Author(s): Jansen Erwin , Peen Jasper
To prepare existing intercity trains for operation on a new slab track line with strict noise limitations, noise control measures were necessary. A new brake system with composite L brake blocks and bogies with low noise wheels were designed and tested. \nDuring the rolling noise measurements on intercity trains with both the old and optimized wheel designs and brake systems at operational speeds of 160 km/h, combined sound and vibration measurements were taken to quantify and separate contributions from the excitation and transmission of rolling noise. This allows for quantification of the acoustic effect of the noise control measures. The measurements on the retrofitted Intercity trains were conducted on both slab track and conventional ballasted sleeper track. This allows for a comparison between the track contribution on the overall pass-by level for both track types. \nIn the low- and mid-frequency range up to 1.2 kHz the 4-5 dB noise reduction was caused by the smooth wheel surface and therefore low roughness, induced by the composite brake L-blocks. For higher frequencies, the improved vibro-acoustic transmission of the wheel was responsible for the 3-4 dB noise reduction, as a result of its new geometry and the installed wheel damper. Even despite the higher noise emission in the low and medium frequency ranges of the slab track compared to a ballasted track, the overall pass-by level of the intercity train on the slab track was reduced significantly and all acoustic goals were achieved.
Name: Mr Erwin Jansen