FprEN 50641-1:2026

• Abstract:

  This document specifies requirements for the acceptance of simulation tools used for the assessment of design of electric traction power supply systems with respect to TSI Energy. This document is applicable to the simulation of AC and DC electric traction power supply systems, in the frame of assessment required by Directive (EU) 2016/797. The methods and parameters defined in this document are only intended for use in the design of the electric traction power supply system, and hence this document solely considers validation of tools within the TSI energy subsystem for all envisaged railway networks

• Status: Not Published
• Publication Date: 04-Mar-2027
• ICS: 29.280 - Electric traction equipment
• Technical Committee: CLC/TC 9X - Electrical and electronic applications for railways
• Drafting Committee: CLC/SC 9XC - Electric supply and earthing systems for public transport equipment and ancillary apparatus (fixed i
• Current Stage: 4599 - Dispatch of FV draft to CMC - Finalization for Vote
• Start Date: 07-Sep-2026
• Due Date: 06-Aug-2025
• Completion Date: 07-Sep-2026
• Directive: 2016/797/EU - Directive (EU) 2016/797 of the European Parliament and of the Council of 11 May 2016 on the interoperability of the rail system within the European Union (Text with EEA relevance)
• Mandate: M/591 - Standardisation request to the European Committee for Standardisation and the European Committee for Electrotechnical Standardisation as regards railway products in support of Directive (EU) 2016/797
• Ref Project: oSIST prEN 50641-1:2025 - Fixed Installations for Railway Applications - Requirements for the validation of simulation tools used for the design of electric traction power supply systems - Part 1: General

• Revises: EN 50641:2020 - Railway applications - Fixed installations - Requirements for the validation of simulation tools used for the design of electric traction power supply systems
• Effective Date: 05-Sep-2023

FprEN 50641-1:2026 is a CLC draft European Standard for fixed installations for railway applications. It specifies how simulation tools used to design electric traction power supply systems are accepted and validated for AC and DC networks, in assessments linked to TSI Energy and Directive (EU) 2016/797. It is written for software suppliers, assessors, and railway engineers who need a clear check of whether a tool’s core calculations for train movement and electrical load flow are fit for design studies.

What does FprEN 50641-1:2026 specify?

FprEN 50641-1:2026 covers the acceptance and validation of simulation tools used for the assessment of electric traction power supply system design. It applies to AC and DC systems and limits its use to validation for design purposes within the TSI energy subsystem.

The document is organized into clauses for scope, references, terms, symbols, general principles, test and model descriptions, plausibility checks, output verification, validation with simulated values, and assessment. It then adds normative annexes with acceptance limits and informative annexes with the tolerance logic, example graphs, and the pantograph-voltage selection method.

Annex	What it covers
Annex A	Normative train output results and validation boundary values
Annex B	Normative substation output results and validation boundary values
Annex C	Informative method for reference values and tolerances
Annex D	Informative individual graphs for each system
Annex E	Informative criteria for selecting the voltage at the pantograph
Annex ZZ	Informative relationship with EU Directive (EU) 2016/797

What are the key requirements of FprEN 50641-1:2026?

Validation focus and limits

FprEN 50641-1:2026 validates the core simulation functions, not measurement-based validation. The core functions are the train-motion algorithms, the electrical load-flow calculation, and the interaction between them. In practice, a tool must reproduce how train demand affects the supply network and how supply limits feed back into train performance.

The document also states that a validated tool can be reused for systems with the same voltage and frequency, but it does not require a particular software package. It also says that model choice and data quality still need competent engineering judgement outside the validation itself.

Test cases and data set

Clause 6 defines a benchmark network with common traffic and train-set data, then splits it into DC and AC cases. The cases cover DC 1.5 kV, DC 3 kV, AC 15 kV lumped impedance, AC 25 kV lumped impedance, AC 25 kV multiconductor, and AC 2 x 25 kV multiconductor.

This matters because the standard checks a tool against the same virtual network, timetable, and rolling-stock data. The engineer or buyer can therefore compare software output on a known scenario instead of on a site-specific project.

Train-set behaviour and electrical limits

Clause 6.3 defines three train sets: HS, SUB, and FR. It gives their mechanical and traction characteristics, running-resistance coefficients, tractive-effort curves, braking behaviour, auxiliary power, and voltage-dependent current limits.

In practice, the tool must model both traction and regenerative braking. For AC cases, current depends on voltage and power factor; for DC cases, the same current logic is used with power factor taken as 1. Clause 6.3 also requires the tractive effort to fall with speed in defined zones and the braking current to reduce linearly between the stated voltage levels.

Infrastructure, timetable, and line models

Clauses 6.4 and 6.5 define the route geometry, station positions, timetable, and electrical infrastructure for each supply system. The standard uses fixed departures, a minimum dwell time in delays, trains starting from 0 km/h, and no signalling constraints.

This is important because the simulation tool must generate the same timing and interaction between trains, substations, and line sections. The AC part allows either a lumped impedance model or a multiconductor model, while the 2 x 25 kV case also uses the autotransformer arrangement defined in the document.

Plausibility check before numerical comparison

Clause 7 requires a first pass based on graphs. The timetable graph must show the events listed for each system, and the supplementary graphs must show the expected shapes for speed, current, tractive effort, voltage, and substation behaviour.

