CEN/TC 256/WG 3 - Noise emission

This document addresses the measurement of source terms for environmental noise calculation for rail traffic (including light rail, such as trams, metros, etc.). It is applicable to the measurement of in-service trains on operational tracks.
It is not applicable to type acceptance testing of rolling-stock or tracks, or to derive source terms for time domain models.
The following rail traffic noise source types are in the scope:
-   rolling noise;
-   traction and equipment noise;
-   aerodynamic noise;
-   impact noise (e.g. rail joints, switch and crossings, wheel flats);
-   braking noise;
-   bridge noise;
-   squeal noise.
Noise from rail vehicles at standstill, such as stationary engine idling and auxiliary equipment at yards and stations, is covered by EN ISO 3095:2013 for measurement procedures and operating conditions, and by EN ISO 3740:2019 and EN ISO 3744 for the determination of sound power. It is therefore not in the scope of this document.
The calculation of the propagation of sound is part of generally standardized propagation models which are not addressed in this document.
Noise from fixed installations (e.g. stations, depots, electricity sub-stations) is not in the scope of this document.
Source terms are specific to a vehicle and track type. The scope includes measurement procedures and conditions and sampling requirements.

This document specifies laboratory test procedures to determine a high-frequency dynamic stiffness, “acoustic stiffness”, of resilient components of rail fastening assemblies.
This document is applicable to complete rail fastening assemblies and to pad components of fastening systems including both discrete and continuous fastening systems.
It is applicable to the measurement of the dynamic transfer stiffness under a prescribed pre-load and the associated hysteretic damping loss factor.
It provides measurement methods and pre-load, excitation and frequency range conditions for application to ground borne and structure borne noise as well as for rolling noise.
It is not applicable to the measurement of the stiffness of pads and fastening assemblies under static or low-frequency dynamic loading used for track mechanics.

This document specifies the measurement method and conditions to obtain reproducible noise levels on-board all kinds of vehicles operating on rails or other types of fixed track, hereinafter conventionally called “unit”, except for track maintenance vehicles in working modes.
This document is applicable to type testing. It does not include all the instructions to carry out monitoring testing or evaluation of noise exposure of passengers or drivers over a whole journey.
This document is not applicable to guided buses.
It provides measurement procedures for vehicle interior noise (in general, a vehicle type test is carried out using only a selected subset of these tests):
—    when the vehicle is moving at constant speed;
—    when the vehicle is stationary;
—    when the vehicle is accelerating or decelerating;
—    in the driver's cab when an external warning horn is sounding (specifically required for European Union regulation application)
It does not provide measurement procedures for:
—    audibility or intelligibility of any audible signals;
—    assessment of warning devices other than warning horns.
The assessment of noise exposure of train crew due to operational conditions is not in the scope of this document.
The results can be used, for example:
—    to characterise the noise inside these units;
—    to compare the internal noise of various units on a particular track section;
—    to collect basic source data for units.
The test procedures specified in this document are of engineering grade (grade 2), the preferred grade for noise declaration purposes as defined in ISO 12001. If test conditions are relaxed, for example as they are for monitoring of in-service trains, then the results are no longer of engineering grade.
The procedures specified for accelerating and decelerating tests are of survey grade (grade 3).

This document specifies procedures to assess acoustic signals at passenger external doors applying to all kind of rolling stock. The following applies to this standard:
-   this document refers to acoustical passenger information indicating the release, opening and closing of passenger doors;
-   this document is applicable to tonal signals with defined frequency components levels and pulse sequences;
-   this document is not applicable to spoken information or to signals comprising a sequence of impulses (such as a door finding signal).
NOTE   Acoustic door signals are defined in EN 16584 2 "Design for PRM use".

1.1   This document specifies a direct measurement method for characterizing the surface roughness of the rail and wheel associated with rolling noise ("acoustic roughness"), in the form of a one-third octave band spectrum.
This document describes a method for:
a)   selecting measuring positions along a track or selecting wheels of a vehicle;
b)   selecting lateral positions for measurements;
c)   the data acquisition procedure;
d)   measurement data processing in order to estimate a set of one-third octave band roughness spectra;
e)   presentation of this estimate for comparison with limits of acoustic roughness;
f)   comparison with a given upper limit in terms of a one-third octave band wavelength spectrum;
g)   the measuring system requirements.
1.2   It is applicable to the:
a)   compliance testing of reference track sections in relation to the acceptance test for noise emitted by railway vehicles;
b)   performance testing of track sections in relation to noise emitted by railway vehicles;
c)   acceptance of the running surface condition only in the case where the acoustic roughness is the acceptance criterion;
d)   assessment of the wheel surface condition as an input for the acoustic acceptance of brake blocks;
e)   assessment of the wheel and rail roughness as input to the calculation of combined wheel rail roughness;
f)   diagnosis of wheel-rail noise issues for specific tracks or wheels;
g)   assessment of the wheel and rail roughness as input to rolling noise modelling;
h)   assessment of the wheel and rail roughness as input to noise source separation methods.
1.3   It is not applicable to the:
a)   measurement of roughness (rail roughness, wheel roughness or combined roughness) using an indirect method;
b)   analysis of the effect of wheel-rail interaction, such as a “contact filter”;
c)   approval of rail and wheel reprofiling, including rail grinding operations, except for those where the acoustic roughness is specifically the approval criterion (and not the grinding quality criteria as provided in e.g. EN 13231-3);
d)   characterization of track and wheel geometry except where associated with noise generation.

