Railway applications - Noise emission - Road test of standard for rail roughness measurement EN 15610:2009

The purpose of the road test is to check that the  standard can be interpreted consistently and  leads to a consistent estimate of roughness  spectrum when used by different measurers with  different instruments. Many of the instructions of  the new standard have not been practiced by  measurers before and so these are also being  tested for practicability and effectiveness. The  exercise is not concerned with testing  instruments or measurement technology. The  standard specifies minimum performance criteria  but otherwise is designed to be as inclusive as  possible with regard to technology. In order to  gain a proper understanding of the practical  difficulties and the outcome in terms of  consistency of practice as well and results, it  was seen as essential that the 'road test' should  take place in an industrial context, i. e. making  measurements with instruments used by the  industry on running railway lines having normal  constraints of access time and safety  procedures, etc.

Bahnanwendungen - Geräuschemission - Feldversuch zu EN 15610:2006 über Messung der Schienenrauheit im Hinblick auf die Entstehung von Rollgeräusch

1.1   Hintergrund
Bekannt ist, dass die kombinierte „Rauheit“ von Rad  und Schienen¬fahrflächen die Rollgeräuschentstehung verursacht. Durch das Abrollen des Rades auf der Schiene erzeugt diese Rauheit zeitlich variierende Rad Schiene Kontaktkräfte, die zu Schwingungen von Rad und Schiene führen. Diese Struktur-schwingungen führen zur Abstrahlung von Geräuschen von Rad, Schiene und Schwelle. Der Vergleich von theoretischen Modellen und sorgfältigen Messungen zeigt, dass es bei niedriger Rauheit einen linearen Zusammenhang zwischen den Werten der Rauheit und der Geräuschemission gibt [1]. Bei einer Reihe von Schienen¬verkehrsunternehmen hat es sich als Maßnahme zur Geräusch¬minderung in der Praxis bewährt, die Rauheit von Schienen   auch bei unverriffelten Schienen – zu überwachen.
In den letzten Jahren sind, in Übereinstimmung mit der Strategie der Europäischen Union für die Harmoni-sierung des internationalen Zugverkehrs in Europa, neue Technische Spezifikationen für die Interopera-bilität (TSI) für die Abnahmeprüfung von neuen Fahrzeugen erarbeitet worden. Die akustisch relevanten TSI spiegeln das Verständnis der Mechanismen der Geräuschentwicklung [2, 3] wider. Um sicherzustellen, dass Abnahmeprüfungen, die an verschiedenen Orten an verschiedenen Fahrzeugen vorgenommen werden dürfen, eine angemessene Prüfung der Fahrzeuge sind und möglichst wenig von der lokalen Strecken¬beschaffenheit abhängen, legt die TSI Bedingungen für ein „Referenzgleis“ fest, auf dem Fahrgeräusch¬messungen vorzunehmen sind. Die erste Bedingung ist durch ein Spektrum der Mindestabklingrate charakterisiert, die auf dem Referenzgleis erzielt werden muss (zu Messverfahren und Geräuschverhalten des Gleises siehe [4] und [5]). Die zweite Bedingung ist die Einhaltung einer Obergrenze für den spektralen Schienenrauheitspegel, die auf dem Referenzgleis vorkommen darf [6].
Um vergleichbare und reproduzierbare Ergebnisse von Geräusch¬messungen sicher¬zustellen, verweisen die TSI auf ISO 3095. Diese Norm enthält auch einen Anhang zur Messung der RauheitN1).
Um die praktische Anwendbarkeit des Messverfahrens in den TSI zu prüfen, wurde ein Programm mit Geräuschmessungen sowohl im Hoch¬geschwindigkeitsverkehr als auch im konven¬tionellen Verkehr durch-geführt (NOEMIE Projekt [7]). In vielerlei Hinsicht waren die Messungen erfolgreich, aber es hat sich erwartungsgemäß gezeigt, dass der Anhang der ISO 3095 zur Rauheitsmessung in folgender Hinsicht zu begrenzt ist:
a)   der festgelegte Wellenlängenbereich ist für den Einsatz bei Hochgeschwindigkeitszügen zu kurz;
b)   es wird eine zu geringe Abtastrate verlangt, um die erforderliche Bestimmtheit des gemessenen Rauheits¬spektrums im benötigten Wellenlängenbereich zu erlangen;
c)   die Norm wurde unter der Annahme eines bestimmten Messverfahrens geschrieben. Vorzuziehen ist, dass statt dessen Anforderungen an die Qualität der Messwerte definiert werden;
d)   ISO 3095 legt ein festes Muster der Stichprobenpositionen fest; das bewirkt manchmal die Messung von Schienenkopfmängeln, die nicht im Signal gewünscht werden, jedoch eine signifikante Auswirkung auf das geschätzte Rauheitsspektrum haben;
e)   die Norm legt die Mittelung der Rauheit über eine Reihe von abgetasteten Linien in unterschiedlichen Abständen über den Schienenkopf fest. Da die Rauheit über den Schienenkopf signifikant variiert, ist eine genauere Vorgabe der Messpositionen nötig, und die Daten für separate Linien sollten getrennt aufgeführt werden.
Aus diesen Gründen ersuchte das TSI-Gremium das CEN/TC 256, Arbeitsgruppe 3, eine neue Norm ausschließlich für die Messung der akustischen Rauheit zu erarbeiten. Es ist beabsichtigt, dass die TSI für diesen Aspekt zukünftig auf den neuen Standard verweisen sollte.