In practice, this catches obvious model errors before the boundary-value check. The document asks readers to check the shape of the curves rather than exact numerical points in these plausibility plots.

Output verification and reporting

Clause 8 defines the outputs that must be reported: pantograph voltage, mean useful voltage, travelling time, substation current, and consumed and regenerated energy. It also sets the averaging rules, the maximum timestep for instantaneous voltage values, and the use of arithmetic means.

The practical point is that the report must be easy to compare with the standard’s tables. Clause 10 then requires a validation report identifying the software, version, provider, chosen power supply system, declared input data, any voluntary extra input, and the statement that the results fit Annexes A and B.

Cross-acceptance and change control

Clause 9 allows cross-acceptance between some model types, but not universally. It distinguishes lumped-element and multiconductor models and states when separate validation is still needed.

The document also requires validation initially and again after any revision of the core functions that can affect results. In practice, that means software updates need traceable internal software quality management before the previous validation can still be relied on.

What terms does FprEN 50641-1:2026 define?

• Assessment - an investigation carried out to reach a judgement, based on evidence, about suitability for a product.
• Simulation tool - software that implements one or more simulation methods.
• Simulation method - a numerical time-step or space-step model for train movement and electric traction power supply performance.
• Simulation accuracy - an indicator of how close simulation output is to a reference value or reference model for a given case.
• Validation - confirmation, through objective evidence, that the requirements for a specific intended use have been fulfilled.
• Verification - confirmation, through objective evidence, that specified requirements have been fulfilled.
• Contact line system (CLS) - the overhead contact line or third rail that supplies the train.
• Mean useful voltage - the weighted pantograph-voltage indicator used to judge supply quality over a zone or for one train.

Who uses FprEN 50641-1:2026?

FprEN 50641-1:2026 is used by software owners and developers who propose a simulation tool for validation, and by assessors who judge whether the tool meets the acceptance limits. It also serves railway electrification engineers, infrastructure designers, and traction-power specialists who use simulation to size and check AC or DC supply systems.

In practice, it is relevant to teams working on electric traction power supply design, TSI-related conformity work, and internal software quality management for validated calculation tools.

What changed in FprEN 50641-1:2026 from the previous edition?

FprEN 50641-1:2026 supersedes EN 50641:2020. The foreword lists these significant technical changes:

• Clause 1: minor changes.
• Clause 3: a new definition of assessment.
• Clause 5: Figure 1 changed.
• Clause 6: the normal and outage situation was replaced by one simulation context, with clarification in the text.
• Clause 7: corrected graphs and minor improvements.
• Clause 8: minor editorial changes.
• Clause 10: minor changes.
• Annexes: graphs updated, mainly because the outage situation was removed and corrections were made.

Which standards are used with FprEN 50641-1:2026?

• EN 50163:2004 - supplies the traction-system voltage terms and limits used in the tool checks, including voltage-related boundaries.
• EN 50388-1:2022 - supplies the coordination criteria between electric traction power supply systems and rolling stock, including the knee point factor, current-limitation rules, and the mean useful voltage definition used in Annex E.
• EN 50641-2 - the related part for the specific DC urban case, mentioned as the companion part to this general document.

What does the FprEN 50641-1:2026 document contain?

The document contains benchmark network descriptions, train-set data, infrastructure models, timetable tables, and the formulas used to simulate traction and braking behaviour. It also includes the current-limitation logic for traction and regenerative braking, plus the electrical models for DC substations and AC transformers.

Annexes A and B provide the acceptance bands that simulated train and substation results must fit. Annex C explains how those bands were derived from reference values and tolerances, Annex D gives example graphs for each system, and Annex E explains how to determine the pantograph voltage indicator used in the assessment.

SLOVENSKI STANDARD
01-december-2025
Fiksni postroji za železniške naprave - Zahteve za ocenjevanje simulacijskih orodij
za snovanje elektroenergetskih napajalnih sistemov električne vleke - 1. del:
Splošno
Fixed Installations for Railway Applications - Requirements for the validation of
simulation tools used for the design of electric traction power supply systems - Part 1:
General
Installations électriques dans les bâtiments - Exigences relatives à la mise en œuvre des
systèmes électriques intelligents - Partie 1 : Exigences générales
Ta slovenski standard je istoveten z: prEN 50641-1:2025
ICS:
29.280 Električna vlečna oprema Electric traction equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD DRAFT
prEN 50641-1
NORME EUROPÉENNE
EUROPÄISCHE NORM
October 2025
ICS 29.280 Will supersede EN 50641:2020
English Version
Fixed Installations for Railway Applications - Requirements for
the validation of simulation tools used for the design of electric
traction power supply systems - Part 1: General
To be completed To be completed
This draft European Standard is submitted to CENELEC members for enquiry.
Deadline for CENELEC: 2026-01-23.

It has been drawn up by CLC/SC 9XC.

