Bsi bs en 14067 4 2013

3.1.1 peak-to-peak pressure change modulus of the difference between the maximum pressure and the minimum pressure for the relevant load case 3.1.2 passage of train head passage of t

BSI Standards Publication

Railway applications — Aerodynamics

Part 4: Requirements and test procedures for aerodynamics on open track

National foreword

This British Standard is the UK implementation of EN 14067-4:2013

It supersedes BS EN 14067-4:2005+A1:2009 and BS EN 14067-2:2002,which are withdrawn

The UK committee draws users’ attention to the distinction between normative and informative elements, as defined in Clause 3 of the CEN/CENELEC Internal Regulations, Part 3

Normative: Requirements conveying criteria to be fulfilled if compliance with the document is to be claimed and from which no deviation is permitted

Informative: Information intended to assist the understanding or use

of the document Informative annexes do not contain requirements, except as optional requirements, and are not mandatory For example, a test method may contain requirements, but there is no need to comply with these requirements to claim compliance with the standard

When rounded values require unit conversion for use in the UK, users are advised to use equivalent values rounded to the nearest whole number The use of absolute values for converted units should

be avoided in these cases For the values used in this standard:

1 km/h has an equivalent value of 0.5 mile/h

20 km/h has an equivalent value of 10 mile/h

160 km/h has an equivalent value of 100 mile/h

200 km/h has an equivalent value of 125 mile/h

250 km/h has an equivalent value of 155 mile/h

300 km/h has an equivalent value of 190 mile/hThe UK participation in its preparation was entrusted by Technical Committee RAE/1, Railway Applications, to Subcommittee RAE/1/-/4, Railway Applications - Aerodynamics

A list of organizations represented on this subcommittee can be obtained on request to its secretary

This publication does not purport to include all the necessary provisions of a contract Users are responsible for its correct application

© The British Standards Institution 2013 Published by BSI Standards Limited 2013

ISBN 978 0 580 75641 2ICS 45.060.01

Compliance with a British Standard cannot confer immunity from legal obligations.

This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 December 2013

Amendments/corrigenda issued since publication

NORME EUROPÉENNE

ICS 45.060.01

English Version

Railway applications - Aerodynamics - Part 4: Requirements and

test procedures for aerodynamics on open track

Applications ferroviaires - Aérodynamique - Partie 4:

Exigences et procédures d'essai pour l'aérodynamique à

l'air libre

Bahnanwendungen - Aerodynamik - Teil 4: Anforderungen und Prüfverfahren für Aerodynamik auf offener Strecke

This European Standard was approved by CEN on 21 September 2013

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

EUROPEAN COMMITTEE FOR STANDARDIZATION

C O M I T É E U R O P É E N D E N O R M A L I S A T I O N

E U R O P Ä I S C H E S K O M I T E E FÜ R N O R M U N G

CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels

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 supersedes EN 14067-4:2005+A1:2009 and EN 14067-2:2003 The results of the EU-funded research project "AeroTRAIN" (Grant Agreement No 233985) have been used

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

EN 14067-2 has been integrated in this document, and EN 14067-4 has been re-structured and extended to support the Technical Specifications for the Interoperability of the Trans-European rail system and requirements on conformity assessment for rolling stock were added

EN 14067, Railway applications — Aerodynamics consists of the following parts:

 Part 1: Symbols and units

 Part 2: Aerodynamics on open track (to be withdrawn)

