Bsi bs en 50617 2 2015

7 Introduction The working group CENELEC/SC9XA WGA4-2 has developed the limits for electromagnetic compatibility between rolling stock and train detection systems, specifically track ci

BSI Standards Publication

Railway Applications — Technical parameters of train detection systems for the

interoperability of the trans-European railway system

Part 2: Axle counters

This British Standard is the UK implementation of EN 50617-2:2015 The UK participation in its preparation was entrusted to TechnicalCommittee GEL/9/1, Railway Electrotechnical Applications -Signalling and communications.

A list of organizations represented on this committee 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 2015

Published by BSI Standards Limited 2015ISBN 978 0 580 76387 8

Amendments/corrigenda issued since publication

Date Text affected

EUROPÄISCHE NORM

English Version

Railway Applications - Technical parameters of train detection

systems for the interoperability of the trans-European railway

system - Part 2: Axle counters

Applications ferroviaires - Paramètres techniques des

systèmes de détection des trains - Partie 2: Compteurs

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 CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom

European Committee for Electrotechnical Standardization Comité Européen de Normalisation ElectrotechniqueEuropäisches Komitee für Elektrotechnische Normung

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

© 2015 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members

Ref No EN 50617-2:2015 E

Contents

Foreword 6

Introduction 7

1 Scope 8

2 Normative references 8

3 Terms, definitions and abbreviations 9

3.1 Terms and definitions 9

3.2 Abbreviations 11

4 Description of train detection system 12

5 Safety relevance per parameter 13

6 Axle counter system parameters 15

6.1 RAMS 15

6.1.1 Reliability 15

6.1.2 Availability 15

6.1.3 Rate of miscounts 15

6.1.4 Maintainability 16

6.1.5 Safety 16

6.2 Immunity against Magnetic fields – in-band and out-of-band 18

6.2.1 General 18

6.2.2 Derivation of Immunity requirements 18

6.2.3 Immunity levels for axle counters / Compatibility margins 19

6.2.4 Frequency range of an ACD 19

6.3 Immunity to traction and short circuit current in the rail 19

6.4 Immunity to harmonics of traction current in the rail 20

6.5 Sensor position integrity control (functional parameter) 20

6.6 Integration time 20

6.6.1 General 20

6.6.2 Product specific integration time 21

6.6.3 Derivation of the integration time – Example 21

6.7 Signalling power supply quality with respect to availability 22

6.8 Requirements on the connection cables 23

7 Requirements for axle counter systems based on train parameters 23

7.1 General 23

7.2 Vehicle, wheel and speed dependent parameters 23

7.2.1 General 23

7.2.2 Wheel parameters 24

7.2.3 Vehicle and speed depending parameters 25

7.3 Material properties of vehicle parts in the detection area (metal free space) 26

7.4 Sinusoidal sway of train 26

7.5 Magnetic track brakes and eddy current brakes 27

8 Track based parameters 27

8.1 Material of sleepers 27

8.2 Rail fittings/mounting area 28

8.3 Slab track 28

9 Environmental and other parameters 29

9.1 General 29

9.2 Pressure 29

3

9.3 Movement of surrounding air 29

9.4 Ambient temperatures 29

9.4.1 General 29

9.4.2 Ambient temperature for axle counter evaluator equipment 30

9.4.3 Ambient temperature for ACD (without axle counter sensor) 30

9.4.4 Ambient temperature for axle counter sensor 30

9.5 Humidity 30

9.6 Precipitation 31

9.7 Sealing of housing 31

9.8 Solar radiation 31

9.9 Overvoltage protection (incl indirect lightning effects) 32

9.10 Contamination 32

9.10.1 General 32

9.10.2 In the track, nearby the track 32

9.10.3 Indoor 32

9.11 Fire Protection 32

9.12 Vibrations / shock 33

9.13 EMC 33

9.13.1 General 33

9.13.2 Requirement and validation for EMC 33

9.14 Definition of Influence from other components 33

Annex A (informative) Design guide for measurement antennas 34

A.1 Measurement antennas characteristics 34

A.2 Termination impedance 34

Annex B (normative) Frequency Management (reproduced from CCS TSI, Index 77) 36

Annex C (normative) Test Equipment, test methodologies and reports to be performed 38

C.1 Test equipment 38

C.1.1 Antenna for generating magnetic fields (FGA) 38

C.1.2 Reference antenna 39

C.1.3 Test signal generator 39

C.2 Test conditions 39

C.2.1 Equipment under test (EUT) 39

C.2.2 Susceptibility criteria 39

C.3 Accuracy of magnetic field measurement 40

C.4 Test methodology to determine immunity (susceptibility border of ACD) to homogenous fields – in-band 40

C.4.1 General 40

C.4.2 Test set up for X-Z direction 41

C.4.3 Test set up for Y-Z direction 41

C.4.4 Test procedure to determine immunity to homogenous steady state fields 42

C.4.5 Transient immunity test / Immunity to intermittent interference 43

C.4.6 Immunity within the filter bandwidth of the EUT 46

C.5 Test methodology to determine immunity to inhomogeneous fields – in band 46

C.5.1 General 46

C.5.2 Test set-up for the movement in X-direction 47

C.5.3 Test set-up for the movement in Y-direction 48

C.5.4 Test procedure 49

C.6 Test methodology for establishing immunity to fields produced by in-band interference currents in the rail 50

C.6.1 General 50

C.6.2 Test set-up 51

C.6.3 Test procedure 52

C.7 Test methodology for out of-band measurements 52

C.8 Immunity to ETCS telepowering fields 52

C.8.1 General 52

C.8.2 Limits and requirements 53

C.8.3 Test methodology to check immunity to ETCS telepowering fields 53

C.9 Test report 57

C.10 Test results according to CCS TSI Index 77 58

C.10.1 General 58

C.10.2 In-band 58

C.10.3 Out-band (10 kHz to 1,3 MHz) 58

Annex ZZ (informative) Relationship between this European Standard and the Essential Requirements of EU Directive 2008/57/EC 59

