kSIST FprEN 50121-3-1:2026

• Abstract:

  This document specifies the emission limits and immunity requirements for all types of rolling stock. It covers traction stock, hauled stock and trainsets including urban vehicles for use in city streets.; The scope of this part of the standard ends at the interface of the rolling stock with its respective energy inputs and outputs. In the case of locomotives, trainsets, trams etc., this is the current collector (pantograph, shoe gear). In the case of hauled stock, this is the AC or DC auxiliary power connector. However, since the current collector is part of the traction stock, it is not entirely possible to exclude the effects of this interface with the power supply line. The slow moving test has been designed to minimize these effects.; The frequency range from 150 kHz to 1 GHz is considered sufficient to protect the environment in the whole frequency range from 0 Hz (DC) to 400 GHz. For demonstration of compatibility in this document only measurements at the specified frequencies are required.

• Status: Not Published
• Public Enquiry End Date: 30-Sep-2025
• ICS: 33.100.01 - Electromagnetic compatibility in general
• ICS: 45.060.01 - Railway rolling stock in general
• ICS: 45.140 - Metro, tram and light rail equipment
• Technical Committee: ŽEN - Electrical applications for railways
• Current Stage: 5020 - Formal vote (FV) (Adopted Project)
• Start Date: 22-Sep-2026
• Due Date: 10-Nov-2026
• Ref Project: FprEN 50121-3-1:2026 - Railway applications - Electromagnetic compatibility - Part 3-1: Rolling stock - Train and complete vehicle

• Revises: SIST EN 50121-3-1:2017/A1:2019 - Railway applications - Electromagnetic compatibility - Part 3-1: Rolling stock - Train and complete vehicle
• Effective Date: 09-Apr-2024
• Revises: SIST EN 50121-3-1:2017 - Railway applications - Electromagnetic compatibility - Part 3-1: Rolling stock - Train and complete vehicle
• Effective Date: 09-Apr-2024

kSIST FprEN 50121-3-1:2026 is a CLC standard for railway applications - Electromagnetic compatibility (EMC) - Part 3-1. It specifies emission limits and immunity requirements for rolling stock, including traction stock, hauled stock and trainsets, so manufacturers, integrators, test labs and purchasers can assess the whole vehicle rather than only the installed equipment.

The standard defines the vehicle-level EMC boundary up to the current collector or auxiliary power connector, and it sets how radiated emissions are measured and judged for stationary and slow-moving tests. In practice, it tells the reader what to test, under which operating modes, and what supporting documents and companion standards to use.

What does kSIST FprEN 50121-3-1:2026 specify?

kSIST FprEN 50121-3-1:2026 specifies the EMC performance of complete rolling stock at the vehicle level. It covers all types of rolling stock, including urban vehicles used in city streets, and it focuses on emissions and immunity at the interface with the energy inputs and outputs of the vehicle.

The document is organised into clauses on scope, normative references, terms and abbreviations, overall aspects, emission, and immunity, followed by four informative annexes.

Annex	What it covers
Annex A	Interference on telecommunication lines, including psophometric current
Annex B	Radiated electromagnetic disturbances - measurement procedure
Annex C	Emission values for the lower frequency range
Annex D	Justification of limits

The scope is limited to the rolling stock itself. For locomotives, trainsets and trams the boundary is the current collector, such as pantograph or shoe gear; for hauled stock it is the AC or DC auxiliary power connector. The document also states that, for compatibility demonstration, only measurements at the specified frequencies are required.

What are the key requirements of kSIST FprEN 50121-3-1:2026?

Test the vehicle in typical operating modes that create the highest emission

Clause 4 requires testing in the operating modes that are expected to produce the largest emissions. Systems normally in continuous service must be energised, but transient functions such as door operation do not need to be exercised, and degraded modes are not required. In practice, the test plan must describe the exact vehicle configuration and mode of operation, and the test report must record the actual test conditions.

Clause 4 also links vehicle-level compliance to apparatus-level compliance. Apparatus intended for integration into a vehicle should meet prEN 50121-3-2:2025, and where that is not fully demonstrated, the standard expects integration measures or an EMC analysis and test to justify the deviation.

