IEC 62236-2:2008

Railway applications - Electromagnetic compatibility - Part 2: Emission of the whole railway system to the outside world

IEC 62236-2:2008 sets the emission limits from the whole railway system including urban vehicles for use in city streets. Describes the measurement method to verify the emissions, and gives the cartography values of the fields most frequently encountered. The main change with respect to the previous edition consists of the distance conversion factor defined in the frequency range from 9 kHz to 150 kHz.

Applications ferroviaires - Compatibilité électromagnétique - Partie 2: Emission du système ferroviaire dans son ensemble vers le monde extérieur

La CEI 62236-2:2008 fixe les limites d'émission provenant du système ferroviaire dans son ensemble et s'applique également au transport urbain. Décrit la méthode de mesure à utiliser pour vérifier les émissions et donne la cartographie des niveaux de champ rencontrés le plus fréquemment. Les modifications principales par rapport à l'édition précédente concernent le facteur de conversion de la distance défini dans la gamme de fréquences de 9 kHz à 150 kHz.

General Information

• Status: Published
• Publication Date: 11-Dec-2008
• ICS: 33.100 - Electromagnetic compatibility (EMC)
• ICS: 45.060.01 - Railway rolling stock in general
• Technical Committee: TC 9 - Electrical equipment and systems for railways
• Drafting Committee: MT 62236 - TC 9/MT 62236
• Current Stage: DELPUB - Deleted Publication
• Start Date: 09-Feb-2018
• Completion Date: 26-Oct-2025

Relations

• Revised: IEC 62236-2:2018 - Railway applications - Electromagnetic compatibility - Part 2: Emission of the whole railway system to the outside world
• Effective Date: 05-Sep-2023
• Revises: IEC 62236-2:2003 - Railway applications - Electromagnetic compatibility - Part 2: Emission of the whole railway system to the outside world
• Effective Date: 05-Sep-2023

Overview

IEC 62236-2:2008 is an international standard published by the International Electrotechnical Commission (IEC) that addresses electromagnetic compatibility (EMC) for railway applications. Specifically, it focuses on the emission limits of the entire railway system to the outside world, including urban vehicles operating on city streets. This standard is essential for ensuring that electromagnetic emissions from railway systems do not interfere with other electronic devices or communication systems in the surrounding environment.

The standard outlines measurement methods to verify compliance with emission limits and provides typical field intensity values encountered near railway systems. It covers emissions in the frequency range from 9 kHz to 1 GHz, with particular attention to changes in the distance conversion factor between 9 kHz and 150 kHz, compared to its previous edition.

Key Topics

• Emission Limits:
  IEC 62236-2 sets strict emission limits for electromagnetic fields generated by railway systems, including open railway routes during train operaton and emissions from railway substations. These limits are designed to protect nearby electronic systems and communication services while allowing safe and efficient railway operations.

• Measurement Methods:
  The standard details precise measurement parameters and conditions necessary for verifying emission levels. Key aspects include:

  • Antenna positioning and frequency selection
  • Consideration of transient events and multiple emission sources
  • Measuring points located 10 meters from the electrified railway track centerline or substation fence
  • Environmental factors such as weather conditions and railway operating modes
    The measurement approach ensures repeatability and reliability in assessing electromagnetic emissions from moving trains and static infrastructure.

• Frequency Ranges and Bandwidths:
  The standard covers a broad frequency spectrum with specific bandwidths used for quasi-peak detection according to CISPR 16-1-1:

  • Up to 150 kHz: 200 Hz bandwidth
  • 150 kHz to 30 MHz: 9 kHz bandwidth
  • Above 30 MHz: 120 kHz bandwidth

• Railway Substations:
  Special attention is given to radio frequency emissions from substations which transform primary supply voltages for contact line systems. Measurements are performed at prescribed points 10 meters from station fences or enclosures.

• Urban Vehicle Considerations:
  For urban rolling stock operating in city streets, the emissions must not exceed limits specified for 750 V direct current conductor rails, ensuring compatibility in densely populated and electronically sensitive environments.

Applications

IEC 62236-2:2008 is crucial for a variety of stakeholders involved in railway design, operation, and regulatory compliance:

• Railway Infrastructure Engineers can utilize the emission limits and measurement methods to design systems that minimize electromagnetic interference with neighboring electronic devices or public communication networks.

