Railway applications - Track - Track geometry quality - Part 6: Characterisation of track geometry quality

This European Standard characterizes the quality of track geometry based on parameters defined in EN 13848 1 and specifies the different track geometry classes which should be considered.
This European Standard covers the following topics:
- description of track geometry quality;
- classification of track quality according to track geometry parameters;
- considerations on how this classification can be used;
- this European Standard applies to high-speed and conventional lines of 1 435 mm and wider gauge;
- this European Standard forms an integral part of EN 13848 series.

Bahnanwendungen - Oberbau - Qualität der Gleisgeometrie - Teil 6: Charakterisierung der geometrischen Gleislagequalität

Diese Europäische Norm beschreibt die Qualität der Gleisgeometrie entsprechend den Parametern nach EN 13848-1 und legt die zu berücksichtigenden unterschiedlichen Gleisgeometrieklassen fest.
Diese Europäische Norm enthält die folgenden Themen:
—   Beschreibung der Gleislagequalität;
—   Klassifizierung der Gleisqualität nach den Parametern der Gleisgeometrie;
—   Hinweise zur Anwendung dieser Klassifizierung;
—   diese Europäische Norm gilt für Hochgeschwindigkeitsstrecken und konventionelle Strecken mit 1 435 mm und größeren Spurweiten;
—   diese Europäische Norm ist Bestandteil der Normenreihe EN 13848.

Applications ferroviaires - Voie - Qualité géométrique de la voie - Partie 6: Caractérisation de la qualité géométrique de la voie

Železniške naprave - Zgornji ustroj proge - Kakovost tirne geometrije - 6. del: Karakterizacija kakovosti tirne geometrije

General Information

Status
Published
Publication Date
07-Dec-2020
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
03-Dec-2020
Due Date
07-Feb-2021
Completion Date
08-Dec-2020

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SLOVENSKI STANDARD
SIST EN 13848-6:2014+A1:2021
01-januar-2021
Železniške naprave - Zgornji ustroj proge - Kakovost tirne geometrije - 6. del:
Karakterizacija kakovosti tirne geometrije

Railway applications - Track - Track geometry quality - Part 6: Characterisation of track

geometry quality

Bahnanwendungen - Oberbau - Qualität der Gleisgeometrie - Teil 6: Charakterisierung

der geometrischen Gleislagequalität
Applications ferroviaires - Voie - Qualité géométrique de la voie - Partie 6:
Caractérisation de la qualité géométrique de la voie
Ta slovenski standard je istoveten z: EN 13848-6:2014+A1:2020
ICS:
45.080 Tračnice in železniški deli Rails and railway
components
93.100 Gradnja železnic Construction of railways
SIST EN 13848-6:2014+A1:2021 en,fr,de

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

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SIST EN 13848-6:2014+A1:2021
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SIST EN 13848-6:2014+A1:2021
EN 13848-6:2014+A1
EUROPEAN STANDARD
NORME EUROPÉENNE
November 2020
EUROPÄISCHE NORM
ICS 93.100
English Version
Railway applications - Track - Track geometry quality -
Part 6: Characterisation of track geometry quality

Applications ferroviaires - Voie - Qualité géométrique Bahnanwendungen - Oberbau - Qualität der

de la voie - Partie 6: Caractérisation de la qualité Gleisgeometrie - Teil 6: Charakterisierung der

géométrique de la voie geometrischen Gleislagequalität

This European Standard was approved by CEN on 3 February 2014 and includes Amendment 1 approved by CEN on 24 August

2020.

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

Poland, Portugal, Republic of North Macedonia, 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

© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 13848-6:2014+A1:2020 E

worldwide for CEN national Members.
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SIST EN 13848-6:2014+A1:2021
EN 13848-6:2014+A1:2020 (E)
Contents Page

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

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

2 Normative references ............................................................................................................................................. 5

3 Terms, definitions, symbols and abbreviations............................................................................................ 5

3.1 Terms and definitions ............................................................................................................................................ 5

3.2 Symbols and abbreviations .................................................................................................................................. 6

4 Basic principles ........................................................................................................................................................ 7

4.1 Introduction ............................................................................................................................................................... 7

4.2 Basic parameters for track geometry quality assessment ........................................................................ 7

4.3 Transparency ............................................................................................................................................................ 7