 Part 3: Aerodynamics in tunnels

 Part 4: Requirements and test procedures for aerodynamics on open track

 Part 5: Requirements and test procedures for aerodynamics in tunnels

 Part 6: Requirements and test procedures for cross wind assessment

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

Contents

Introduction 5

1 Scope 6

2 Normative references 6

3 Terms, definitions and symbols 6

3.1 Terms and definitions 6

3.2 Symbols 7

4 Requirements on locomotives and passenger rolling stock 10

4.1 Limitation of pressure variations beside the track 10

4.1.1 General 10

4.1.2 Requirements 10

4.1.3 Full conformity assessment 11

4.1.4 Simplified conformity assessment 11

4.2 Limitation of slipstream effects beside the track 13

4.2.1 General 13

4.2.2 Requirements 13

4.2.3 Full conformity assessment 14

4.2.4 Simplified conformity assessment 14

4.3 Aerodynamic loads in the track bed 16

5 Requirements on infrastructure 16

5.1 Train-induced pressure loads acting on flat structures parallel to the track 16

5.1.1 General 16

5.1.2 Requirements 16

5.1.3 Conformity assessment 16

5.2 Train-induced air speeds acting on infrastructure components beside the track 16

5.3 Train-induced aerodynamic loads in the track bed 16

5.4 Train-induced air speed acting on people beside the track 16

6 Methods and test procedures 17

6.1 Assessment of train-induced pressure variations beside the track 17

6.1.1 General 17

6.1.2 Pressure variations in the undisturbed pressure field (reference case) 20

6.1.3 Pressure variations on surfaces parallel to the track 29

6.1.4 Effect of wind on loads caused by the train 35

6.2 Assessment of train-induced air flow beside the track 36

6.2.1 General 36

6.2.2 Slipstream effects on persons beside the track (reference case) 36

6.2.3 Slipstream effects on objects beside the track 39

6.4.2 Full-scale tests 40

Annex A (informative) Procedure for full-scale tests regarding train-induced air flow in the track bed 43

A.1 General 43

A.2 Track configuration 43

A.3 Vehicle configuration and test conditions 43

A.4 Instrumentation and data acquisition 44

A.5 Data processing 44

Bibliography 45

Introduction

Trains running on open track generate aerodynamic loads on objects and persons they pass If trains are being passed by other trains, trains are also subject to aerodynamic loading themselves The aerodynamic loading caused by a train passing an object or a person near the track, or when two trains pass each other, is

an important interface parameter between the subsystems of rolling stock, infrastructure and operation and, thus, is subject to regulation when specifying the trans-European railway system

Trains running on open track have to overcome a resistance to motion which has a strong effect on the required engine power, achievable speed, travel time and energy consumption Thus, resistance to motion is often subject to contractual agreements and requires standardized test and assessment methods

1 Scope

This European Standard deals with requirements, test procedures and conformity assessment for aerodynamics on open track Addressed within this standard are the topics of aerodynamic loadings and resistance to motion, while the topic of cross wind assessment is addressed by EN 14067-6

This European Standard refers to rolling stock and infrastructure issues This standard does not apply to freight wagons It applies to railway operation on gauges GA, GB and GC according to EN 15273 The methodological approach of the presented test procedures may be adapted to different gauges

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 1991-2, Eurocode 1: Actions on structures — Part 2: Traffic loads on bridges

EN 15273 (all parts), Railway applications — Gauges

EN 15663, Railway applications — Definition of vehicle reference masses

ISO 8756, Air quality — Handling of temperature, pressure and humidity data

3 Terms, definitions and symbols

3.1 Terms and definitions

For the purposes of this document, the following terms and definitions apply

3.1.1

peak-to-peak pressure change

modulus of the difference between the maximum pressure and the minimum pressure for the relevant load case

3.1.2

passage of train head

passage of the front end of the leading vehicle which is responsible for the generation of the characteristic pressure rise and drop, over and beside, the train and on the track bed

streamline shaped vehicle

vehicle with a closed and smooth front which does not cause flow separations in the mean flow field greater than 5 cm from the side of the vehicle

3.1.5

bluff shaped vehicle

vehicle that is not streamlined

3.2 Symbols

For the purposes of this document, the following symbols apply

Table 1 — Symbols

distance from track centre Y

height above top of rail h

distance from track centre Y

C2 vtr N momentum drag due to air flow for traction

and auxiliary equipment and the air conditioning systems

C3 vtr N aerodynamic drag in the resistance to

motion formula

force during the passage

the full cross section of the leading vehicle is achieved

according to EN 15663

Table 1 (2 of 4)

p 1k Pa characteristic value of distributed load

p 2k Pa characteristic value of distributed load

p 3k Pa characteristic value of distributed load

3,00 m at full scale

ui m/s resultant horizontal air speed of the i-th

um,i m/s measured resultant horizontal air speed of

the i-th passage

Ui m/s maximum resultant horizontal air speed of

the i-th passage after averaging and correction to the characteristic train speed