Applications ferroviares - Emission de bruit - Essai de route relatif de norme pour la mesure de rugosité de rail EN 15610:2009

Il est bien établi que le bruit de roulement tient son origine de la « rugosité » combinée des surfaces de roulement de la roue et du rail. A travers l’interaction du roulement de la roue et du rail, cette rugosité impose une variation temporelle du déplacement relatif transversal au contact roue-rail qui crée la vibration de la roue et de la voie. Cette vibration, en retour, engendre les composantes du bruit rayonnées par la roue, le rail et la traverse. Le fait qu’à des niveaux faibles (‘normaux’), la rugosité génère le rayonnement de bruit linéairement et est la seule cause du bruit, a été démontré par la comparaison de modèles théoriques et de mesures soigneusement contrôlées [1]. Le contrôle de la rugosité même pour des voies sans usure ondulatoire, fait d’ailleurs partie des mesures de réduction du bruit adoptées par de nombreuses compagnies ferroviaires.
Ces dernières années, en accord avec la stratégie de l’Union Européenne pour l’harmonisation des services de circulation des trains en Europe, des nouvelles Spécifications Techniques pour l’Interopérabilité (STI) ont été rédigées pour l’essai d’homologation de nouveaux matériels roulants. Les STI acoustiques reflètent la compréhension des mécanismes de génération du bruit[2, 3]. Afin d’assurer que l’essai d’homologation, qui peut être réalisé sur différents sites avec différents matériels roulants, est un essai juste du matériel roulant et dépend aussi peu que possible de la conception locale de la voie, les STI spécifient les conditions pour une ‘voie de référence’ sur laquelle des mesures du bruit de passage doivent être faites. La voie de référence est contrôlée en termes de bruit produit par niveau d’unité de rugosité combinée et de rugosité de la surface de roulement du champignon de rail. (...)

Železniške naprave - Hrup - Izvedba preskusa z zahtevami, določenimi v standardu EN 15610:2009

General Information

Status
Published
Publication Date
11-Jun-2009
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
03-Jun-2009
Due Date
08-Aug-2009
Completion Date
12-Jun-2009

Buy Standard

Technical report
SIST-TP CEN/TR 15874:2009 - BARVNE FOTOGRAFIJE IN GRAFI!
English language
52 pages
sale 10% off
Preview
sale 10% off
Preview
e-Library read for
1 day

Standards Content (Sample)

SLOVENSKI STANDARD
SIST-TP CEN/TR 15874:2009
01-september-2009
äHOH]QLãNHQDSUDYH+UXS,]YHGEDSUHVNXVD]]DKWHYDPLGRORþHQLPLYVWDQGDUGX
(1
Railway applications - Noise emission - Road test of standard for rail roughness
measurement EN 15610:2009
Bahnanwendungen - Geräuschemission - Feldversuch zu EN 15610:2006 über Messung
der Schienenrauheit im Hinblick auf die Entstehung von Rollgeräusch