4.4 Complexity .................................................................................................................................................................. 7

4.5 Track-vehicle interaction ..................................................................................................................................... 7

5 Assessment of track geometry quality: state-of-the-art ............................................................................ 7

5.1 General ......................................................................................................................................................................... 7

5.2 Standard deviation (SD) ........................................................................................................................................ 7

5.3 Isolated defects ......................................................................................................................................................... 8

5.4 Combination of various parameters ................................................................................................................. 9

5.4.1 Combined standard deviation (CoSD) .............................................................................................................. 9

5.4.2 Standard deviation of the combinations of parameters ............................................................................ 9

5.4.3 Point mass acceleration method (PMA) ........................................................................................................ 10

5.5 Methods based on vehicle response ................................................................................................................ 11

5.5.1 Use of theoretical model ...................................................................................................................................... 11

5.5.2 Use of direct measurement ................................................................................................................................ 11

5.6 Power Spectral Density (PSD) ........................................................................................................................... 11

6 Levels of aggregation and calculation methods .......................................................................................... 12

7 Classes of track geometry quality .................................................................................................................... 13

7.1 General ....................................................................................................................................................................... 13

7.2 Description of track quality classes (TQC) .................................................................................................... 13

7.3 Values of track quality classes .......................................................................................................................... 15

7.4 Assignment of TQCs ............................................................................................................................................... 16

7.5 Possible application of TQCs .............................................................................................................................. 16

Annex A (informative) Point mass acceleration method (PMA) ........................................................................ 18

A.1 Introduction ............................................................................................................................................................. 18

A.2 Description of the PMA model ........................................................................................................................... 18

A.3 Calculation of the PMA-assessment figure .................................................................................................... 18

A.4 Features of the PMA method .............................................................................................................................. 19

Annex B (informative) Vehicle Response Analysis methods (VRA) .................................................................. 21

B.1 Introduction ............................................................................................................................................................. 21

B.2 Determination of the assessment functions ................................................................................................. 21

B.3 Application of the assessment functions ....................................................................................................... 23

B.4 Features of VRA methods .................................................................................................................................... 25

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SIST EN 13848-6:2014+A1:2021
EN 13848-6:2014+A1:2020 (E)

Annex C (normative) Method for calculating reference TQIs (TQI ) .............................................................. 26

ref

C.1 Introduction ............................................................................................................................................................. 26

C.2 Description of the reference method.............................................................................................................. 26

Annex D (informative) Method of classification of alternative TQI using the TQCs .................................... 28

D.1 Introduction ............................................................................................................................................................. 28

D.2 Description of the conversion method ........................................................................................................... 28

Bibliography .......................................................................................................................................................................... 30

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SIST EN 13848-6:2014+A1:2021
EN 13848-6:2014+A1:2020 (E)
European foreword

This document (EN 13848-6:2014+A1:2020) 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 May 2021, and conflicting national standards shall be withdrawn at

the latest by May 2021.

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

rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.

This document includes Amendment 1 approved by CEN on 2020-07-24.
This document supersedes !EN 13848-6:2014".

The start and finish of text introduced or altered by amendment is indicated in the text by tags !".

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

European Free Trade Association.

This European Standard is one of the series EN 13848 “Railway applications – Track – Track geometry quality”

as listed below:
— Part 1: Characterisation of track geometry
— Part 2: Measuring systems – Track recording vehicles
— Part 3: Measuring systems – Track construction and maintenance machines
— Part 4: Measuring systems – Manual and lightweight devices
— Part 5: Geometric quality levels – Plain line
— Part 6: Characterisation of track geometry quality

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, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.

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SIST EN 13848-6:2014+A1:2021
EN 13848-6:2014+A1:2020 (E)
1 Scope

This European Standard characterizes the quality of track geometry based on parameters defined in

EN 13848-1 and specifies the different track geometry classes which should be considered.

