Measurement of the lateral noise emission of an UIC 60 rail with a custom device

In this work a simplified device for the measurement of the noise emitted laterally by an UIC 60 rail is presented. It consists of three convergent parallel ducts with an anechoic termination to collect the sound energy in a straight, cross-square section pipe where measuring microphones are located. The acoustic design of the device is described with reference to the shape definition, based on FEM analysis, and to the optimization of the multilayered anechoic termination with experimental and numerical techniques. Laboratory tests performed to calibrate and to validate the device are shown and its acoustical performance is analyzed and discussed. The overall dimension and the very limited weight of the device ensures the portability and hence its practical use; the limited cost and the use with standard instrumentation make possible its use for the detection of an excessive wear of wheel tread. The results of the first application of the device are shown, and a comparison is made between the noise emitted by the rail head, the rail web and the rail foot at the passage of damaged and non-damaged wheels.