Applications ferroviares - Emission de bruit - Essai de route relatif de norme pour la

mesure de rugosité de rail EN 15610:2009
Ta slovenski standard je istoveten z: CEN/TR 15874:2009
ICS:
17.140.30 Emisija hrupa transportnih Noise emitted by means of
sredstev transport
45.060.01 Železniška vozila na splošno Railway rolling stock in
general
SIST-TP CEN/TR 15874:2009 en

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

---------------------- Page: 1 ----------------------
SIST-TP CEN/TR 15874:2009
---------------------- Page: 2 ----------------------
SIST-TP CEN/TR 15874:2009
TECHNICAL REPORT
CEN/TR 15874
RAPPORT TECHNIQUE
TECHNISCHER BERICHT
May 2009
ICS 17.140.30; 93.100
English Version
Railway applications - Noise emission - Road test of standard for
rail roughness measurement EN 15610:2009

Applications ferroviares - Emission de bruit - Essai de route Bahnanwendungen - Geräuschemission - Feldversuch zu

relatif de norme pour la mesure de rugosité de rail EN EN 15610:2006 über Messung der Schienenrauheit im

15610:2009 Hinblick auf die Entstehung von Rollgeräusch

This Technical Report was approved by CEN on 28 March 2009. It has been drawn up by the Technical Committee CEN/TC 256.

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

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

Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: Avenue Marnix 17, B-1000 Brussels

© 2009 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TR 15874:2009: E

worldwide for CEN national Members.
---------------------- Page: 3 ----------------------
SIST-TP CEN/TR 15874:2009
CEN/TR 15874:2009 (E)
Contents Page

Foreword ..............................................................................................................................................................3

1 Introduction ............................................................................................................................................4

1.1 Background ............................................................................................................................................4

1.2 Objectives of the road test ....................................................................................................................5

2 Brief review of the nature and requirements of the new standard ...................................................5

2.1 Longitudinal position of measurement records and sample length ................................................5

2.2 Lateral position of the measurements on the rail head .....................................................................5

2.3 Processing ..............................................................................................................................................6

3 The measurement programme .............................................................................................................6

3.1 The test procedure.................................................................................................................................6

3.2 Test sites ................................................................................................................................................7

3.2.1 Loriol .......................................................................................................................................................7

3.2.2 Wildenrath ..............................................................................................................................................8

3.3 Teams and instruments ........................................................................................................................9

4 Comparison of the practices of the teams ..........................................................................................9

4.1 Choice of lateral position ......................................................................................................................9

4.1.1 Loriol .......................................................................................................................................................9

4.1.2 Wildenrath ........................................................................................................................................... 11

4.1.3 Conclusion on success of the provisions for identifying the reference surface ......................... 12

4.2 Longitudinal sampling and cleaning the rail head .......................................................................... 12

5 The common analysis applied to the raw data ................................................................................ 13

5.1 Spike processing ................................................................................................................................ 13

5.2 DFT and filtering analysis techniques .............................................................................................. 13

5.3 Treatment of long records in which rail-head defects are present ............................................... 13

5.4 Chatter/screech ................................................................................................................................... 13

5.5 Observations made on results presented in Appendices A and B ............................................... 15

5.5.1 Loriol .................................................................................................................................................... 15

5.5.2 Wildenrath ........................................................................................................................................... 15

5.6 Overall observations .......................................................................................................................... 17

6 Comparisons of roughness spectra ................................................................................................. 17

6.1 The datum line spectra ....................................................................................................................... 17

6.2 The 100 m test section results .......................................................................................................... 19

7 Conclusions ........................................................................................................................................ 23

Annex A (informative) Results from Loriol for all instruments processed using the common

processing method ............................................................................................................................. 24

Annex B (informative) Results from Wildenrath for all instruments processed using the common

processing method ............................................................................................................................. 39

Annex C (informative) Review of rail-head defects encountered at Loriol ................................................. 50

Bibliography ..................................................................................................................................................... 52

---------------------- Page: 4 ----------------------
SIST-TP CEN/TR 15874:2009
CEN/TR 15874:2009 (E)
Foreword

This document (CEN/TR 15874:2009) has been prepared by Technical Committee CEN/TC 256 “Railway

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

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.