Use separate emission methods for hauled stock and traction stock

Clause 5 distinguishes between hauled stock and traction stock. Hauled stock is tested in a stationary, energised condition, with auxiliary converters, battery chargers and similar equipment operating. Traction stock is tested both while stationary and while moving slowly, because the moving test captures emissions linked to traction and current collection.

For traction stock, the stationary test keeps the auxiliary converters operating while the traction converters are under voltage but not operating. The slow-moving test uses a low speed that avoids arcing or bouncing of the sliding contact but still allows electric braking. If the slow-moving test is replaced by a stationary test with tractive effort, the slow-moving limits still apply. Vehicles using onboard energy storage for traction also use the slow-moving procedure and limits for the charging process.

Control the test site and background noise

Clause 5.3.1 requires measurements in a well-defined, reproducible environment. The site should give a clear view between the antenna and the vehicle under test, with no obstacles above rail level that can influence the measurement. The exact site and relevant features of the overhead system should be recorded.

The standard also requires ambient noise measurements at the beginning and end of the test series. If ambient noise at a frequency is less than 6 dB below the limit, those frequencies are not used for the evaluation and must be identified in the report. This matters because nearby power systems, resonances and other railway traffic can otherwise distort the result.

Apply the defined limit lines and receiver settings

Clause 5.3.3 sets the emission limits at 10 m from the centre of the track. Stationary testing uses quasi-peak (QP) values, while slow-moving testing uses peak values. The receiver bandwidths are linked to EN IEC 55016-1-1:2019.

This is the part of the standard that turns the test into an acceptance decision. The reader needs to know the distance, the detector type and the receiver settings, because changing any of them changes the measured result.

Treat immunity at the complete-vehicle level through integration

Clause 6 states that no immunity tests are applied to the complete vehicle. Instead, the assembly of the apparatus into the complete vehicle is considered to provide adequate immunity when an EMC plan has been prepared and implemented, taking installation and cabling rules into account.

For a buyer or integrator, this means the document does not ask for a vehicle-level immunity campaign. It expects the vehicle design process to control immunity by how equipment is selected, installed and interconnected.

Use Annex A for telecommunication-line interference, if that is part of the procurement

Annex A gives background on interference to telecommunication lines caused by harmonics in traction current. It explains the psophometric current concept and shows how the purchaser of tractive stock may specify a weighted current limit at the vehicle interface.

In practice, Annex A is the place to look when a project must control interference with nearby analogue telecommunication lines. It also notes that alternative frequency-weighting methods may be specified if they suit the project better.

What terms does kSIST FprEN 50121-3-1:2026 define?

• Traction stock - electric and diesel locomotives, high speed trainsets, multiple units, and light rail vehicles such as trams, trolleybuses and underground trainsets.
• Hauled stock - passenger coaches and freight wagons that can be hauled by locomotives, including vehicles with electric apparatus such as freezing equipment.
• Main line vehicle - a vehicle mainly designed to operate between cities, such as a high speed train, suburban train or freight train.
• Urban vehicle - a vehicle mainly designed to operate within a city boundary, such as an underground trainset, tram, LRV or trolleybus.
• Unit - the smallest part of a vehicle, for example a coach, wagon or locomotive.
• Electro Magnetic Compatibility (EMC) - the ability of the vehicle and its equipment to operate without creating unacceptable disturbance or suffering unacceptable disturbance.
• Equipment Under Test (EUT) - the vehicle or unit being measured during the EMC test programme.

Who uses kSIST FprEN 50121-3-1:2026?

This standard is used by rolling stock manufacturers, vehicle integrators, EMC engineers, test laboratories, railway operators, purchasers of tractive stock and infrastructure managers. They use it to define the EMC test plan, choose test modes, position antennas, record ambient noise, and document compliance for complete vehicles.

It is also relevant to teams responsible for installation and cabling inside the vehicle, because Clause 6 ties immunity at the complete vehicle to the way equipment is integrated. For procurement, Annex A is especially relevant where interference with telecommunication lines must be specified in the contract or technical conditions.

What changed in kSIST FprEN 50121-3-1:2026 from the previous edition?

