for the installation of rail web dampers in the Moselle valley. Under this invitation to tender of DB Netz AG, innovative noise reduction systems on cross town link No. 98 (Löf) were to be installed and tested. The noise emission reduction to be achieved had to be ≥2dB(A). If the measurement was lower than the ≥2dB(A) specified, the contractual requirement was not met and the product had to be removed again within a period set by the customer.
To ensure that the rail dampers achieved the result of greater or equal to 2 dB(A), the following conditions had to be met and proofs provided by the supplier. Before installation of the rail dampers the track must have a vertical track decay rate of, on average, less than 2 dB/m for the third-octave frequencies 500 Hz to 2 kHz.
In July 2011, after consultation with DB Netz AG, Calmmoon Rail rail web shielding was installed over a length of 100 m at km 23.25 on the Trier to Koblenz line and the reduction in the noise level was determined. The track consisted of ballasted track with concrete sleepers and rail profile UIC 60.
First, the base measurement without Calmmoon Rail was carried out on the rails for 7 days. Then Calmmoon Rail was installed and the reduction in the noise level compared to the base measurement was measured at the same point.
Noise reduction LpA,pb
Beforehand, the vertical track decay rate as per TSI-CR-Noise was measured as 8.1 dB/m which was considerably above the specified value. The rail roughness was also measured; this was below the ISO and TSI specifications. Finally, the noise reduction (average value) LpA,pb was measured in consultation with and as agreed with DB Netz AG. This was 1.9 dB for goods trains and 2.0 dB for passenger trains for a track decay rate of 8.1 dB/m (TSI).