This European Standard covers the following topics:
— description of track geometry quality;
— classification of track quality according to track geometry parameters;
— considerations on how this classification can be used;

— this European Standard applies to high-speed and conventional lines of 1 435 mm and wider gauge;

— this European Standard forms an integral part of EN 13848 series.
2 Normative references

The following documents, in whole or in part, are normatively referenced in this document and are

indispensable for its application. For dated references, only the edition cited applies. For undated references,

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

EN 13848-1, Railway applications - Track - Track geometry quality - Part 1: Characterization of track geometry

!EN 13848-5, Railway applications - Track - Track geometry quality - Part 5: Geometric quality levels - Plain

line, switches and crossings

EN 14363, Railway applications – Testing and simulation for the acceptance of running characteristics of

railway vehicles – Running behaviour and stationary tests"
3 Terms, definitions, symbols and abbreviations
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1.1
re-colouring

algorithm which modifies the spectral content of a signal aimed to compensate or apply the characteristics of

a specific measuring system

Note 1 to entry: The re-colouring is used in EN 13848 series to convert a chord measurement signal into a D1 or D2

measurement signal.
3.1.2
track quality class (TQC)

characterization of track geometry quality as a function of speed and expressed as a range of TQIs

3.1.3
track quality index (TQI)

value that characterises track geometry quality of a track section based on parameters and measuring

methods compliant with EN 13848 series
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EN 13848-6:2014+A1:2020 (E)
3.2 Symbols and abbreviations

For the purposes of this document, the following symbols and abbreviations apply.

Table 1 — Symbols and abbreviations
Symbol Designation Unit
AL Alignment mm
ATQI Alternative Track Quality Index
CL Cross level mm
CoSD Combined standard deviation mm
D1 Wavelength range 3 m < λ ≤ 25 m m
D2 Wavelength range 25 m < λ ≤ 70 m m
D3 Wavelength range 70 m < λ ≤ 150 m for longitudinal level m
Wavelength range 70 m < λ ≤ 200 m for alignment
λ Wavelength m
G Track gauge mm
LL Longitudinal level mm
MBS Multi Body System
NTQI National Track Quality Index
PMA Point Mass Acceleration (method)
PSD Power Spectral Density m /(1/
SD Standard deviation mm
SD Standard deviation longitudinal level mm
SD Standard deviation alignment mm
TQI Track Quality Index
TQI Reference Track Quality Index
ref
TQC Track Quality Class
V Speed km/h
VRA Vehicle Response Analysis (method)

NOTE In this European Standard, AL stands for “alignment” and is not to be confused with AL standing for “alert

limit” as defined in EN 13848–5:2008+A1:2010.
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EN 13848-6:2014+A1:2020 (E)
4 Basic principles
4.1 Introduction

It is necessary to standardize the way that track geometry quality is assessed in order to permit safe and cost-

effective railway traffic by focusing on the functional requirements of both track and vehicle.

4.2 Basic parameters for track geometry quality assessment"

As track geometry measurement, vehicles present their outputs in accordance with the parameters specified

in EN 13848-1, any standardized assessment method shall be based on these parameters.

4.3 Transparency

Any algorithm for track geometry quality assessment complying with this standard shall be fully documented,

reproducible and available in the public domain.
4.4 Complexity

Track geometry quality should be assessed by as few TQIs as possible and the algorithm should be

understandable by the user.
4.5 Track-vehicle interaction

Track quality assessment should reflect the principles of track-vehicle interaction. For example, the track

geometry defects of the same amplitude but different wavelengths lead to different vehicle responses and the

required wavelength range will be different depending on the track-vehicle interaction parameters to be

assessed.
5 Assessment of track geometry quality: state-of-the-art
5.1 General

Track geometry quality can be characterized by various TQIs according to the level of aggregation they are

used for. The TQIs described in the following sub-clauses are used by at least one of the European Railway

Networks. They represent the current state-of-the-art of description of track geometry quality.

5.2 Standard deviation (SD)

The standard deviation is one of the most commonly used TQIs by European Railway Networks. It represents

the dispersion of a signal over a given track section, in relation to the mean value of this signal over the

considered section.
(x −x)
i=1
SD=
N−1
where
N is the number of values in the sample;
x is the current value of a signal;
is the mean value of a signal;
SD is the standard deviation.
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EN 13848-6:2014+A1:2020 (E)

NOTE 1 Standard deviation is linked to the energy of the signal in a given wavelength range [λ1, λ2] according to the

following relationship: , where S is the PSD described in 5.6 below.
SD = 2 S (ν)dν xx
SD is commonly calculated for the following parameters:
— Longitudinal level D1;
— Alignment D1.
It is also calculated for other parameters such as:
— Twist;
— Track gauge;
— Cross level;
— Longitudinal level D2;
— Alignment D2.

