SIST EN 15610:2019

Railway applications - Acoustics - Rail and wheel roughness measurement related to rolling noise generation

This European Standard specifies a direct 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
standard 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.
It is applicable to:
a) the performance testing of reference track sections in relation to the acceptance test for noise emitted by
railway vehicles;
b) the performance testing of track sections in relation to noise emitted by railway vehicles;
c) the acceptance of the running surface condition only in the case where the acoustic roughness is the
acceptance criterion;
d) the assessment of the wheel surface condition as an input for the acoustic acceptance of brake blocks;
e) the assessment of the wheel and rail roughness as input to the calculation of combined wheel rail
roughness;
f) the diagnosis of wheel-rail noise issues for specific tracks or wheels;
g) the assessment of the wheel and rail roughness as input to rolling noise modelling;
h) the assessment of the wheel and rail roughness as input to noise source separation methods.
It is not applicable to the:
a) measurement of roughness using an indirect method;
b) direct measurement of combined wheel-rail roughness;
c) analysis of the effect of wheel-rail interaction, such as a “contact filter”;
d) 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);
e) characterisation of track and wheel geometry except where associated with noise generation.

Bahnanwendungen - Akustik - Messung der Schienen- und Radrauheit im Hinblick auf die Entstehung von Rollgeräuschen

1.1   Diese Europäische Norm legt ein direktes Verfahren zur Charakterisierung der Rauheit der Rad- und Schienenfahrfläche im Hinblick auf das Rollgeräusch fest („Akustische Rauheit“), dargestellt in Form eines Terzspektrums.
Die vorliegende Norm gibt ein Verfahren an zur:
a)   Auswahl der Messpositionen entlang einer Strecke oder Auswahl der Räder eines Fahrzeugs;
b)   Auswahl der Messpositionen in Querrichtung;
c)   Messwerterfassung;
d)   Verarbeitung der Messwerte mit dem Ziel, eine Reihe von Rauheits-Terzspektren abzuschätzen;
e)   Darstellung dieser Schätzung zum Vergleich mit Grenzen der akustischen Rauheit;
f)   Vergleich in Bezug auf eine obere Grenze, die als Terzspektrum über der Wellenlänge vorgegeben ist;
g)   Anforderung an das Messsystem.
1.2   Sie ist anwendbar zur:
a)   Güteprüfung von Referenz-Gleisabschnitten in Bezug auf die Abnahmeprüfung für Geräuschemissionen von Schienenfahrzeugen;
b)   Güteprüfung von Gleisabschnitten in Bezug auf Geräuschemissionen von Schienenfahrzeugen;
c)   Abnahme der Fahrflächenqualität, sofern die akustische Rauheit das Abnahmekriterium ist;
d)   Beurteilung der Radflächenbeschaffenheit als eine Eingabe für die akustische Abnahme von Bremsklötzen;
e)   Beurteilung der Rad-Schiene-Rauheit als eine Eingabe für die Berechnung der kombinierten Rad-Schiene-Rauheit;
f)   Diagnose von Rad-Schiene-Aspekten für bestimmte Gleise oder Räder;
g)   Beurteilung der Rad-Schiene-Rauheit als Eingabe für Rollgeräusch-Modellierung;
h)   Beurteilung der Rad-Schiene-Rauheit als Eingabe für Verfahren zur Geräuschquellentrennung.
1.3   Sie ist nicht anwendbar zur:
a)   Messung der Rauheit (Schienenrauheit, Radrauheit oder kombinierte Rauheit) mittels eines indirekten Verfahrens;
b)   Analyse der Auswirkungen von Rad-Schiene-Wechselwirkung, wie ein Kontaktfilter;
c)   Abnahmeprüfung der Rad-Schiene-Fahrflächenqualität nach erfolgter Reprofilierung, es sei denn, die akustische Rauheit ist ausdrücklich das Abnahmekriterium (und nicht die Schleifqualitätskriterien, wie z. B. in EN 13231 3);
d)   Beschreibung der Gleis- und Radgeometrie, es sei denn sie gehört zur Geräuschentstehung.