Bibliography 63

5

Figures

Figure 1 – System boundary of an axle counter system 12

Figure 2 – Correlation between hazard rate and time between trains 17

Figure 3 – Areas for evaluation 19

Figure 4 – Immunity versus duration of interference field 21

Figure 5 – ACD immunity as a function of time duration of in-band disturbance 22

Figure 6 – Filter curves measured and calculated 22

Figure 7 – Definition of the parameters 24

Figure 8 – Axle to axle distance 26

Figure 9 – Definition of sinusoidal sway 27

Figure A.1 – Side view (Y and Z coils, dimensions 50 mm to 150 mm) 34

Figure B.1 – Areas for evaluation 37

Figure C.1 – Homogenity of field generation antenna (FGA) 39

Figure C.2 – ACD, schematic diagram 40

Figure C.3 – Test set-up for homogeneous fields in X-Z-direction (front view for α = 0°) 41

Figure C.4 – Test set-up for homogeneous fields in X-Z-direction (side view for α = 0°) 41

Figure C.5 – Test set-up for homogeneous fields in Y-Z-direction (front view) 42

Figure C.6 – Test set-up for homogeneous fields in Y-Z-direction (side view for α = 0°) 42

Figure C.7 – ACD response to intermittent sinusoidal waves 44

Figure C.8 – Test set-up for inhomogeneous field tests in X-direction (side view) 47

Figure C.9 – Test set-up for inhomogeneous field tests in X-direction (front view) 48

Figure C.10 – Test set-up for inhomogeneous field tests in Y-direction (side view) 48

Figure C.11 – Test set-up for inhomogeneous field tests in Y-direction (front view) 49

Figure C.12 – FGA movement / field distribution for inhomogeneous field tests 50

Figure C.13 – Test set-up for rail current tests 51

Figure C.14 – Frequency mask 53

Figure C.15 – Influence zones of magnetic fields 54

Figure C.16 – Test setup 55

Figure C.17 – Test set-up for conducted immunity testing 56

Tables Table 1 – Overview of safety relevance in the subclauses 14

Table B.1 – Emission limits and evaluation parameters (narrow band) 36

Table B.2 – Increased magnetic field limits 37

Foreword

This document (EN 50617-2:2015) has been prepared by CLC/SC 9XA "Communication, signalling and processing systems" of CLC/TC 9X "Electrical and electronic applications for railways"

The following dates are fixed:

• latest date by which this document has to be

implemented at national level by publication of

an identical national standard or by

endorsement

(dop) 2016-03-09

• latest date by which the national standards

conflicting with this document have to

be withdrawn

(dow) 2018-03-09

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights CENELEC [and/or CEN] shall not be held responsible for identifying any or all such patent rights This document has been prepared under a mandate given to CENELEC by the European Commission and the European Free Trade Association, and supports essential requirements of EU Directive(s)

For relationship with EU Directive 2008/57/EC amended by Commission Directive 2011/18/EU, see informative Annex ZZ, which is an integral part of this document

This document is Part 2 of the EN 50617 series, which consists of the following parts under the common title

"Railway Applications - Technical parameters of train detection systems”:

- Part 1: Track circuits;

- Part 2: Axle counters

7

Introduction

The working group CENELEC/SC9XA WGA4-2 has developed the limits for electromagnetic compatibility between rolling stock and train detection systems, specifically track circuits and axle counter systems, and correspondingly published two technical specifications: CLC/TS 50238-2 and CLC/TS 50238-3 These limits and associated measurement methods are based on characteristics of existing systems that are well established and still put forward for signalling renewals by infrastructure managers

To meet the requirements for compatibility between train detection systems and rolling stock in the future and

to achieve interoperability and free movement within the European Union, it is necessary to define a “FrM” and

a complete set of interface requirements

Track circuits and axle counter systems, are an integral part of the CCS trackside subsystem in the context of the Rail Interoperability Directive The relevant basic parameters are enumerated in the CCS and LOC&PAS TSI and specified in the mandatory Specification CCS TSI Index 77 “Interfaces between Control-Command and Signalling Trackside and other Subsystems” This standard refers whenever needed to the mandatory specification

The already published specifications CLC/TS 50238-2 and CLC/TS 50238-3 can be used to ascertain conformity of individual train detection systems to the requirements of the TSIs and to the Notified National Rules, which will be in place for the parameters still declared “open points” in CCS TSI Index 77

The requirements defined in this standard are either compliant with those of CCS TSI Index 77 or can be used

as input information for the closure of open points of the CCS TSI Index 77 Where applicable, the standard should refer to the rolling stock FrM in the TSI CCS and the parameter values defined in the CCS TSI Index

77

1 Scope

This European Standard specifies parameters for the design and usage of axle counter systems

For this, the standard specifies the technical parameters of axle counter systems associated with the magnetic field limits for RST in the context of interoperability In addition test methods are defined for establishing the conformity and the performance of axle counter products

The specified parameters are structured and allocated according to their basic references as follows:

- Axle counter system parameters

- Train based parameters

- Track based parameters

- Environmental and other parameters

Each parameter is defined by a short general description, the definition of the requirement, the relation to other standards and a procedure to show the fulfilment of the requirement as far as necessary An overview

on the safety relevance of each parameter is given – in the context of this European Standard – in a separate table