• Rolling Stock Manufacturers rely on this standard to certify their vehicles meet EMC requirements during operation both on urban and mainline tracks.

• Regulatory Authorities reference this standard when defining national requirements for railway electromagnetic compatibility, ensuring public safety and service continuity.

• Substation Designers and Operators ensure that RF emissions remain within tolerable limits, protecting surrounding communities from electromagnetic disturbances.

• EMC Testing Laboratories employ the measurement procedures outlined in the standard to conduct verification testing and produce compliance reports.

This standard helps mitigate risks of electromagnetic interference which could cause operational disruptions, data corruption, or safety hazards, thereby promoting reliable and interference-free railway operations worldwide.

Related Standards

IEC 62236-2:2008 is part of the IEC 62236 series addressing electromagnetic compatibility in railways and works alongside:

• IEC 62236-1: Railway applications – Electromagnetic compatibility – Part 1: General principles
• IEC 62236-3-1: Railway applications – Electromagnetic compatibility – Part 3-1: Rolling stock – Train and complete vehicle
• CISPR 16-1-1: Specification for radio disturbance and immunity measuring apparatus and methods
• CISPR 22: Information technology equipment – Radio disturbance characteristics – Limits and methods of measurement

Together, these standards create a comprehensive framework for managing EMC challenges in rail transport, from infrastructure to onboard systems.

---

Keywords: IEC 62236-2, railway electromagnetic compatibility, railway EMC standards, railway emission limits, urban railway emissions, EMC measurement method, railway substation emissions, railway rolling stock EMC, electromagnetic interference railway, IEC railway standards

Standards Content (Sample)

IEC 62236-2
Edition 2.0 2008-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Railway applications – Electromagnetic compatibility –
Part 2: Emission of the whole railway system to the outside world

Applications ferroviaires – Compatibilité électromagnétique –
Partie 2: Emission du système ferroviaire dans son ensemble vers le monde
extérieur
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IEC 62236-2
Edition 2.0 2008-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Railway applications – Electromagnetic compatibility –
Part 2: Emission of the whole railway system to the outside world

Applications ferroviaires – Compatibilité électromagnétique –
Partie 2: Emission du système ferroviaire dans son ensemble vers le monde
extérieur
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
T
CODE PRIX
ICS 45.060 ISBN 978-2-88910-646-2
– 2 – 62236-2 © IEC:2008
CONTENTS
FOREWORD.3

1 Scope.5

2 Normative references .5

3 Terms and definitions .5

4 Emission limits .6

4.1 Emission from the open railway route during train operation.6

4.2 Radio frequency emission from railway substations .6

5 Method of measurement of emission from moving trains.7
5.1 Measurement parameters.7
5.2 Frequency selection .9
5.2.1 Selected frequencies .9
5.2.2 Sweep frequency.9
5.3 Transients .10
5.4 Measuring conditions .10
5.4.1 Weather conditions.10
5.4.2 Railway operating modes.10
5.4.3 Multiple sources from remote trains .10
5.5 Test report .10
5.6 Antenna positions.10
Annex A (normative) Method of measurement of electromagnetic emission from
railway substations .17
Annex B (informative) Background to the method of measurement.18
Annex C (informative) Cartography – Electric and magnetic fields at traction
frequencies.23
Bibliography.24

Figure 1 – Emission limits in frequency range 9 kHz to 1 GHz.12
Figure 2 – Emission limit for substations.13
Figure 3 – Position of antenna for measurement of magnetic field in the 9 kHz to
30 MHz frequency band .14
Figure 4 – Position (vertical polarisation) of antenna for measurement of electric field
in the 30 MHz to 300 MHz frequency band.15

Figure 5 – Position (vertical polarisation) of antenna for measurement of electric field
in the 300 MHz to 1 GHz frequency band.16
Figure B.1 – Time variation of emissions from a moving train with many transient
events.22

Table C.1 – Typical maximum electric and magnetic field values at fundamental
frequency of different electrification systems.23

62236-2 © IEC:2008 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________
RAILWAY APPLICATIONS –
ELECTROMAGNETIC COMPATIBILITY –

Part 2: Emission of the whole railway system

to the outside world
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.