For longitudinal level and alignment it is recommended to calculate SD separately for each rail. It may also be

calculated differently (for example: mean of both rails, worst or best of either rail or outer rail in curves).

Length of track section used for standard deviation has influence on the result. If comparable results are

expected, only one length should be used. Commonly, for maintenance reasons standard deviation is

calculated over a length of 200 m. It may be calculated either at fixed distances without overlap or with

overlap, as a sliding standard deviation. Calculation of standard deviation is also done over longer distances

such as 1 km, an entire line or an entire network.

NOTE 2 Distinction between specific track sections, such as plain lines, stations and switches and crossings, can also

be made.

When calculating SD for twist, track gauge and cross level attention should be paid on the possible influence of

the quasi-static part of the signals.
5.3 Isolated defects

Isolated defects may present a derailment risk; however counting the number of isolated defects exceeding a

specified threshold such as intervention limit and alert limit on a given fixed length of track can be

representative of the track geometry quality. This method is used by several European Railway Networks.

The number of isolated defects per unit of track length is commonly counted for the following parameters:

— Longitudinal level D1;
— Alignment D1;
— Twist;
— Track gauge;
— Cross level.
It can be also counted for the following parameters:
— Longitudinal level D2;
— Alignment D2.
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SIST EN 13848-6:2014+A1:2021
EN 13848-6:2014+A1:2020 (E)

Commonly, the number of isolated defects is counted over 1 km or more. It may also be counted over 100 m or

200 m of track.

If required, distinction between specific track sections can be made, such as plain lines, stations and switches

and crossings.

Alternatively a calculation can be made to specify what percentage of a line exceeds a certain threshold level.

5.4 Combination of various parameters
5.4.1 Combined standard deviation (CoSD)

Assessment of the overall track geometry quality of a track section (200 m, 1 000 m...) can be done by a

combination of weighted standard deviations of individual geometric parameters. An example of such a TQI is

given below.
2 2 2 2
CoSD= w .SD +w SD +w .SD +w SD
G G CL CL
AL AL LL LL
where
SD standard deviation of the individual geometry parameters;
w weighting factor of the individual geometry parameters;
with the indices:
AL alignment, average of left and right rails;
G track gauge;
CL cross level;
longitudinal level, average of left and right rails.

It is up to the Infrastructure Manager to determine the weighting factors, e.g. for tamping purposes the

weighting factor w should be zero.

Another method might be to transform the standard deviations of geometry parameters or their combinations

into a dimensionless number that can be used without distinction of line category, speed range and track

geometry parameter.
5.4.2 Standard deviation of the combinations of parameters

Standard deviation for a combination of track geometry parameters can be evaluated. This is based on the

observation that the level of the combined signals may better reflect the vehicle behaviour than the individual

signals.

For example, a standard deviation, over a sliding 200 m length of track, can be evaluated for the sum of

alignment and cross level in D1 as follows:

— the alignments of left and right rails are combined into one signal, in curves by choosing the outer rail and

on tangent track by either averaging or choosing one of the two rails;

— cross level and alignment signals are combined together by using a sign convention so that an alignment

defect to the right is added with the same sign to a cross level defect where right rail is lower than the left

rail. Figure 1 shows an example of the combination of cross level Δz and alignment y where the signs are

both positive;

— the standard deviation of the combined signals is calculated over a sliding 200 m length of track.

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SIST EN 13848-6:2014+A1:2021
EN 13848-6:2014+A1:2020 (E)
Key
1 reference position
combination of alignment
y = (ALright + ALleft) /
Δz = z - z cross level
right left
s sum of cross level and alignment
Figure 1 — Combination of alignment and cross level
5.4.3 Point mass acceleration method (PMA)
The PMA method is based on the following principles:

— The PMA model considers an unsprung virtual vehicle. It is assumed to be a point mass, thus only the

motion of the centre of gravity is investigated. This point mass is guided in a certain distance over the

track centre line.

— The point mass is moved at a constant speed corresponding to the maximum allowed speed over the

measured track section.

— Due to the geometrical imperfection of the track, which is described by the longitudinal level and

alignment of both rails, the point mass incurs accelerations a and a in the horizontal and vertical

y z
directions.