The draft states that it will supersede EN 50121-3-1:2017 and EN 50121-3-1:2017/A1:2019. The changes listed in the European foreword are:

• clarification of the scope, especially the last paragraph
• update of the normative references
• new definition of unit
• new Clause 4 on overall aspects
• update of Clause 5 on emission, including Figures 1 and 2
• update of Clause 6 on immunity
• update of Annex B, especially B.2 on measuring equipment and test method
• update of Annex C, including Figures C.1 and C.2
• new informative Annex D with justification of limits
• deletion of Annex ZZ

Which standards are used with kSIST FprEN 50121-3-1:2026?

Standard	What it contributes
prEN 50121-1:2025	General part of the EN 50121 series; the document is read with it
prEN 50121-3-2:2025	Apparatus-level EMC requirements for equipment installed in rolling stock
EN IEC 55016-1-1:2019	Measuring apparatus and methods for radio disturbance and immunity receivers
IEC 60050-161:1990	EMC terminology used for definitions in Clause 3
prEN 50121-2:2025	Measurement method guidance for whole railway system emissions, cited in Annex B
EN 50388-1:2022	Background on coordination between traction power supply and rolling stock, cited in Annex C
ITU-T O.41 and ITU-T K.68	Psophometric weighting and protection of telecommunication lines, used in Annex A
CLC/TS 50238-2:2020 and CLC/TS 50238-3:2022	Compatibility with track circuits and axle counters, cited in the bibliography

What does the kSIST FprEN 50121-3-1:2026 document contain?

kSIST FprEN 50121-3-1:2026 contains the main EMC framework for complete rolling stock, plus annexes that explain measurement and justification. The body includes the test boundary, operating-mode rules, emission clauses, and the immunity approach.

Annex B provides a practical radiated-emission measurement procedure, including time-domain scanning, receiver subranges and equipment requirements. Annex A explains psophometric current for telecommunication-line interference, including how to measure and interpret it on board the traction vehicle.

Annex C presents informative emission values in the lower frequency range, and Annex D explains why the limits are set the way they are. Annex D also includes the method for combining ambient noise with vehicle emissions when the background signal is correlated with the measurement.

SLOVENSKI STANDARD
oSIST prEN 50121-3-1:2025
01-september-2025
Železniške naprave - Elektromagnetna združljivost - 3-1. del: Vozna sredstva - Vlak
in celotno vozilo
Railway applications - Electromagnetic compatibility - Part 3-1: Rolling stock - Train and
complete vehicle
Bahnanwendungen - Elektromagnetische Verträglichkeit - Teil 3-1: Bahnfahrzeuge – Zug
und gesamtes Fahrzeug
Applications ferroviaires - Compatibilité électromagnétique – Partie 3-1 Matériel roulant –
Trains et véhicules complets
Ta slovenski standard je istoveten z: prEN 50121-3-1:2025
ICS:
33.100.01 Elektromagnetna združljivost Electromagnetic compatibility
na splošno in general
45.060.01 Železniška vozila na splošno Railway rolling stock in
general
oSIST prEN 50121-3-1:2025 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

oSIST prEN 50121-3-1:2025
oSIST prEN 50121-3-1:2025
EUROPEAN STANDARD DRAFT
prEN 50121-3-1
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2025
ICS 45.060.01; 45.140; 33.100.01 Will supersede EN 50121-3-1:2017; EN 50121-3-
1:2017/A1:2019
English Version
Railway applications - Electromagnetic compatibility - Part 3-1:
Rolling stock - Train and complete vehicle
Applications ferroviaires - Compatibilité électromagnétique - Bahnanwendungen - Elektromagnetische Verträglichkeit -
Partie 3-1 Matériel roulant - Trains et véhicules complets Teil 3-1: Bahnfahrzeuge - Zug und gesamtes Fahrzeug
This draft European Standard is submitted to CENELEC members for enquiry.
Deadline for CENELEC: 2025-10-24.

It has been drawn up by CLC/TC 9X.

If this draft becomes a European Standard, 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.

This draft European Standard was established by CENELEC 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, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Türkiye and the United Kingdom.

Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are aware and to
provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without notice and
shall not be referred to as a European Standard.