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: 78575 Ref. No. prEN 50641-1:2025 E

prEN 50641-1:2025 (E)
Contents Page
European foreword . 3
1 Scope . 5
2 Normative references . 6
3 Terms and definitions . 6
4 Symbols and abbreviated terms . 8
5 General . 9
6 Test and models description . 11
6.1 General . 11
6.2 Common parameters . 11
6.3 Train set descriptions . 12
6.4 Parameters for DC models . 16
6.5 Parameters for AC models . 20
7 Plausibility of expected outputs . 26
7.1 General . 26
7.2 Validation of driven timetable . 27
7.3 Complementary Information on train journeys . 29
7.4 Complementary Information for substation results . 31
8 Verification of expected output . 32
8.1 General . 32
8.2 Train results . 33
8.3 Substation results . 34
9 Validation with simulated values . 35
10 Assessment . 36
Annex A (normative) Train output results: validation boundary value. 38
Annex B (normative) Substation output results: validation boundary values . 44
Annex C (informative) Determination of reference values and their tolerances . 48
C.1 Tolerances for determination of applied boundary values . 48
C.2 Determination of reference values . 49
Annex D (informative) Individual graphs for each system . 50
Annex E (informative) Selection criteria determining the voltage at the pantograph . 59
Annex ZZ (informative) Relationship between this European Standard and the Essential
Requirements of EU Directive (EU) 2016/797 aimed to be covered . 61
Bibliography . 62

prEN 50641-1:2025 (E)
European foreword
This document (prEN 50641-1:2025) has been prepared by CLC/SC 9XC “Electric supply and earthing
systems for public transport equipment and ancillary apparatus (Fixed installations)”, of Technical
Committee CLC/TC 9X “Electrical and electronic applications for railways”.
This document is currently submitted to the Enquiry.
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 (to be
conflicting with this document have to be confirmed or modified
withdrawn when voting)
This document will supersede EN 50641:2020 and all of its amendments and corrigenda (if any).
prEN 50641-1:2025 includes the following significant technical changes with respect to EN 50641:2020:
• Clause 1: minor changes,
• Clause 3: new definition of assessment
• Clause 5: change in Figure 1,
• Clause 6: normal and outage situation are abandoned for only one context of simulation. Clarification
in the text.
• Clause 7: corrected graphs and minor improvements,
• Clause 8: minor editorial changes,
• Clause 10: minor changes,
• Annexes: graphs have been updated, mainly due to the outage situation which disappeared and
corrections.
EN 50641 “Fixed installations for railway applications - Requirements for the validation of simulation tools
used for the design of electric traction power supply systems” consists of the following parts:
• EN 50641-1, General
• EN 50641-2, specific DC urban case
Experts representing approximately ten member states worked to draft this new document. The results and
data are taken from the most well-known representative simulation software in Europe and related experts.
This document provides a means of assessing simulation tools and provides assurance to anyone who
depends upon their output.
prEN 50641-1:2025 (E)
This document has been prepared under a standardization request addressed to CENELEC by the
European Commission. The Standing Committee of the EFTA States subsequently approves these
requests for its Member States.
For the relationship with EU Legislation, see informative Annex ZZ, which is an integral part of this
document.
prEN 50641-1:2025 (E)
1 Scope
This document specifies requirements for the acceptance of simulation tools used for the assessment of
design of electric traction power supply systems with respect to EN 50388-1:2022, Clause 8.
NOTE 1 This assessment might be done with respect to TSI Energy and Directive (EU) 2016/797.
This document is applicable to the simulation of AC and DC electric traction power supply systems. The
methods and parameters defined in this document are only intended for use in the validation of tools applied
for the design of the electric traction power supply system, for all envisaged railway networks including
those concerned by the TSI energy subsystem.
This document does not deal with validation of simulation tools by measurement.
This document focuses on the core simulation functions comprising the equations and functions which
calculate the mechanical movement of trains and also which calculate the load flow of the electrical traction
power supply system. In doing so this document provides all requirements necessary to demonstrate that
a simulation tool may be used for the purposes of TSI approval of electric traction power supply systems.
Any simulation tool which meets the acceptance requirements of the test cases in this document can be
used to determine TSI compatibility for all systems of the same voltage and frequency without any
requirement for further validation as part of the TSI assessment process.
This document includes controls for the modification of simulation tools, in particular the limits of applicability
of validation when tools are modified. These controls focus on determining whether the core functions of
the simulation model are modified.
This document provides only the requirements for demonstration of the algorithms and calculations of core
functions. The use of a certified simulation tool in accordance with this document does not, in itself,
demonstrate good practice in electric traction power supply system design, neither does it guarantee that
the simulation models and data for infrastructure or trains used in the tool are correct for a given application.
The choice and application of any models and data, of individual system components, in a design is
therefore subject to additional verification processes and not in the scope of this document. Competent
development of design models and full understanding of the limits of design tools remain requirements in
any system design. This document does not reduce any element of the need for competent designers to
lead the design process.
The test cases and data shown in Clause 6 in this document do not represent an existing network, but this
data are used as theoretical/virtual network only for the purpose of verification of the core functionality.
NOTE 2 The test case considering metro, tramways and trolleybuses using DC 600 V or DC 750 V is part 2 of this
document. This document can also be applied to subway, tram and trolley bus systems.
Additionally, the application of this document ensures that the output data of different simulation tools are
consistent when used with the same set of input data listed in Clause 6.
This document only applies to the simulation of electric traction power supply systems characteristics at
their nominal frequency for AC or DC systems. It does not consider harmonic studies, electrical safety
studies (e.g. rail potential), short circuit or electromagnetic compatibility studies over a wide frequency
spectrum. This document does not mandate the use of a particular simulation tool in order to validate the
design of an electric traction power supply system.
This document does not consider complex models with active components such as static frequency
converters.
prEN 50641-1:2025 (E)
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements 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.
EN 50163:2004, Railway applications - Supply voltages of traction systems
EN 50388-1:2022, Railway Applications - Fixed installations and rolling stock - Technical criteria for the
coordination between electric traction power supply systems and rolling stock to achieve interoperability -
Part 1: General
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 50163:2004 , EN 50388-1:2022
and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
assessor
entity that carries out an assessment
[SOURCE IEC 60050-821:2017, 821-12-05]
3.2
assessment
Undertaking of an investigation in order to arrive at a judgement, based on evidence, of the suitability of a
product
[SOURCE: IEC 60050-821:2017, 12-04]
3.3
electric traction system
electric traction power supply system
railway electric distribution network used to provide energy for rolling stock
[SOURCE: IEC 60050-811:2017, 811-36-21, modified – “electric traction power supply system” has been
added as synonym and the Note 1 to entry has been removed.]
3.4
proposer
organisation which proposes the simulation and validation
Note 1 to entry: This will normally be the software owner and or developer.
3.5
simulation accuracy
indicator dedicated to the characterization of the accuracy of the simulation output regarding a reference
(measure or theoretical model) for a given case

