Calibration of an on-board noise measuring device by simultaneous measurements of trackside noise of three different wheelsets for the ETR500 FS train

An on-board device for bolting to the axlebox of a railway vehicle or locomotive to measure rolling noise close to the wheel surface has been developed by the authors (1, 2). Even though laboratory calibration and test runs have shown that the measured noise data are consistent, there was no way to prove that they were in accordance with the on-ground measured ones. Italian State Railways (FS) have performed tests with different wheelsets to evaluate the efficiency of several noise-reduction solutions; during these tests it was possible to repeat noise measurements on-board, therefore obtaining a sufficient amount of data to calibrate the device and to analyse in detail the behaviour of such wheelsets. Calculated calibration constants prove that on-board measured data can be used with confidence to estimate noise levels at several distances from the track, thereby reducing the necessity of long and expensive on-ground tests to measure environmental noise pollution.