---------------------- Page: 5 ----------------------
SIST-TP CEN/TR 15874:2009
CEN/TR 15874:2009 (E)
1 Introduction
1.1 Background

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 repeatable pass by noise measurements are made, the TSI calls upon ISO 3095.

This standard also contains an Annex concerning the measurement of roughness.

A programme of measurements of noise from both high-speed and some conventional speed rolling stock was

undertaken to test the practical applicability of the TSI method of measurements (NOEMIE project [7]). In

most respects the tests were successful but it was shown, as previously realised, that the part of ISO 3095

concerning roughness measurements is too limited in the following respects:
a) the wavelength range specified is too short for use for high speed trains;

b) too little data sampling is demanded to give the required certainty in the measured spectrum of roughness

over the wavelength required;

c) the standard is written on the assumption of a particular measurement technology; it is preferred that only

a performance criterion be implied for the quality of measurements obtained;

d) ISO 3095 imposes a fixed pattern of sample records; this sometimes causes the measurement of rail-

head defects that are not wanted in the signal and have a significant effect on the estimated spectrum;

e) the standard specified the averaging of the roughness across a number of lines at different distances

across the rail head. Since the variation across the rail-head is significant, closer specification of where to

measure is required and the data for separate lines should be presented separately.

For these reasons the TSI Committee requested CEN/TC 256, Working Group 3, to draft a new standard

solely for the measurement of acoustic roughness. It is the intention that the TSI should, in future, refer to the

new standard for this aspect.
---------------------- Page: 6 ----------------------
SIST-TP CEN/TR 15874:2009
CEN/TR 15874:2009 (E)
1.2 Objectives of the road test

The purpose of the road test is to check that the standard can be interpreted consistently and leads to a

consistent estimate of roughness spectrum when used by different measurers with different instruments. Many

of the instructions of the new standard have not been practiced by measurers before and so these are also

being tested for practicability and effectiveness. The exercise is not concerned with testing instruments or

measurement technology. The standard specifies minimum performance criteria but otherwise is designed to

be as inclusive as possible with regard to technology.

In order to gain a proper understanding of the practical difficulties and the outcome in terms of consistency of

practice as well and results, it was seen as essential that the ‘road test’ should take place in an industrial

context, i.e. making measurements with instruments used by the industry on running railway lines having

normal constraints of access time and safety procedures, etc.
2 Brief review of the nature and requirements of the new standard

For the method of pass-by noise measurement, the current High Speed Rolling Stock TSI (2008) refers to

EN ISO 3095: 2005 [8]. The current Conventional Rail TSI refers to ISO 3095:2001. Having said this, there is

not a significant difference between the two versions.

The EN ISO 3095 standard itself already sets a limit spectrum for the track on which acceptance tests are

made and prescribes a method for its measurement. The limit spectrum set in EN ISO 3095 is not used in the

TSI’s, rather a tighter limit is set from within the TSI’s according to what was found possible by the associated

NOEMIE project [7]. The project also found, for high speed trains (above 200 km/h), that a minimum

wavelength range up to 0,25 m is required.
2.1 Longitudinal position of measurement records and sample length

EN ISO 3095 specifies a set of six positions for 1 or 1,2 m records of the rail-head profile. These are fixed with

respect to ‘the microphone position’. This leads occasionally to the measurement of rail-head defects, welds

etc. Such large localised irregularities are not appropriate to include in the roughness spectrum since they

create forces and noise that are not linear with their depth (the contact geometry, and therefore the contact

stiffness, changes radically). They also strongly distort the mean of the six sample records leading to both an

overestimate of the level and uncertainty in the true operational roughness level. This has been a problem

many times in the past and specifically at one of the test sites in the NOEMIE project. In the new standard, the

choice of location of the measurement records is made by the measurers and they are advised not to include

such irregularities. Moreover, the new standard envisages that a certain track section is to be characterised

rather than assuming a microphone position. (The placing of a microphone might be decided on the results or

there may be no associated noise measurements at all.)