As impacted by EN 50163:2004/AC:2013, EN 50163:2004/A1:2007, EN 50163:2004/A2:2020 and EN
50163:2004/A3:2022.
prEN 50641-1:2025 (E)
3.6
simulation method
construction and solution of a numerical time-step or space-step model of train movement and electric
traction power supply performance
3.7
simulation tool
software implementing a simulation method(s)
3.8
software quality management
management system for software to be updated
Note 1 to entry: The processes are the following:
— software development process comprising the steps of development request, software test, release;
— life cycle process with the steps release plan, versioning with code protection and changelog, bug tracking,
documentation (user manual, help system, developer's guide if any).
3.9
track layout model
model describing the physical characteristics of the track such as curves, tunnels and gradient description
3.10
train set
combination of vehicles coupled together
Note 1 to entry: Vehicle includes banking locomotives.
3.11
train set model
model describing the electrical and mechanical characteristics of the train set
3.12
train traffic model
model of the train service and the timetable over a given time period
3.13
validation
confirmation, through the provision of objective evidence, that the requirements for a specific intended use
or application have been fulfilled
Note 1 to entry: Verification is a prerequisite for validation.
[SOURCE: IEC 60050-192:2024, 192-01-18, modified – Notes 1 to 2 to entry have been removed and a
new Note 1 to entry has been added.]
3.14
verification
confirmation, through the provision of objective evidence, that specified requirements have been fulfilled
Note 1 to entry: Whilst the general term in this document is assessment, verification is commonly understood in the
assessment of models and data analysis and its use is more specific than the general term conformity.
[SOURCE: IEC 60050-192:2024, 192-01-17, modified – Notes 1 to 3 to entry have been removed and a
new Note 1 to entry has been added.]
prEN 50641-1:2025 (E)
4 Symbols and abbreviated terms
For the purposes of this document, the following symbols and abbreviated terms apply.
A coefficient of running resistance independent of speed
a knee point factor (see EN 50388–1:2022, 7.3)
AT autotransformer
ATPP autotransformer paralleling post including paralleling of CLS
B coefficient of running resistance for linear dependence of speed
C coefficient of running resistance for quadratic dependence of speed
CLS contact line system (overhead contact line or third rail)
cos φ power factor for the traction and auxiliary power
EMU electrical multiple unit
F tractive effort
F maximum tractive effort
m
FR freight train set
F running resistance
res
HS high speed train set
NOTE This name is used as a general term and does not relate to similar definitions given in
Directive (EU) 2016/797.
I current
I current for train set auxiliaries (e.g. air conditioning)
aux
I braking current of the train set
braking
I maximum current consumed by the train set at U
max n
Ind inductive behaviour
N/A not applicable
P auxiliary active power
aux
P maximum mechanical power
max
PP paralleling post where CLS of both tracks are electrically connected
R equivalent internal resistance of a substation
eq
SP sectioning point of the CLS for each track.
SS substation including paralleling of CLS
SUB suburban train set
TSI technical specification of interoperability
U no load voltage at a substation for DC traction system
di0
U no load voltage at a substation for AC traction system
U short circuit voltage of a transformer
cc
UIC60 rail profile with a mass of 60 kg/m, also referenced as CEN 60E1 within
EN 13674-1:2011+A1:2017, Table A.1
U highest permanent voltage (see EN 50163:2004 )
max1
U highest non-permanent voltage (see EN 50163:2004 )
max2
U mean useful voltage (see EN 50388–1:2022, 8.2)
mean useful
U lowest non-permanent voltage (see EN 50163:2004 )
min2
prEN 50641-1:2025 (E)
U nominal voltage for a given electrical supply system
n
U current collector voltage
p
V speed in km/h
v transfer speed 1 (transfer from adhesion characteristic to maximum voltage characteristic of
drive)
v transfer speed 2 (transfer from maximum voltage characteristic to torque limitation
characteristic of drive)
v maximum speed
v maximum allowed speed (track, train set)
max
Z transformer impedance
TR
η traction/braking efficiency
µ relative permeability
r
5 General
This document considers the acceptance of typical impedance based models of electric traction power
supply systems at fundamental frequency or DC. Both lumped and multiconductor impedance models are
covered, but this document does not consider complex models of active components such as a static
frequency converter.
The theoretical study of the interactions between the operation of rolling stock and the power supply system
by means of computer simulation is generally used to obtain detailed information about a traction power
system. This minimizes the costs of live tests, and as a consequence optimises the investment to be made
for a given performance of the electrical railway system.
Depending on the type of the supply system (for example: AC or DC system), the simulation tools require
different data and different system descriptions. Therefore the scope of the simulation should be defined in
advance, taking account of possible supply systems (see Figure 1). The assessment process of the
simulation is in two parts. Firstly, a validation process is undertaken which compares in a qualitative way
specific characteristics of the key simulation output graphs, in order to validate the performance of the
simulation at critical events. Secondly, the quantitative verification of the simulation is assessed by
comparing key calculated values with those given in this document. The verification process laid out in this
document is based on a verification using a defined benchmark example of an electric traction power supply
system, and employing a common set of input data incorporating the infrastructure (including station
locations, gradient, speed limit), types of train sets and timetable.
NOTE The output data sets have been developed through assessment with several existing simulation tools,
currently used in electric traction power supply system design, and which therefore represent a range of differences
within core algorithms. The simulation accuracy of the outputs from these tools were compared, and tolerances applied
to cover the range of variation considered reasonable across all tools. The observed variation in these tools has no
effect on their applicability for use in TSI assessments, and hence this range of tolerance can be applied to the
acceptance of new tools. Annex C gives information on the calculation methodology of tolerances for determination of
applied boundary values.
The following cases are provided in the standard:
— DC 1,5 kV,
— DC 3 kV,
— AC 15 kV, lumped element,
— AC 25 kV, lumped element,
— AC 25 kV, multi-conductor model,
prEN 50641-1:2025 (E)
— AC 2x25 kV, multi-conductor model.
In order to obtain an acceptable verification of a simulation tool, the results of the simulation tool shall be
compared with the output results presented in this document according to the criteria described in
Annexes A and B.
In order to use a simulation tool with confidence, it shall be validated initially and after each revision of the
core functions of the software that have an impact on the simulation results. If the modification affects a
core function then a new validation is necessary. The validation shall be done by following the steps shown
in Figure 1.
Core functions of the simulation tools are the algorithms to:
— solve the differential equations of train sets movement resulting in power demand at current
collector(s);
— calculate the load flow (current-voltage) of the electrical network with changing configurations caused
by moving loads.
Interaction between mechanical and electrical core functions are required to provide an integrated solution,
where lack of electrical power will feedback to influence the train set movement including iterations as
necessary.
The core functionality comprises the algorithms of mechanical train movement, the electrical network load
flow, and the interaction between mechanical and electrical core functions required to provide an integrated
solution.
Any change of the validated simulation tool requires an internal validation as described in Figure 1.
The organization holding the validation certificate may assess such changes, subject to the requirements
for internal software quality management to provide a traceable audit process to these changes.
prEN 50641-1:2025 (E)
Figure 1 — Steps of validation
6 Test and models description
6.1 General
Common parameters for both AC and DC systems are given in 6.2 and 6.3. Parameters specific to DC and
AC systems are given respectively in 6.4 and 6.5.
The test case configurations and data are used for the purpose of the standard only. They do not represent
typical applications for system design.
6.2 Common parameters
The test case describes simple traffic along a given open air double track straight line. Although there are
some differences due to the different supply systems, some parameters remain identical among the test
cases, in particular:
— traffic timetable;
prEN 50641-1:2025 (E)
— train set.
The maximum track operational speed is 200 km/h for all train types.
The general description of the case is described in Figure 2. Distances are indicated in Tables 2 and 3 for
DC cases and Tables 6 and 7 for AC cases.

