SIST EN 50617-2:2015

SLOVENSKI STANDARD
01-september-2015
Železniške naprave - Osnovni parametri sistemov za detekcijo vlakov - 2. del:
Števci osi
Railways applications - Basic parameters of train detection systems - Part 2: Axle
counters
Bahnanwendungen - Basic Parameters der Gleisfreimeldesystemen - Teil 2: Achszähler
Applications ferroviaires - Paramètres de base des systèmes de détection des trains -
Partie 2 : Compteurs d'essieux
Ta slovenski standard je istoveten z: EN 50617-2:2015
ICS:
45.020 Železniška tehnika na Railway engineering in
splošno general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN 50617-2
NORME EUROPÉENNE
EUROPÄISCHE NORM
April 2015
ICS 29.280
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 Bahnanwendungen - Technische Parameter von
systèmes de détection des trains - Partie 2: Compteurs Gleisfreimeldesystemen - Teil 2: Achszähler
d'essieux
This European Standard was approved by CENELEC on 2015-03-09. CENELEC 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 CENELEC 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 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 Electrotechnique
Europäisches 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 Page
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
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

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 (dop) 2016-03-09
implemented at national level by publication of
an identical national standard or by
endorsement
(dow) 2018-03-09
• latest date by which the national standards
conflicting with this document have to
be withdrawn
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.
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)
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
3.1.5
bandwidth
difference between the upper and lower frequencies in a contiguous set of frequencies and is typically
measured in Hz
3.1.6
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.
3.1.11
inflection point
defines the transition between the static (continuous wave) and dynamic immunity (short duration) behaviour
of the ACD
3.1.12
integration time
parameter for evaluation defined as the window size over which the root mean square (rms) of the output of
the band-pass filter is calculated

3.1.13
measurement antenna
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
3.1.16
sinusoidal sway
maximum movement of a wheel in y-direction with the running of a train in relation to the inner flange of the
rail head
3.1.17
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
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

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
Direct
Subclause safety Explanation
relevance
6.1.2 Availability no Part of the fail-safe behaviour of axle counter system
Not following the established maintenance regime can
6.1.4 Maintainability no lead to RSF and potentially increase the risk of a WSF in
certain cases.
Safety criteria and safely level form determine the safety
6.1.5 Safety yes
concept and design of the axle counter system.
6.2 Immunity against Magnetic
no
fields – in-band and out-of-band
C.4.5.3 Immunity to multiple
no
transients
The parameter is safety related, as it influences the
6.1.5.2 Maximum time between
no reliability. Exceedances do not lead directly to a hazard,
trains
however, the probability of WSF increases with time.
6.3 Immunity to traction and short
no
circuit current in the rail
6.4 Immunity to harmonics of
no
traction current in the rail
A sensor position integrity control is required to detect if an
6.5 Sensor position integrity
yes axle counter sensor has become detached from the rail
control (functional parameter)
and is not able to detect wheels.
Exceedances may cause a reliability problem which will be
6.6 Integration time no
detected by the axle counter system.
6.7 Signalling power supply quality Exceedances may cause a reliability problem which will be
no
with respect to availability detected by the axle counter system.
6.8 Requirements on the Exceedances may cause a reliability problem which will be
no
connection cables detected by the axle counter system.
7.2 Vehicle, wheel and speed Wheel dimensions which do not meet these requirements
yes
dependent parameters may lead to the wheel not being detected.
7.3 Material properties of vehicle
Exceedances may cause a reliability problem which will be
parts in the detection area (metal no
detected by the axle counter system.
free space)
Exceedances may cause a reliability problem which will be
7.4 Sinusoidal sway of train no
detected by the axle counter system.
7.5 Magnetic track brakes and Exceedances may cause a reliability problem which will be
no
eddy current brakes detected by the axle counter system.
Exceedances maycause a reliability problem which will be
8.1 Material of sleepers no
detected by the axle counter system.
Exceedances may cause a reliability problem which will be
8.2 Rail fittings/mounting area no
detected by the axle counter system.
Exceedances may cause a reliability problem which will be
8.3 Slab track no
detected by the axle counter system.
Direct
Subclause safety Explanation
relevance
9 Environmental and other
no
parameters
6 Axle counter system parameters
6.1 RAMS
6.1.1 Reliability
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:
Axles per train: 25 (average)
Train movements per day per track: 100
MTBF
Availability = 100%⋅
(MTBF+ MTTR)
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
-7
The counting error rate shall be equal or better than 10 .
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.
Other aspects
- In-House equipment  If there are any then they have to be described in the product specific user’s
guide,
- Cabling/wiring/connection boxes,
- Time without train runs (refer to 6.1.5.2).
6.1.5 Safety
6.1.5.1 General
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
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 spe
...