This European Standard is intended to be used to assess compliance of axle counter systems and other forms of wheel sensors used for train detection, in the context of the European Directive on the interoperability

of the trans-European railway system and the associated technical specification for interoperability relating to the control-command and signalling track-side subsystems

The frequency bands and rolling stock emission limits are currently defined in the axle counter FrM as specified in the CCS TSI Index 77

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 50121-4, Railway applications — Electromagnetic compatibility — Part 4: Emission and immunity of the

signalling and telecommunications apparatus

EN 50124-2, Railway applications — Insulation coordination — Part 2: Overvoltages and related protection

EN 50125-3:2003, Railway applications — Environmental conditions for equipment — Part 3: Equipment for

signaling and telecommunications

EN 50126 (all parts), Railway applications — The specification and demonstration of Reliability, Availability,

Maintainability and Safety (RAMS)

EN 50128, Railway applications — Communication, signalling and processing systems — Software for railway

control and protection systems

EN 50129, Railway applications — Communications, signalling and processing systems — Safety related

electronic systems for signalling

EN 50238-1, Compatibility between rolling stock and train detection systems — Part 1: General

EN 60068-2-1, Environmental testing — Part 2-1: Tests — Tests A: Cold (IEC 60068-2-1)

9

EN 60068-2-2, Environmental testing — Part 2-2: Tests — Test B: Dry heat (IEC 60068-2-2)

EN 60068-2-30, Environmental testing — Part 2-30: Tests - Test Db: Damp heat, cyclic (12 h + 12 h cycle) (IEC 60068-2-30)

EN 60529, Degrees of protection provided by enclosures (IP Code) (IEC 60529)

EN 61000 (all parts), Electromagnetic compatibility (EMC) (IEC 61000, all parts)

CCS TSI Index 77, ERTMS/ETCS UNIT — Interfaces between control-command and signalling trackside and other subsystems

UNISIG SUBSET-023, Glossary of UNISIG Terms and Abbreviations

UNISIG SUBSET-036, FFFIS for Eurobalise

UNISIG SUBSET-085, Test Specification for Eurobalise FFFIS

3 Terms, definitions and abbreviations

3.1 Terms and definitions

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

3.1.1

antenna for generating magnetic fields

square loop antenna to generate the magnetic fields for testing of the immunity

3.1.2

axle counter detector (ACD)

detector consisting of the axle counter sensor and of the detection circuit, which includes in general filters and rectifiers

3.1.3

axle counter sensor

sensor head mounted in the track

3.1.4

axle counter system

whole system including the axle counter detector ACD with its sensor, and the evaluation unit

direct safety relevant

failure results in a wrong side failure

3.1.7

equipment under test

test object is the set of ACD connected to a rail

3.1.8

immunity level

maximum level of interfering signal at which the correct operation of the equipment is granted to be in line with expectations

3.1.9

in-band

working frequency area of an ACD

3.1.10

indirect safety relevant

every not autocorrected fault count will lead to a reset of the section, which itself is a safety issue

Note 1 to entry: These faults are indirectly safety relevant

antenna, mounted on the rail to capture magnetic field

Note 1 to entry: The measurement covers the axes X, Y and Z

3.1.14

out-of-band

frequency bands out of the working frequency area of an ACD

3.1.15

right side failure

failure of a signalling system which results in a more restrictive condition for the movement of traffic than is appropriate

working frequency range

frequency area or field where the sensors are operating

3.1.18

wrong side failure

failure of a signalling system which results in a less restrictive condition for the movement of traffic than is appropriate

11

3.2 Abbreviations

For the purposes of this document, the following abbreviations apply

ACD axle counter detector

AM amplitude modulation

CCS control-command and signalling

DC direct current

EMC electromagnetic compatibility

ERTMS European Rail Traffic Management System

ETCS European Train Control System

EUT equipment under test

FFFIS form fit functional interface specification

FGA field generating antenna

FrM frequency management

FSK frequency shift key

HR hazard rate

IR Infrared (electromagnetic radiation)

IP(xx) ingress protection (rating)

LC inductor/capacitor resonant circuit

MA measurement antenna

MIZ metallic influencing zone

MTBF mean time between failure

MTTR mean time to repair

PS power supply

rms root mean square

RSF right side failure

RST rolling stock

TEU trackside electronic unit

THR tolerable hazard rate

TSI technical specification for interoperability

UV Ultraviolet (electromagnetic radiation)

WSF wrong side failure

4 Description of train detection system

Train detection systems for route proving as a fully automatic train detection system are integrated into railway signalling and safety systems The train detection is part of the route proving procedure contributing to a safe and reliable railway operation

The train detection equipment provides information about whether track sections are clear of or occupied by rail vehicles

Axle counting systems operate on the principle of difference calculation The evaluation unit evaluates the signals received from each counting head associated with a section, compares the number of axles which have entered the train detection section with the number of axles which have left this section and generates a

"track clear" or "track occupied" indication

The figure below defines the system boundaries of a train detection system using axle counter systems:

Figure 1 – System boundary of an axle counter system

13

5 Safety relevance per parameter

There are two degrees of safety relevance which may be assigned to the technical parameters of axle counter systems:

NOTE The issue safety relevance is defined in general in EN 50126 and EN 50129 (see also 6.1.5) The information below is given only with respect to the parameters defined in this document

- Direct safety relevant parameters:

Failure to meet the direct safety relevant requirement can result directly in a wrong side failure

- Indirect safety relevant parameters:

Failure to meet the indirect safety relevant requirement may cause a right side failure, but may result

in the occurrence of a second failure or human error which could subsequently lead to an accident Indirect safety relevant parameters are generally availability related A deviation may result in a reset being required Human error may then lead to an accident

The consequences of right side failures and errors shall therefore be evaluated in the context of risk analysis and appropriately mitigated in the equipment and system design, and in the operational rules