International Standard IEC 62236-2 has been prepared by IEC technical committee 9:
Electrical equipment and systems for railways.
This second edition cancels and replaces the first edition published in 2003. It constitutes a
technical revision and is based on EN 50121-2:2006.
The main change with respect to the previous edition is listed below:
– distance conversion factor n defined in the frequency range from 9 kHz to 150 kHz.

– 4 – 62236-2 © IEC:2008
The text of this standard is based on the following documents:

FDIS Report on voting
9/1185/FDIS 9/1213/RVD
Full information on the voting for the approval of this standard can be found in the report on

voting indicated in the above table.

This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

A list of all parts of IEC 62236 series, published under the general title Railway applications –
Electromagnetic compatibility, can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in
the data related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
62236-2 © IEC:2008 – 5 –
RAILWAY APPLICATIONS –
ELECTROMAGNETIC COMPATIBILITY –

Part 2: Emission of the whole railway system

to the outside world
1 Scope
This part of IEC 62236 sets the emission limits from the whole railway system including urban
vehicles for use in city streets. It describes the measurement method to verify the emissions,
and gives the cartography values of the fields most frequently encountered.
The limits refer to the particular measuring points defined in Clause 5 and Annex A. These
emissions should be assumed to exist at all points in the vertical planes which are 10 m from
the centre lines of the outer electrified railway tracks, or 10 m from the fence of the
substations.
Also, the zones above and below the railway may be affected by electromagnetic emissions
and particular cases shall be considered individually.
These specific provisions are to be used in conjunction with the general provisions in
IEC 62236-1.
2 Normative references
The following referenced documents are indispensable for the application of this document.
For dated references, only the edition cited applies. For undated references, the latest edition
of the referenced document (including any amendments) applies.
IEC 60050-161, International Electrotechnical Vocabulary (IEV) – Chapter 161:
Electromagnetic compatibility (EMC)
IEC 62236-1, Railway applications – Electromagnetic compatibility – Part 1: General
IEC 62236-3-1, Railway applications – Electromagnetic compatibility – Part 3-1: Rolling stock
– Train and complete vehicle
CISPR 16-1-1, Specification for radio disturbance and immunity measuring apparatus and
methods – Part 1-1: Radio disturbance and immunity measuring apparatus – Measuring
apparatus
CISPR 22, Information technology equipment – Radio disturbance characteristics – Limits and
methods of measurement
3 Terms and definitions
For the purposes of this document, the terms and definitions of IEC 60050-161 and the
following apply.
– 6 – 62236-2 © IEC:2008
3.1
apparatus
electric or electronic product with an intrinsic function intended for implementation into a fixed

railway installation
3.2
environment
the surrounding objects or region which may influence the behaviour of the system and/or

may be influenced by the system

3.3
external interface
boundary where a system interacts with any other or where a system interacts with its
environment
3.4
railway substation
installation the main function of which is to supply a contact line system at which the voltage
of a primary supply system, and in some cases the frequency, is transformed to the voltage
and frequency of the contact line
3.5
railway supply lines
conductors running within the boundary of the railway which supply power to only the railway
but are not energised at railway system voltage
4 Emission limits
4.1 Emission from the open railway route during train operation
The emission limits in the frequency range 9 kHz to 1 GHz are given in Figure 1 and the
measurement method is defined in Clause 5. For non-electrified lines, the limits are the same
as those given for 750 V d.c.
Annex C gives guidance values for typical maximum field values at fundamental frequency of
different electrification systems which may occur. They depend on numerous geometrical and
operational parameters which may be obtained from the infrastructure controller.
For urban vehicles operating in city streets, the emission limits given in Figure 1 for 750 V d.c.
conductor rail shall not be exceeded.

NOTE 1 There are very few external radio services operating in the range 9 kHz to150 kHz with which the railway
can interfere. If it can be demonstrated that no compatibility problem exists, any emission level exceeding the
relevant limits given in Figure 1 may be acceptable.
NOTE 2 It is not possible to undertake complete tests with quasi-peak detection due to the reasons stated in
Annex B.
4.2 Radio frequency emission from railway substations
Radio frequency noise emission from the railway substation to the outside environment
measured according to the method defined in Annex A shall not exceed the limits in Figure 2.
The limits are defined as quasi-peak values and the bandwidths are those used in
CISPR 16-1-1:
Bandwidth
frequencies up to 150 kHz 200 Hz
frequencies from 150 kHz to 30 MHz 9 kHz

62236-2 © IEC:2008 – 7 –
frequencies above 30 MHz 120 kHz

The distance of 10 m defined in Annex A shall be measured from the fence of the substation.

