"Smooth wheels on smooth rails” is the most effective way to reduce noise at the source. The LL blocks are made of composite materials which have a positive effect on the surface of the wheel by polishing it, and thus reducing the level of noise. The traditional cast-iron brake blocks, on the contrary, make the wheel surface rough, which leads to higher noise levels. Using composite brake blocks (combined with good quality tracks) can reduce the pass-by noise of trains by up to 10 dB, equivalent to 50% of the noise perceived by humans.
Currently, most of the existing freight wagons circulating in the EU do not have to conform to the EU noise standards since these are binding only for new wagons. These "old" wagons are therefore the main source of rail noise which is a nuisance for citizens and an obstacle for development of rail transport. Now, it will be possible to replace the noisy cast iron blocks by the new composite LL blocks in a simple and relatively cost efficient way. Retrofitting in LL blocks does not require any changes to the braking system and is far less costly and complicated than retrofitting with the alternative K blocks.
Currently, the European Railway Agency works on the EU requirements and assessment procedures covering all types of brake blocks, which will be integrated into a revised Technical Specifications on Interoperability on Wagons. This would allow producers to develop new brake blocks and get them certificated quickly and efficiently according to harmonised EU procedures.