— The vectorial summation of these accelerations is used to characterize the track geometry quality.

Theoretical background information as well as features of the PMA method are given in Annex A.

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EN 13848-6:2014+A1:2020 (E)
5.5 Methods based on vehicle response
5.5.1 Use of theoretical model

Vehicle response analysis (VRA) can be used to make objective, quantified statements about the relationship

between the track geometry quality and the vehicle’s responses at various speeds. It takes into consideration

factors such as successions of isolated defects that might generate resonance, combinations of defects at the

same location and local track design (e.g. curvature and cant).
The VRA method is based on the following principles:

— Calculation of vehicle response to the track geometry measured according to EN 13848-1. The vehicle

response being represented by the wheel-rail forces and by accelerations of the vehicle running gear and

car body;

— Consideration of different vehicle types and speeds, taking into account the worst response of all vehicles

considered at every measuring point;

— The output can be referred back to single parameters like longitudinal level, twist and alignment;

— The assessment criteria take into account the limit values given by EN 14363.

When using this method attention should be paid to the consistency between the wavelength domain of the

track geometry and the frequency range of the vehicle response parameters.

An example of a VRA method as well as features of such methods are given in Annex B.

5.5.2 Use of direct measurement

Although not generally used for TQIs calculation, direct measurements of vehicle response can help in

assessing interaction between running vehicle and track, with respect to safety as well as ride quality.

Usually the accelerations of bogie and car body are measured in both lateral and vertical directions, but

measurement of wheel-rail forces, such as lateral and vertical forces (Y and Q), can also be made.

Inspection runs are usually made on high speed lines, but they can also be of interest on conventional lines.

The following principles should be respected when using direct measurement:

— The vehicles used for these evaluations are representative of the rolling stock used on the assessed lines.

— The runs are made at the maximum speed of the line, with a tolerance of ± 10 %.

— The measurements are made at the parts of the vehicle where the highest response is expected, e.g. the

leading bogie or wheelset.
— The state of the rail surface (wet or dry) is taken into account.

— The position of the train shall be known to be able to locate any defects found.

5.6 Power Spectral Density (PSD)

The PSD gives the energy of the signal in relation to frequency for a given track geometry parameter measured

over a given track section.
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EN 13848-6:2014+A1:2020 (E)

For a track geometric parameter x, the most commonly used formula to calculate the PSD is given by:

S (ν)= lim X(ν)X(ν)
λ→∞
where
λ is the wavelength and ν the respective spatial frequency;
is the Fourier transformation of x(λ);
−i2πνλ
X(ν)= x(λ)e dλ
is the complex conjugate of X(ν) .
X(ν)
In order to be representative, the PSD should be calculated:

— over a sufficient length of track, typically 5 km. However, shorter lengths can also be used by applying

Short Time Fourier Transform techniques in order to analyse changes of the spectral characteristics of

track geometry;

— over a section of track with features and quality as homogeneous as possible, e.g. same track layout or

same components;
— for a wide range of wavelengths including at least D1 and D2.

PSD can be of help for characterizing geometric quality over a section of track or a line for:

— vehicle manufacturers to have a better knowledge of the quality of the track the vehicles will run on;

— infrastructure managers to know which defect wavelengths are present on the track.

One of the main advantages of PSD is that it can show typical peaks corresponding to the existence of

repetitive defects such as welds.

As there are other methods for calculating PSD, the method used !deleted word" should be specified.

6 Levels of aggregation and calculation methods

Track geometry quality is analysed for a variety of purposes. Different kinds of analysis may be necessary and

it is recommended to classify them into different levels of aggregation, according to the expected use of the

particular analysis. Hereunder three levels of aggregation of track geometry data are defined:

— Detailed level: this level contains the analyses required for deciding local interventions, short term track

maintenance and operational restrictions. These analyses can also be of value in case studies by vehicle

designers and vehicle-track interaction studies.

— Intermediate level: this level contains the analyses used to do medium term track maintenance and

renewal planning. This level of aggregation can also be of interest for vehicle design and acceptance

procedures.

— Overview level: this level contains the analyses required for strategic decisions. A large amount of data

are summarized into a few indicators to gain an overview of all or part of a net
...

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