If no fence exists, the measurements shall be taken at 10 m from the apparatus or from the

outer surface of the enclosure if it is enclosed.

Emission of trains shall not enter into the measurement.

NOTE 1 There are very few external radio services operating in the range 9 kHz to 150 kHz with which the railway
can interfere. If it can be demonstrated that no compatibility problem exists, any emission level exceeding the

relevant limits given in Figure 2 may be acceptable.

NOTE 2 For other kinds of fixed installations like auto-transformers, the same limit and measuring distance shall
be applied.
5 Method of measurement of emission from moving trains
The method of measurement is adapted from the CISPR 16-1-1 to a railway system with
moving vehicles. The background to the method of measurement is given in Annex B.
The electromagnetic fields generated by rail vehicles when operating on a railway network are
measured by means of field strength meters with several different set frequencies. The
horizontal component of the magnetic field perpendicular to the track and both the vertical
and horizontal (parallel to the track) components of the radiated electric field are measured.
5.1 Measurement parameters
5.1.1 The peak measurement method is used. The duration at selected frequency shall be
sufficient to obtain an accurate reading. This is a function of the measuring set and the
recommended value is 50 ms.
5.1.2 Frequency bands and bandwidths at –6 dB used for measurements are in accordance
with CISPR 16-1-1.
These are:
Frequency bands: 9-150 kHz 0,15-30 MHz 30-300 MHz 300 MHz -1 GHz
Bandwidth: 200 Hz 9 kHz 120 kHz 120 kHz
5.1.3 When connected to the antenna, the error of measurement of the strength of a uniform
sine-wave field shall not differ more than ± 4,0 dB from CISPR 16-1-1 equipment.

5.1.4 The noise may not attain its maximum value as the traction vehicle passes the
measuring point, but may occur when the vehicle is a long distance away. Therefore, the
measuring set shall be active for a sufficient duration before and after the vehicle passes by
to ensure that the maximum noise level is recorded.
5.1.5 To cover the full frequency range, antennas of different design are required. Typical
equipment is described below:
– for 9 kHz to 30 MHz, a loop or frame antenna is used to measure H field (see Figure 3);
– for 30 MHz to 300 MHz, a biconical dipole is used to measure E field (see Figure 4);
– for 300 MHz to 1,0 GHz, a log-periodic antenna is used to measure E field (see Figure 5).
Calibrated antenna factors are used to convert the terminal voltage of the antenna to field
strength.
– 8 – 62236-2 © IEC:2008
5.1.6 The preferred distance of the measuring antenna from the centreline of the track on

which the vehicle is moving is 10 m. In the case of the log-periodic antenna, the 10 m

distance is measured to the mechanical centre of the array.

It is not considered necessary to carry out two tests to examine both sides of the vehicle,

even if it contains different apparatus on the two sides, since the majority of the emission is

produced by the sliding contact if the train is moving.

Where the tests are carried out at a site which meets all the recommended criteria except that

the antennas are not 10 m from the track centreline, the results can be converted to an

equivalent 10 m value by using the following formula:

E = E + n × 20 × log (D/10)
10 x 10
where
E is the value at 10 m;
E is the measured value at D m;
x
n is a factor taken from the table below.

Frequency range
n
9 kHz to 150 kHz 2
0,15 MHz to 0,4 MHz 1,8
0,4 MHz to 1,6 MHz 1,65
1,6 MHz to 110 MHz 1,2
110 MHz to 1 000 MHz 1,0
The measured values (at the equivalent 10 m distance) shall not exceed the limits given in
Figure 1 for the appropriate system voltage.
Where the physical layout of the railway totally prevents the use of reference distances, a
method shall be agreed to suit the particular circumstances. For example, if the railway is in
tunnel, miniature antennas can be used on the wall of the tunnel. In such a case, the limits
selected shall take into account the method of measurement.
5.1.7 The height above rail level of the antenna centre shall be within the range 1,0 m to 2,0
m for the loop antenna, and within 2,5 m to 3,5 m to the centre of dipole or log-periodic
antennas. If the level of the ground at the antenna differs from the rail level by more than 0,5
m, the actual value shall be noted in the test report.

