ISO 23340

• Abstract:

  This document specifies the functional requirements for rail vehicle windscreens, including type testing, routine testing and inspection methods for high speed rail, heavy rail, light rail and metro applications. This document is also applicable for tram vehicles. For on-track machines (OTMs) when in transport mode (self-propelled or hauled) the requirements of this standard are applicable. OTMs in working configuration are outside the scope of this document. Determination of the size, shape, orientation and position of windscreens is outside the scope of this document. These data form part of the windscreen technical specification. This document applies to windscreens made of laminated glass, which is the most commonly used material, but also to other materials, subject to the performance requirements being satisfied. This document does not specify requirements for the interfaces between the windscreen and the vehicle. Accordingly this document does not address issues relating to: installation, structural integrity and crashworthiness.

• Status: Not Published
• ICS: 45.060.01 - Railway rolling stock in general
• Technical Committee: ISO/TC 269/SC 2 - Rolling stock
• Drafting Committee: ISO/TC 269/SC 2 - Rolling stock
• Current Stage: 6000 - International Standard under publication
• Start Date: 10-Sep-2026
• Completion Date: 12-Sep-2026

Overview

ISO 23340: Railway applications - Windscreens for trains is an international standard published by ISO that specifies the functional requirements, type testing, routine testing, and inspection methods for windscreen glazing used on railway vehicles. Applicable to high speed, heavy rail, light rail, metro, and tram vehicles, the standard addresses windscreens made primarily from laminated glass, as well as other materials that meet performance standards. This document is critical for ensuring safety, visibility, durability, and quality of train windscreens across a wide range of rail applications. It specifically excludes requirements for installation, structural integrity, crashworthiness, and windscreen interfaces.

Key Topics

• Functional Requirements: Establishes the expected performance of windscreens under operational and environmental conditions, including optical clarity and mechanical strength.
• Testing Procedures: Defines type tests, routine production tests, and inspection methods to ensure ongoing compliance and product quality, such as impact resistance and visual inspection protocols.
• Windscreen Areas: Differentiates between primary vision, secondary vision, and peripheral areas, each with distinct optical and defect criteria to maintain driver and passenger safety.
• Material Flexibility: While focused on laminated glass, permits use of alternative materials that satisfy all defined performance requirements.
• Marking and Traceability: Requires permanent and readable markings on each windscreen for supplier identification, date of manufacture, and compliance data, excluding primary vision areas.
• Defect Classification and Acceptance: Details permissible number, type, and size of defects, supported by a robust classification and acceptance criteria to maintain high vision quality.
• Storage and Handling: Provides guidelines for proper storage and handling of windscreens to avoid damage, maintain quality, and reduce the risk of injury during transport and installation.

Applications

ISO 23340 is implemented by:

• Rail Industry Manufacturers: Ensuring design and production of windscreens for high speed trains, metros, trams, and on-track machines meet rigorous international requirements for safety and performance.
• Rail Operators and Maintenance Providers: Verifying that installed windscreens comply with inspection and periodic test protocols, minimizing risks related to optical defects, impact damage, and environmental stressors.
• Design Engineers and Specification Teams: Integrating compliant windscreens into rolling stock design, with clear guidance on required performance characteristics, optical quality, and marking.
• Quality Assurance and Testing Laboratories: Applying standardized routine and type tests for windscreen products, ensuring conformity to international benchmarks before approval and installation.

Related Standards

• ISO 22752 - Railway applications - Bodyside windows for rolling stock: Addresses standards for non-windscreen glazing.
• ISO 12543-5 - Glass in building - Laminated glass and laminated safety glass: Provides edge finishing and dimensional requirements for laminates.
• ISO 3537, ISO 3538, ISO 3917 - Safety glazing materials - Testing and performance methods.
• ISO 48-2 - Determination of hardness for vulcanized rubber.
• IEC 60571 - Railway applications - Electronic equipment used on rolling stock.
• CIE 15, CIE 38 - Colorimetry and photometric characteristics: Relevant for optical measurements.

ISO 23340 is a key document that enhances the manufacture, safety, and inspection of railway windscreens, supporting global interoperability and high standards in railway vehicle glazing. Compliance ensures clearer, safer train operation, reduced down-time, and harmonization across international railway fleets.

FINAL DRAFT
International
Standard
ISO/FDIS 23340
ISO/TC 269/SC 2
Railway applications —
Secretariat: AFNOR
Windscreens for trains
Voting begins on:
Applications ferroviaires — Vitres frontales pour véhicules 2026-07-15
ferroviaires
Voting terminates on:
2026-09-09
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WITH THEIR COMMENTS, NOTIFICATION OF ANY
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INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
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TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
Reference number
ISO/FDIS 23340:2026(en) © ISO 2026

FINAL DRAFT
ISO/FDIS 23340:2026(en)
International
Standard
ISO/FDIS 23340
ISO/TC 269/SC 2
Railway applications —
Secretariat: AFNOR
Windscreens for trains
Voting begins on:
Applications ferroviaires — Vitres frontales pour véhicules
ferroviaires
Voting terminates on:
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 SUPPOR TING DOCUMENTATION.
© ISO 2026
IN ADDITION TO THEIR EVALUATION AS
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
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TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
or ISO’s member body in the country of the requester.
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
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Published in Switzerland Reference number
ISO/FDIS 23340:2026(en) © ISO 2026

ii
ISO/FDIS 23340:2026(en)
Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
3.1 Terms, definitions and abbreviations .2
3.2 Abbreviated terms .4
4 Functional requirements . 4
4.1 General .4
4.1.1 Windscreen classification .4
4.1.2 Driver's windscreens . .6
4.1.3 Passenger windscreens and vehicle end windows .7
4.1.4 Contractual agreements .7
4.2 Optical areas .7
4.3 Windscreen test requirements .8
4.3.1 General .8
4.3.2 Type tests .9
4.3.3 Routine tests .10
4.3.4 Periodic tests .10
4.4 Marking .10
4.5 Service requirements .10
4.6 Storage and handling of finished windscreens .11
5 Visual and optical requirements .11
5.1 Appearance defects .11
5.1.1 General .11
5.1.2 Visual inspection procedure for appearance defects .11
5.1.3 Definition and classification of defects . 13
5.1.4 Defect acceptance criteria . 15
5.2 Optical characteristics . 15
5.2.1 Secondary image separation . 15
5.2.2 Optical distortion .16
5.2.3 Haze .18
5.2.4 Light transmittance .18
5.2.5 Chromaticity .19
6 Mechanical characteristics .22
6.1 Impact resistance . 22
6.1.1 Impact test requirements . 22
6.1.2 Spalling assessment .24
6.1.3 Impact test projectile velocity .24
6.1.4 Impact test procedure . 26
6.1.5 Impact test acceptance criteria .27
6.2 Residual visibility .27
6.2.1 General .27
6.2.2 Test samples .27
6.2.3 Test method .27
6.2.4 Acceptance criteria .27
6.3 Resistance against abrasion . 28
6.4 Resistance to impact from small particles from track (gravelling) . . 28
6.4.1 General . 28
6.4.2 Test samples . 28
6.4.3 Test method . 28
6.5 Bullet resistance . 29
6.5.1 General . 29
6.5.2 Test samples . 29

