The real sound emission of ‘‘Rasengleis’’ Free

The ‘‘Rasengleis’’ (railway lines which are covered by meadow and bedded on conventional ballasted tracks) has indeed a lower noise emission level. Various investigations focusing on the acoustical behavior of the ‘‘Rasengleis’’ were carried out in the last years. The results were rather different. The first sequence of measurements took place before changing the construction of the second part of the railway line. That was to counterbalance errors due to locality, time (the last measurement was carried out almost 2 years later than the first one), and other ambient conditions. The levels could be easily compared among each other using the results of the reference point. Additionally, the measurements were repeated after at least a year to take aging processes of the meadow into account. Two different types of trams were used. They differ among other things in the kind of absorption used for the wheels. One wheel type contains rubber parts stressed of shearing (Tatra T4D), the other wheel rubber parts are stressed of pressure (Bochum). ‘‘Rasengleis’’ reduces noise emission depending on the kind of wheel up to 3 dB (minimum 2 dB). There will be measured levels of drive past, standardized values, and sonograms.