To keep the variance in the estimated spectrum at 0,25 m wavelength consistent with that at 0,1 m in EN ISO

3095, the new standard requires there to be a 15 m sample length in total.
2.2 Lateral position of the measurements on the rail head

EN ISO 3095 requires that the ‘running band’ on the rail head be identified (as ‘clearly visible’) and 1 or 3 lines

of roughness measurement record be taken depending on its width. The new standard refers to a ‘reference

surface’ that must be defined by the measurer. The relationship of noise measurements to the measured

roughness will then be valid as long as the wheel-rail contact remains inside the reference surface. Its

identification from the running band or otherwise is an important subject in the new standard. Three different

criteria depending on the situation and the purpose of the measurements are offered:

a) the running band is visible and is known to be a product of the rolling stock for which the roughness

measurement is to be used,

b) the contact position can be measured for the specific rolling stock at the time of roughness measurement,

---------------------- Page: 7 ----------------------
SIST-TP CEN/TR 15874:2009
CEN/TR 15874:2009 (E)

c) the contact position can be predicted from the geometry of rail and wheel transverse test section.

2.3 Processing

The data must be processed to remove some unwanted ‘pits and spikes’ and produce a one-third octave level

roughness spectrum. EN ISO 3095 does not prescribe how the processing is done although it recognises that

large differences can result. The processing is much more tightly controlled in the new standard. To remove

the effects of dust or grains of dirt on the railhead, an algorithm is included that removes ‘spikes’, i.e. very

short (much shorter than the wheel-rail contact patch), sharp, upward deviations. This recognises that such

features would be crushed or strongly deformed in the contact not leading to significant relative displacement

between wheel and rail. A second algorithm, ‘curvature processing’ is specified to deal with downward

features short in the direction along the rail head, found by the small tip radius probe of the instrument and

that would not affect a much larger radius wheel.

For the production of the wavelength spectrum of roughness from the measured data, the new standard

specifies alternative analysis methods,

a) Hanning window, discrete Fourier transform and averaging in one-third octave bands

b) digital one-third octave band filtering.
3 The measurement programme
The idea of the ‘road test’ of the new standard is

a) to have a number of different teams measure roughness according to their own interpretation of the

standard;
b) to observe the practices of the teams; and then
c) to examine the data for consistency of output.

Thus the standard should be tested in its practicality, whether it produces a consistent interpretation

implemented in the practice of different teams and whether it results in consistent roughness spectra.

Two sites were offered for the measurement exercise, one on a running line at Loriol in the south east of

France and the second at the Siemens Transportation Systems test track facility at Wildenrath in northern

Germany. Since the purpose of the standard is to fulfil the requirement of the TSI’s, it is important that the

sites should exercise the measurement of low roughness levels around and below the TSI limit curve.

A number of measurement teams were invited to come to each site and carry out measurements according to

their reading of EN 15610:2009. The measurement teams had to bear their own costs and so it was not

reasonable to require all teams to attend both sites. It was requested therefore that all teams taking part

should attend the site at Loriol. Thus, seven teams attended measurements at Loriol and five at Wildenrath.

All teams taking part were provided with software by the coordinator that attempted to perform the analysis

defined in the standard. The software was provided in open Matlab code used by some of teams and in open

FORTRAN. This was done so that teams could test and comment on the calculation procedure and raise any

areas of uncertainty in the definition of the processing.
3.1 The test procedure

At each site the teams measured separately so that there was no cross-contamination in the interpretation of

the standard. The host team at each location, required to be present for the safety arrangements, therefore

went first.
---------------------- Page: 8 ----------------------
SIST-TP CEN/TR 15874:2009
CEN/TR 15874:2009 (E)

Each team was shown the test section of track, in each case 100 m long between kilometre markers at the

trackside. The teams were then asked to characterise the roughness of the test section with no other

information given except that indicated in the text below concerning the rolling stock to which their reference

surface should correspond. After the measurement was made according to their free interpretation of the

standard, each team was asked to measure a 15 m sample of roughness along a single line specified by the

coordinator. This was done to provide a means of identifying any differences in results that may be due to

instruments or the natural limits of repeatability, from those that may be due to different choices of

measurement line lateral line positions and longitudinal sampling.