Figure 2 — Test case general description
Three different kinds of train set are defined throughout the test case:
a) high speed train set;
b) suburban train set;
c) freight train set.
6.3 Train set descriptions
6.3.1 Type of train set and mechanical characteristics
The mechanical characteristics for the three different kinds of train set of this test case are provided as
follows:
a) high speed train set (HS): locomotive and coaches;
b) suburban train set (SUB): EMU;
c) freight train set (FR): locomotive and wagons.
The parameters shall be as specified in Table 1.
prEN 50641-1:2025 (E)
Table 1 — Train set mechanical and traction characteristics
SUB
Type Unit HS FR
(2 units)
Speed v km/h 110 50 80
Speed v km/h 180 140 140
Speed v km/h 220 160 160
Maximum allowed train set speed km/h 220 160 100
Maximum Tractive effort F kN 250 320 250
m
Tractive effort at v kN 152,8 114,3 143
Tractive effort at v kN 102 87,5 109,4
Total mass t 580 400 1 580
Rotating mass t 58 40 158
Efficiency (η) - 85 % 85 % 85 %
Power factor at the pantograph (traction /
- 0,96 ind. 0,96 ind. 0,96 ind.
a
braking and auxiliaries)
Auxiliary active power P MW 0,5 0,4 0
aux
A kN 9,23 3,351 6 24,3
B kN/(km/h) 0,015 8 0,008 208 0,084 7
C kN/(km/h) 0,001 23 0,000 66 0,004 03
Locomotive(s) - 1 2 (EMU) 1
Coaches/wagon - 10 - 25
Max permissible deceleration m/s 0,8 1 0,5