Applications ferroviaires - Acoustique - Mesurage de la rugosité des rails et des roues relative à la génération du bruit de roulement

1.1   La présente Norme européenne spécifie une méthode directe de caractérisation des rugosités de la surface du rail et de la roue associées au bruit de roulement (« rugosité acoustique »), sous la forme d'un spectre par bandes de tiers d'octave.
Le présent document décrit une méthode pour :
a)   le choix des positions de mesurage le long d'une voie ou le choix des roues d'un véhicule ;
b)   le choix des positions latérales de mesurage ;
c)   la procédure d'acquisition des données ;
d)   le traitement des données de mesurage de façon à estimer un jeu de spectres de rugosité par bandes de tiers d'octave ;
e)   la présentation de ces estimations pour la comparaison avec des limites de rugosité acoustique ;
f)   la comparaison avec une limite supérieure donnée, en termes de spectre de longueurs d'ondes par bandes de tiers d'octave ;
g)   les exigences sur le système de mesurage.
1.2   Le présent document est applicable pour :
a)   l'essai des performances de sections de voie de référence, dans le cadre d'essais de réception  pour le bruit émis par les véhicules ferroviaires ;
b)   l'essai des performances de sections de voie pour le bruit émis par les véhicules ferroviaires ;
c)   la réception de la qualité de surface de roulement, seulement dans le cas où la rugosité acoustique est le critère de réception établi ;
d)   l'évaluation de la qualité de surface des roues comme élément d'entrée pour la réception acoustique des semelles de freins ;
e)   l'évaluation de la rugosité de la roue et du rail comme élément d'entrée pour le calcul de la rugosité combinée roue-rail ;
f)   le diagnostic des problèmes de bruit issu du contact roue-rail pour des rails ou des roues spécifiques ;
g)   l'évaluation de la rugosité de la roue et du rail comme élément d'entrée pour la modélisation du bruit de roulement ;
h)   l'évaluation de la rugosité de la roue et du rail comme élément d'entrée pour les méthodes de séparation des sources de bruit.

Železniške naprave - Akustika - Merjenje valovitosti vozne površine tirnice in kolesa, ki povzroča hrup med vožnjo

Ta evropski standard določa neposredno metodo za ovrednotenje valovitosti vozne površine tirnice in kolesa, ki povzroča hrup med vožnjo (»akustična hrapavost«), v obliki frekvenčnega pasu ene tretjine oktave. Ta standard opisuje metodo za: a) izbiranje merilnih položajev vzdolž tirnic ali izbiranje koles vozila; b) izbiranje stranskih položajev za meritve; c) postopek zbiranja podatkov; d) obdelavo merilnih podatkov za oceno hrapavosti v obliki frekvenčnega pasu ene tretjine oktave; e) predstavitev te ocene za primerjavo z mejami akustične hrapavosti; f) primerjavo z določeno zgornjo mejo glede na valovno dolžino frekvenčnega pasu ene tretjine oktave; g) zahteve merilnega sistema. Uporablja se za: a) preskušanje učinkovitosti referenčnih odsekov tirnic glede na preskus sprejemljivosti hrupa, ki ga oddajajo železniška vozila; b) preskušanje učinkovitosti odsekov tirnic glede hrupa, ki ga oddajajo železniška vozila; c) sprejemljivost stanja vozne površine samo, če je akustična hrapavost merilo za sprejemljivost; d) oceno stanja površine kolesa kot vnosa za akustično sprejemljivost zavornih blokov; e) oceno valovitosti kolesa in tirnice kot vnosa za izračun valovitosti kombinacije kolesa in tirnice; f) diagnozo spornosti hrupa koles in tirnic za določene tirnice ali kolesa; g) oceno valovitosti koles in tirnic kot vnosa pri modeliranju hrupa med vožnjo; h) oceno valovitosti koles in tirnic kot vnosa za metode ločevanja virov hrupa. Ne uporablja se za: a) merjenje valovitosti s posredno metodo; b) neposredno merjenje kombinacije valovitosti koles in tirnic; c) analizo učinka interakcije kolo-tirnica, kot je »kontaktni filter«; d) odobritev preoblikovanja tirnic in koles, vključno z operacijami brušenja tirnic, razen tistih, pri katerih je akustična hrapavost posebno merilo za sprejemljivost (in ne merilo kakovosti brušenja, kot je določeno v standardu EN 13231); e) opredelitev geometrije tirnic in koles, razen kadar je to povezano s povzročanjem hrupa.