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2025 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Project: 79749 Ref. No. prEN 50121-3-1:2025 E

oSIST prEN 50121-3-1:2025
prEN 50121-3-1:2025 (E)
1 Contents Page
2 European foreword . 3
3 Introduction . 5
4 1 Scope . 6
5 2 Normative references . 6
6 3 Terms definitions and abbreviations . 6
7 3.1 Terms and definitions . 6
8 3.2 Abbreviations . 7
9 4 Overall aspects . 7
10 5 Emission . 8
11 5.1 General . 8
12 5.2 Interference on outside party telecommunication lines . 8
13 5.3 Radiated electromagnetic disturbances . 8
14 5.3.1 Test site . 8
15 5.3.2 Test conditions . 9
16 5.3.3 Emission limits . 9
17 6 Immunity . 11
18 Annex A (informative) Interference on telecommunication lines . 12
19 A.1 Harmonics in the traction current . 12
20 A.1.1 General . 12
21 A.1.2 Relationship between currents in railway system and noise on telecommunication lines . 12
22 A.2 Psophometric current definition . 13
23 A.3 Limits and test conditions . 13
24 A.4 Measurement of the psophometric current . 14
25 A.5 Calculation of the overall psophometric current of a trainset . 14
26 A.5.1 Current of one tractive unit. 14
27 Annex B (informative) Radiated electromagnetic disturbances - Measurement procedure . 16
28 B.1 Purpose . 16
29 B.2 Measuring equipment and test method . 16
30 Annex C (informative) Emission values for lower frequency range. 17
31 Annex D (informative) Justification of limits . 20
32 D.1 Rationale of the emission limits . 20
33 D.2 Addition of field strength . 21
34 Bibliography . 24
oSIST prEN 50121-3-1:2025
prEN 50121-3-1:2025 (E)
36 European foreword
37 This document (prEN 50121-3-1:2025) has been prepared by CLC/TC 9X “Electrical and electronic applications
38 for railways”.
39 This document is currently submitted to the Enquiry.
40 The following dates are proposed:
• latest date by which the existence of this (doa) dav + 6 months
document has to be announced at national
level
• latest date by which this document has to be (dop) dav + 12 months
implemented at national level by publication of
an identical national standard or by
endorsement
• latest date by which the national standards (dow) dav + 36 months
conflicting with this document have to be (to be confirmed or
withdrawn modified when voting)
41 This document has been prepared according to Decision 69/09 taken during the TC 9X meeting.
42 This document will supersede EN 50121-3-1:2017.
43 prEN 50121-3-1:2025 includes the following significant technical changes with respect to EN 50121-3-1:2017:
44 — clarification of scope, last paragraph;
45 — update of normative references;
46 — new definition 3.1.5 unit;
47 — new Clause 4 overall aspects;
48 — update of Clause 5 emission including Figures 1 and 2;
49 — update of Clause 6 immunity;
50 — update of normative Annex B, B.2 measuring equipment and test method;
51 — update of informative Annex C including Figures C.1 and C.2;
52 — introduction of new informative Annex D with justification of limits;
53 — deletion of Annex ZZ.
54 This document is read in conjunction with EN 50121-1:2025.
55 This standard forms Part 3-1 of the EN 50121 series published under the general title “Railway applications -
56 Electromagnetic compatibility”. The series consists of:
57 — Part 1: General;
58 — Part 2: Emission of the whole railway system to the outside world;
59 — Part 3-1: Rolling stock - Train and complete vehicle;
oSIST prEN 50121-3-1:2025
prEN 50121-3-1:2025 (E)
60 — Part 3-2: Rolling stock – Apparatus;
61 — Part 4: Emission and immunity of the signalling and telecommunications apparatus;
62 — Part 5: Emission and immunity of fixed power supply installations and apparatus.
oSIST prEN 50121-3-1:2025
prEN 50121-3-1:2025 (E)
63 Introduction
64 High power electronic equipment, together with low power microcontrollers and other electronic devices, are
65 being installed on trains in great numbers. Electromagnetic compatibility has therefore become a critical issue
66 for the design of train-related apparatus as well as of the train as a whole.
67 This Product Standard for rolling stock sets limits for electromagnetic emission and immunity in order to ensure
68 a well-functioning system within its intended environment.
69 Immunity limits are not given for the complete vehicle. prEN 50121-3-2:2025 defines requirements for the
70 apparatus installed in the rolling stock, since it is impractical to test the complete unit. An EMC plan includes
71 equipment covered by this standard.
oSIST prEN 50121-3-1:2025
prEN 50121-3-1:2025 (E)
72 1 Scope
