Wabtec is tackling the challenge of reducing fine particles in tunnels on train networks through technology that drastically reduces friction brake emissions.
The issue of fine particles in tunnels
It has been shown that the level of fine particles is too high in most tunnels within urban transport networks. This is a particular problem for metro users since networks are mostly underground, but there is similar room for improvement when it comes to main line trains operating in tunnels.
Passengers, often through associations, and tunnel workers' unions have regularly sounded the alarm on the subject of fine particles in tunnels. Over time it has become a real concern for train operators, who are now looking for solutions to address the issue.
Tunneling into the problem of friction
The friction brake potentially has an important role to play in improving tunnel air quality. While modern trains have very efficient electrodynamic (E/D) brakes that put less strain on the friction brake than older trains, the lifetime of the average train is somewhere between 30 and 40 years, which means it will take a years to replace the older trains with modern ones.
In addition, even on modern trains, performance of the E/D brake disappears at about 5 km/h. This means that the last few meters of deceleration still require use of the friction brake.
Wabtec has developed a range of Green Friction materials which, in addition to ensuring the required performance for various applications, can reduce the emission of brake particles by up to 90% for the finest particles (PM 2,5 and PM 1).