The plane of the loop antenna shall be vertical and parallel to the line of the track. The
biconical dipole shall be placed in the vertical and horizontal axis. The log periodic antenna
shall be arranged to measure the vertical and horizontal polarisation signal, with the antenna
directed towards the track.
Figures 3, 4 and 5 show the positions and vertical alignments of the antennas.
5.1.8 In the case of elevated railway systems, if the antenna heights specified above cannot
be achieved, the height of the antenna centre can be referenced to the level of the ground
instead of to the rail level. The conversion formula in 5.1.6 shall be employed where D is the
slant distance between the train and the antenna. The train shall be visible from the location
of the antenna and the axis of the antenna shall be elevated to point directly at the train. A
measurement distance of 30 m from the track centreline is preferred for highly elevated
railways. Full details of the test configuration shall be noted in the test report.

62236-2 © IEC:2008 – 9 –
5.1.9 If tests are being done on a railway with overhead electrified supply, the measuring

point shall be at the mid-point between the support masts of the overhead line and not at a

discontinuity of the contact wire. It is recognised that resonance can exist in an overhead

system at radio frequencies and this may require changes in the values of frequency chosen

for measurement. If resonance exists, this should be noted in the test report.

The radio frequency emission will be affected by the state of the railway supply system.

Switching of feeder stations and temporary works will influence the response of the system. It

is therefore necessary to note the condition of the system in the test record and, if possible,

all similar tests should be carried out within the same working day. Where the railway has a
track-side conductor rail power supply, the test location should be at least 100 m from gaps in
the rail, to avoid inclusion of the transient fields associated with the make and break of

collector contact. The conductor rail and the antennas shall be on the same side of the track.
5.1.10 The test sites do not correspond to the definition of a completely clear site because
they are influenced by overhead structures, rails and the catenary. However, wherever
possible, antennas shall be placed well away from reflecting objects. If overhead power lines
are nearby, other than those which are part of the railway network, they should be no closer
than 100 m to the test site.
5.1.11 The values measured are expressed as:
– dBμA/m for magnetic fields,
– dBμV/m for electrical fields.
These are obtained by using the appropriate antenna factors and conversions.
5.1.12 Background noise shall be measured at the test site in the absence of train effects.
This will give the noise values from the energised power supply conductors. If this is
significant, it is advisable to measure also at 100 m from the test site, to identify any high
non-railway sources of noise.
5.2 Frequency selection
5.2.1 Selected frequencies
The selection of the actual frequencies to be measured will depend on the circumstances of
the test site.
If high signals exist, for example from public broadcasting stations, the selection of test
frequencies shall take this into account.

It is recommended that test frequencies are selected so that there are at least three
frequencies per decade.
5.2.2 Sweep frequency
In view of the short time available for measurement in one train passage, the use of a sweep
frequency measuring technique, in which the peak noise is measured with a peak-hold circuit
as the frequency is changed, may offer adequate information concerning generation of noise.
There will still remain problems of time because the rate of change of frequency is a function
of the bandwidth, due to considerations of accuracy. A sweep analyser will usually set its own
sweep rate to meet this requirement. If this method is used, sweep rate as well as bandwidth
shall be noted.
– 10 – 62236-2 © IEC:2008
5.3 Transients
During the test, transients due to switching may be detected, such as those caused by

operation of power circuit breakers. These shall be disregarded when selecting the maximum

signal level found for the test.