73 This document specifies the emission limits and immunity requirements for all types of rolling stock. It covers
74 traction stock, hauled stock and trainsets including urban vehicles for use in city streets.
75 The scope of this part of the standard ends at the interface of the rolling stock with its respective energy inputs
76 and outputs. In the case of locomotives, trainsets, trams etc., this is the current collector (pantograph, shoe
77 gear). In the case of hauled stock, this is the AC or DC auxiliary power connector. However, since the current
78 collector is part of the traction stock, it is not entirely possible to exclude the effects of this interface with the
79 power supply line. The slow moving test has been designed to minimize these effects.
80 The frequency range from 150 kHz to 1 GHz is considered sufficient to protect the environment in the whole
81 frequency range from 0 Hz (DC) to 400 GHz. For demonstration of compatibility in this document only
82 measurements at the specified frequencies are required.
83 2 Normative references
84 The following documents are referred to in the text in such a way that some or all of their content constitutes
85 requirements of this document. For dated references, only the edition cited applies. For undated references, the
86 latest edition of the referenced document (including any amendments) applies.
87 prEN 50121-1:2025, Railway applications - Electromagnetic compatibility - Part 1: General
88 prEN 50121-3-2:2025, Railway applications - Electromagnetic compatibility - Part 3-2: Rolling stock – Apparatus
89 EN IEC 55016-1-1:2019, Specification for radio disturbance and immunity measuring apparatus and methods -
90 Part 1-1: Radio disturbance and immunity measuring apparatus - Measuring apparatus (CISPR 16-1-1:2019)
91 IEC 60050-161:1990, International Electrotechnical Vocabulary. Chapter 161: Electromagnetic compatibility
92 3 Terms definitions and abbreviations
93 3.1 Terms and definitions
94 For the purposes of this document, the terms and definitions given in IEC 60050-161:1990 and the following
95 apply.
96 ISO and IEC maintain terminology databases for use in standardization at the following addresses:
97 — ISO Online browsing platform: available at https://www.iso.org/obp/
98 — IEC Electropedia: available at https://www.electropedia.org/
99 3.1.1
100 traction stock
101 electric and diesel locomotive, high speed trainset, elementary fixed combination of traction stock and hauled
102 stock, electric and diesel multiple unit (no locomotive, distributed traction equipment), Light Railway Vehicle
103 (LRV) such as tram, trolley bus or any other electrical vehicle for urban mass transit, underground trainset
104 3.1.2
105 hauled stock
106 independent passenger coaches and freight wagons (if they contain electric apparatus such as freezing
107 equipment) which can be hauled in random combinations by different types of locomotives
108 3.1.3
109 main line vehicle
110 vehicle mainly designed to operate between cities
111 EXAMPLE High speed train, suburban train, freight train.
oSIST prEN 50121-3-1:2025
prEN 50121-3-1:2025 (E)
112 3.1.4
113 urban vehicle
114 vehicle mainly designed to operate within the boundary of a city
115 EXAMPLE Underground trainset, tram, LRV (Light Rail Vehicle), trolleybus.
116 3.1.5
117 unit
118 smallest part of a vehicle
119 EXAMPLE Coach, wagon or locomotive.
120 3.2 Abbreviations
121 For the purposes of this document, the following abbreviations apply.
AC Alternating Current
DC Direct Current
E Electric (field)
EMC Electro Magnetic Compatibility
EUT Equipment Under Test
H Magnetic (field)
ITU-T International Telegraph Union – Telecommunication Standardization Sector
LRV Light Rail Vehicle
QC Quadrant converters
QP Quasi-Peak
RBW Resolution Bandwidth
xDSL all types of digital subscriber lines
122 4 Overall aspects
123 Generally, it is not possible to test electromagnetic compatibility invoking every function of the rolling stock. The
124 tests shall be made at typical operating modes considered to produce the largest emission.
125 The typical operating mode shall require all systems to be energised which are normally in continuous operation
126 during service. It is not necessary during the test to exercise systems which operate transiently such as for
127 example operation of internal doors, although they should be energised. It is not necessary to test degraded
128 modes of operation.
129 The configuration and mode of operation shall be specified in the test plan based on the EMC plan according
130 prEN 50121-1:2025 and the actual conditions during the tests shall be precisely noted in the test report.
