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DIN/VDI Standards Committee Acoustics, Noise Control and Vibration Engineering

Abstract

The method described in this document is used to determine combined wheel-rail roughness and track decay rates from rail vibration during the pass-by of a train. By combining sound pressure measurement from the same pass-by, a vibro-acoustic transfer function for rolling noise is determined. The track decay rate is a vibration quantity that characterises the attenuation of rail vibration along the track for a given wheel/rail contact excitation, and thereby affects the amount of sound radiation from the track. Combined roughness is a quantity that determines the level of excitation of wheel-rail rolling noise. It can be determined from vertical rail vibration during a train pass-by and the vertical track decay rate. The transfer function can be used to characterise the vibro-acoustic behaviour of the vehicle-track system for a given roughness excitation and in relation to rolling noise. Combined roughness, track decay rates and transfer functions are determined as one-third octave spectra. The method can be used for the following purposes: - to measure track decay rates under operational conditions; - to characterise the effectiveness of noise control measures in terms of combined roughness, transfer function and track decay rate; - to compare the combined roughness before and after noise control measures are implemented (thereby quantifying the effect of any change in wheel or rail roughness); - to monitor wheel roughness during a pass-by, either of whole trains or parts of trains; - to separate rolling noise from other sources; - to assess a threshold for the rail roughness, by measuring multiple pass-bys; - to obtain combined roughness and transfer functions for input to environmental noise calculations. The method is not for approval of sections of reference track in terms of acoustic rail roughness and track decay rates, which are covered by EN 15610 and EN 15461, respectively. The method is applicable to trains on conventional tracks, i.e. normal ballasted tracks with wooden or concrete sleepers and on slab tracks. If the method is applied for: - non-standard wheel types such as small wheels, resilient tram wheels; - non-standard track types such as embedded rail or grooved rail. then the A2 factor should be calculated following the Formula (A.1) in Annex A.

Begin

2025-07-11

WI

00256A5M

Planned document number

prEN 16891 rev

Responsible national committee

NA 001-01-07 AA - Measurement of sound exposition on rail vehicles, including measurements inside the passenger compartment and at the workplace  

Responsible european committee

CEN/TC 256/SC 4/WG 3 - Acoustics  

previous edition(s)

Railway applications - Acoustics - Measurement method for combined roughness, track decay rates and transfer functions
2016-05