U2σ m/s upper bound of a 2 σ interval of maximum

air speed

U95% m/s maximum resultant horizontal air speed characteristic air speed

U95%,max m/s permissible maximum resultant horizontal

air speed permissible characteristic air speed

vtr,c m/s full scale train speed

vtr,i m/s train speed during the i-th passage

vtr,max m/s maximum train speed

vtr,ref m/s reference speed

vtr,test m/s nominal test speed

Table 1 (3 of 4)

vw,x,i m/s wind speed component in x-direction

during the i-th passage

Ymin m minimum lateral distance from track centre

Ymax m maximum lateral distance from track centre

γ m/s2 train acceleration measured during the

coasting test

∆C p,2σ − pressure change coefficient Upper bound of a 2 σ interval of

the peak-to-peak pressure change coefficient The peak-to-peak pressure change coefficient is defined in Formula 2

p

change determined over all measurements ∆pi or by CFD

∆p2σ Pa upper bound of a 2 σ interval of the

peak-to-peak pressure change

∆p95% Pa maximum peak-to-peak pressure change characteristic pressure change

∆p95%,max Pa permissible maximum peak-to-peak

pressure change permissible characteristic pressure change

∆pi Pa maximum peak-to-peak pressure value of

the i-th passage

∆pm,i Pa maximum peak-to-peak pressure value

measured during the i-th passage

∆psim the head pressure variation from unsteady

between pressure peaks

∑Ri N sum of all the resistances to motion

ρi kg/m3 air density determined during the i-th

passage

Table1 (4 of 4)

σsim Pa standard deviation of simulated pressure

a) Side view

Figure 1 – Coordinate system

4 Requirements on locomotives and passenger rolling stock

4.1 Limitation of pressure variations beside the track

∆p95%, refers to the maximum pressure change which occurs during the passage of the train head

4.1.2.2 Fixed or pre-defined train compositions

A fixed or pre-defined train composition, running at the reference speed in the reference case scenario shall not cause the maximum peak-to-peak pressure changes to exceed a value ∆p95%,max as set out in Table 2

over the range of heights 1,50 m to 3,00 m above the top of rail during the passage of the train head For identical end cars the requirement applies for each possible running direction

non-Table 2 — Maximum permissible peak-to-peak pressure change ∆p95%,maxdepending on maximum

design speed Maximum design speed Permissible pressure change ∆p95%,max at

4.1.2.3 Single rolling stock units fitted with a driver’s cab

Single rolling stock units fitted with a driver’s cab running as the leading vehicle at the reference speed in the reference case scenario shall not cause the maximum peak-to-peak pressure changes to exceed a value

∆p95%,max as set out in Table 2 The range of heights to be considered are 1,50 m to 3,00 m above the top of rail during the passage of the front end of this unit For single rolling stock units capable of bidirectional operation as a leading vehicle the requirement applies for each possible running direction

4.1.2.4 Other passenger rolling stock

For passenger rolling stock which is not covered in 4.1.2.2 or 4.1.2.3 there is no requirement

4.1.3 Full conformity assessment

A full conformity assessment of interoperable rolling stock shall be undertaken according to Table 3

Table 3 — Methods applicable for the full conformity assessment of rolling stock

Maximum design speed Methods

vtr ≤ 160 km/h No assessment needed

160 km/h < vtr Assessment by:

 full-scale tests according to 6.1.2.1; or

 reduced-scale moving model tests according to 6.1.2.2; or

 CFD simulations according to 6.1.2.4

4.1.4 Simplified conformity assessment

A simplified conformity assessment may be carried out for rolling stock that are subject to minor design differences in comparison to rolling stock for which a full conformity assessment already exists

With respect to pressure variations beside the track, the only relevant design differences are differences in external geometry and differences in design speed