131 Basically, all apparatus to be integrated into a vehicle shall meet the requirements of prEN 50121-3-2:2025. In
132 exceptional cases, where apparatus meets another EMC Standard, but full compliance with
133 prEN 50121-3-2:2025 is not demonstrated, EMC shall be ensured by adequate integration measures of the
134 apparatus into the vehicle system and/or by an appropriate EMC analysis and test which justifies deviating from
135 prEN 50121-3-2:2025.
136 Apparatus in compliance with prEN 50121-3-2 which is incorporated into a rolling stock does not affect the
137 already proven compliance of the rolling stock with prEN 50121-3-1:2025. This excludes apparatus exempted
138 by prEN 50121-3-2:2025, Clause 4.2.
oSIST prEN 50121-3-1:2025
prEN 50121-3-1:2025 (E)
139 5 Emission
140 5.1 General
141 The emission tests and limits for rolling stock in this standard has been used since the 1990s and show sufficient
142 compatibility of rolling stock with radio and telecommunications equipment or other equipment.
143 Measurements shall be performed in well-defined and reproducible conditions. It is not possible to totally
144 separate the effects of the railway system (e.g. resonances) and the environment from the rolling stock under
145 test. The test conditions are defined in 5.3.1 and 5.3.2.
146 NOTE 1 Signalling and communication, train radio and other railway systems (axle counters, track circuits, train control
147 systems, etc.) are different in every country in terms of operating frequencies and waveforms. Therefore, compatibility
148 requirements are specified according to the type of signalling and communication systems used (see e.g.
149 CLC/TS 50238-2:2020 and CLC/TS 50238-3:2022).
150 Information about cases with radio or other railway external services with working frequencies below 150 kHz
151 can be found in the informative Annex C.
152 5.2 Interference on outside party telecommunication lines
153 No harmonized limits apply.
154 Information about interference on telecommunication lines can be found in informative Annex A.
155 5.3 Radiated electromagnetic disturbances
156 5.3.1 Test site
157 It can be assumed, that measurements will not take place in laboratory conditions. Trees, walls, bridges, tunnels
158 or other conductive objects in the vicinity of the measurement antenna could have an impact on the
159 measurement. Fences (inbetween antenna and vehicle under test) should be removed to have a clear view of
160 the antenna to the vehicle under test (poles can be left). The view must be at least clear for the unit to be
161 measured. Other railway vehicles operating in the same feeding section or nearby the measuring point can
162 affect the measurement result. Overhead/third rail discontinuities as well as substations, power lines, buried
163 lines, transformers, neutral sections, section insulators, feeding lines, etc. close to the measuring point can
164 cause additional variations.
165 These influences shall be reduced as far as practical but in any case no obstacles above rail level which can
166 influence the measurements shall be located between antenna and EUT.
167 The overhead/third rail should be a continuous line as far as practical on both sides of the measurement point
168 (typically at least 200 m).
169 Since it is impossible to avoid the support masts of the overhead, the measurement point shall be at the midpoint
170 between masts, on the opposite side of the track, in case of a double track, on the side of the track which is
171 being used. If the railway system is powered by a third rail, the antenna shall be on the same side of the track
172 (worst case).
173 Since resonances can occur in the overhead line at radio-frequencies, it can be necessary to change the test
174 site. The exact location of the test site and features of both the site and the overhead system layout shall be
175 noted.
176 NOTE 1 The contribution of the substation can be considered when assessing the emissions from the vehicle.
177 At the beginning and at the end of the test series the ambient noise shall be recorded. This measurement shall
178 be done without any influence of the vehicle.
179 If at specific frequencies or in specific frequency ranges the ambient noise is higher than the limit values less
180 6 dB, the measurements at these frequencies need not be considered. These frequencies shall be noted in the
181 test report.
oSIST prEN 50121-3-1:2025
prEN 50121-3-1:2025 (E)
182 NOTE 2 It can be helpful to perform this ambient noise measurement also with the vehicle completely powered down in