General Information

• Status: Published
• Public Enquiry End Date: 30-Nov-2017
• Publication Date: 13-May-2019
• ICS: 17.140.30 - Noise emitted by means of transport
• ICS: 45.080 - Rails and railway components
• ICS: 93.100 - Construction of railways
• Technical Committee: IŽNP - Reilway applications
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 10-May-2019
• Due Date: 15-Jul-2019
• Completion Date: 14-May-2019
• Directive: 2008/57/EC - Directive 2008/57/EC of the European Parliament and of the Council of 17 June 2008 on the interoperability of the rail system within the Community (Recast)
• Directive: TP102 - Pravilnik o zgornjem ustroju železniških prog
• Mandate: M/483 - Mandate for programming and standardisation addressed to the European standardisation bodies under directive 2008/57/EC in the field of the interoperability of the rail system within the European Union
• Ref Project: EN 15610:2019 - Railway applications - Acoustics - Rail and wheel roughness measurement related to noise generation

RELATIONS

• Revised: SIST EN 15610:2009 - Railway applications - Noise emission - Rail roughness measuement related to rolling noise generation
• Effective Date: 18-Jun-2014
• Replaces: SIST EN 15610:2009 - Railway applications - Noise emission - Rail roughness measuement related to rolling noise generation
• Effective Date: 08-May-2019

Standards Content (sample)

SLOVENSKI STANDARD
SIST EN 15610:2019
01-julij-2019
Nadomešča:
SIST EN 15610:2009
Železniške naprave - Akustika - Merjenje valovitosti vozne površine tirnice in
kolesa, ki povzroča hrup med vožnjo

Railway applications - Acoustics - Rail and wheel roughness measurement related to

rolling noise generation
Bahnanwendungen - Akustik - Messung der Schienen- und Radrauheit im Hinblick auf
die Entstehung von Rollgeräuschen

Applications ferroviaires - Acoustique - Mesurage de la rugosité des rails et des roues

relative à la génération du bruit de roulement
Ta slovenski standard je istoveten z: EN 15610:2019
ICS:
17.140.30 Emisija hrupa transportnih Noise emitted by means of
sredstev transport
45.080 Tračnice in železniški deli Rails and railway
components
93.100 Gradnja železnic Construction of railways
SIST EN 15610:2019 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 15610:2019
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SIST EN 15610:2019
EN 15610
EUROPEAN STANDARD
NORME EUROPÉENNE
May 2019
EUROPÄISCHE NORM
ICS 17.140.30; 93.100 Supersedes EN 15610:2009
English Version
Railway applications - Acoustics - Rail and wheel
roughness measurement related to noise generation

Applications ferroviaires - Acoustique - Mesurage de la Bahnanwendungen - Akustik - Messung der Schienen-

rugosité des rails et des roues relative à la génération und Radrauheit im Hinblick auf die Entstehung von

du bruit de roulement Rollgeräuschen
This European Standard was approved by CEN on 21 January 2019.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this

European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references

concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN

member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by

translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management

Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,

Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,

Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,

Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 15610:2019 E

worldwide for CEN national Members.
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EN 15610:2019 (E)
Contents Page

European foreword ....................................................................................................................................................... 4

1 Scope .................................................................................................................................................................... 5

2 Normative references .................................................................................................................................... 6

3 Terms and definitions ................................................................................................................................... 6

4 Symbols ............................................................................................................................................................... 9

5 Rail roughness .................................................................................................................................................. 9

5.1 Measuring system requirements ............................................................................................................... 9

5.1.1 General ................................................................................................................................................................ 9

5.1.2 Accuracy of the output signal ...................................................................................................................... 9

5.1.3 Dimensions of the sensor ............................................................................................................................. 9

5.1.4 Tracking of the sensor ................................................................................................................................ 10

5.1.5 Sampling interval ......................................................................................................................................... 10

5.1.6 Record length................................................................................................................................................. 10

5.1.7 Calibration and traceability to a national measurement standard ........................................... 10

5.2 Data acquisition ............................................................................................................................................ 10

5.2.1 General ............................................................................................................................................................. 10

5.2.2 Test section requirements ........................................................................................................................ 10

5.2.3 Reference surface choice ........................................................................................................................... 11

5.2.4 Data sampling ................................................................................................................................................ 12

5.2.5 Preparation of the rail head surface ..................................................................................................... 13

5.2.6 Acoustic roughness acquisition .............................................................................................................. 13

5.3 Data processing ............................................................................................................................................. 13