Table 1 – Overview of safety relevance in the subclauses

6.1.2 Availability no Part of the fail-safe behaviour of axle counter system

6.1.4 Maintainability no Not following the established maintenance regime can lead to RSF and potentially increase the risk of a WSF in

circuit current in the rail no

6.4 Immunity to harmonics of

traction current in the rail no

6.5 Sensor position integrity

control (functional parameter) yes

A sensor position integrity control is required to detect if an axle counter sensor has become detached from the rail and is not able to detect wheels

6.6 Integration time no Exceedances may cause a reliability problem which will be detected by the axle counter system 6.7 Signalling power supply quality

with respect to availability no Exceedances may cause a reliability problem which will be detected by the axle counter system 6.8 Requirements on the

connection cables no Exceedances may cause a reliability problem which will be detected by the axle counter system 7.2 Vehicle, wheel and speed

dependent parameters yes Wheel dimensions which do not meet these requirements may lead to the wheel not being detected 7.3 Material properties of vehicle

parts in the detection area (metal

Reliability is defined in EN 50126 A single reliability figure cannot be harmonized because it is a combination

of qualitative and quantitative aspects

6.1.2 Availability

The following information and definitions are derived from EN 50126

The availability is one of the most significant parameters of an axle counter system It is dependent on the sufficient immunity margin (compatibility margin between susceptibility threshold and the radiated emission level from RST) To ensure an adequate operational availability, a margin of 9 dB between the established immunity and the limit for rolling stock has to be applied The value of 9 dB ensures a correct count

NOTE Concerning the margin 9 dB see also 6.2.3

For a standardised (typical) axle counter system section the following example of parameters may be used to determine an acceptable availability in terms of failures per train:

Train movements per day per track: 100

Availability

MTTR) (MTBF

MTBF 100%

+

⋅

=

Mean Time to repair (MTTR): 30 min (best case) - 300 min (worst case)

MTBF is calculated on the basis of component data and is for this reason product specific The rate of miscounts is a separate parameter which may be affected by the geometry of wheels and other mechanical subsystems and EMC characteristics of rolling stock

MTBF is a parameter of the equipment of the train detection system required for a single detection section The integrity of the trackside cables and tracks/rails are excluded from the MTBF requirement calculations

6.1.3 Rate of miscounts

The counting error rate shall be equal or better than 10-7

For example:

Minimum time between miscounts using the operational parameter values shown above

Validation of parameters and performance during the development process is permissible The rate of miscounts in the field shall be demonstrated in an adequate field test

6.1.4 Maintainability

The following information and definitions are derived from EN 50126 and EN 50129

The proper function of the axle counter system depends on correct installation, initial adjustment, preventive and corrective maintenance of the cabling, connections to the rail and position of the sensors

The maintainability of the axle counter system shall be seen in the context of the complete integrated system including the ACD, the communication links, the evaluator unit and the power supplies

The maintenance cycle shall have a frequency lower than or equal to once a year per ACD The cycle for indoor equipment shall be described in the product specific user's guide This guide shall be checked for validation

The scope and frequency of the maintenance cycle of the axle counter shall be described in the product specific user’s guide A validation of these documents shall be done

The supplier shall provide the information related to equipment failure modes and their rates of occurrence This will enable infrastructure managers to estimate the corresponding MTTR and clarify the implications for their maintenance specification Aspects to be taken into consideration on the trackside maintenance:

- Axle counter sensor has been damaged or knocked off the rail,

- Sensor sensitivity requires readjustment due to a deterioration of rail conditions (e.g worn rail surface),

- Train wheel conditions changed (introduction of a new type of vehicle),

- Cabling is incorrectly connected to the sensor and or the connection box,

- Short circuit of two or more wires in the outdoor cable

The following information and definitions are derived from EN 50126, EN 50128 and EN 50129

The safe movement of the trains on railways relies on the train detection equipment The following levels of safety integrity may be assigned

NOTE THR is a term used in evolving safety related standards and means a specific calculable failure rate, which can

be converted to a defined SIL level

The safety integrity shall be validated based on the safety case of the axle counter system It shall be shown

in the safety case that the safety integrity level required is achieved Requirements are described in

EN 50126, EN 50128 and EN 50129

Examples of applications with different safety requirements:

• Lower safety integrity levels

17

For systems designed with the lowest level of safety integrity, the equipment is not safety relevant There is no level of automatic train protection that can be achieved with these systems In such circumstances, the train driver is responsible for the safe train movement Based on the reaction time of drivers, the train speed shall be restricted to ensure safe operation A set of "drive on sight" rules shall be defined These types of low safety integrity train detection are applicable for example to manually operated trams which share the track with normal road traffic vehicles

• Another application is where tracks are designed to transport freight only or with a very limited number of passengers per day In this case the risk of injuries is limited to an acceptable level A degree of safety integrity level is required to protect the train and the driver Examples of such applications may be found in freight yards and depots where driverless train movements are permitted

• Highest safety integrity level (SIL 4)

• On lines used to transport passengers and designed for speeds > 80 km/h or where the direct line of sight is not always assured (e.g in tunnels) the safety cannot be left to the responsibility of the drivers, and additional protection shall be provided This scenario will occur on interoperable and on main lines with mixed passenger and freight traffic In this case usually a safety integrity level of SIL 4 for the complete train detection system is required within the context of its application

6.1.5.2 Maximum time between trains

This subclause defines the maximum time allowed between two train runs – the “maximum time without train runs”

To alleviate any remaining hazards, it is recommended to specify a maximum time between trains of one year This requirement for a SIL4 train detection system is deemed reasonable because no additional operating expenses are to be expected Furthermore, an annual ‘check run’ is considered more practicable from a maintenance point of view

