Reducing noise emissions is among the most pressing tasks in rail transportation and rail traffic noise from highly frequented track sections presents a particular burden for residents. In its capacity as one of the leading wagon hire and rail logistics companies in Europe, VTG is fully aware of and accepts its responsibilities in this matter.
We consistently invest in innovative technologies for new and existing wagons, in order to continually make freight traffic quieter. It is our declared aim to improve the quality of life of the people affected by noise and to sustainably ensure the future of rail, which is the most environmentally-friendly form of transportation.
VTG has fitted what are known as quiet brake blocks on its entire fleet in Germany, Switzerland and the relevant border regions. Compliance with thresholds defined in Germany’s new Rail Noise Protection Act is thus given, while the burden on residents near busy lines is eased. For more information, please visit our press release.
“Sound” is only perceived as “noise” to the human ear once it becomes exceptionally loud, long-lasting and unpleasant. Yet noise has no measurable size and it is only accessible indirectly through the intensity or volume of a noise. In order to determine sound volume, sound pressure and frequency are measured and expressed in a conversion scale in decibels.
It is interesting that in terms of human perception, a 10 decibel increase in volume corresponds to 50 percent more noise, regardless of how many decibels the initial noise is. The same also applies in reverse: reducing the volume by 10 decibels represents a 50 percent decrease in noise to the human auditory system.
Reducing noise directly at its source
Rail transport is setting new standards in safety and environmental protection. Although it is still as popular as ever today, persistent rail noise is a threat to this broad-scale acceptance. Noise-reduction measures, such as equipping wagons with low-noise brake systems, are set to provide relief for this situation in the future.
The volume of freight traffic in Europe is steadily increasing and, as a result, so are noise pollution levels. One part of the national transport budget is already allocated to noise abatement measures, especially for the construction of sound barriers. As a consequence, innovative technologies are becoming more common in an attempt to contain noise from its main source: the contact between the wheel and the rails.
Whisper brakes: effective noise reducers
Brake blocks are traditionally made of gray cast iron which is a coarse iron-graphite mixture. These particular blocks have been used as the starting point for the current noise-reduction measures. In addition to tests which are still being carried out, such as a noise-reduction coating for the wheelset axle and sound absorbers on the wheelset disc, changing to composite brake blocks also pledges sustained improvement.
These so-called ‘whisper brakes’ are made of new material mixtures, i.e. mineral fibers, rubber and resins. Without impacting the braking process itself, the composite brake blocks effectively prevent the wheels from scraping. Retrofitting with whisper brakes can reduce noise by up to 10 decibels, which corresponds to a 50 percent decrease (see info box below). However, in order for the human ear to appreciate this difference, at least 80 percent of all wagons per train have to be converted.
K- and LL-brake blocks
There are currently two different options available for equipping wagons with quieter brake blocks. K-brake blocks (composite material brake blocks) are primarily fitted for newbuild wagons and existing wagons can be fitted with LL-brake blocks (low-noise, low-friction brake blocks), which were approved for use throughout Europe in 2013. However, a higher degree of wheelset disc wear and tear leads to significantly higher operating costs, regardless of which brake block type is fitted.
INEA Support for Low-Noise LL-Brake Block Conversion
For wagon keepers, changing over to composite ‘whisper brakes’ poses a great challenge. VTG alone has to retrofit thousands of wagons by the end of 2020. Wherever possible, this is performed as part of standard revisions, but it is also frequently carried out by mobile service teams or through additional workshop stays. Not only does this imply an enormous amount of work, but also a significant financial burden – both due to the conversion itself, and as using LL-brake blocks generates considerably higher operational costs.
In order to mitigate the impact on the rail industry, the European Commission is supporting the conversion with its “Innovation and Networks Executive Agency” (INEA) organization. A total of EUR 34 billion has been allocated to INEA to support more than 2000 projects in the transport, energy and telecom sectors until the year 2020. A key aspect of INEA is the “Connecting Europe Facility” (CEF). The CEF Transport branch implements the EU’s transport policy and is the most important funding instrument for infrastructure projects, with the objective of supporting investments in building new transport infrastructure or upgrading the existing one.
VTG also receives financial support within the framework of the CEF instrument for the switch to LL brake blocks for its wagons. After visiting the VTG Rail Train training workshop, representatives from INEA and the German Federal Ministry of Transport and Digital Infrastructure (BMVI) are more than satisfied with the progress of the work carried out to date. VTG’s mobile service team had the opportunity to demonstrate how the brake blocks are changed over and what needs to be considered in the process.