5.3.1 Principle .......................................................................................................................................................... 13

5.3.2 Spike removal technique ........................................................................................................................... 14

5.3.3 Curvature processing .................................................................................................................................. 15

5.3.4 Spectral analysis ........................................................................................................................................... 16

5.3.5 Procedure for extending the wavelength range ............................................................................... 17

5.3.6 Averaging process ........................................................................................................................................ 17

6 Wheel roughness .......................................................................................................................................... 17

6.1 Measuring system requirements ............................................................................................................ 17

6.1.1 General ............................................................................................................................................................. 17

6.1.2 Accuracy of the output signal ................................................................................................................... 17

6.1.3 Dimensions of the sensor .......................................................................................................................... 17

6.1.4 Tracking of the sensor ................................................................................................................................ 17

6.1.5 Sampling interval ......................................................................................................................................... 17

6.1.6 Calibration and traceability to a national measurement standard ........................................... 18

6.2 Data acquisition ............................................................................................................................................ 18

6.2.1 General ............................................................................................................................................................. 18

6.2.2 Data sampling ................................................................................................................................................ 18

6.2.3 Vehicle preparation ..................................................................................................................................... 19

6.2.4 Acoustic roughness acquisition .............................................................................................................. 19

6.2.5 Data quality checks ...................................................................................................................................... 19

6.2.6 Localized geometric wheel features ...................................................................................................... 20

6.3 Data processing ............................................................................................................................................. 20

6.3.1 Principle .......................................................................................................................................................... 20

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6.3.2 Spike removal technique ........................................................................................................................... 20

6.3.3 Curvature processing .................................................................................................................................. 21

6.3.4 Spectral analysis ........................................................................................................................................... 21

6.3.5 Averaging the roughness spectra ........................................................................................................... 22

7 Acceptance criteria ...................................................................................................................................... 22

7.1 Rail roughness ............................................................................................................................................... 22

7.2 Wheel roughness .......................................................................................................................................... 22

8 Presentation of the rail and wheel roughness spectra ................................................................... 22

9 Report ............................................................................................................................................................... 23

9.1 Rail roughness ............................................................................................................................................... 23

9.2 Wheel roughness .......................................................................................................................................... 23

Annex A (informative) Examples of localized geometrical features on the rail .................................... 25

Annex B (normative) Algorithm used to synthesize a one-third octave band spectrum from a

corresponding narrow band spectrum for rail roughness ............................................................ 27

Annex C (informative) Determination of the combined roughness (and contact filters) ................. 28

Annex D (informative) Quantification of measurement uncertainties according to

ISO/IEC Guide 98-3 ....................................................................................................................................... 29

D.1 General ............................................................................................................................................................. 29

D.2 Mathematical model .................................................................................................................................... 30

D.3 Determination of the standard uncertainties .................................................................................... 30

D.4 Determination of the combined standard uncertainty ................................................................... 31

D.5 Determination of the expanded uncertainty ...................................................................................... 32

Annex E (informative) An example of a rail roughness report sheet ........................................................ 33

Annex ZA (informative) Relationship between this European Standard and the Essential

Requirements of EU Directive 2008/57/EC aimed to be covered............................................... 34

Bibliography ................................................................................................................................................................. 35

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European foreword

This document (EN 15610:2019) has been prepared by Technical Committee CEN/TC 256 “Railway

applications”, the secretariat of which is held by DIN.

This European Standard shall be given the status of a national standard, either by publication of an

identical text or by endorsement, at the latest by November 2019, and conflicting national standards

shall be withdrawn at the latest by November 2019.

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CEN shall not be held responsible for identifying any or all such patent rights.

This document supersedes EN 15610:2009.

This document has been prepared under a mandate given to CEN by the European Commission and the

European Free Trade Association, and supports essential requirements of EU Directive 2008/57/EC.

For relationship with EU Directive 2008/57/EC, see informative Annex ZA, which is an integral part of

this document.
The main changes with respect to the previous edition are listed below:

— The most significant technical change is the introduction of a measurement procedure for the

characterization of the wheel acoustic roughness.

— Slight improvements of the section related to the characterization of the acoustic rail roughness

have also been implemented.

According to the CEN-CENELEC Internal Regulations, the national standards organizations of the

following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,

Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia,

France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,

Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,

Turkey and the United Kingdom.
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1 Scope

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);
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d) characterization of track and wheel geometry except where associated with noise generation.