iii
ISO/FDIS 23340:2026(en)
6.5.3 Procedure . 29
6.5.4 Acceptance criteria . 30
7 Performance in service .30
7.1 Heating system . 30
7.1.1 General . 30
7.1.2 Heating uniformity . 30
7.1.3 Coating based heating systems .31
7.1.4 Wire based heating systems .31
7.1.5 Resistance measurement .31
7.1.6 Voltage withstand test .31
7.2 Resistance against ageing .31
7.2.1 General .31
7.2.2 Accelerated weathering test .32
7.2.3 Thermal cycling .32
7.2.4 Humidity test . 33
7.2.5 Windscreen heating test. 33
Annex A (normative) Determination of windscreen angles .35
Annex B (normative) Transmittance calculation for inclined windscreen .40
Annex C (normative) Windscreen test sample mounting .42
Annex D (normative) Impact test projectile .45
Annex E (normative) Gravelling test projectile .47
Annex F (informative) Test samples .48
Annex G (normative) Bullet resistance testing device .49
Annex H (informative) Alternative method for testing resistance to ultraviolet radiation .50
Annex I (informative) List of information and requirements to be discussed and agreed
between contracted parties .51
Bibliography .53

iv
ISO/FDIS 23340:2026(en)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement. For an explanation of the voluntary nature of standards, the meaning of ISO
specific terms and expressions related to conformity assessment, as well as information about ISO's
adherence to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 269, Railway applications, Subcommittee SC 2,
Rolling stock.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

v
FINAL DRAFT International Standard ISO/FDIS 23340:2026(en)
Railway applications — Windscreens for trains
1 Scope
This document specifies the functional requirements for rail vehicle windscreens, including type testing,
routine testing and inspection methods for main line railway and urban guided transport systems.
This document applies to windscreens made of laminated glass, which is the most commonly used material.
This document also applies to other materials, subject to the performance requirements being satisfied.
This document is also applicable to railbound machines in running mode (self-propelled or hauled).
Railbound machines in travelling and working mode are outside the scope of this document.
This document is not applicable to the determination of the size, shape, orientation and position of
windscreens.
This document does not specify requirements for the interfaces between the windscreen and the vehicle.
This document does not address issues relating to installation, structural integrity and crashworthiness.
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.
ISO 48-2, Rubber, vulcanized or thermoplastic — Determination of hardness — Part 2: Hardness between 10
IRHD and 100 IRHD
ISO 3537, Road vehicles — Safety glazing materials — Mechanical tests
ISO 3538:1997, Road vehicles — Safety glazing materials — Test methods for optical properties
ISO 3917:2016, Road vehicles — Safety glazing materials — Test methods for resistance to radiation, high
temperature, humidity, fire and simulated weathering
ISO 4892-2, Plastics — Methods of exposure to laboratory light sources — Part 2: Xenon-arc lamps
ISO 4892-3, Plastics — Methods of exposure to laboratory light sources — Part 3: Fluorescent UV lamps
ISO 6362-2, Wrought aluminium and aluminium alloys — Extruded rods/bars, tubes and profiles — Part 2:
Mechanical properties
ISO/TR 8941, Railway infrastructure — Rail mounted construction, maintenance and inspection machines —
Explanation of machine type
ISO/CIE 11664-3, Colorimetry — Part 3: CIE tristimulus values
ISO 12543-5:2021, Glass in building — Laminated glass and laminated safety glass — Part 5: Dimensions and
edge finishing
ISO 14782, Plastics — Determination of haze for transparent materials
ISO/FDIS 22575, Railway applications — General vocabulary
ISO 22752, Railway applications — Bodyside windows for rolling stock
IEC 60571, Railway applications - Electronic equipment used on rolling stock

ISO/FDIS 23340:2026(en)
CIE 15, Colorimetry
CIE 38, Radiometric and Photometric Characteristics of Materials and Their Measurement
CIE 1931, Standard colorimetric system
CIE S 004, Colours of light signals
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/FDIS 22575, ISO/TR 8941 and the
following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1 Terms, definitions and abbreviations
3.1.1
glazing
material that allows the transmittance of light
[1]
[SOURCE: ISO 22752:2021 , 3.4]
3.1.2
windscreen
glazing (3.1.1) in front of a driver or passengers through which infrastructure ahead can be observed
Key
A urban guided transport
B main line rail
1 driver's windscreen (3.1.3)
2 side windscreen (3.1.4)
3 bodyside window
4 external glazing (3.1.1) (e.g. covers for lights, information displays)
Figure 1 — Example of a windscreen, window and glazing (3.1.1)

ISO/FDIS 23340:2026(en)
Note 1 to entry: Figure 1 shows examples of the different types of windscreen (3.1.2) , bodyside windows and external
glazing (3.1.1).
3.1.3
driver's windscreen
windscreen (3.1.2) at the leading end of a vehicle through which a driver observes infrastructure, signals and
obstacles
3.1.4
side windscreen
additional glazing (3.1.1) positioned at the side of a windscreen (3.1.2) in the cab
3.1.5
passenger windscreen
windscreen (3.1.2) at the leading end of a vehicle in front of the passenger area
3.1.6
vehicle end window
window at the ends of vehicles or train composition that is never at the leading end of the train in service
Note 1 to entry: Vehicle end window can occasionally be at the leading end of the train operated at reduced speed
(specified by the customer) in a yard.
3.1.7
primary vision area
area of the windscreen (3.1.2) through which track and signals are visible from the driving position
Note 1 to entry: See Figure 4 for an illustration of all optical areas.
3.1.8
secondary vision area
area of the windscreen (3.1.2) outside the primary vision area (3.1.7), through which the driver can also look
from the driving position
Note 1 to entry: See Figure 4 for an illustration of all optical areas.
3.1.9
peripheral area
area of the windscreen (3.1.2) outside the secondary vision area (3.1.8)
Note 1 to entry: The peripheral area includes any screen-printed areas.
3.1.10
secondary image separation
angular separation between the primary and the brightest secondary images (due to internal reflection) of a
distant light source or object when viewed through glazing (3.1.1)
3.1.11
ultraviolet radiation
UV radiation, noun
optical radiation for which the wavelengths are shorter than those for visible radiation
Note 1 to entry: The range between 100 nm and 400 nm is commonly subdivided into:
— UV-A: 315 nm to 400 nm;
— UV-B: 280 nm to 315 nm;
— UV-C: 100 nm to 280 nm.
Note 2 to entry: A precise border between ultraviolet radiation and visible radiation cannot be defined because visual
sensation at wavelengths shorter than 400 nm is noted only for very bright sources.
[2]
[SOURCE: IEC 60050-845:2020 ED2: 2020 , 1-008, modified — Notes 3, 4 and 5 to entry have been removed.]