5.4 Measuring conditions
5.4.1 Weather conditions
To minimise the possible effect of weather on the measured values, measurements should be

carried out in dry weather, (after 24 h during which not more than 0,1 mm rain has fallen),

o
with a temperature of at least 5 C, and a wind velocity of less than 10 m/s.
Humidity should be low enough to prevent condensation on the power supply conductors.
Since it is necessary to plan the tests before the weather conditions can be known, tests will
have to be made in weather conditions which do not meet the target conditions. In these
circumstances, the actual weather conditions shall be recorded with the test results.
5.4.2 Railway operating modes
Two test conditions are specified for the traction mode and are:
a) measurement at a speed of more than 90 % of the maximum service speed, (to ensure
that the dynamics of current collection are involved in the noise level) and at the maximum
power which can be delivered at that speed.
b) at the maximum rated power and at a selected speed, (particularly if the lower frequencies
are of concern).
If the vehicle is capable of electric braking, tests are required at a brake power of at least
80 % of the rated maximum brake power.
5.4.3 Multiple sources from remote trains
For the purpose of limits, the presence of "physically-remote but electrically-near" vehicles out
of the test zone is regarded as insignificant when considering radio noise.
5.5 Test report
The test report shall contain the following information.
– description of site;
– description of measuring system;
– description of railway vehicle (type and configuration);
– numerical results;
– graphical results where relevant (the results shall include information such as bandwidths,
date, time);
– weather conditions;
– name of person in charge at site.
5.6 Antenna positions
Figure 3 shows the position of the antenna for measurement of the magnetic field in the
9 kHz to 30 MHz frequency band.

62236-2 © IEC:2008 – 11 –
Figure 4 shows the position (vertical polarisation) of the antenna for measurement of the

electric field in the 30 MHz to 300 MHz frequency band. For the measurement of the

horizontal field parallel to the track, the antenna is turned by 90°.

Figure 5 shows the position (vertical polarisation) of the antenna for measurement of the

electric field in the 300 MHz to 1 GHz frequency band. For the measurement of the horizontal

field parallel to the track, the antenna is turned by 90°.

– 12 – 62236-2 © IEC:2008
IEC 2172/08
NOTE 1 The discontinuities of the curves are due to changing of the bandwidth of the measurement receiver:
bw1 = 200 Hz; bw2 = 9 kHz; bw3 = 120 kHz.
NOTE 2 Values are 10 m from the railway track.
Figure 1 – Emission limits in frequency range 9 kHz to 1 GHz
Peak values
dB  (μA/m)
dB  (μV/m)
120 120
100 100
A
B
80 80
C
60 60
A
A
B
B
C
C
0 0
100 kHz 1 MHz 10 MHz
1 GHz
10 kHz
100 MHz
Frequency  Hz
150 kHz
30 MHz
9 kHz
bw3
bw1 bw2
E field
H field
A = 20/25 kV a.c. B = 15 kV a.c., 3 kV d.c. and 1,5 kV d.c. C = 750 V and 600 V d.c. including trams/trolleybuses for
use in city streets
62236-2 © IEC:2008 – 13 –
Quasi-peak values
H field dB(μA/m) E field dB(μV/m)

−10
0,001 0,1 10 1 000
Frequency  (MHz)
IEC 2173/08
Figure 2 – Emission limit for substations

dB
– 14 – 62236-2 © IEC:2008
Sensor: loop antenna for magnetic field H

1 to 2 m
Track on which rolling stock to
be tested is running
10 m
to mechanical centre of antenna
Measuring receiver Graph recorder
Computer Printer
IEC 2174/08
Figure 3 – Position of antenna for measurement of magnetic field
in the 9 kHz to 30 MHz frequency band

62236-2 © IEC:2008 – 15 –
Sensor: biconical dipole
3 m
Track on which rolling stock to
be tested is running
10 m
to mechanical centre of antenna
Measuring receiver Graph recorder
Computer Printer
IEC 2175/08
Figure 4 – Position (vertical polarisation) of antenna for measurement
of electric field in the 30 MHz to 300 MHz frequency band

– 16 – 62236-2 © IEC:2008
X
Sensor: log periodic antenna
3 m
X X
2 2
Track on which rolling stock to
be tested is running
10 m
to mechanical centre of antenna
Measuring receiver Graph recorder
Computer Printer
IEC 2176/08
Figure 5 – Position (vertical polarisation) of antenna for measurement
of electric field in the 300 MHz to 1 GHz frequency band