This method 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 characterizes 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 characterize 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 characterize 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.
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 ballastless track systems.
The method has not yet been validated for:
-   non-standard wheel types such as small wheels, resilient tram wheels;
-   non-standard track types such as embedded rail or grooved rail.

ISO 3095:2013 specifies measurement methods and conditions to obtain reproducible and comparable exterior noise emission levels and spectra for all kinds of vehicles operating on rails or other types of fixed track, hereinafter conventionally called "unit".
ISO 3095:2013 is applicable to type testing of units. It does not include all the instructions to characterize the noise emission of the other infrastructure related sources (bridges, crossings, switching, impact noise, curving noise, etc.).
ISO 3095:2013 is not applicable to:
-      the noise emission of track maintenance units while working;
-      environmental impact assessment;
-      noise emmission assessment;
-      guided buses;
-      warning signal noise.
The results may be used, for example:
-      to characterize the exterior noise emitted by units;
-      to compare the noise emission of various units on a particular track section;
-      to collect basic source data for units.

This European Standard specifies a method for characterizing the dynamic behaviour of the structure of a track relative to its contribution to the sound radiation associated with the rolling noise.
This European Standard describes a method for:
a)   acquiring data on mechanical frequency response functions on a track;
b)   processing measurement data in order to calculate an estimate of the vibration decay rates along the rails in an audible frequency range associated with the rolling noise;
c)   presenting this estimate for comparison with the lower limits of the decay rates.
It is applicable for evaluating the performance of sections of reference tracks for measuring railway vehicle noise within the framework of official approval tests.
The method is not applicable for characterizing the vibration behaviour of tracks on loadbearing structures such as bridges or embankments.

It is well established that rolling noise originates in the combined ‘roughnesses’ of the wheel and rail running surfaces. Through the rolling interaction of the wheel and rail this roughness imposes a time history of relative displacement across the wheel-rail contact that leads to vibration of the wheel and of the track. This vibration, in turn, gives rise to the noise components radiated by the wheel, the rail and the sleeper. The fact that at low (‘normal’) levels, the roughness gives rise to noise radiation linearly and accounts for the noise fully, has been shown by the comparison of theoretical models and carefully controlled measurements [1]. It has furthermore entered the practice of a number of railways to control the roughness, even of uncorrugated, track as a measure to reduce noise.  In recent years, in line with the European Union’s strategy for harmonisation of internationally running train services in Europe, new Technical Specifications for Interoperability (TSI) have been written for the acceptance testing of new rolling stock. The acoustic TSI reflects the understanding of the noise generation mechanisms [2, 3]. In order to ensure that the acceptance test, that may be made at different locations on different rolling stock, is a fair test of the rolling stock and depends as little as possible on the local track design, the TSI specifies conditions for a ‘reference track’ on which pass-by noise measurements are to be made. The reference track is controlled in terms of the noise produced per unit level of combined roughness and the roughness of the rail head running surface. The first condition is characterised by a minimum decay rate spectrum that must be obtained on the reference track (for how this relates to the noise performance of the track see [4] and to [5] for the method of measurement). The second condition is a limit to the spectral level of rail roughness that may exist on the reference track [6].  To ensure comparable and...(...)...

1.1   This document specifies a direct measurement method for characterizing the surface roughness of the rail and wheel associated with rolling noise ("acoustic roughness"), in the form of a one-third octave band spectrum.
This document describes a method for:
a)   selecting measuring positions along a track or selecting wheels of a vehicle;
b)   selecting lateral positions for measurements;
c)   the data acquisition procedure;
d)   measurement data processing in order to estimate a set of one-third octave band roughness spectra;
e)   presentation of this estimate for comparison with limits of acoustic roughness;
f)   comparison with a given upper limit in terms of a one-third octave band wavelength spectrum;
g)   the measuring system requirements.
1.2   It is applicable to the:
a)   compliance testing of reference track sections in relation to the acceptance test for noise emitted by railway vehicles;
b)   performance testing of track sections in relation to noise emitted by railway vehicles;
c)   acceptance of the running surface condition only in the case where the acoustic roughness is the acceptance criterion;
d)   assessment of the wheel surface condition as an input for the acoustic acceptance of brake blocks;
e)   assessment of the wheel and rail roughness as input to the calculation of combined wheel rail roughness;
f)   diagnosis of wheel-rail noise issues for specific tracks or wheels;
g)   assessment of the wheel and rail roughness as input to rolling noise modelling;
h)   assessment of the wheel and rail roughness as input to noise source separation methods.
1.3   It is not applicable to the:
a)   measurement of roughness (rail roughness, wheel roughness or combined roughness) using an indirect method;
b)   analysis of the effect of wheel-rail interaction, such as a “contact filter”;
c)   approval of rail and wheel reprofiling, including rail grinding operations, except for those where the acoustic roughness is specifically the approval criterion (and not the grinding quality criteria as provided in e.g. EN 13231-3);
d)   characterization of track and wheel geometry except where associated with noise generation.