ISO/FDIS 23340:2026(en)
3.1.12
spall
small particles which detach from the face of a windscreen (3.1.2) when it is subjected to impact on the
opposite side
Note 1 to entry: Spalling in this document describes the detachment of spall from the inside face of a windscreen (3.1.2)
or window, when the outer face is subjected to impact.
3.1.13
hot-spot
highly localised area where the temperature deviates significantly from the surrounding area
3.1.14
inspector
person that undertakes the technical or visual inspection of products
3.1.15
seat reference point
SRP, noun
reference point at the back pan of a new seat design with a horizontal distance of 135 mm and vertical
[3]
distance of 98 mm from the H point according to ISO 20176:2020
[4]
Note 1 to entry: See EN 16186-1:2014 , Figure 2 for background information on seat reference points based on
anthropometric characteristics.
[4]
[SOURCE: EN 16186-1:2014 , 3.1.6 modified — Note 1 to entry has modified and Note 2 to entry has been
deleted.]
3.1.16
specific power
total heating power divided by the heated surface area
Note 1 to entry: Specific power is expressed in W/m .
3.2 Abbreviated terms
IRHD international rubber hardness degree
YI yellowness index
4 Functional requirements
4.1 General
4.1.1 Windscreen classification
Windscreens are positioned to allow observation of the track and signals ahead of a vehicle. Additional side
windscreens or windows may be provided to the side of the windscreen or windscreens (see Figure 2).

ISO/FDIS 23340:2026(en)
Key
1 windscreen
2 side windscreen
3 side windscreen (cab window forward of seat reference point, see 4.1.2)
4 bodyside window
5 driver's seat (or passenger seats, for example, in automatic vehicles)
6 seat reference point (SRP)
Θ , Θ plan view angles (for curved windscreens, the values vary with position)
i n
Figure 2 — Windscreen and side windscreens
The classification of rail vehicle glazing (windscreen, side windscreens or bodyside windows) affects the
characteristics required and primarily depends on the orientation relative to the track.
For the determination of a windscreen ’s orientation, only the parts of the glazing which, if removed, would
create an aperture and expose the occupants of a vehicle to the outside shall be considered.
glazing that covers lights, information displays or extends over the structure for aesthetic purposes is
therefore excluded.
If the projected forward-facing area determined according to Annex A is less than or equal to 0,065 m , and
unless requirements for driver's cabs apply (see 4.1.2), then the glazing shall be considered to be a bodyside
window and shall be in accordance with ISO 22752.
For windscreens that can be considered to be forward facing (including those which are not required or
intended for direct observation of the track and signals), the maximum and minimum plan view angles, Θ
(see Figure 2), shall be determined in accordance with Annex A.

ISO/FDIS 23340:2026(en)
For driver's windscreens, with a central driving position, the plan view angle, Θ, may be assumed to be = 0°.
The maximum and minimum rake angles, Φ, shall be determined in accordance with Annex A.
For curved windscreens, the method set out in Annex A should be followed for the determination of plan
view and rake angles.
The maximum and minimum installation angles Ψ shall be determined from the maximum and minimum
plan view angles Θ and the maximum and minimum rake angles Φ using the relation cos(Ψ) = cos(Θ)·cos(Φ).
The maximum and minimum windscreen plan view angles, rake angles and installation angles shall form
part of the technical specification for manufacture and testing.
If samples are used to determine optical properties, the maximum installation angle shall be used (e.g. see
5.2).
If samples are used to determine mechanical properties such as impact resistance, the minimum installation
angle shall be used (e.g. see 6.1).
Figure 3 shows different types of windscreens and windows.
Key
1 leading vehicle (alternate cab types shown)
2 driver seat in forward direction of travel
3 driver's windscreen(s)
4 passenger windscreen
5 vehicle end windows
6 driver's cab partition wall
X direction of travel
Figure 3 — Examples of windscreens and vehicle end windows
4.1.2 Driver's windscreens
All windows in driver’s cabs that are fully or partially in front of the driver’s seat reference point (SRP),
measured in the longitudinal direction shall be considered as windscreens or side windscreens (see
Figure 2). Exceptions according to Clause A.1 are acceptable if the angle Ɵ is greater than 70° if agreed by
contracted parties.
Where two or more windscreens are fitted and only one of which is required to be a driver’s windscreen, the
requirements for driver’s windscreens shall apply to both (or all) windscreens (see Figure 3).

ISO/FDIS 23340:2026(en)
For driver’s windscreens, the plan view angle shall be determined using the points defining the primary
vision area (see 4.2, see zone A in Figure 4).
4.1.3 Passenger windscreens and vehicle end windows
Windscreens or side windscreens that are only provided for observation by passengers without occasional
driver or crew member (e.g. in degraded mode, training or testing phase) shall be referred to as passenger
windscreens (see Figure 3).
[5]
The following may be considered to be equivalent to bodyside windows (see ISO 22752 ) and therefore
outside the scope of this document if agreed by contracted parties:
— forward facing vehicle end windows, located at an intermediate end of a vehicle, if they are shielded by
an adjacent vehicle from the risk of a direct longitudinal impact (see Figure 3);
— forward facing vehicle end windows, for example, in vehicle end doors where people are not present
during operation;
— vehicle end windows that only face to the rear in normal service (see Figure 3).
4.1.4 Contractual agreements
Where options are provided in this document, contracted parties should document the choices made.
Annex I gives the list of items that should be recorded.
The requirements specified throughout this document and the options documented in (see Annex I shall be
satisfied before a claim of conformity to this document can be made and verified.
4.2 Optical areas
A windscreen can be divided into a maximum of three optical areas as shown in Figure 4.
A primary vision area shall be defined for driver’s windscreens. The boundary between secondary and
peripheral areas shall form part of the windscreen technical specification.
For windscreens other than driver's windscreen, a primary vision area may be optional. In this case, the
boundaries between optical areas shall form part of the windscreen technical specification.

ISO/FDIS 23340:2026(en)
Key
A primary vision area
B secondary vision area
C peripheral area
0 assumed eye position
1 driver's sightlines
W, X, Y, Z sightline intersection points
Figure 4 — windscreen optical areas
The four points W, X, Y and Z, shown on Figure 4, represent the intersections between the windscreen and
the driver’s sightlines. These points are joined by lines as shown in Figure 4 to define the primary vision
area.
The definition of the driver’s sightlines (for the observation of track and signals) is outside of the scope of
this document. Data to define these points shall form part of the windscreen technical specification.
NOTE ISO 26053-1 is under development and will set those visibility criteria.
The peripheral area may be deliberately obscured (in whole or in part) e.g. by silk-screen printing for any of
the following reasons:
— elimination of distracting items from the field of vision;
— for windscreens that are bonded into position, to protect the bonded area from the effect of ultraviolet
(UV) radiation;
— aesthetic purposes.
4.3 Windscreen test requirements
4.3.1 General
The windscreen design shall be validated by satisfactory completion of the assessments and tests described
in this document. Table 1 contains a summary of the tests defined in this document.