a
Applicable only to the AC cases; for DC cases the power factor is 1.
For the locomotives for the HS and FR train sets, the individual parameters shall be:
— mass: 80 t.
The running resistance shall be defined using a formula: F = A + B x v + C x v with v the speed in km/h.
res
The A, B and C coefficients apply to the whole train set.
Additionally, it shall be understood that:
— the tractive effort for the SUB train set is provided for the whole train set, thus the two units combined
have a total tractive effort of 320 kN;
— the adhesion factor and the acceleration are not provided as the tractive effort is assumed to be
transferred to the track under all circumstances;
— for braking, it is assumed that it is possible to brake with the desired deceleration under all
circumstances;
— train set mass model is concentrated;
NOTE 1 If train mass model is distributed, then a length of 1 m can be used.
— current collection point is located at the front end of the train;
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— the efficiency (η) refers to the whole traction chain from current collector to the wheels not taking into
account the auxiliary power;
— the efficiency (η) and the power factor are both applicable to the whole train set speed range;
— the tractive effort is dependent upon the line voltage caused by current limitation as defined in 6.3.3.
NOTE 2 Some data are given to provide more clarity, precise formulae are given in this document.
6.3.2 Tractive and braking effort characteristics
The tractive effort of the train set used is described according to a standardized tractive effort (F) versus
speed (v) characteristic which will be defined according to a set of parameters. The model and the
parameters are described hereafter in Figure 3.
The curve for regenerative braking effort shall be the same as the tractive effort versus speed curve.