This simplified conformity assessment shall take one of the following forms in accordance with Table 4:

 a statement and rationale that the design differences have no impact on the pressure variations beside the track;

 a comparative evaluation of the design differences relevant to the rolling stock for which a full conformity assessment already exists

Table 4 — Methods and requirements applicable for simplified conformity assessment of rolling stock Design differences Methods and requirements

Differences in external geometry limited to

 locations either downstream of the distance of

the maximum cross-section from the train

nose or downstream of the distance of the

minimum pressure peak relative to the train

nose,

 the inner region of the underpart of the train

(under the train and between rails),

 minor differences in external geometry,

 wipers and handles,

 antennae with a volume smaller than 5 l,

 long isolated protruding objects or gaps not

being vertical or close to the front-side radius

or edge smaller than 50 mm in the crosswise

dimensions,

 small isolated protruding objects and gaps

smaller than 50 mm in each dimension

Documentation of differences, statement of no impact and reference to an existing compliant full conformity assessment

Other differences in external geometry (e.g in

buffers, front couplers, snow ploughs, front or side

windows) keeping the basic head shape features

Documentation of differences and reference to an existing compliant full conformity assessment AND

assessment of the relative effect of differences by

 reduced-scale moving model tests according to 6.1.2.2

(

) ( ) ( − <

A p

A p B p

∆

∆

∆

NOTE B refers to the new train geometry A refers to the

existing compliant train

and (ii) the difference does not exceed 50 % of the margin available on the compliance with 4.1.2

)) ( (

5 , 0 )) ( ) ( ( ∆ p B − ∆ p A < ⋅ ∆ p

− ∆ p

A

Increase of design speed

 less than 10 % for a train with original design

4.2 Limitation of slipstream effects beside the track

4.2.1 General

A train generates a varying flow field beside the track which has an effect on persons and objects at the track side and at platforms In order to define a clear interface between the subsystems of the rolling stock and the infrastructure, the train-induced slipstream effects need to be known and limited

In order to describe and to limit the train-induced slipstream effects, a reference case for rolling stock assessment is defined

NOTE Ensuring track workers' and passengers' safety at the platform involves additional issues on the operational and infrastructure side

4.2.2 Requirements

4.2.2.1 Reference case

For standard GA, GB, GC gauges according to EN 15273, in the absence of embankments, cuttings and any significant trackside structures, the undisturbed flowfield generated by a passing train at a position of 3,00 m from the centre of a straight track with standard track formation profile is referred to as the reference case The air flows occurring are characterized by the upper bound of the 95 % confidence interval of maximum

resultant horizontal air speeds This maximum horizontal air speed U95% refers to the whole passage of the train and its wake

4.2.2.2 Fixed or pre-defined train compositions

A full-length, fixed or pre-defined train composition, running at reference speed in the reference case scenario

shall not cause the maximum resultant horizontal air speed to exceed a value U95%,max as set out in Table 5

at a height of 0,20 m above the top of rail during the passage of the whole train and its wake For symmetrical train compositions, the requirement applies for each possible running direction For fixed or pre-defined train compositions consisting of more than one train unit, it is sufficient to assess a train composition consisting at least of two units and of a minimum length of 120 m

non-Table 5 — Maximum resultant permissible horizontal air speed U95%,max depending on maximum

design speed Maximum design speed

vtr,max Height above

the track horizontal air speed Permissible

U95%,maxat reference speed

Reference speed vtr,ref

4.2.2.3 Single rolling stock units fitted with a driver’s cab

A single unit fitted with a driver's cab running at reference speed in the reference case scenario shall not

cause the maximum resultant horizontal air speed to exceed a value U95%,max as set out in Table 5 at heights

of 0,20 m and 1,40 m above the top of rail during the passage of the whole train and its wake

Conformity shall be assessed for units at the front and rear of a rake of passenger carriages of at least 100 m

in length Assessments shall be carried out with either one unit, or with two identical units, one at the front and one at the rear of the train The carriages should be comprised of those likely to be used in operational conditions

The requirement applies for each possible running direction

4.2.2.4 Other passenger rolling stock

Carriages that are operated within trains of different formations are compliant, if similar to existing or proven compliant single rolling stock with respect to:

 design speed (lower or equal to existing); and

 bogie external arrangement (position, cavity and bogie envelope); and

 train envelope (i.e body width, height) changes above the bogies of less than 10 cm

The similarity and compliance for this approach shall be documented!

