with regard to the reverberation typically created in such tunnels.

Lining tunnels with the appropriately attuned material has been repeatedly proven, including in this instance, to make a significant difference to increasing sound attenuation within the tunnel. When it came time to engineer the acoustic properties of the tunnel, it came under the jurisdiction and expertise of Renzo Tonin & Associates.

Turning to a very high NRC performance, proven at 0.95 – which is an excellent result on its own, let alone part of a well-designed system – Reapor was a known solution, so naturally it would be included from the beginning.

The more challenging part? Creating a more robust, trafficable ‘between the track’ sound absorber.

Viterolite 900 was designed with specific porosity and airflow resistivity to provide maximum noise absorption within these applications. Furthermore, Pyrotek offers a bespoke solution where tile design requires consideration for ease of handling, accommodation of services or other design requirements, while maintaining a high sound absorption over a broad frequency range.

Network of new tunnels and infrastructure projects occurring across the globe

In aiming for compliance with acoustic and design specifications, the materials actually exceeded expectations, reducing tunnel noise levels to under 78dB(A). Key requirements here essentially meant addressing noise discomfort in the carriage created by wheel rail impact, evacuation safety for passengers, and total non-combustibility or smoke risk if the material were to become too hot.

With safety also comes more comfortable journeys that have better speed and comfort. For those who have ridden the new Sydney Metro – you’ll notice it’s a very different experience. It feels lighter somehow, and its quietness when there are fewer passengers around feels very new. While the current schedule isn’t running at peak capacity, tests show that it’s built for the future.

Addressing tunnel noise reverberation to this degree means improved ambience and a truly world- class travel experience.

Upon descending down the long escalators, travellers on the new Sydney Metro experience great heights and vast spatial proportions, so its relevant to note that noise from the rail mechanisms can travel up through the 13 new stations. But does it? If it weren’t for these sound absorbers, it could be deafening for users and nearby residents.

With today’s result you can easily hold a phone conversation. It’s impressive when tested officially and also in the day-to-day commute, creating not only comfort, but value.

More than 42,000 panels were used to line the 15km of tunnels so far. Work continues on the new lines as they make their way all the way to Central and onward towards the CBD. Working in Australia and internationally to develop innovative noise mitigation solutions, Pyrotek is one of the world’s leading manufacturers of unique, high performance acoustic and thermal materials.

Sydney Metro train arriving at a station

The new material developed by Pyrotek, VITEROLITE, has successfully mitigated noise for passengers in Sydney Metro’s twin tunnels.

This partner content is brought to you by Pyrotek. Working in Australia and internationally to develop innovative noise mitigation solutions, Pyrotek has been specified by the world’s leading acoustic consultants. For more information, visit

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