ISO/FDIS 23340:2026(en)
Table 1 — Tests
Feature to be tested Type test Routine test Periodic test
Appearance (see 5.1) W W
Secondary images (see 5.2.1) W
Optical distortion (see 5.2.2) W W
Haze (see 5.2.3) S or W
Transmittance (see 5.2.4) S or W S or W
Chromaticity (see 5.2.5) S or W
Impact (including spalling) (see 6.1) S or W
Residual visibility (see 6.2) S
Abrasion resistance (see 6.3) S
a
Gravelling (see 6.4) S
a
Bullet resistance (see 6.5) S
Heating (see 7.1) W W
Ageing (see 7.2) S or W
Voltage withstand W W
Key
S sample
W complete windscreen
a
If required by the windscreen technical specification.
4.3.2 Type tests
All type tests are listed in Table 1.
If a windscreen is fitted with a heating device, the following tests shall be repeated with the heating device
in use:
— secondary images (see 5.2.1);
— optical distortion test (see 5.2.2).
When type tests are repeated with the heating device in use:
— the heater shall be operated at its nominal voltage;
— thermal stabilization shall be reached before measurements are undertaken.
This requirement shall not apply to additional start-up heating provided for use on a stationary vehicle to
accelerate the removal of ice or snow.
Test samples properties are summarized in Annex F.
If a windscreen validated in accordance with this document is modified, a new type test may be omitted
where it can be shown that the required performance is not affected for a given type test.
For passenger windscreens, the following tests are optional:
— secondary images (see 5.2.1);
— haze (see 5.2.3);
— transmittance (see 5.2.4), a minimum transmittance of 40 % may be accepted;
— chromaticity (see 5.2.5).
ISO/FDIS 23340:2026(en)
4.3.3 Routine tests
Routine testing shall be undertaken during production on all windscreens for the following:
— appearance (see 5.1);
— optical distortion (see 5.2.2);
— heating (see 7.1);
— voltage withstand.
4.3.4 Periodic tests
Transmittance (see 5.2.4) shall be tested periodically at a frequency given in the windscreen technical
specification.
4.4 Marking
The windscreen shall be permanently marked, to show, as a minimum, the following information:
— name or logo of windscreen supplier;
— date of manufacture (month and the last two numerals of the year or a code by which this information
can be identified).
The following information should be included in the marking:
— unique identification number (part number and serial number);
— nominal voltage and type of current (AC or DC) of the heater (if applicable);
— total power of the heater (if applicable);
— the applicable version of this document.
The marking shall be outside of the primary vision area. If there are no conflicting requirements, it should
be in the upper right hand corner of the windscreen.
The marking shall be readable and visible from inside the cab. The marking shall be readable without
viewing aids and the minimum height of characters should be 3 mm.
4.5 Service requirements
Windscreens shall be designed to withstand normal operational conditions, including induced static and
dynamic loadings and environmental conditions such as temperature and humidity, when installed in a
railway vehicle.
Requirements for use in a specific environment which are in addition to the requirements set out in this
document shall form part of the windscreen technical specification.
A heating system should be incorporated into a driver’s windscreen for de-icing and de-misting so that the
driver can maintain a clear external view in most weather and operating conditions. If such an integral
heating system is provided it shall satisfy the requirements set out in 7.1.
Driver’s windscreens, when impacted or cracked, shall have sufficient residual visibility to allow the train
to be moved, subject to operational rules. This requirement shall be deemed to be satisfied by achieving the
residual visibility requirements set out in 6.2.
NOTE For passenger windscreens, a pendulum test and passenger containment test according to ISO 22752:2021
[1]
can be set out in the windscreen technical specification.

ISO/FDIS 23340:2026(en)
4.6 Storage and handling of finished windscreens
Windscreens should be stored in a well ventilated area, protected from the weather and out of direct
sunlight.
Flat windscreens should be stored on a solid base in a vertical orientation, inclined at a rake angle of
approximately 6 degrees. The windscreens should be continuously supported by brackets along each edge.
The supporting brackets should be covered with soft material to prevent damage.
Storage for curved windscreens should follow the same principles adapted for the specific geometry of the
product.
Glazing edges shall be finished in accordance with ISO 12543-5:2021, 5.3.2, 5.3.3 or 5.3.4.
NOTE The purpose of the finished edges is to prevent injury to handlers of the glazing by sharp edges.
5 Visual and optical requirements
5.1 Appearance defects
5.1.1 General
Appearance defects (blemishes) are characteristics of one of the following elements of the windscreen or the
processes in its manufacture:
— glazing material(s);
— interlayer(s);
— assembly;
— handling;
— anti-spall layer, if fitted.
To ensure an acceptable quality of vision to the driver, windscreens shall be inspected in accordance with
the procedure set out in 5.1.2. Any defects shall be classified in accordance with5.1.3 and the number and
size of such defects shall not exceed the limits listed in 5.1.4.
These requirements with regard to 5.1.2 and 5.1.3 may be modified if agreed by the contracted parties.
5.1.2 Visual inspection procedure for appearance defects
Windscreens shall be inspected in a darkened test chamber equipped with a vertical luminous screen.
The light from the luminous screen passing through the windscreen shall be used to determine by a visual
inspection if there are defects in the windscreen. If defects are found, their type and size shall be recorded
and the acceptability of the windscreen determined. The test arrangement is shown in Figure 5.

ISO/FDIS 23340:2026(en)
Key
A windscreen
B luminous screen
C inspector
D Moving inspection zone
Figure 5 — Device for checking the appearance, front view and top view
1)
The luminous screen shall be NCS 7502-B grey or equivalent. The use of any other screen colour shall be
part of the windscreen technical specification.
The windscreen shall be assessed in accordance with the following procedure:
— The windscreen shall be positioned vertically in front of the luminous screen at a distance of 3,0 m. For
curved windscreens the distance shall be measured from the centre of the primary vision area. The
outside surface of the windscreen shall face the luminous screen.
— The glazing shall be clean, dry and free of deposits of material or fluid that can affect the inspection.
— The test chamber should be substantially dark. The ambient illuminance shall be measured at the inner
face of the windscreen with the luminous screen powered off. This illuminance value shall not be greater
than 20 lx and shall be recorded in the test report.
— The luminous screen shall be lit to give a uniform illuminance from 500 lx to 1500 lx measured at the
inner face of the windscreen.
— The inspector shall be positioned behind the windscreen at a distance of 1,5 m. Alternatively, the
inspector shall be positioned in accordance with the distance between the driver and the windscreen
defined in the technical specification.
1) NCS 7502-B is the trade name of a product supplied by the Universal Standard for Colour Communication. This
information is given for the convenience of users of this document and does not constitute an endorsement by ISO of the
product named. Equivalent products may be used if they can be shown to lead to the same results.

ISO/FDIS 23340:2026(en)
— The examination duration shall be equal to 1 min for a windscreen with a surface area less or equal to
1,5 m and shall be equal to 2 min for a windscreen with a greater surface area.
— The windscreen shall be divided into sufficient inspection zones to cover the entire surface of the
windscreen . Inspection zones should be arranged to minimize overlapping and areas beyond the
boundaries of the vision areas.
— The size of the inspection zones should be 0,5 m × 0,5 m.
— The inspector shall examine the complete windscreen surface by looking through each inspection zone
in turn. The inspector shall change position horizontally and vertically as required to look through each
inspection zone perpendicularly to the luminous screen.
— The position of any suspect points identified during the examination shall be recorded.
The inspector shall remain in the test chamber for the duration of the visual inspection.
At the end of the visual inspection, if any suspect points have been identified, the inspector shall re-examine
the glazing to analyse them and to classify them in accordance w
...