If this criterion does not apply, the coach running at reference speed in the reference case scenario shall not

cause the maximum resultant horizontal air speed to exceed a value U95%,max as set out in Table 5 at heights

of 0,20 m and 1,40 m above the top of rail during the passage of the whole train and its wake It should be tested in two configurations with the rolling stock likely to be used in operation; positioned directly behind an existing or proven compliant locomotive with a rake of carriages of at least 100 m in length behind it, and at the rear of a rake of carriages at least 100 m in length behind a compliant locomotive If the coach has a dedicated purpose, e.g restaurant car, which will dictate its position to be always mid-train, it should be tested only in the middle of a rake of carriages at least 100 m long

4.2.3 Full conformity assessment

A full conformity assessment of rolling stock shall be undertaken according to Table 6

Table 6 — Methods applicable for full conformity assessment of rolling stock

Maximum design speed Methods

vtr ≤ 160 km/h no assessment needed

160 km/h < vtr assessment by full-scale tests according to 6.2.2.1 or documentation of

compliance according to 4.2.2.4

4.2.4 Simplified conformity assessment

A simplified conformity assessment may be carried out for rolling stock which are subject to minor design differences in comparison to rolling stock for which a full conformity assessment already exists

For a train composition that has been fully assessed for one direction of running, a simplified conformity assessment may be used for the other direction of running based on the full assessment

With respect to resultant horizontal air speeds beside the track, the only relevant design differences are differences in external geometry and differences in design speed

This simplified conformity assessment shall take one of the following forms in accordance with Table 7:

 a statement and rationale that the design differences have no impact on the resultant horizontal air speeds beside the track;

 a comparative evaluation of the design differences relevant to the rolling stock for which a full conformity assessment already exists

Table 7 — Methods and requirements applicable for simplified conformity assessment of rolling stock

Design differences Method / Requirement

Differences in external geometry limited to

 the inner region of the underpart of the train

(under the train and between rails),

 roof equipment, namely pantographs,

anten-nae, electrical wiring and pipes,

 other roof equipment changes smaller than

20 cm in each physical dimension,

 fittings, seals, bonded joints, handles and

handle bars, wipers, rear view installations,

surface roughness, doors, windows, glazing,

signal lights, pipes, cabling and plugs,

 other parts with changes in lateral dimensions

smaller than 5 cm

Documentation of differences, statement of no impact and reference to an existing compliant full conformity assessment

Other differences in external geometry keeping

the basic head shape features Documentation of differences and reference to an existing compliant full conformity assessment AND

assessment of relative effect of differences by

 moving model rig test, see 6.2.2.2, AND evidence and documentation that

i) the difference does not cause changes in

U95% bigger than ± 10 % and ii) the new design under investigation still fulfils (on the basis of the original value from a compliant full conformity assessment and found relative difference) the requirements listed in 4.2.2

Decrease in design speed Documentation of differences and reference to an

existing compliant full conformity assessment Increase of design speed

 less than the smaller of 20 km/h or 10 % for a

train with original design speed < 300 km/h,

 for a train with original design speed ≥ 300

km/h

Documentation of differences and reference to an existing compliant full conformity assessment AND evidence and documentation based on linear

extrapolation of slipstream velocity U95% at new design speed that the new design under investigation still fulfils the requirements listed in 4.2.2

4.3 Aerodynamic loads in the track bed

This point is not covered by this standard

NOTE 1 National regulations may exist to cover this point

NOTE 2 EN 50125-3:2003 addresses the environmental conditions for signalling and telecommunication equipment NOTE 3 A test method for the measurement of aerodynamic loads in the track bed in connection with the assessment

of ballast projection is described in Annex A (informative)

train-5.1.2 Requirements

The design of flat structures parallel to the track with GA, GB, GC gauge according to EN 15273 shall account for train-induced pressure loads as indicated in EN 1991-2 Dynamic effects need to be accounted for To include the effect of ambient wind on the train-induced pressure loads, the wind speed component parallel to the track should be added to the train speed