NOTE Train runs, where a fault occurs are not applicable as "check runs" for the purposes of this definition The check run constitutes a physical train movement over the train detection section, to prove intended operation

Typically the maximum time allowed without any train runs between two train runs is an input parameter for safety case and fault tree analysis Validation is successful if

• the hazard rate (HR) of the overall axle counter system < tolerable hazard rate

Failures that can only be revealed through a train run influence the hazard rate by increasing the risk when extending the duration of time between train runs The limit for the maximum time is reached when:

• the hazard rate (HR) ≥ tolerable hazard rate (THR)

Figure 2 – Correlation between hazard rate and time between trains

6.2 Immunity against magnetic fields – in-band and out-of-band

6.2.1 General

ACD can be influenced in different ways Within the frequency range of the ACD, the influence of magnetic fields generated by rolling stock is dominant As a result of these fields, spurious wheel pulses may be generated in the ACD, potentially creating unreliability which can lead, in the worst case, to a safety risk

To ensure proper compatibility between rolling stock and ACDs, electromagnetic emission of rolling stock has

to be taken into account Therefore it is necessary to test the immunity levels of ACDs to verify their conformity The emission limits for rolling stock have been defined in the FrM and are the basis for deriving the immunity levels of the ACDs

The following parameters are associated with the immunity of the ACD:

• immunity level to magnetic fields within the working frequency range:

o continuous magnetic fields;

o discontinuous (transient) magnetic fields;

• sesponse bandwidth (3dB and 20db);

• immunity to current in the rail;

• immunity to magnetic fields outside the working frequency range;

• immunity to magnetic field generated by the ETCS vehicle antenna

The following subclauses describe the requirements for the axle counter immunity The limits effectively encompass interference from magnetic fields of all sources which may occur at rail level, either generated by rail current or equipment on the vehicles, or both

The associated measurement procedures for the determination of the magnetic field immunity levels of ACDs

in all three directions X, Y and Z are described in Annex C

6.2.2 Derivation of immunity requirements

The immunity requirements for the axle counters shall be derived from the FrM as specified in the CCS TSI Index 77

The FrM defined in the CCS TSI Index 77 specifies the reserved frequency bands for the ACD with the corresponding emission limit values for rolling stock The FrM defines three frequency bands for axle counters:

19

6.2.3 Immunity levels for axle counters / Compatibility margins

To ensure sufficient immunity of ACDs to emission from rolling stock, the immunity level of the ACD shall be higher than the emission limits of the rolling stock within the frequency ranges reserved for axle counters defined in the FrM in CCS TSI Index 77

The immunity level of an ACD shall be at least 9dB higher than the rolling stock emission limit in the respective band 1, 2 or 3

The immunity level of an ACD shall be at least 3dB higher than the rolling stock emission limit in the frequency range 10kHz to 1,3MHz, out-of-band

For out-of-band frequencies from 0kHz to 10kHz and 1,3MHz to 30MHz no extra margin for ACD has to be applied

For new ACDs with working frequency in the out-of-band areas a 9dB margin has to be fulfilled in general The measurement shall be made in the laboratory and documented as defined in C.10

The 9dB includes the following:

- 6dB signal-to-noise ratio to guarantee the probability requirements of miscounting within the equipment operating tolerances;

- 3dB accounting for:

1) uncertainty of measuring chain,

2) antenna positioning,

3) overlapping effects (analysing methods),

4) other effects like rain, temperature, etc.,

5) presence of wheel

6.2.4 Frequency range of an ACD

Figure 3 The complete frequency response of the ACD shall be compliant with the defined FrM

Figure 3 – Areas for evaluation

6.3 Immunity to traction and short circuit current in the rail

The ACD shall be designed to operate reliably under normal operational conditions These include the maximum operational traction current in the rail The following examples provide an overview

A nominal operational limit for return current for all power supply systems except DC PS Systems may be assumed to be 2 kA per rail In DC Systems currents between 6,8 kA up to 10 kA per rail can be expected The ACDs shall be immune and work reliably up to these defined limits

The maximum current in the rail will occur under short circuit conditions

The following information may be useful to take rail saturation effects into account when designing the ACD It

is derived from CLC/TS 50238-3 and EN 50238-1

The magnetic flux density B around the rail can be approximated with

R π 2

I μ μ

Ferrite saturates at 0,35T however the current in the system will already use some of this margin Therefore

in the engineering of coils and transformers it is common to engineer the coil to use 90% of this saturation limit This means that currents higher than 18kA may saturate the ferrite

On site testing or tests in a special laboratory are necessary to establish immunity to these very high currents

6.4 Immunity to harmonics of traction current in the rail

The following explanations and requirements are derived from CLC/TS 50238-3 and EN 50388-1

Tests shall be performed without a wheel over the axle counter sensor / train inside the track vacancy area to establish the immunity limit (refer to C.6.2)

Power converters in the vehicle produce broad spectrum currents Part of the current will flow from the wheels towards the power station, another part may circulate under the train via the path: converter – bogie – rails – bogie – line filter

NOTE The immunity to harmonics of traction current in the rails is taken into account in the FrM

6.5 Sensor position integrity control (functional parameter)

The following information and definitions are derived from EN 50129

A sensor shall be designed to detect a wheel reliably and safely when it has been correctly installed on the rail Due to loosening or damage, its position may change and it may no longer be able to detect a wheel This shall be taken into account in the design and safety case of the axle counter The axle counter shall be designed to detect safety related changes of position or damage and generate an error message when a wheel may no longer be detected

NOTE Electromagnetic interferences with the same effect, for example the loss of the correct mounting place, may result in the same error message