ISO/FDIS 23340
ISO/TC 269/SC 2
Secretariat: AFNOR
Date: 2026-04-0807-01
Railway applications — Windscreens for trains
Applications ferroviaires — Vitres frontales pour véhicules ferroviaires
FDIS stage
ISO/FDIS 23340:2026(en)
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication
may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying,
or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO
at the address below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: + 41 22 749 01 11
E-mail: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
ISO/FDIS 23340:2026(en)
Contents
Foreword . iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
3.1 Terms, definitions and abbreviations . 2
3.2 Abbreviated terms . 5
4 Functional requirements . 6
4.1 General . 6
4.2 Optical areas . 11
4.3 Windscreen test requirements . 13
4.4 Marking . 14
4.5 Service requirements . 15
4.6 Storage and handling of finished windscreens . 15
5 Visual and optical requirements . 15
5.1 Appearance defects . 15
5.2 Optical characteristics . 22
6 Mechanical characteristics . 29
6.1 Impact resistance . 29
6.2 Residual visibility . 35
6.3 Resistance against abrasion . 36
6.4 Resistance to impact from small particles from track (gravelling) . 36
6.5 Bullet resistance . 37
7 Performance in service . 38
7.1 Heating system . 38
7.2 Resistance against ageing . 40
Annex A (normative) Determination of windscreen angles . 44
Annex B (normative) Transmittance calculation for inclined windscreen . 51
Annex C (normative) Windscreen test sample mounting . 54
Annex D (normative) Impact test projectile . 57
Annex E (normative) Gravelling test projectile . 60
Annex F (informative) Test samples . 61
Annex G (normative) Bullet resistance testing device . 62
Annex H (informative) Alternative method for testing resistance to ultraviolet radiation . 63
Annex I (informative) List of information and requirements to be discussed and agreed
between contracted parties . 64
Bibliography . 66

iii
ISO/FDIS 23340:2026(en)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. The
procedures used to develop this document and those intended for its further maintenance are described in
the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types of
ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights
in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s)
which may be required to implement this document. However, implementers are cautioned that this may not
represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement. For an explanation of the voluntary nature of standards, the meaning of ISO
specific terms and expressions related to conformity assessment, as well as information about ISO's adherence
to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 269, Railway applications, Subcommittee SC 2,
Rolling stock.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
ISO/FDIS 23340:2026(en)
Railway applications — Windscreens for trains
1 Scope
This document specifies the functional requirements for rail vehicle windscreens, including type testing,
routine testing and inspection methods for main line railway and urban guided transport systems.
This document applies to windscreens made of laminated glass, which is the most commonly used material.
This document also applies to other materials, subject to the performance requirements being satisfied.
This document is also applicable to railbound machines in running mode (self-propelled or hauled). Railbound
machines in travelling and working mode are outside the scope of this document.
This document is not applicable to the determination of the size, shape, orientation and position of
windscreens.
This document does not specify requirements for the interfaces between the windscreen and the vehicle. This
document does not address issues relating to installation, structural integrity and crashworthiness.
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.
ISO 48-2, Rubber, vulcanized or thermoplastic — Determination of hardness — Part 2: Hardness between 10
IRHD and 100 IRHD
ISO 3537, Road vehicles — Safety glazing materials — Mechanical tests
ISO 3538:1997, Road vehicles — Safety glazing materials — Test methods for optical properties
ISO 3917:2016, Road vehicles — Safety glazing materials — Test methods for resistance to radiation, high
temperature, humidity, fire and simulated weathering
ISO 4892-2, Plastics — Methods of exposure to laboratory light sources — Part 2: Xenon-arc lamps
ISO 4892-3, Plastics — Methods of exposure to laboratory light sources — Part 3: Fluorescent UV lamps
ISO 6362-2, Wrought aluminium and aluminium alloys — Extruded rods/bars, tubes and profiles — Part 2:
Mechanical properties
ISO/TR 8941, Railway infrastructure — Rail mounted construction, maintenance and inspection machines —
Explanation of machine type
ISO/CIE 11664-1, Colorimetry — Part 1: CIE standard colorimetric observers
ISO/CIE 11664-3, Colorimetry — Part 3: CIE tristimulus values
ISO 12543-5:2021, Glass in building — Laminated glass and laminated safety glass — Part 5: Dimensions and
edge finishing
ISO 14782, Plastics — Determination of haze for transparent materials
ISO/FDIS 23340:2026(en)
ISO/FDIS 22575, Railway applications — General vocabulary
ISO 22752:2021, Railway applications — Bodyside windows for rolling stock
IEC 60571, Railway applications - Electronic equipment used on rolling stock
CIE 15, Colorimetry
CIE 38, Radiometric and Photometric Characteristics of Materials and Their Measurement
CIE 1931, Standard colorimetric system
CIE S 004, Colours of light signals
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/FDIS 22575, ISO/TR 8941, and the
following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— — ISO Online browsing platform: available at https://www.iso.org/obp
— — IEC Electropedia: available at https://www.electropedia.org/
3.1 Terms, definitions and abbreviations
3.1.1
glazing
material that allows the transmittance of light
[SOURCE: ISO 22752:2021ISO 22752:2021,, 3.4]
3.1.2
windscreen
glazing (3.1.1) in front of a driver or passengers through which infrastructure ahead can be observed