NOTE The predictive formulae stated in 6.1.3.5 of this standard are equivalent to the pressure loads graphically given in EN 1991-2, but allow a wider range of application

5.1.3 Conformity assessment

A standard on fatigue due to dynamic loads on noise barriers from passing trains is in preparation inside CEN TC256 and will be considered for conformity assessment for noise barriers and similar structures (wind barriers, environmental screens) in a future revision of this document

5.2 Train-induced air speeds acting on infrastructure components beside the track

This point is not covered by this standard

NOTE National regulations may exist to cover this point

5.3 Train-induced aerodynamic loads in the track bed

This point is not covered by this standard

NOTE 1 National regulations may exist to cover this point

NOTE 2 EN 50125-3:2003 addresses the environmental conditions for signalling and telecommunication equipment

5.4 Train-induced air speed acting on people beside the track

This point is not covered by this standard

NOTE 1 National regulations may exist to cover this point

NOTE 2 Safety of passengers at platforms and workers near the track is a system issue and measures are required to control this, e.g safe-standing clearances

6 Methods and test procedures

6.1 Assessment of train-induced pressure variations beside the track

6.1.1 General

A moving train causes pressure variations beside the track, which act on nearby objects Examples for such pressure variations on a nearby vertical wall induced by the passage of a single and a double unit train are shown in Figure 2 The pressure change at a stationary point at the trackside in the absence of any object or obstacle shows qualitatively similar behaviour

a) Single unit train

b) Double unit train Key

Figure 2 — Examples of instantaneous pressure distributions on a vertical wall caused by the passing

of a single and a double unit train

The pressure field sweeps along with the train, and therefore at a stationary point at the side of the track, the

pressure p will change with time as the train passes by in a similar way to the variation with position along the

length of the train

The most severe variation of pressure is usually caused by the passage of the train head and is of the form shown in Figure 3

Other positions where significant pressure changes may occur are at the train tail and at couplings as shown

in Figure 2 However, the pressure change at the train head is considered as characteristic of all three mentioned positions (front, couplings and tail)

Figure 3 — Pressure variation linked to head passage of train

As the train passes, the static pressure rises to a positive peak and drops rapidly to a negative peak The most important parameter is the peak-to-peak pressure ∆p It is related to the nose shape and is generally

smaller for a longer streamlined shape than for a bluff sharp-edged shape The time between the pressure peaks ∆t can be related to the time for the length Ln of the train nose to pass

A smaller peak-to-peak pressure occurs as the rear of the train passes, but the order of the pressure change

is reversed, such that the negative peak precedes the positive peak Additional smaller peak-to-peak pressure occurs as the couplings of the traction train pass

The peak-to-peak pressure is approximately proportional to the square of the speed of the train

A non-dimensional pressure change coefficient ∆C p is defined by:

2 tr

min max

2

v

p p

fundamental aerodynamic property of a particular train

An example is given in Figure 4

Key

1 longer streamlined nose shape

2 bluff sharp-edged nose shape

Figure 4 — Typical variation of pressure change coefficient ∆C p with lateral distance Y

Train-induced pressure variations beside the track are of special interest when they act on (i) structures parallel to the track, such as noise barriers or wind barriers, and (ii) on passing trains

To define a clear interface between the subsystems of rolling stock and infrastructure the characteristic pressure variations beside the track are referred to the undisturbed pressure field around the train (i.e in the absence of other objects) This also allows the train-induced pressure loads to be limited on the basis of corresponding rolling stock requirements

Subclause 6.1.2 presents the methods for the assessment of train-induced pressure variation in the undisturbed pressure field, while subclause 6.1.3 refers to train-induced pressure loads on structures parallel