Each team were at liberty to process the data themselves but all data in terms of displacement along the rail

head, were given to the coordinator. The coordinator then processed all data with the software distributed

before the measurements. This is the basis of the comparisons presented in this report.

All measurements were made within the space of a few days of one another at each site but it remains an

assumption of the exercise that no significant change in roughness occurred due to the train running during

that time.
3.2 Test sites
3.2.1 Loriol

Measurements were carried out between 14th and 24th May 2007 at Loriol on a conventional-speed service

line in southern France. The line at this site is mostly trafficked by freight trains with some regional multiple

units, locomotive-hauled passenger stock and a few TGV’s. Figure 1 shows a sample of the rail head typical

of the Loriol test section. Here the running band was wider and less distinct than at Wildenrath. In these

circumstances the teams were guided to test the contact position of the passenger stock in deciding the

position of the reference surface. A method used by one team is illustrated in Figure 1.

Figure 1 — Photograph of the railhead at Loriol
---------------------- Page: 9 ----------------------
SIST-TP CEN/TR 15874:2009
CEN/TR 15874:2009 (E)

Figure 2 — Layout of the test section of track at Loriol ( — reference section, - - - datum)

3.2.2 Wildenrath

Further measurements were carried out between 22nd and 25 April on the main ring of the Siemens Test

Track Centre at Wildenrath in northern Germany. The rail-head had been ground about 6 months before the

test using a special ‘acoustic grinding’ with longitudinal grinding action. Figure 3 shows a typical sample of the

rail head at this site. There were very few significant defects of the rail head within the 100 m ‘reference

section’ of track. However, an interesting consideration arises; the site is used for testing rolling stock with

(mainly new) 1 in 20 and 1 in 40 coned wheel profiles. This has resulted in two clear separate (narrow)

running bands. The line speed is 120 km/h.
Figure 3 — Photograph of the railhead at the Wilderath test site

Figure 4 — Layout of the test section of track at Wildenrath (— reference section, - - - datum)

---------------------- Page: 10 ----------------------
SIST-TP CEN/TR 15874:2009
CEN/TR 15874:2009 (E)
3.3 Teams and instruments

At the Loriol site, seven teams took part with eight instruments. Three separate types of instrument measured

1.2 m records using linear voltage displacement transducers (LVDT’s) that moved along a straight edge fixed

in position relative to the rail. Two types of instrument measured continuously over the whole 100 m using an

accelerometer moved along the rail head by a light ‘trolley’. All teams that took part in the test measured at

Loriol. The team-instrument combinations for the measurements at Loriol are indicated in Table 1.

Table 1 — The team-instrument combinations at Loriol
Team- Instrument type Technology
instrument
A 1 1,2 m fixed straight edge with moving displacement transducer
B 1 1,2 m fixed straight edge with moving displacement transducer
C 2 1,2 m fixed straight edge with moving displacement transducer
D 2 1,2 m fixed straight edge with moving displacement transducer
E 4 1,2 m fixed straight edge with moving displacement transducer
G 5 Accelerometer trolley
H 3 Accelerometer trolley

At the Wildenrath site, five teams took part using four of the 1,2-metre fixed straight-edge instruments of two

different types. The fifth team used an accelerometer trolley. The team-instrument combinations are set out in

Table 2.
Table 2 — The team-instrument combinations at Wildenrath
Team- Instrument type Technology
instrument
A 1 1,2 m fixed straight edge with moving displacement transducer
B 1 1,2 m fixed straight edge with moving displacement transducer
C 2 1,2 m fixed straight edge with moving displacement transducer
D 2 1,2 m fixed straight edge with moving displacement transducer
F 2 1,2 m fixed straight edge with moving displacement transducer
I 3 Accelerometer trolley
4 Comparison of the practices of the teams

The test coordinator observed the practice of each team in response to the instructions in the standard.