183 front of the antenna.
184 5.3.2 Test conditions
185 The tests shall cover the operation of all systems onboard the rolling stock which can produce radiated
186 emissions.
187 Hauled stock (a representative version) shall be tested while stationary in an energised mode (auxiliary
188 converters, battery chargers, etc. in operation). The antenna should be sited opposite the equipment expected
189 to produce the greatest emissions at the frequencies under measurement.
190 Tests for identical coaches or wagons are performed only once.
191 Traction stock shall be tested while stationary and at slow moving speed. During the stationary test, the auxiliary
192 converters shall operate (it is not inevitably under maximum load conditions that the maximum emission level is
193 produced) and the traction converters shall be under voltage but not operating. The antenna shall be in front of
194 the middle of each unit.
195 For the slow moving test, the speed shall be low enough to avoid arcing at or bouncing of the sliding contact
196 and high enough to allow for electric braking. The recommended speed range is (20 ± 5) km/h for urban vehicles
197 and (50 ± 10) km/h for main line vehicles. When passing the antenna, the vehicle shall accelerate or decelerate
198 with approximately 1/3 of its maximum tractive effort within the given speed range.
199 The slow moving test may be replaced by a stationary test with the vehicle operating at 1/3 of its maximum
200 tractive effort against the mechanical brakes, if the following conditions are fulfilled:
201 — the traction equipment can be operated while the vehicle is stationary;
202 — tests of electric braking are not required, if no different circuits are used in braking.
203 If the slow moving test is replaced by a stationary test with tractive effort, then the slow moving limits shall be
204 applied. In this case the test plan shall clarify that the maximum emission can be measured in front of the middle
205 of each unit. Otherwise appoint an additional location to cover for example the brake resistors.
206 Any vehicles using onboard energy storage for traction shall use the test procedure and limits for slow moving
207 test for the charging process.
208 NOTE Slow moving test procedure and limits are used for the charging process (for traction energy storing devices)
209 because it has a short duration with high energy transfer.
210 5.3.3 Emission limits
211 For details of test procedure and rational, see informative Annex B and informative Annex D.
oSIST prEN 50121-3-1:2025
prEN 50121-3-1:2025 (E)
213 Values are 10 m from the railway track
214 Figure 1 — Emission limits for stationary test, 150 kHz to 1 GHz (QP)
215 The limits are defined as quasi-peak values and the bandwidths are those used in EN IEC 55016-1-1:2019
Bandwidth
Frequencies from 150 kHz to 30 MHz 9 kHz (RBW 1)
Frequencies from 30 MHz to 1 GHz 120 kHz (RBW 2)
216 All values are measured at a distance of 10 m from the centre of the track.
oSIST prEN 50121-3-1:2025
prEN 50121-3-1:2025 (E)
218 Values are 10 m from the railway track
219 Figure 2 — Emission limits for slow moving test, 150 kHz to 1 GHz (PK)
220 All values measured at a distance of 10 m from the centre of the track in peak values.
221 6 Immunity
222 No tests are applied to the complete vehicle. The assembly of the apparatus into a complete vehicle will give
223 adequate immunity, provided that an EMC plan has been prepared and implemented, taking into account the
224 requirements in prEN 50121-3-2:2025 and rules of installation and cabling.
oSIST prEN 50121-3-1:2025
prEN 50121-3-1:2025 (E)
225 Annex A
226 (informative)
228 Interference on telecommunication lines
229 A.1 Harmonics in the traction current
230 A.1.1 General
231 The harmonics in the traction current of a railway system can induce noise in a conventional analogue
232 telecommunication system. The acceptable level of noise on conventional analogue telephone lines is specified
233 by ITU-T. The value of this noise is measured with a psophometric filter. The relationship between the current
234 absorbed or generated by the traction vehicle and the noise in the telephone line is neither under the total control
235 of the vehicle manufacturer nor of the operator of the network. Thus, it is in the responsibility of the purchaser
236 of the tractive stock in accordance with the rules of the Infrastructure manager to specify a frequency weighted
237 current limit at the vehicle interface.
238 One method commonly used is to specify the psophometric curr
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