The correct sensor position integrity control shall be approved in the safety case according to EN 50129 and shall be validated

6.6 Integration time

6.6.1 General

Transients or short time disturbances having spectral components in the working frequency range of an ACD may cause functional disturbances e.g miscounts of axles The immunity of ACDs to those disturbances

21

increases with a decreasing duration of disturbances as soon as the ratio between duration of disturbances and integration time is less than one

6.6.2 Product specific integration time

The “Integration Time” is the time constant of an ACD indicating the range of time in which the immunity of the regarded ACD to sinusoidal in-band disturbances rises with a shorter time duration of these disturbances (short term interference) It is product specific and is one parameter for the evaluation of the measurement results of the compatibility tests of vehicles (see CCS TSI Index 77) It is defined as the window size over which the root mean square (rms) of the output of the band-pass filter is calculated

The integration time of an ACD is given by the design of the sensor circuitry and is being considered during immunity tests against magnetic fields It is used as an indicator for the immunity of an existing ACD circuitry without consideration of additional measurements within the digital signal processing of the whole ACD ACDs use various filtering techniques within their measuring chains between sensors and evaluation units in order to reject possible interferences mainly coming from passing trains Depending on the types of filters used for ACDs, the integration times of these filters may vary in a defined range

Example A shows a linear behaviour of an axle counter detector

Example B shows an exponential behaviour of an axle counter detector (digital sensor system with A/D converter)

Figure 5 shows the measurement result of an ACD under test (solid line) compared to the simulation result of

an approximated band pass filter (dashed line)

The solid line shows the measured increase of immunity depending on the time duration of in-band disturbances The in-band disturbances are formed by intermittent sine wave voltages with different pulse durations according to C.4.5 The repetition time of the intermittent voltages is set to a value that allows complete recovery to the initial condition of the ACD under test

The dashed line shows the responses of a LC Butterworth band pass filter with nearly the same filter characteristic as the measuring system of the ACD under test

The corresponding filter curves are given in Figure 6

The parameter “Integration time Ti” is indicated by the interception point of the tangent defined by 6dB/octave slope with the X-axis The graphical display of the tangent in a diagram needs to use a dB linear and time logarithmic scaling The evaluation of the measured curve in Figure 5 leads to an integration time of

Ti ≈ 3,4 ms

-2 0 2 4 6 8 10 12 14 16 18

Axle counter systems are high integrity train detection systems that require continuous operation Interruption

in power supply has an immediate effect on the availability of the axle counter system

Limits and requirements on power supply are required to be described in the manufacturer’s users guide for the axle counter system

Ti ≈ 3,4 ms

23

It shall be checked if the power supply complies with the requirements of the axle counter system

The validation during the development shall include a power supply described in the system manuals

Preferred power supply voltages (DC) shall be 24V, 36V, 48V or 60V with a maximum tolerance of -10% / +20 %

6.8 Requirements on the connection cables

There are two interfaces types with their associated connection cables shown in Figure 1 – System boundary

of an axle counter system:

1 connecting cables between the axle counter evaluation unit and the ACDs,

2 cabling between the axle counter evaluation unit and the interlocking, and possibly neighbouring evaluation units

The first type in particular is exposed to electromagnetic emissions and to mechanical and environmental stress, all of which may affect the availability of axle counter systems

Both types of cable used within the system borders have to be defined in the manufacturer’s users guide describing the axle counter system

Limits and requirements on each cable connection shall be described in the manufacturer's users guide for the axle counter system (concerning cable length, parameters and distance limits) It shall be checked if cables provided by the customer comply with the requirements of the axle counter system To avoid potential problems the manufacturer shall provide information and proposals concerning:

- Cable parameters,

- Type of shielding of the cables,

- Earthing method of cable shielding,

- Specific aspects of laying the cables, installation, reinforcement and connecting methods,

- Water drainage and sealing

The conformity assessment tests shall be performed with cables compliant with the manufacturer’s specification

7 Requirements for axle counter systems based on train parameters

7.1 General

The axle counter system shall work correctly under the conditions described in this section

7.2 Vehicle, wheel and speed dependent parameters

7.2.1 General

This subclause describes the requirements resulting from the railway vehicle design concerning the train speed, wheel dimensions and performance requirements The following information and definitions are derived from 2006/964/EC, UIC 510-2 and CCS TSI Index 77

The function of most ACDs is based on electromagnetic principles and as such requires a specified minimum influence time and a certain amount of metallic mass of the wheel for correct function and depends amongst others on the following parameters:

- sensor dimensions,

- sensor technology (physical operating principle, principle of wheel flange detection),

- speed of vehicle,

- distance between two axles,

- integration time,

- wheel dimensions and material

These parameters shall be met under all conditions Vehicles which will not meet these requirements may not

be detected The values and factors defined are limits defined for the worst case of maximum speed and/or minimum wheel diameters All parameters can be validated with measurements The correct function of an axle counter system working under the described parameters has to be confirmed by the manufacturer

7.2.2 Wheel parameters

7.2.2.1 General

The parameters for wheel dimensions are shown below The compatibility with these parameters shall be met under all operating conditions These parameters are applicable to both new and worn wheels Wheel dimensions which do not meet these requirements may lead in the worst case to a safety risk

NOTE Wheels without a flange or with spokes may or may not be detected

B R = width of the rim

S d = thickness of the flange

S h = height of the flange

D = wheel diameter

Figure 7 – Definition of the parameters 7.2.2.2 Wheel material

The wheels have ferromagnetic and electrically conducting characteristics

7.2.2.3 Width of the rim

The dimension BR shall be taken from Index 77 of CCS TSI

25

7.2.2.4 Thickness of the flange

The dimension Sd is specified according to Index 77 of CCS TSI

7.2.2.5 Height of the flange

The dimension S h is specified in Index 77 of CCS TSI

7.2.2.6 Wheel diameter

The dimension D is specified in Index 77 of CCS TSI

7.2.3 Vehicle and speed depending parameters

The axle distance ai shall not be less than: ai = v x 7,2 with v in km/h and ai in mm