4.1 Choice of lateral position
4.1.1 Loriol

At this site the running band is the product of mixed traffic and this led to a little difficulty for some in deciding

the width of the reference surface. Each team used a method of marking the rail at both ends of the test

section (some teams used additional positions) and observing the width rubbed off by passing trains (the

---------------------- Page: 11 ----------------------
SIST-TP CEN/TR 15874:2009
CEN/TR 15874:2009 (E)

second method prescribed in the standard). The method worked well with a wide range of paints and markers

used, but best with thin coating of ink from marker pens rather than thick coating of paint.

When this method carried out for the modern passenger stock this led to a narrower assessment than for the

older, more worn wheels of the freight stock. Team G in particular made a wider estimate than others on the

far rail based on the passage of a freight train. Thus team G initially placed three lines 10 mm apart on the far

rail. However, all teams were asked to consider the reference surface for the modern passenger stock and

this led to a re-evaluation by team G to measure at positions 5 mm apart.

Team H used a lateral rail-head profile measuring device on site before making their decision. The lateral

profile was then used in a ‘static’ geometrical calculation of the running position with a standard unworn profile

of the wheel. For illustration the output of this calculation is shown in Figure 5. This information was then used

in conjunction with the erased band of paint in order to reach the decision. While it was unnecessary under the

circumstances of the test with the relevant rolling stock passing regularly so that the marker method could be

used, the exercise showed the practicality of the third method offered in the draft standard.

Figure 5 — Output of the on-site guide calculation of likely running position

The decisions on reference surface width and line positions chosen by the different teams is summarised in

Table 3.
---------------------- Page: 12 ----------------------
SIST-TP CEN/TR 15874:2009
CEN/TR 15874:2009 (E)
Table 3 — Chosen lateral measurement positions at Loriol
Team- Line position(s) chosen Comments
Width identified (mm)
instrument (mm from gauge face)
near far near far The coordinator chose a line at
rail rail rail rail 39 mm for the datum
measurements
A 22 19 39 ± 5 39 ± 5 Centre-line chosen to be same
on both rails for convenience
B 28 28 37 ± 5 34 ± 5
C 22 22 38 ± 5 38 ± 5 Centre-line chosen to be same
on both rails for convenience
D - - 36 ± 5 36 ± 5
E 15 – 30 15 – 30 39,5 ± 5 39,5 ± 5
G 25 35, 25 43 ± 5 37 ± 5, 10 Revised decision on far rail for
modern passenger stock
H - - 37 ± 5 37 ± 5

All teams decided to measure 3 lines at Loriol, 5 mm apart. For the near rail, the range of the centre-lines was

from 36 mm to 43 mm with no team placing their centre-line further than 4,5 mm from the mean position of

38,5 mm. For the far rail, the situation is not very different with a range of centre-lines from 34 to 39,5 mm

from the gauge face. Thus no centre-line was placed more than 3 mm from the mean position of 37 mm.

4.1.2 Wildenrath

The nature of the two running bands at Wildenrath has already been shown in Figure 3. This situation may

well arise in measurements of rail roughness in the future and in connection with the TSI’s where two

country’s rolling stock runs on the same tracks. The measurers were directed to consider the more recent,

brighter band of the two. The decisions on the width of the running band, the number of lines of roughness

required and their lateral position at Wildenrath are summarised in Table 4.
Table 4 — Chosen lateral measurement positions at Wildenrath
Team- Comments
Line position(s) chosen
Width identified (mm)
instrument
(mm from gauge face)
near far near far The coordinator chose a line at
rail rail rail rail 40 mm for the datum
measurements
A 10 10 37 37
B 16, 11 11 34 37 Initial estimate of running band
width was re-evaluated during
measurements
C 11 11 35 35
D 10 10 40 40
F 10 10 37 37
I 12 15, 12 37 38 Measured three lines on far rail
but decided only one was
needed when re-evaluated the
consistency of the running band
width along the site
---------------------- Page: 13 ----------------------
SIST-TP CEN/TR 15874:2009
CEN/TR 15874:2009 (E)
At Wildenrath all teams eventually decided
...

Questions, Comments and Discussion

Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.