2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

EN 61260-1:2014, Electroacoustics – Octave-band and fractional-octave-band filters – Part 1:

Specifications (IEC 61260-1:2014)
EN ISO 266:1997, Acoustics – Preferred frequencies (ISO 266:1997)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— IEC Electropedia: available at http://www.electropedia.org/
— ISO Online browsing platform: available at http://www.iso.org/obp
3.1
acoustic roughness
r(x)

variation in the height of the running surface associated with rolling noise excitation expressed as a

function of distance x along the running surface
3.2
acoustic roughness spectrum
r()λ
amplitude of the acoustic roughness expressed as a function of the wavelength λ
3.3
acoustic roughness level
level expressed in decibels, given by the following formula:
2
RMS
L 10⋅log (1)
r 10
2
where
L is the acoustic roughness level in dB;
r is the root mean square roughness in μm;
RMS
r is the reference roughness; r = 1 μm.
0 0

Note 1 to entry This definition applies to values measured either in the form of a one-third octave band

wavelength spectrum, or for a specific wavelength band.
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3.4
combined effective roughness
roughness function that excites rolling noise

Note 1 to entry: The combined effective roughness is the RMS of the rail and wheel roughness spectra. It

becomes the combined effective roughness when the effect of the contact patch filter is included.

3.5
direct roughness measurement method

acoustic roughness measurement method for which the sensor measures the running surface

roughness so that either the rail or the wheel roughness is measured independently of any effect of

wheel-rail interaction
3.6
indirect roughness measurement method

acoustic roughness measurement method that measures a quantity that is the result of wheel-rail

interaction, such as noise, rail or axle box vibration, whereby the original excitation by the combined

effective wheel and rail roughness is inferred
3.7
test section
specific section of track associated with a particular set of measurements
3.8
RMS

root mean square average which is required in the standard where averaging of spectra is required

Note 1 to entry: This is defined for each spectral band as:
22 2
a + a ++ a
1 2 N
(2)
RMS=
where:
a is a spectral amplitude; and

N is the number of spectral band value from which the average is being calculated.

Note 2 to entry: In terms of levels, this is equivalent to:
LL//10 10 L /10
1 2 N
10 + 10 ++ 10
L = 10log (3)
average 10
3.9
running surface

part of the wheel tread or of the rail head, along which the wheel-rail contact passes during rolling

Note 1 to entry: In the case of the rail this is the bright band of the surface of the rail head that contains all the

running positions of the wheel-rail contact, associated with current traffic.
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3.10
partially conditioned surface

part of the rail head outside the rail running surface that nevertheless can appear to have been affected

by the passage of vehicles
3.11
reference surface

surface of the rail head, within the running surface, that is chosen for the acoustic roughness

assessment
3.12
reference length
dimension of the reference surface in the longitudinal rail direction
3.13
reference width
ref
dimension of the reference surface across the rail
Note 1 to entry: Figure 1 shows an example of some of the defined terms
Key
1 running surface
2 reference surface
3 partially conditioned surface
Figure 1 — Example showing defined parameters
3.14
field face

outer face of the railhead, offering a reference position constant during the rail wear process

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4 Symbols
Symbol Meaning
C(x) circular curve used for the acoustic roughness processing

d position, relative to the outer surface of the rail head, of the longitudinal axis of symmetry

ref
of the reference surface
h height of a spike
L acoustic roughness level
r(x) acoustic roughness

r'(x) acoustic roughness processed with the spike removal and curvature algorithm

w width of a spike
w width of the reference surface
ref
x variable of the distance along the rail
x particular position along the rail
z mean value of height over a given interval
discrete Fourier Transform of r(x)
r()λ
λ wavelength
5 Rail roughness
5.1 Measuring system requirements
5.1.1 General

This subclause summarizes the requirements of the measuring system and its calibration. The

measuring devices shall be checked and calibrated regularly.
5.1.2 Accuracy of the output signal

The measuring system shall be capable of making valid measurements in the wavelength range and at

the acoustic roughness levels for the test site being characterized.

NOTE Typical rail roughness spectra can be found in [11], [18], [22], [23] and [25].

However, where it is required simply to show that the estimated acoustic roughness does not exceed a

given upper limit, the measuring system shall effect valid measurements for one-third octave band

acoustic roughness levels equal to or greater than this limit. This case applies particularly for test

section approval.