Atypical measurement positions, which provide sheltering against the train-induced pressure field, shall be excluded Tests shall be carried out on a straight line on open track The layout of the chosen test site shall be recorded It shall include the description of location; topography; track cant; track profile; track interval, track formation profile and slopes

For assessment, the rolling stock configuration shall comply with 4.1.2 Correct identification and recording of the passing train type, its speed, length and composition are mandatory (e.g by video or by recording the passage of axles)

The meteorological conditions (air temperature, air pressure, air humidity, wind speed, wind direction) shall be measured and the state of weather recorded Acquisition of temperature, pressure and humidity data shall comply with ISO 8756 For any rake of pressure sensors the wind speed and direction are determined by a meteorological station It shall be installed at 2 m above top of rail, about 4 m from the track centre and as close as possible to the rake of pressure sensors, at a maximum distance of 30 m to any rake

The reference wind speed is equivalent to the mean wind speed in the 15 s interval before the train nose passes the wind sensor If the distance between a rake of pressure sensors and its associated meteorological station is less than 3 m, a short time wind averaging (1 s interval starting 1,2 s before the train nose passes the wind sensor) should be used to improve the correlation to the actual wind during head passage

The tests shall consist of at least 10 independent and comparable test samples measured with reference wind speeds not exceeding 2 m/s If available, at least 10 of those runs having the lowest wind fluctuations (i.e the lowest standard deviation in wind speed) should be considered The considered event of passage is at least the time period 1 s before the head passing until 1 s after the train passing For a valid set of measurements,

at least 50 % of the measurements shall be taken within ± 5 %, and 100 % of the measurements within

± 10 % of the nominal test speed vtr,test

The nominal test speed vtr,test is equal to the reference speed vtr,ref

Positions for pressure measurement shall be at a distance of 2,50 m from the centre of track and at heights of 1,50 m; 1,80 m; 2,10 m; 2,40 m; 2,70 m; and 3,00 m; above the top of rail The uncertainty of sensor positioning shall be less than 0,02 m The actual position of the sensors shall be recorded A number of pressure rakes are permitted to be used to obtain several independent measurements from one train passage Such rakes shall be separated from each other by a distance of at least 20 m

The pressure sensors used shall be capable of measuring the pressure with a minimum of 150 Hz resolution

It is recommended to use sensors with a measurement range of at least 1 500 Pa

All pressure sensors should be connected to the static pressure opening of Prandtl tubes directed in the negative x-direction, i.e towards the train A constant reference pressure (e.g as stored in an insulated pressure tank) is used In order to prevent a loss in (dynamic) information, the tubes and pipes between pressure hole and pressure sensor shall not exceed 50 cm To prevent phase shift, all tubes shall be of equal length

If Prandtl tubes are not used, then the alternative measurement method shall be shown to be equivalent The uncertainty of the pressure measurement shall be determined and may not exceed ± 2 % The uncertainty of train speed measurement shall be determined and may not exceed ± 1 %

The pressure signal shall be filtered with a 75 Hz 6 pole Butterworth low pass filter (or another filter with equivalent filter characteristics) and sampled at a minimum of 300 Hz For each pressure sensor and run, the maximum peak-to-peak pressure value generated during the passage of the train head, ∆p,i, shall be computed and then corrected to the reference speed and to standard air density ρ0 = 1,225 kg/m3 using Formula (3):

i 0 2 i x, w, i tr,

tr i

v p

where

vw,x,i is the wind speed component in the x-direction

If a correlation to cross wind is obvious, i.e the coefficient of determination being larger than 0,5, the individual run results shall be corrected to zero cross wind speed using a linear regression of the ∆pi as a function of the mean cross wind speeds A diagram showing the dependency on the cross wind and the regression line shall be reported

The characteristic pressure difference used for further analysis is the upper bound of a 2σ interval of

∆

∆

∆ p

= p

= p + 2 ⋅

p

∆ is the mean value over all ∆pi;