Figure 3 — Tractive effort diagram example for a train set at nominal voltage
The maximum tractive effort behaviour illustrated in Figure 3 shall be as follows:
— Zone 1: F = F from v = 0 km/h to v = v
m 1
— Zone 2: F = F(v ) × v / v from v = v to v = v ;
1 1 1 2
2 2
— Zone 3: F = F(v ) × v / v ;
2 2
— when v > v , F = 0.
The v , v , v characteristics are provided in 6.3.1.
1 2 3
6.3.3 Current limitation in traction
The current limitation with respect to the voltage level shall be taken into account according to EN 50388-
1:2022, 7.3, for the traction mode only (not for regenerative braking). Figure 4 is representative of the
limiting current:
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Figure 4 — Maximum traction current as a function of voltage
, U , U shall be as
The value a shall be as specified according to EN 50388-1:2022, 7.3, and Un min2 max2
. The current limitation applies to the current at the current collector and the
specified in EN 50163:2004
and I shall be calculated as follows:
parameters Iaux max
— I = P / (U × cos φ) ;
aux aux min2
= (P / (η × cos φ) + P / cos φ) / U , with P the maximum mechanical power at U ;
— Imax max aux n max n
For the DC case, use the formula above taking into account the value for cos φ equal to 1.
NOTE According to EN 50388–1:2022, Imax is the maximum current consumed by the train set at Un.
6.3.4 Current limitation in regenerative braking
The current limitation due to regenerative braking shall be as defined in Figure 5.
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Figure 5 — Regenerative braking, current limitation vs current collector voltage
I shall be calculated as follows:
braking
I = (η × P – P ) / (cos φ × U )
braking max aux max1
where
η is equal to 85 %, in accordance with the value provided in 6.3.1;
P is the maximum available mechanical power provided by the regenerative braking
max
effort when in the braking phase;
I is the current at the current collector;
braking
— In zone 1, there is no limitation of the regenerated current;
— In zone 2, between U and U the decrease of available regenerated
max1 max2
current is strictly linear.
6.3.5 Additional information for the train set models
Even if the following parameters have very limited influence, and for the purpose of the simulation and
production of results as defined in Table 15 with the limits given in the headings of columns from E to I, the
following general information shall be provided:
— the current collector position at which the train set voltage is calculated,
— train set reference position at which the train stops in a station.
6.4 Parameters for DC models
6.4.1 Track layout model
6.4.1.1 Route gradient
The route gradient shall be as specified in Table 2, and is based on the description set out in Figure 2:
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Table 2 — Gradient description along the route
Position
Gradient
km
‰
Start End
0 20,5 0
20,5 29,5 5
29,5 30,5 0
30,5 34,5 10
34,5 35,5 0
35,5 39,5 −10
39,5 40,5 0
40,5 49,5 −5
49,5 52 0
For example, the first line of Table 2 indicates that from position 0 km to position 20,5 km, the gradient is
0 ‰.
Negative gradient indicates downhill in direction of increasing position.
6.4.1.2 Station locations
The station positions shall be as specified in Table 3, and is based on the description set out in Figure 2:
Table 3 — Station position along the line
Position
Station
km
Station A 0
Station B 10
Station C 20
Station D 30
Station E 40
Station F 50
6.4.2 Train traffic model
The train traffic model, including the timetable, shall be as specified in Table 4.
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Table 4 — Timetable description
Departure
Train Train set Departure End
time
Additional information
no type position position
hh:mm
101 HS Station A (0 km) 00:00 Station F
Station A (0 km) 00:05
Stop at every intermediate
Station B (10 km) 00:12
station
201 SUB Station C (20 km) 00:19 Station F
Minimum dwell time for each
Station D (30 km) 00:26
station: 1 min
Station E (40 km) 00:33
103 HS Station A (0 km) 00:30 Station F
301 FR Station A (0 km) 00:35 Station F
102 HS Station F (50 km) 00:10 Station A
104 HS Station F (50 km) 00:40 Station A
The following additional data shall be used:
— all trains use the shortest running time;
— there are fixed departure times for all stations and a minimum fixed dwell time of 1 min in case of delay;
— after arrival at the last station, the train is removed immediately from the simulation;
— there is no dwell time at the first and last station (except if convenient from an implementation point of
view);
— every train stops at station F and station A;
— all trains are starting at a speed of 0 km/h;
— there are no constraints on train running as a result of signalling.
6.4.3 Electrical infrastructure model
Different infrastructure configurations are defined for each type of traction supply system. The
characteristics defined in Table 5 shall be used.
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Table 5 — Infrastructure electrical characteristics
Traction
Supply Station A  B  C  D  E  F
System
Position (km) 0,0 7,5 10,0 15,0 20,0 22,5 30,0 32,5 40,0 45,0 50,0
Type of facility SS PP SS SS SS PP PP PP SS SS SS
Permanent paralleling of the CLS of each track in SS and PP only
CLS
DC
0,029 5 Ω/km per track
1,5 kV
Track resistance: 0,020 Ω/km per track,
Track
if no permanent paralleling of the rail/track, rail/track paralleling every 250 m
Specificity No earthing cable, rails not earthed
Position (km) 0,0  10,0  20,0   33,0  45,0
Type of facility SS  PP  PP   PP  SS
Permanent paralleling of the CLS of each track in SS and PP only
CLS
DC
0,059 Ω/km per track
3 kV
Track resistance: 0,020 Ω/km per track,
Track
if no permanent paralleling of the rail/track, rail/track paralleling every 500 m
Specificity No earthing cable, rails not earthed
Key
CLS Contact line system,
PP Paralleling post location
SS Substation location, including paralleling
The track numbering is defined in Figure 2, and can be summarized as follows:
— Track 1: increasing km;
— Track 2: decreasing km.
Direct connections of negligible resistance may be assigned a resistance value of 0,0001 Ω if a value is
specifically required by the simulation tool.
The voltage source equivalent circuit for a DC substation is shown in Figure 6:
prEN 50641-1:2025 (E)
Key
U ideal direct voltage
di0
R equivalent source resistance
eq
Figure 6 — Substation, transformer and rectifier model
For the no load voltages of each substation, the value provided as U in EN 50163:2004 shall be used.
max1
According to Figure 6, the values of each system shall be:
– DC 1,5 kV: R = 0,01 Ω and U = 1,8 kV,
eq di0
– DC 3 kV: R = 0,01 Ω and U = 3,6 kV.
eq di0
6.5 Parameters for AC models
6.5.1 Track layout model
6.5.1.1 Route gradient
The route gradient shall be as specified in Table 6, and is based on the description set out in Figure 2.
Table 6 — Gradient description along the line, AC systems
Position
Gradient
km
‰
Start End
0 41 0
41 59 5
59 61 0
61 69 10
69 71 0
71 79 −10
79 81 0
81 99 −5
99 104 0
6.5.1.2 Station locations
The station locations shall be as specified in Table 7, and is based on the description set out in Figure 2:
prEN 50641-1:2025 (E)
Table 7 — Station locations along the line
Position
Station
km
Station A 0
Station B 20
Station C 40
Station D 60
Station E 80
Station F 100
Stations shall allow passing and crossing of trains.
6.5.2 Train traffic model
The train traffic model, including the timetable, shall be as specified in Table 8.
Table 8 — Timetable description
Departure
Train Train set Departure End
time
Additional information
no type position position
hh:mm
101 HS Station A (0 km) 00:00 Station F
Station A (0 km) 00:05
Stop at every intermediate
Station B (20 km) 00:24
station
201 SUB Station C (40 km) 00:38 Station F
Minimum dwell time for each
Station D (60 km) 00:52
station: 1 min
Station E (80 km) 01:06
103 HS Station A (0 km) 00:30 Station F
301 FR Station A (0 km) 00:35 Station F
102 HS Station F (100 km) 00:10 Station A
104 HS Station F (100 km) 00:40 Station A
The following additional data shall be used:
— all trains use the shortest running time;
— there are fixed departure times for all stations and a minimum fixed dwell time of 1 min in case of delay;
— after arrival at the last station, the train is removed immediately from the simulation;
— there is no dwell time at the first and last station (except if convenient from an implementation point of
view);
— every train stops at station F and station A;
— all trains are starting at a speed of 0 km/h;
— there are no constraints on train running as a result of signalling.
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6.5.3 Electrical infrastructure model
The infrastructure definition is dependent upon the traction supply system. The characteristics defined in
Table 9 shall be used.
In AC systems the data for the rail is not used and is only informative when using the lumped impedance
model.
Table 9 — Infrastructure electrical characteristics
Station A B C  D E F
System
Position (km) 0,00 20,00 40,00 50,00 60,00 80,00 100,00
type of facility SS PP PP PP PP PP PP
Lumped impedance for one track: (0,1 + j0,1) Ω/km
AC 15 kV
Permanent paralleling of the CLS of each track in SS and PP
CLS and rail loop
16,7 Hz
only
impedance
Paralleling and bonding of all rails every 250 m
Substation earthing resistance is 1 Ω
type of facility SS PP PP PP PP PP PP
Lumped impedance for one track: (0,15 + j0,45) Ω/km
For multi-conductor model, refer to Table 10, Figure 9 and
AC 25 kV
Figure 7
CLS and rail loop
50 Hz
Permanent paralleling of the CLS of each track in SS and PP
impedance
only
Paralleling and bonding of all rails every 250 m
Substation earthing resistance is 1 Ω
type of facility SS ATPP ATPP  ATPP PP
Refer to Table 10, Figure 9 and Figure 8
Permanent paralleling of the CLS of each track in SS, PP and
AC 2 × 25 kV CLS and Return
ATPP only
50 Hz circuit
Paralleling and bonding of all rails every 250 m
Substation and AT earthing resistance is 1 Ω