A measurement device shall be considered making valid measurements if the uncertainty resulting

from the measuring device, expressed in terms of its standard uncertainty, does not exceed 3 dB.

5.1.3 Dimensions of the sensor

If a contact sensor is used, the sensor tip shall be spherical and its radius shall not exceed 7 mm.

In the case of a non-contacting sensor, its effective width shall be less than the sampling interval.

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5.1.4 Tracking of the sensor

The measuring system sensor shall follow a line on the rail head parallel to the field (outer) face of the

rail head, with a tolerance of ± 1 mm.
5.1.5 Sampling interval

The measuring system shall measure data with a sampling interval less than or equal to 1 mm to an

accuracy of no worse than 3 %.
5.1.6 Record length
The system shall provide records of length ≥ 1 m.
5.1.7 Calibration and traceability to a national measurement standard

The calibration shall verify the accuracy and the compliance of the measuring device

The calibration shall include the traceability to a national measurement standard or a primary standard.

This shall be done in terms of a reference roughness standard (e.g. a section of a reference rail or beam).

The surface geometry of the reference roughness standard shall be measured by a national or primary

standards laboratory. For comparing the measurement values to a limit curve, the roughness of this

reference roughness standard shall be of a measureable value and shall be no greater than 10 dB above

the respective limit curve over the whole wavelength range of the limit curve.

The calibration procedure shall be documented. The documentation shall justify the calibration and the

checking of all aspects of the instrument including the electronics and processing.

An instrument shall always be recalibrated if it has been repaired or is suspected of fault or damage or

wear. The maximum time from the last calibration of the instrument shall be 24 months.

5.2 Data acquisition
5.2.1 General

The aim of the data acquisition procedure is to obtain digitized records of the acoustic roughness of the

two rails in the test section measured at a sufficiently high sampling rate (samples per unit length) and

with a record length sufficient to derive from it the acoustic roughness spectrum. Record lengths of at

least 1 m are required to estimate the acoustic roughness spectrum covering the wavelength range up

to the 0,25 m one-third octave band.

To attain wavelengths greater than 0,25 m, records longer than those specified in this sub clause shall

be obtained. The record length shall be at least 4 times of mid wavelength the one-third octave band

wavelength.
5.2.2 Test section requirements
5.2.2.1 Track structure

The track structure design shall be constant along the test section, at least in terms of the following

parameters: rail cross-section, rail inclination and rail supporting structure. In the case of a ballasted

track, the rail supporting structure parameters are: the rail pad type, the rail fasteners, the sleeper type,

the sleeper spacing and the ballast.

If the track structure changes, separate test sections shall be defined and the acoustic roughness of each

shall be assessed and presented.
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SIST EN 15610:2019
EN 15610:2019 (E)
5.2.2.2 Localized geometric features

There is no specific requirement for the test section to be free from localized defects. However, it may

contain some localized geometrical features (e.g.: weld, large dips, wheel burns) that it is permitted to

exclude in the assessment of the acoustic roughness related to the generation of rolling noise. See

Annex A for guidance concerning features that may be edited out of the record.

NOTE The generation of noise at localized defects is not linearly related to their amplitude compared to

general roughness so that defects are less significant in the assessment of the source of rolling noise.

5.2.3 Reference surface choice
5.2.3.1 General

The acoustic roughness of the test section shall be assessed over a reference surface. The reference

surface shall be inside the running surface and is specified as follows:
a) length along the rail;
b) transverse width w ;
ref
c) relative distance d to the field face of the rail.
ref

The running surface can be wide and experience shows that there is considerable variation of the

acoustic roughness with lateral position. It is common that particular vehicles will only use part of this

surface. Therefore, the standard allows for an assessment to apply only to a part of the running surface

that may correspond to the requirements of a particular test, i.e. the reference surface.

5.2.3.2 Cases

It is the responsibility of the measurement team to define the length, width and position of the

reference surface of the two rails and to justify its decision.
The reference length may be given by standards.

Where the acoustic rail roughness measurement is required for rolling stock type acceptance testing,

any of the three following cases for that justification shall be used:

a) Case 1: the running surface (band) on the rail head is clear visually and it is known that this running

surface is produced by the rolling stock to be measured.

Considering that the wheel-rail contact patch is approximately 10 mm wide, any partially conditioned

area at the edges o
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