The axle distance ai shall not be less than: ai = D x 2,18 with D in mm

The maximum result of both calculations has to be taken into account

NOTE 1 The maximum distance ai will be considered when applying (i.e position of axle counter sensors) an axle counter system

NOTE 2 The requirement in CCS TSI Index 77, 3.1.2.2 is based on a minimum time gap between two consecutive axles of 25,9 ms

a1 a2 a3 a4 a5

L

Figure 8 – Axle to axle distance

The longitudinal vehicle dimensions are defined as:

- v = speed of vehicle in km/h,

- n = total number of axles of the vehicle,

- ai = axle distance between following axles, where i = 1, 2, 3, …, n-1 with ai in mm,

- b1/b2 = longitudinal distance from first axle (b1) or last axle (b2) to the nearest end of the vehicle, i.e nearest buffer/nose,

- L = total length of the vehicle in mm

7.3 Material properties of vehicle parts in the detection area (metal free space)

The following information and definitions are derived from EN 50238-1 and CCS TSI Index 77

The correct function of ACDs is not only influenced by magnetic fields Metal constructions in direct vicinity of axle counter sensors can also significantly influence the correct detection of wheels

Metal constructions mounted within the “Metallic Influencing Zone“ (MIZ) can corrupt the detection of wheels

by passive influence The parameter MIZ for compatibility between rolling stock and ACDs is mentioned and explained in EN 50238-1 The MIZ itself and a procedure for dealing with metallic parts in the MIZ are described here

The MIZ is located around the rail and its size has been reduced with respect to the existing EN 50238-1 Eddy current and magnetic track brakes will encroach the MIZ (refer to 7.4.)

Even under worst case operational conditions like pitching, under load, spring compression and worn wheels the MIZ shall remain clear of metal parts mounted on rolling stock

Only wheels or non-metallic and non-conductive components are permitted within the MIZ Permitted exceptions are sanding pipes, guard irons/life guards etc which are defined in the CCS TSI Index 77

Compatibility with relevant ACDs shall be demonstrated for identified metallic parts either by cross-check geometry with pre-defined maximum allowed geometrical dimensions or component / rolling stock tests The validation for axle counters shall be done by laboratory or field tests

7.4 Sinusoidal sway of train

The following information and definitions are derived from requirements on the “Maximum variation of rail to rail distances” in EN 13848-5 and the “Maximum distances between flange contact faces” defined in the TSI RST freight / wagon

Figure 9 – Definition of sinusoidal sway

NOTE For the maximum distance of ACD sensor from rail head the flange thickness of the wheel will be considered

7.5 Magnetic track brakes and eddy current brakes

The compatibility between rolling stock and the axle counters shall be demonstrated if these brakes are used for normal operational braking, if these brakes are used only for emergency braking, demonstration of compatibility may not be required

8 Track based parameters

Because the working principle of the ACD is based on magnetic fields the wooden sleepers have no influence Concrete and metal sleepers shall be taken into consideration The ACDs shall operate correctly with the above listed types of sleepers

The validation shall be done by laboratory or field tests

NOTE Polymer sleepers, if used have no influence over the operation of the axle counters, similar to wooden sleepers

8.2 Rail fittings/mounting area

The following information and definitions are derived from 2006/679/EC, 2006/860/EC and CLC/TS 50238-3 This subclause defines the areas where an ACD can be installed in the track environment

The axle counter sensor can be installed at the rail in between two sleepers or above a sleeper

Axle counter sensors shall not be installed within the structure gauge of the track (individual for each country), The rules for the installation can be given by the infrastructure manager in accordance with the target system requirements

For the installation of axle counter sensors in slab track environment see 8.3

Axle counter sensors can be fixed to the rail by foot clamps or with drilling holes in the rail The minimum horizontal distance between two holes is 85 mm with a maximum diameter of 13 mm With distance between holes greater than 85 mm, hole diameters can be increased beyond 13 mm The prefered area to drill the holes is in the neutral zone of the rail The mounting position can be adapted in case of vertical wear of the rail

All cables connected to the ACD shall be designed to lay on or in the ballast The manufacturer shall specify how to lay the cables

The earthing of the cables and the equipment shall be agreed with the infrastructure manager

The validation shall be done by laboratory or field tests

no metal part will influence it It is product specific Where possible the axle counter shall be designed to use

an 88 mm gap between the foot of the rail and the concrete slab

It shall be demonstrated that the specified reliability of the ACD is not impaired by the influence of the material outside this free space (e.g steel reinforcement rebar of concrete) Proper drainage in the pit of the free space shall be ensured (e.g to avoid accumulation of water and ice formation)

The bending radius of the cable (including the protection tubes) shall be considered

The mechanical arrangement and the possible electrical influence of the reinforced concrete slab track shall

be checked by measurement and possibly be electrical tests

EN 50125-3 Class A1, altitude up to 1 400 m, has to be applied This results in:

- min air-pressure: 84 kPa (defined in EN 60721-3-4, category 4Z10);

- max air-pressure: 106 kPa (defined in EN 60721-3-4, category 4K*)

The following shall be taken into account:

Air-pressures above and below the above range may cause malfunction or damage to the ACD isolation The lower air pressure at higher altitudes will reduce heat transfer

The manufacturer’s user's guide shall state that the product is designed for this altitude and pressures