This European Standard specifies a method for characterizing the dynamic behaviour of the structure of a track relative to its contribution to the sound radiation associated with the rolling noise.

ISO 3381:2005 specifies the conditions for obtaining reproducible and comparable measurement results of levels and spectra of noise inside all kinds of vehicles on rails or other types of fixed track, except for track maintenance vehicles in operation.
It is applicable to type testing and periodic monitoring testing.
The results may be used, for example, to characterize the noise inside these vehicles and to compare the internal noise of various vehicles on a particular track section.
The test procedures specified in this ISO 3381:2005 are of engineering grade (grade 2, with a precision of 2 dB), that is the preferred one for noise declaration purposes, as defined in ISO 12001.

This European Standard specifies a type test method to measure noise levels inside the driver's cabs of railway vehicles for assessing compliance with the relevant European legislation.
NOTE   The relevant European legislation includes Directive 2003/10/EC of 6 February 2003 and the Commission Decisions of 23 December 2005 (Technical specification for interoperability relating to the subsystem ‘rolling stock - noise’ of the trans-European conventional rail system) and of 21 February 2008 (Technical specification for interoperability relating to the ‘rolling stock’ sub-system of the trans-European high-speed rail system).
This method is applicable to:
-   the measurement of noise inside driver's cab resulting from the sounding of external warning horns when the vehicle is stationary;
-   the measurement of noise inside the driver cab while the vehicle is running.
The method is not applicable to:
-   complementary measurements that can be requested for acceptance tests, but which are not required by the TSIs referred to in this standard;
-   the measurement of the noise from internal and external audible devices other than external warning horns;
-   routine monitoring of the noise exposure of train crew.
The test procedures specified in this European Standard are of engineering grade (grade 2) with a precision of ± 2 dB, which is the preferred method for noise declaration purposes, as defined in EN ISO 12001.

1.1 This European Standard specifies a direct method for characterizing the surface roughness of the rail
associated with rolling noise ("acoustic roughness"), in the form of a one-third octave band spectrum.
This standard describes a method for:
a) selecting measuring positions;
b) data acquisition;
c) measurement data processing in order to estimate a set of one-third octave band roughness spectra;
d) presentation of this estimate for comparison with limits of acoustic roughness;
e) comparison with a given upper limit in terms of a one-third octave band wavelength spectrum.
1.2 It is applicable to the:
a) performance testing of reference track sections for the measurement, within a period of three months
before or after roughness characterization, of noise emitted by railway vehicles for acceptance testing
purposes;
b) acceptance of the rail surface condition only in the case where the result of the direct measurement of the
acoustic roughness is regarded as an established acceptance criterion.
1.3 It is not applicable to the:
a) measurement of rail roughness using an indirect method;
b) measurement of combined wheel-rail roughness;
c) analysis of the effect of wheel-rail interaction, such as a “contact filter”;
d) approval of rail reprofiling, including rail grinding operations, except for those where the acoustic
roughness (and not the level of corrugation) is an established approval criterion;
e) characterization of track geometry.
Testing and approval of measuring apparatus are not part of the scope of this standard.

ISO 3095:2005 specifies the conditions for obtaining reproducible and comparable measurement results of levels and spectra of noise emitted by all kinds of vehicles operating on rails or other types of fixed track, except for track maintenance vehicles in operation.
It is applicable to type testing and periodic monitoring testing.
The results may be used, for example, to characterize the noise emitted by these trains, to compare the noise emission of various vehicles on a particular track section, and to collect basic source data for trains.
The test procedures specified in ISO 3095:2005 are of engineering grade (grade 2, with a precision of 2 dB), that is the preferred one for noise declaration purposes, as defined in ISO 12001.
The procedures specified for accelerating and decelerating tests are of survey grade.

ISO 3381:2005 specifies the conditions for obtaining reproducible and comparable measurement results of levels and spectra of noise inside all kinds of vehicles on rails or other types of fixed track, except for track maintenance vehicles in operation.
It is applicable to type testing and periodic monitoring testing.
The results may be used, for example, to characterize the noise inside these vehicles and to compare the internal noise of various vehicles on a particular track section.
The test procedures specified in this ISO 3381:2005 are of engineering grade (grade 2, with a precision of 2 dB), that is the preferred one for noise declaration purposes, as defined in ISO 12001.

This WI defines the measuring procedures to assess the dynamic properties of the track and the roughness level of rails. It covers the following subjects:
1. Definition of data acquisition and processing procedures to determine track vibration decay with distance for both vertical and lateral direction under measured excitation;
2. rail roughness measurement protocol application.