ISO/FDIS 23340:2026(en)
a) Urban guided transport
b) Main line rail
Key
A urban guided transport
B main line rail
1 driver's windscreen (3.1.3)
2 side windscreen (3.1.4)
3 bodyside window
4 external glazing (3.1.1) (e.g. covers for lights, information displays)
ISO/FDIS 23340:2026(en)
Figure 1 — Example of a windscreen, window and glazing (3.1.1)
Note 1 to entry: Figure 1 shows examples of the different types of windscreen (3.1.2) , bodyside windows and external
glazing (3.1.1) .).
3.1.3
driver's windscreen
windscreen (3.1.2) at the leading end of a vehicle through which a driver observes infrastructure, signals and
obstacles
3.1.4
side windscreen
additional glazing (3.1.1) positioned at the side of a windscreen (3.1.2) in the cab
3.1.5
passenger windscreen
windscreen (3.1.2) at the leading end of a vehicle in front of the passenger area
3.1.6
vehicle end window
window at the ends of vehicles or train composition that is never at the leading end of the train in service
Note 1 to entry: Vehicle end window can occasionally be at the leading end of the train operated at reduced speed
(specified by the customer) in a yard.
3.1.7
primary vision area
area of the windscreen (3.1.2) through which track and signals are visible from the driving position
Note 1 to entry: See Figure 4 for an illustration of all optical areas.
3.1.8
secondary vision area
area of the windscreen (3.1.2) outside the primary vision area (3.1.7), through which the driver can also look
from the driving position
Note 1 to entry: See Figure 4 for an illustration of all optical areas.
3.1.9
peripheral area
area of the windscreen (3.1.2) outside the secondary vision area (3.1.8)
Note 1 to entry: The peripheral area includes any screen-printed areas.
3.1.10
secondary image separation
angular separation between the primary and the brightest secondary images (due to internal reflection) of a
distant light source or object when viewed through glazing (3.1.1)
3.1.11
ultraviolet radiation
UV radiation, noun
optical radiation for which the wavelengths are shorter than those for visible radiation
Note 1 to entry: The range between 100 nm and 400 nm is commonly subdivided into:
— UV-A: 315 nm to 400 nm;
ISO/FDIS 23340:2026(en)
— UV-B: 280 nm to 315 nm;
— UV-C: 100 nm to 280 nm.
Note 2 to entry: A precise border between ultraviolet radiation and visible radiation cannot be defined because visual
sensation at wavelengths shorter than 400 nm is noted only for very bright sources.
[SOURCE: IEC 60050-845:2020 ED2, 1-008, modified — Notes 3, 4 and 5 to entry have been removed.]
3.1.12
spall
small particles which detach from the face of a windscreen (3.1.2) when it is subjected to impact on the
opposite side
Note 1 to entry: Spalling in this document describes the detachment of spall from the inside face of a windscreen (3.1.2)
or window, when the outer face is subjected to impact.
3.1.13
hot-spot
highly localised area where the temperature deviates significantly from the surrounding area.
3.1.14
inspector
person that undertakes the technical or visual inspection of products
3.1.15
seat reference point
SRP, noun
reference point at the back pan of a new seat design with a horizontal distance of 135 mm and vertical distance
of 98 mm from the H point according to ISO 20176:2020
[4]
Note 1 to entry: See EN 16186-1:2014 , Figure 2 of for background information to explain Seat Reference Pointon seat
reference points based on anthropometric characteristics.
[SOURCE: EN 16186-1:2014,, 3.1.6 modified: — Note 1 to entry washas modified, and Note 2 to entry washas
been deleted.]
3.1.16
specific power
total heating power divided by the heated surface area,
Note 1 to entry: Specific power is expressed in W/m .
3.2 Abbreviations
3.2 Abbreviated terms
IRHD International Rubber Hardness Degreeinternational rubber hardness degree
YI Yellowness Indexyellowness index
ISO/FDIS 23340:2026(en)
4 Functional requirements
4.1 General
4.1.1 windscreenWindscreen classification
Windscreens are positioned to allow observation of the track and signals ahead of a vehicle. Additional side
windscreens or windows may be provided to the side of the windscreen or windscreens (see Figure 2).
ISO/FDIS 23340:2026(en)
ISO/FDIS 23340:2026(en)
Key
1 windscreen
2 side windscreen
3 side windscreen (cab window forward of seat reference point, see 4.1.2)
4 bodyside window
5 driver's seat (or passenger seats, for example., in automatic vehicles)
6 seat reference point (SRP)
Θi, Θn plan view angles (for curved windscreens, the values vary with position)
Figure 2— windscreen — Windscreen and side windscreens
The classification of rail vehicle glazing (windscreen, side windscreens or bodyside windows) affects the
characteristics required and primarily depends on the orientation relative to the track.
For the determination of a windscreen ’s orientation, only the parts of the glazing which, if removed, would
create an aperture and expose the occupants of a vehicle to the outside shall be considered.
glazing that covers lights, information displays or extends over the structure for aesthetic purposes is
therefore excluded.
If the projected forward-facing area determined in accordance withaccording to Annex A is less than or equal
to 0,065 m , and unless requirements for driver's cabs apply (see 4.1.2), then the glazing shall be considered
to be a bodyside window and shall be in accordance with ISO 22752:2021.
ISO/FDIS 23340:2026(en)
For windscreens that can be considered to be forward facing (including those which are not required or
intended for direct observation of the track and signals), the maximum and minimum plan view angles, Θ (see
Figure 2), shall be determined in accordance with Annex A.
For driver's windscreens, with a central driving position, the plan view angle, Θ, may be assumed to be = 0°.
The maximum and minimum rake angles, Φ, shall be determined in accordance with Annex A.
For curved windscreens, the method set out in Annex A should be followed for the determination of plan view
and rake angles.
The maximum and minimum installation angles Ψ shall be determined from the maximum and minimum plan
view angles Θ and the maximum and minimum rake angles Φ using the relation cos(Ψ) = cos(Θ)·cos(Φ).
The maximum and minimum windscreen plan view angles, rake angles and installation angles shall form part
of the technical specification for manufacture and testing.
If samples are used to determine optical properties, the maximum installation angle shall be used (e.g. see
5.2).
If samples are used to determine mechanical properties such as impact resistance, the minimum installation
angle shall be used (e.g. see 6.1).
Figure 3 shows different types of windscreens and windows.
ISO/FDIS 23340:2026(en)
Key
1 leading vehicle (alternate cab types shown)
2 driver seat in forward direction of travel
3 driver's windscreen(s)
4 passenger windscreen
5 vehicle end windows
6 driver's cab partition wall
X direction of travel
Figure 3 — Examples of windscreens and vehicle end windows
4.1.2 Driver's windscreens
All windows in driver’s cabs that are fully or partially in front of the driver’s seat reference point (SRP),
measured in the longitudinal direction shall be considered as windscreens or side windscreens (see Figure 2).
Exceptions according to Clause A.1 are acceptable if the angle Ɵ is greater than 70° if agreed by contracted
parties.
Where two or more windscreens are fitted and only one of which is required to be a driver’s windscreen, the
requirements for driver’s windscreens shall apply to both (or all) windscreens (see Figure 3).
ISO/FDIS 23340:2026(en)
For driver’s windscreens, the plan view angle shall be determined using the points defining the primary vision
area (see 4.2, see Zonezone A in Figure 4).
4.1.3 Passenger windscreens and vehicle end windows
Windscreens or side windscreens that are only provided for observation by passengers without occasional
driver or crew member (e.g. in degraded mode, training or testing phase) shall be referred to as passenger
windscreens (see Figure 3).
The following may be considered to be equivalent to bodyside windows (see ISO 22752ISO 22752:2021)) and
therefore outside the scope of this document if agreed by contracted parties:
— forward facing vehicle end windows, located at an intermediate end of a vehicle, if they are shielded by an
adjacent vehicle from the risk of a direct longitudinal impact (see Figure 3);
— forward facing vehicle end windows, for example, in vehicle end doors, where people are not present
during operation;
— vehicle end windows that only face to the rear in normal service (see Figure 3).
4.1.4 Contractual agreements
Where options are provided in this document, contracted parties should document the choices made. Annex I
gives the list of items that should be recorded.
Both the definitiveThe requirements specified throughout this document and the itemsoptions documented
in (see Annex I shouldshall be satisfied before a claim of compliance withconformity to this document can be
made and verified.
4.2 Optical areas
A windscreen can be divided into a maximum of three optical areas as shown in Figure 4.
A primary vision area shall be defined for driver’s windscreens. The boundary between secondary and
peripheral areas shall form part of the windscreen technical specification.
For windscreens other than driver's windscreen, a primary vision area may be optional. In this case, the
boundaries between optical areas shall form part of the windscreen technical specification.
ISO/FDIS 23340:2026(en)
Key
A primary vision area
B secondary vision area
C peripheral area
0 assumed eye position
1 driver's sightlines
W, X, Y, Z sightline intersection points
Figure 4 — windscreen optical areas
The four points W, X, Y and Z, shown on Figure 4, represent the intersections between the windscreen and the