9.3 Movement of surrounding air

The maximum resulting aerodynamic forces at open air and in tunnels can be calculated and defined for specific situations by the manufacturer on the basis of data of the infrastructure manager The calculation method is defined in EN 50125-3

All parameters shall be validated by one of the following methods:

- testing the correct function and the resistance against air flow (e.g in wind-tunnels or by putting mechanical pressure on certain points of the housing);

- calculation of the relevance for the chosen solution

Aerodynamic forces may lift the cabling, loose lids of electronic housing and loose parts of the sensor in general

The components of an axle counter system are installed in different locations:

- Axle counter evaluator equipment: in a cubicle or in a container (without or with temperature control)

or in a building (without or with climatic control),

- ACD: valid for those components, electronics and/or connectors from sensors to trackside cables next

to the track e.g cubicle / junction box,

- Axle counter sensor: in the track on the rail

Therefore there are different ambient temperature ranges to be applied for these kinds of axle counter system components

The ambient temperature range is a basic requirement for all technologies to ensure the correct functionality and reliability of electric and electronic equipment in the target application environment

The following test procedures shall apply for validation:

- EN 60068-2-1 Environmental testing – Part 2-1: Tests – Tests A: Cold ;

- EN 60068-2-2 Basic environmental testing procedures - Part 2: Tests - Tests B: Dry heat

NOTE For applications in climatic or temperature controlled environments this test list is obsolete

9.4.2 Ambient temperature for axle counter evaluator equipment

The axle counter evaluator equipment shall work in the temperature range and under the conditions which are described in EN 50125-3, class T1 and T2 in cubicles or containers (with or without temperature control) or in buildings (with or without climatic control) This means the upper temperature of T1 and lower temperature from T2 have to be applied

The location of the applications and the operating temperature range of the electronic components shall be specified accordingly by the manufacturer

9.4.3 Ambient temperature for ACD (without axle counter sensor)

The ACD components located near the track (e.g junction box or cubicle) shall work in the temperature range and under the conditions as defined in EN 50125-3, class T1 and T2 in a cubicle

These temperature ranges cover the following thermal influences:

- Ambient temperature at the ground on railway tracks (including thermal radiation from the ground of the track),

- power dissipation from other components installed inside,

- influence of solar radiation

NOTE If the trackside equipment is located in a cubicle together with other equipment it is important to ensure that the internal temperature of the cubicle will not exceed the specified temperature range

9.4.4 Ambient temperature for axle counter sensor

The axle counter sensor installed on the rail shall work under the following thermal influences:

- ambient air temperature near the ground at the track as defined in EN 50125-3 T1 and T2,

- temperature increase caused by sun radiation,

- if eddy current brakes are in operation the rails may heat up additionally to the other temperature influences by +15 K (maximum temperature increasement in the rail head)

This leads to the following thermal requirements for the axle counter sensor:

- Limits of microclimatic temperature: -40 °C to + 70 °C,

- Temporary contact temperature at the rail of additional 15 K (caused by operational eddy current brakes)

9.5 Humidity

The humidity application conditions for signalling equipment are described in EN 50125-3 The EN 50125-3 offers a list of several climate classes The applicable category for axle counter systems is defined here

Rain: rain amount: 6 mm/min together with air flow

Snow: all type of snow together with air flow

Hail: hail with a maximum diameter of 15 mm

NOTE Larger diameters are possible This does not need to be considered in the design

Ice: In the design of the axle counter two factors shall be considered:

a) Ice lost by trains which may cause physical damage,

b) Ice caused by water ingress in cables and housings which can lead to physical or electrical damage

If required, deflection plates mounted on the rail in front of the sensors can provide additional protection against ice falling from trains Specific ice tests are not within the scope of this standard Validation of the design associated with a) and b) shall be done by laboratory, field tests or by argumentation

9.7 Sealing of housing

The following information and definitions are derived from EN 60529

In certain local areas and under some extreme climate conditions it may occur that the part of the ACD that is installed on the rail submerged in water If any water gets into the sensor housing, the electronic parts may get damaged and the ACD will be disturbed or not work correctly

The part of axle counter sensor mounted on the track shall withstand water to a depth of 820 mm from the top

of the housing for the duration of one hour

This parameter shall be validated by laboratory tests based on EN 60529, category IP 68

Proper functionality of this sensor shall be checked during (so far as possible) or after the test respectively Every other type of outdoor cubicle shall comply with EN 60529, catogary IP 65

9.8 Solar radiation

According to EN 50125-3 the ACDs shall work correctly up to the following defined maximum solar radiation of

1 120 W/m2

NOTE This value includes the complete radiation spectrum (UV, visible, IR)

The thermal effect of the parameter “solar radiation” has already been covered by the parameter "Ambient temperature" (see 9.4)

For unprotected surfaces and materials against UV-radiation suitable materials shall be used

Currently for validation of this parameter no short time aging tests are available

9.9 Overvoltage protection (incl indirect lightning effects)

EN 50124-2 shall be applied

Overvoltages caused by lightning strikes may damage electronic parts

A proposal how to protect the axle counter system against overvoltage shall be described in the manufacturer’s user's guide

The proposal shall, as far as is reasonable, take the rules of the infrastructure manager regarding lightning protection into account

9.10 Contamination

9.10.1 General

The contamination conditions of signalling equipment are described in EN 50125-3 This European Standard offers a list of several categories of contamination The applicable classes for the axle counter system are defined here

9.10.2 In the track, nearby the track

The ACD shall withstand influences according to:

According to EN 50125-3 fire protection has to be defined

The axle counter manufacturer shall state which fire protection standards have been applied and which measures have been taken to reduce the flammability of the product

The infrastructure manager shall make his specific requirements known to the manufacturer, in order that they can be taken into account