Key
AT Autotransformer location with one AT. AT values are given in 6.5.5.

ATPP Autotransformer paralleling post location, including paralleling of CLS
CLS Contact line system
PP Paralleling post location
SP Sectioning point location
SS Substation location, including paralleling
The track numbering is defined in Figure 2, and can be summarized as follows:
— Track 1: increasing km;
— Track 2: decreasing km.
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6.5.4 Transformer model
A simple lumped transformer model shall be used as shown in Figure 7.

Key
U0 no load voltage at the substation for a given electrical supply system
ZTR transformer impedance
Figure 7 — Substation and transformer model for standard system
For the no load voltages of each substation, the value provided as U in EN 50163:2004 shall be used.
max1
As given in Figure 7, the values for each system shall be:
— AC 15 kV - 16,7 Hz: Z = (0,05 + j 0,5) Ω and U = 16,5 kV,
TR 0
— AC 25 kV - 50 Hz: Z = (0,2 + j 2) Ω and U = 27,5 kV.
TR 0
For the 2 × 25 kV – 50 Hz case: Z = (0,2 + j 2) Ω, U = 27,5 kV as given in Figure 8. For the 2 × 25 kV –
TR 0
50 Hz case, a specific model shall be used as shown in Figure 8. The model given in Figure 8 refers to the
equivalent transformer impedance Z seen from the secondary winding side.
TR
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Key
U0 no load voltage at the substation for a given electrical supply system
ZTR transformer impedance
Figure 8 — Substation and transformer model for 2 × 25 kV – 50 Hz system
NOTE The model given in Figure 8 includes the primary winding impedance.
6.5.5 AC electrical infrastructure complement and multi-conductor model
No length for a neutral section zone shall be used between 2 electrical sections (for example: for 25 kV –
50 Hz and 2 × 25 kV – 50 Hz systems).
For AC systems, there is a choice of whether to use a lumped impedance model or a multi-conductor model.
The choice of model between the lumped impedance or multi-conductor models leads to different results.
Therefore, no strict comparison can be done between the two types of model.
The multi-conductor model shall use the geometry in Figure 9 using the conductor characteristics in
Table 10.
The direction of arrows is explained in EN 50388-1.
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Figure 9 — AC conductor geometry (AC model only)
Based on the conductor numbers in Figure 9, Table 10 gives the characteristics of each conductor
Catenary wire (4 and 9) and contact wire (3 and 8) of the same track are considered continuously connected
and geometrically parallel. Feeder wires number 5 and 10 have a constant height.
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Table 10 — Individual conductor characteristics and geometry (AC model only)
DC
Equivalent Relative
Resistivity
Conductor Section
Track Conductor Use Remark x y Material radius permeability
(1e-8
no. (mm )
(mm) (µr)
Ω⋅m )
Return
1 1 Rail UIC60  −1,00 0,00 Steel 7 000 20,00 75 50
current
Return
2 1 Rail UIC60  −2,50 0,00 Steel 7 000 20,00 75 50
current
Contact Supply
3 1  −1,75 5,70 Copper 120 1,60 6 1
wire current
Catenary Supply
4 1  −1,75 6,90 Bronze 70 3,00 5 1
wire current
Only for
Negative
5 1 Feeder 2 × 25 kV −4,75 8,50 Aluminium 288 2,80 10 1
feeder
case
Return
6 2 Rail UIC60  1,00 0,00 Steel 7 000 20,00 75 50
current
Return
7 2 Rail UIC60  2,50 0,00 Steel 7 000 20,00 75 50
current
Contact Supply
8 2  1,75 5,70 Copper 120 1,60 6 1
wire current
Catenary Supply
9 2  1,75 6,90 Bronze 70 3,00 5 1
wire current
Only for
Negative
10 2 Feeder 2 × 25 kV 4,75 8,50 Aluminium 288 2,80 10 1
feeder
case
NOTE Catenary wire is also known as messenger wire.
Rails: self-impedance and the radius for the running rails for the multiconductor simulations:
For the rail, a longitudinal self impedance of Z = (0,08 + j0,63) Ω/km shall be used
The additional data used to calculate the conductor impedances shall be as follows:
— earth resistivity: 100 Ω m;
— rail to earth conductance: 1 S/km (per rail). For the AC 2 × 25 kV system, the AT characteristics
...