New brake system slashes PM emissions on Paris metro

A braking system for trains called Green Friction is being fitted to trains operating on the RER A line in Paris, following a year of trials aimed at reducing emissions caused by braking. 

US-based Wabtec tested its Green Friction materials on ten RER A trains for more than a year, covering over a million kilometres  and found that they could reduce emissions from braking by between 70% and 90%.

Philippe Nogues-Cubelles, Vice President Friction at Wabtec said: ‘Particulate matter emissions from train braking are a worldwide challenge. Green Friction tackles the source of the fine particle problem. Today, Wabtec is the only company in the rail industry offering operational, rapidly deployable and cost-effective equipment to reduce pollution levels linked to braking.’

To mitigate the emission of particulates, modern trains are equipped with electrodynamic brakes that put less strain on the friction brake than older trains, however there is still a sizable number of older trains without such a system and they will remain in service for years.

Furthermore, the performance of even the electrodynamic brakes disappears at about 5 km/h. This means that the last few metres of deceleration still require use of the friction brake.

The material used in the Green Friction system ensures no deterioration in braking performance and can be fitted without any modification of the braking system settings.

Tests demonstrated a minimum 70% reduction in PM10 particles, a 85% reduction in PM 2.5 particles and 60% for PM1,  the finest and potentially most harmful particles.

Green Friction brake linings will now be deployed on all MI09 trains operating on the RER A line starting this year, benefiting more than one million daily passengers.

Announcing the news, Wabtech said: ‘The development of the Wabtec Green Friction range represents a milestone on the journey towards cleaner and healthier tunnels for passengers and network personnel. Our work with RATP, both a longstanding customer and one of the world’s biggest operators, is a major step forward for us, our client and the industry as a whole. It will hopefully lead to a worldwide rollout of this technology, making rail and metro safer for everyone.’