The Lyon metro is testing out Wabtec eco-responsible brake pads

Reducing fine particulate emissions: an environmental and public health issue 

Air quality in underground rail facilities has become a major concern for urban transport operators, especially in Lyon. Air pollution from fine particles produced by metro train brakes presents significant environmental and public health challenges.

With this situation in mind, Keolis Lyon has explored several different solutions to limit these particulate emissions, including air purification systems in stations and dust recovery systems installed directly on braking mechanisms. However, none of these solutions survived the trial phase because they required significant investments and major infrastructure work (in stations or on metro train cars) to achieve tangible benefits. 

Instead, a more efficient, easy-to-install and economically viable solution was retained: replacing traditional metro train brake pads with new pads that produce fewer particulate emissions. Developed by rail equipment manufacturer Wabtec Corporation, a partner of the Keolis Group since 2020, these brake pads eliminate pollution at the source rather than offsetting the problem. 

After a few conclusive tests of braking performance carried out by Wabtec in 2023, the test project was approved in early 2024 by Keolis Lyon and SYTRAL Mobilités, the mobility organizing authority in the Lyon area.

Low-emission brake pads by Wabtec: a promising solution for combatting air pollution 

Under the name Green Friction, Wabtec’s “green” brake pads are made from advanced materials that make it possible to reduce PM10 particulate emissions (under 10 microns in diameter) by 70%, as well as PM2.5 and PM1 particulates (under 2.5 microns and 1 micron) by up to 90%, compared with traditional materials. The system offers improved environmental performance without compromising on braking efficiency or noise pollution. This helps to maintain the same level of passenger safety and comfort.

From an operational standpoint, this innovation is very easy to implement: the new brake pads can be installed on existing systems with no significant modifications, thus facilitating their deployment while limiting the cost of installation.

The second test phase conducted by Keolis began in summer 2024. Scheduled to last through the end of 2024, the tests should make it possible to approve the solution for use on trains in early 2025. 

From testing to approval: one year of testing with Keolis Lyon 

Wabtec’s Green Friction brake pads will be rolled out over several test phases, whose results will make it possible to verify the different aspects of the brake pads for the Lyon network: 

- Comparative measurement of particulate emissions between current equipment and the Wabtec brake pads to determine the actual benefit.

- Assessment of brake rotors aiming to test the resistance of the new materials. 

- Brake performance tests on the same “road profile” as the Lyon metro by fitting out a commercial train car.

In spring 2025, the last step will consist in approving the new Wabtec braking system, a necessary precondition for its widespread use across the Keolis Lyon metro network.