σ is the standard deviation over all ∆pi

In addition to the characteristic peak-to-peak pressure difference ∆p95%during the passage of the train head, the pressure differences for the coupling passage and the tail passage should be assessed in the same manner Further, in addition to all the characteristic peak-to-peak values, a separate analysis of the major positive and negative pressure variations should be done in a similar manner

6.1.2.2 Reduced-scale moving model tests

The test set up shall be chosen according to the reference case specification in 4.1.2 The ground configuration should be in accordance with Figure 5

NOTE 1 Unless otherwise stated, all dimensions are given as full-scale values

Dimensions in millimetres

Key

1 top of rail

Figure 5 — Sketch of the track and its environment

For the determination of train head passing pressure pulse effects, it is sufficient to model the leading vehicle

of the train Models of the test train shall be constructed which accurately represent the train head The vehicle surface shall be modelled with a tolerance of ± 10 mm full-scale maximum deviation from the original shape of the car body The smoothness of the exterior surfaces shall be hydraulically comparable, i.e showing relevant details, and the original vehicle design data (or real train geometry, if available) shall be provided

Aerodynamically significant features on the train side and roof shall be modelled; it is not necessary to represent small protruding objects such as antennae, handles, etc (diameters, gaps, obstacles smaller than

50 mm) It is less important to model the under-body of the train with precision; however, the general shape of the under-body, particularly in the regions of the snowplough and the bogies, shall be represented

The geometry of the bogies may be simplified, with features smaller than 100 mm being ignored However, their relative blockage effect shall be represented correctly The pantographs may be ignored

The Reynolds number, based on train speed, shall be larger than 250 000 to ensure that the non-dimensional

∆C p,2σ values are representative of full scale The non-dimensional ∆C p,2σ values shall be demonstrated

Reynolds number independent in the range 0,6 Remax to Remax within ± 3 % The Reynolds number

requirement implicitly specifies the model scale The chosen scale shall be applied to the whole model configuration

Mach number effects may be neglected provided the full-scale Mach number vtr / c is lower than 0,25 When

the train Mach number exceeds 0,25, the model train test speeds shall match actual train operational speeds The test rig parameters and ambient air conditions, i.e temperature, pressure and humidity, shall be recorded

at the time of the tests

The tests shall consist of at least 10 independent and comparable test samples For a valid set of measurements, at least 50 % of the measurements shall be taken within ± 5 %, and 100 % of the

measurements within ± 10 % of the reference speed vtr The considered event of train passing shall be at least the time period starting 1 / (model scale) seconds before head passing and ending 1 / (model scale) seconds after train passing

Data shall be sampled at a rate of at least 10 vtr / (Ln ⋅ (model scale)) Hz (e.g 2 500 Hz for a 1:25 scale model

train travelling at 50 m/s and with Ln = 5 m), and then filtered at 1/4 of the sampling rate by means of a 1st

order Butterworth filter or equivalent

The pressure sensors used shall be capable of measuring the pressure with a minimum resolution of the data sampling rate The sensors shall be calibrated prior to use over the expected pressure range The measurement error shall be less than 2 % of the expected range The uncertainty of the train speed measurement shall be determined and shall not exceed ± 1 %

For each pressure sensor and moving model run, the maximum peak-to-peak pressure value generated during the passage of the train head, ∆pm,i, shall be computed and then corrected to the train speed of interest and to standard air density ρ0 = 1,225 kg/m3, using Formula (5):

ref tr, i m,

p

∆ is the mean value over all measurements ∆pi;

σ is the standard deviation over all measurements ∆pi

Measuring positions shall be at a distance of 2,50 m from the centre of track and at heights of 1,50 m; 1,80 m; 2,10 m; 2,40 m; 2,70 m; and 3,00 m; above the top of rail The uncertainty of sensor positioning shall be less than 0,02 m The actual position of the sensors shall be recorded (All heights and distances based on full scale.)

If the complete passing pressure is of interest, in addition to the characteristic peak-to-peak pressure difference ∆p95%during the passage of the train head, the pressure differences for the coupling passage and the tail passage should be assessed in the same manner In this case the modelling requirements stated above apply to the whole model train, especially the tail Further, in addition to all the characteristic peak-to-