driver’s sightlines. These points are joined by lines as shown in Figure 4 to define the primary vision area.
The definition of the driver’s sightlines (for the observation of track and signals) is outside of the scope of this
document. Data to define these points shall form part of the windscreen technical specification.
NOTE ISO 26053-1 is under development and will set those visibility criteria.
The peripheral area may be deliberately obscured (in whole or in part) e.g. by silk-screen printing for any of
the following reasons:
— elimination of distracting items from the field of vision;
ISO/FDIS 23340:2026(en)
— for windscreens that are bonded into position, to protect the bonded area from the effect of ultraviolet
(UV) radiation;
— aesthetic purposes.
4.3 Windscreen test requirements
4.3.1 General
The windscreen design shall be validated by satisfactory completion of the assessments and tests described
in this document. Table 1 contains a summary of the tests defined in this document.
Table 1 — Tests
Feature to be tested Type test Routine test Periodic test
Appearance (see 5.1) W W
Secondary images (see 5.2.1) W
Optical distortion (see 5.2.2) W W
Haze (see 5.2.3) S or W
Transmittance (see 5.2.4) S or W S or W
Chromaticity (see 5.2.5) S or W
Impact (including spalling) (see 6.1) S or W
Residual visibility (see 6.2) S
Abrasion resistance (see 6.3) S
a
Gravelling (see 6.4) S
a
Bullet resistance (see 6.5) S
Heating (see 7.1) W W
Ageing (see 7.2) S or W
Voltage withstand W W
Key
S sample
W complete windscreen
a
If required by the windscreen technical specification.
4.3.2 Type tests
All type tests are listed in Table 1.
If a windscreen is fitted with a heating device, the following tests shall be repeated with the heating device in
use:
— secondary images (see 5.2.1);
— optical distortion test (see 5.2.2).
When type tests are repeated with the heating device in use:
— the heater shall be operated at its nominal voltage;
ISO/FDIS 23340:2026(en)
— thermal stabilization shall be reached before measurements are undertaken.
This requirement shall not apply to additional start-up heating provided for use on a stationary vehicle to
accelerate the removal of ice or snow.
Test samples properties are summarized in Annex F.
If a windscreen validated in accordance with this document is modified, a new type test may be omitted where
it can be shown that the required performance is not affected for a given type test.
For passenger windscreens, the following tests are optional:
— secondary images (see 5.2.1);
— haze (see 5.2.3);
— transmittance (see 5.2.4), a minimum transmittance of 40 % may be accepted;
— chromaticity (see 5.2.5).
4.3.3 Routine tests
Routine testing shall be undertaken during production on all windscreens for the following:
— appearance (see 5.1);
— optical distortion (see 5.2.2);
— heating (see 7.1);
— voltage withstand.
4.3.4 Periodic tests
Transmittance (see 5.2.4) shall be tested periodically at a frequency given in the windscreen technical
specification.
4.4 Marking
The windscreen shall be permanently marked, to show, as a minimum, the following information:
— name or logo of windscreen supplier;
— date of manufacture (month and the last two numerals of the year or a code by which this information can
be identified).
The following information should be included in the marking:
— unique identification number (part number and serial number);
— nominal voltage and type of current (AC or DC) of the heater (if applicable);
— total power of the heater (if applicable);
— the applicable version of this document.
ISO/FDIS 23340:2026(en)
The marking shall be outside of the primary vision area. If there are no conflicting requirements, it should be
in the upper right hand corner of the windscreen.
The marking shall be readable and visible from inside the cab. The marking shall be readable without viewing
aids and the minimum height of characters should be 3 mm.
4.5 Service requirements
Windscreens shall be designed to withstand normal operational conditions, including induced static and
dynamic loadings and environmental conditions such as temperature and humidity, when installed in a
railway vehicle.
Requirements for use in a specific environment which are in addition to the requirements set out in this
document shall form part of the windscreen technical specification.
A heating system should be incorporated into a driver’s windscreen for de-icing and de-misting so that the
driver can maintain a clear external view in most weather and operating conditions. If such an integral heating
system is provided it shall satisfy the requirements set out in 7.1.
Driver’s windscreens, when impacted or cracked, shall have sufficient residual visibility to allow the train to
be moved, subject to operational rules. This requirement shall be deemed to be satisfied by achieving the
residual visibility requirements set out in 6.2.
NOTE For passenger windscreens, a pendulum test and passenger containment test according to ISO
22752:2021ISO 22752:2021 can be set out in the windscreen technical specification.
4.6 Storage and handling of finished windscreens
Windscreens should be stored in a well ventilated area, protected from the weather and out of direct sunlight.
Flat windscreens should be stored on a solid base in a vertical orientation, inclined at a rake angle of
approximately 6 degrees. The windscreens should be continuously supported by brackets along each edge.
The supporting brackets should be covered with soft material to prevent damage.
Storage for curved windscreens should follow the same principles adapted for the specific geometry of the
product.
Glazing edges shall be finished in accordance with ISO 12543-5:2021, 5.3.2 or, 5.3.3 or 5.3.4.
NOTE The purpose of the finished edges is to prevent injury to handlers of the glazing by sharp edges.
5 Visual and optical requirements
5.1 Appearance defects
5.1.1 General
Appearance defects (blemishes) are characteristics of one of the following elements of the windscreen or the
processes in its manufacture:
— glazing material(s);
— interlayer(s);
— assembly;
ISO/FDIS 23340:2026(en)
— handling;
— anti-spall layer, if fitted.
To ensure an acceptable quality of vision to the driver, windscreens shall be inspected in accordance with the
procedure set out in 5.1.2. Any defects shall be classified in accordance with5.1.3 and the number and size of
such defects shall not exceed the limits listed in 5.1.4.
These requirements with regard to 5.1.2 and 5.1.3 may be modified if agreed by the contracted parties.
5.1.2 Visual inspection procedure for appearance defects
Windscreens shall be inspected in a darkened test chamber equipped with a vertical luminous screen. The
light from the luminous screen passing through the windscreen shall be used to determine by a visual
inspection if there are defects in the windscreen. If defects are found, their type and size shall be recorded and
the acceptability of the windscreen determined. The test arrangement is shown in Figure 5.
ISO/FDIS 23340:2026(en)
Key
A windscreen
B luminous screen
C inspector
D Moving inspection zone
Figure 5 — Device for checking the appearance, front view and top view
ISO/FDIS 23340:2026(en)
1)
The luminous screen shall be NCS 7502-B grey or equivalent. The use of any other screen colour shall be part
of the windscreen technical specification.
The windscreen shall be assessed in accordance with the following procedure:
— The windscreen shall be positioned vertically in front of the luminous screen at a distance of 3,0 m. For
curved windscreens the distance shall be measured from the centre of the primary vision area. The outside
surface of the windscreen shall face the luminous screen.
— The glazing shall be clean, dry and free of deposits of material or fluid that can affect the inspection.
— The test chamber should be substantially dark. The ambient illuminance shall be measured at the inner
face of the windscreen with the luminous screen powered off. This illuminance value shall not be greater
than 20 lx and shall be recorded in the test report.
— The luminous screen shall be lit to give a uniform illuminance from 500 lx to 1500 lx measured at the inner
face of the windscreen.
— The inspector shall be positioned behind the windscreen at a distance of 1,5 m. Alternatively, the inspector
shall be positioned in accordance with the distance between the driver and the windscreen defined in the
technical specification.
— The examination duration shall be equal to 1 min for a windscreen with a surface area less or equal to 1,5
m and shall be equal to 2 min for a windscreen with a greater surface area.
— The windscreen shall be divided into sufficient inspection zones to cover the entire surface of the
windscreen . Inspection zones should be arranged to minimize overlapping and areas beyond the
boundaries of the vision areas.
— The size of the inspection zones should be 0,5 m × 0,5 m.
— The inspector shall examine the complete windscreen surface by looking through each inspection zone in
turn. The inspector shall change position horizontally and vertically as required to look through each
inspection zone perpendicularly to the luminous screen.
— The position of any suspect points identified during the examination shall be recorded.
The inspector shall remain in the test chamber for the duration of the visual inspection.
At the end of the visual inspection, if any suspect points have been identified, the inspector shall re-examine
the glazing to analyse them and to classify them in accordance with 5.1.3.
Only features identified as suspect points during the visual inspection shall be analysed and classified.
A defect that can be seen from the outer surface of the windscreen , but which is not detected by this
assessment method, shall not be included in the assessment.
The criteria set out in 5.1.4 shall be used to determine if the windscreen is acceptable.