62236-2 © IEC:2008 – 17 –
Annex A
(normative)
Method of measurement of electromagnetic emission

from railway substations
A.1 Positions for tests
In view of the special geometry of a railway traction supply system, it is necessary to define

the conditions for the measurement of emission of electromagnetic fields under normal load
conditions.
A.2 Substation load
A feature of railway substations is that the load can change widely in short times. Since
emission can be related to load, the actual loading of the substation shall be noted during
emission tests.
A.3 Method of measurement
Emission shall be measured at a distance of 10 m from the outer fence of the substation, at
the midpoints of the three sides, excluding the side which faces the railway, unless this side is
more than 30 m from the centre of the nearest electrified railway track. In this case all four
sides shall be measured. If the length of the side of the substation is more than 30 m,
measurements shall be taken additionally at the corners.
The accuracy of the measuring equipment for the radio frequency tests shall not differ by
more than ± 4,0 dB from the requirements of CISPR 16-1-1.
At each measuring position, the following shall be measured:
a) the maximum radio emission at a frequency in the neighbourhood of 1 MHz (selected on
site to avoid other transmissions), measured by vertical plane loop antenna, noting the
orientation of the antenna. The loading of the substation shall be at least 30 % of the rated
load. The base of the loop antenna shall be between 1 m and 1,5 m above ground;
b) the radio emission over the frequency range 9 kHz to 30 MHz, measured with the loop in
the maximum orientation position as under a). The loading of the substation shall be at
least 30 % of the rated load during these measurements;
NOTE It is accepted that the fixed antenna position may result in values being less than the absolute
maximum at some frequencies.
c) the maximum radio emission over the frequency range 30 MHz to 300 MHz, measured
typically by vertical dipole or vertical biconical antenna. The loading of the substation shall
be at least 15 % of the rated load during the measurements. The centre of the antenna
shall be 3 m above ground,
d) the maximum radio emission at a frequency in the neighbourhood of 350 MHz (selected on
site to avoid other transmissions), measured typically by vertical polarised log-periodic
antenna, noting the orientation of the antenna. The loading of the substation shall be at
least 15 % of the rated load. The centre of the antenna shall be 3 m above ground,
e) the radio emission over the frequency range 300 MHz to 1 GHz, be measured typically
with the log-periodic antenna in the maximum orientation position as under d). The loading
of the substation shall be at least 15 % of the rated load during these measurements. The
centre of the antenna shall be 3 m above ground.

– 18 – 62236-2 © IEC:2008
Annex B
(informative)
Background to the method of measurement

B.1 General
This annex describes a method of measuring the electromagnetic noise emitted by a railway

network when railway vehicles are moving on the network. Existing methods are not

considered to be appropriate because the vehicles may be moving at significant speeds.
IEC 62236-3-1 covers the case of stationary and slow moving vehicles. Both traction and
trailer vehicles should be examined since the trailers may contain electric equipment which
can emit noise. It is also necessary to test diesel traction vehicles since they may contain
sources of radio emission. The method allows an assessment to be made of the disturbance
which would be caused to other users of the electromagnetic spectrum. The standard
describes a reference method of measurement.
B.2 Requirement for a special method of measurement
For frequencies above 9 kHz, there is a standard method of measuring radio fields and this is
described in CISPR 16-1-1.
A railway network has particular features which make necessary the use of a special method
of measurement. These features include a rapidly moving source and the possibility of
radiation from the long antenna formed by the electrical supply conductors of an electrified
railway.
The example given in Figure B.1 shows the time variation of emission from a moving train with
many transient events.
This method of measuring railway noise does not follow the quasi-peak method of CISPR 16-
1-1 because measurements conducted on the basis of that method are not sufficient to enable
the full extent of the disturbances affecting other systems in the vicinity to be identified. The
method of CISPR 16-1-1 is only designed to protect radio communication from interference
and takes no account of electronic safety systems such as those used beside the railway
track or at airports, where short-time transients may cause interference. If the CISPR 16-1-1
method were to be selected as a basis for European Standards, it would still be necessary to
apply peak detection methods to meet the needs of local industry and undertake realistic
simulation exercises. In the case of railways, this need for double testing would lead to

difficulties.
It appears difficult to establish an exact link between the values obtained with the peak and
quasi-peak methods, in view of the fact that the disturbances created by the vehicle may be
almost constantly sinusoidal at the working frequency of some of the on-board ground-to-train
transmission equipment, or a series of repeated pulses for other sources, for example the
pantograph/overhead line contact. However, in all cases, the value measured with a peak
detection system will be greater than or equal to the value obtained with a quasi-peak system
in accordance with CISPR 16-1-1.
B.3 Justification for a special method of measurement
Fields are not measured using the method of CISPR 16-1-1, but are made with peak detection
within a short time window, 50 ms being recommended, at the selected frequency because:

62236-2 © IEC:2008 – 19 –
– this gives a better representation of the effect on any system (electronic or computer),

whereas the weighting principles applied with quasi-peak detection are only representative

of interference in relation to radio transmission, the time window of 50 ms will capture the

peak emission from a.c. railways which tends to occur at current reversals. On 16,7 Hz,

these reversals are 33 ms apart and one will always be detected within the 50 ms window;

– it is also faster, for with some quasi-peak detector systems as much as 1 s is necessary

because of the requirements of galvanometer-type instruments. This is far too long in the

case of a moving train;
– it gives the maximum value that could be measured with the method of CISPR 16-1-1 and

is representative of the "worst possible case" for interference to radio transmission.

B.4 Frequency range
Although the railway vehicle and sliding contact current collection are also sources of noise
above 1 GHz, the emission levels are low and attenuation with distance is high. Therefore, no
proposals are made at present for measurements above 1 GHz.
B.5 Comments to bandwidth
Bandwidths other than those given in 5.1.2 are available in suitable measuring equipment,
such as 300 Hz for the 9 kHz to 150 kHz band, and 7,5 kHz or 10 kHz for 0,15 MHz to
30 MHz. In the 9 kHz to 150 kHz band, the bandwidth is small, but this is valuable since it
improves the ability to find specific sources of noise. In the 0,15 MHz to 30 MHz range, the
difference between 7,5 kHz, 9 kHz and 10 kHz will not be significant in terms of identification.
If bandwidths other than those given above are used, the results shall be converted to the
approved bandwidth on the basis that the noise is impulsive in nature
B.6 Accuracy of the measurement equipment
The accuracy value ± 4 dB given in 5.1.3 is chosen since it is known that a test repeatability
of ± 10 dB or more is found for nominally similar conditions. The measuring sets defined in
CISPR 16-1-1 are very accurate but this accuracy is unreal when the emission varies so much
between tests. The use of measuring apparatus of less accuracy may be permitted (sweep
frequency analysers for example), where it has been verified that the results do not differ by
more than ± 4 dB from CISPR 16-1-1 apparatus. Sweep analysers are available with peak and
quasi-peak detection, and bandwidths given in CISPR 16-1-1.
B.7 Antenna positions
There are options for choosing the distance of the antenna from the centre-line of the track.
The usual distances used for radio frequency tests are 1 m, 3 m, 10 m and 30 m. A value of
1,0 m is impossible and if 3 m is chosen, there is a possibility that the vehicle body will have a
very strong local effect and this may give a false impression of the field at greater distances.
A distance of 10 m is preferred since, with an electric traction supply, the sliding contact is
directly viewed by the antenna and body effects are less. Another standard distance is 30 m
and this may be easier to provide at particular sites, but the signal strength is lower and local
noise may make it more difficult to obtain values of railway noise. Hence, the distance
selected for measurements is 10 m in relation to the centre line of the track on which the
vehicles are running.
NOTE Steps should be taken to ensure that the measuring equipment and any associated power supply and
apparatus does not affect the readings.

– 20 – 62236-2 © IEC:2008
B.8 Conversion of results if not measured at 10 m

The values of n are based on observations made with overhead power lines and are for open

country sites. In built-up urban areas, higher values of n will be found. The values of n listed

in 5.1.6 are known to be adequately accurate since the value of n for 100 MHz was

specifically measured for a railway and was found to be 1,25, for distances up to 100 m.

CISPR 22 uses –20 dB per decade of distance (n = 1), but this is a special case for a

conducting ground plane.
When testing at 10 m, it is important to recall that the induction field and the radiation field

have different characteristics near to the source. If the distance is small compared to the

wavelength, the induction field will predominate. The position with respect to a point source at
which these two fields have equal magnitudes is at a theoretical distance of (wavelength/2π).
Hence, if 10 m is taken as the measuring distance, all tests below about 5 MHz are in the
near field where the magnetic induction signal dominates. Results are then most accurately
expressed in A/m. In the near field, the E field is low and is not usually a cause of
disturbance. With an extended source such as a train, the near field
...