1)
NCS 7502-B is the trade name of a product supplied by the Universal Standard for Colour Communication. This
information is given for the convenience of users of this document and does not constitute an endorsement by ISO of the
product named. Equivalent products may be used if they can be shown to lead to the same results.

ISO/FDIS 23340:2026(en)
5.1.3 Definition and classification of defects
Table 2, Table 3 and Table 4 are used to classify defects according to their characteristics.
Table 2 — Classification of defects
DefectsDefect Range
Bubble:
0,8 mm < d ≤ 2 mm
Air air pocket, sometimes coloured,
entrapped in glazing
Impurities:
0,8 mm < d ≤ 2 mm
Small small impurity in glazing or interlayer,
or an embedded particle
Point defects
Spot:
0,8 mm < d ≤ 2 mm
Local local translucent area on interlayer
Surface defect:
Blemish blemish caused by minor impact or
0,8 mm < d ≤ 2 mm
abrasion (e.g. between two sheets of material
during storage)
Fine scratch or other linear defect detectable
13 mm < d ≤ 40 mm
by touch (with a fingernail)
Hairline scratches hardly detectable by touch
13 mm < d ≤ 40 mm
but visible on the surface
Linear defects: Defects where the
length to width ratio is high. The
Print of attenuated (repaired) scratch 13 mm < d ≤ 40 mm
dimension given is the direct
Lint, fibre, hair:
distance between the extremities
of the defect. There shall be no Elongated elongated impurity trapped
13 mm < d ≤ 40 mm
chipping along the sides of a
between glazing ply and interlayer when
scratch
laminating
Streak, mark (drag) trace:
totalTotal surface ≤ : ≤800 mm
Whitish whitish area in the interlayer, hardly
detectable under daylight condition
Point defects: shell, chips, impacts, etc. 1 mm < d ≤ 2mm2 mm
Result of the loss of small fragments from the
edges, not totally eliminated by grinding.
Small loss of glass fragment, at the edge, not
totally eliminated by grinding. The grinding
Edge defects
to eliminate these defects can extend up to 10
mm from the edge of the glass.
Linear defects: chips, burns, lack of grinding, <25 mm per defect ,
etc.
summation ≤ : ≤25 mm / 1 m
Table 3 — Classification of screen printing defects
Defect Range
Dot fade-out: Visualvisual inspection shall 1,5 mm < d ≤ 3 mm
confirm that the uniformity of the dot fade-out
pattern is acceptable and any irregularity does
Impurities under silk screen
not attract the eye at 3 m from the product

ISO/FDIS 23340:2026(en)
Defect Range
Key
1 hole, 2 dividing point
Circular-type defect:
2 mm < d ≤ 4 mm
Linear defect:
S = L × T
Solid colour surface
2 2
20 mm < S ≤ 80 mm
with
T ≤ 1 mm
Defects on the edge of the solid colour surface: Inner edge (nearest to vision
area):
2 mm < P ≤ 3 mm and
10 mm < L ≤ 40 mm
Outer edge:
3 mm < P ≤ 5 mm peripheral
ISO/FDIS 23340:2026(en)
Defect Range
Table 4 — Classification of anti-spall layer defects
Defect Range
Skin blister: Localizedlocalized deformation of the transparent surface 1,5 mm < d ≤ 3 mm
Cord: A relatively thick and very obvious thread of material 5 mm < L ≤ 10 mm
Coating drip: Unevenuneven thickness of final coating 5 mm < d ≤ 10 mm
In addition, the following defects are allowed in the peripheral area:
— irregularity in external dimension of individual layers (maximum 3 mm per edge);
— bubbling;
— delamination (only in case of sealed edge);
— opacity of the interlayer;
— impressions made in glazing by the tips of the tongs (local deformation, iridescence and hairline
scratches);
— impressions made by bending tools.
5.1.4 Defect acceptance criteria
For a new windscreen, the number of identified defects classified in accordance with Table 2, Table 3 and
Table 4 shall not exceed the limits set out in Table 5.
If the size of a defect exceeds the upper value of the appropriate range defined in Table 2, Table 3 and Table 4,
the windscreen shall not be accepted. If for an observed defect the value is less than the lower value of the
range, it shall be classified as a negligible defect.
An accumulation of defects occurs if four or more negligible defects are all at a distance of less than 200 mm
from each other. An accumulation of defects shall be considered to be equivalent to a single defect for
determining conformity to the acceptance limits given in Table 5. Otherwise, negligible defects may be
ignored.
ISO/FDIS 23340:2026(en)
Table 5 — Defect acceptance limits
Vision area Acceptance limits
primaryPrimary vision area A maximum of 3 defects within any circular area of d = 300 mm. No
accumulation of negligible defects shall be allowed.
secondarySecondary vision area A maximum of 3 defects within any circular area of d = 100 mm
peripheralPeripheral area A maximum of 3 defects inside any region of length 100 mm
5.2 Optical characteristics
5.2.1 Secondary image separation
Tests shall be conducted in accordance with ISO 3538:1997, 5.2. The test optical axis shall be the vehicle body
longitudinal axis. The windscreen shall be positioned to give the correct rake and plan view angles relative to
the vehicle body longitudinal axis. The rake and plan view angles shall be determined in accordance with 4.1.1.
The secondary image separation shall not exceed 15 min of arc in the primary vision area measured in the
installation position.
The secondary image separation should not exceed 25 min of arc in the secondary vision area measured in the
installation position.
These requirements may be modified if agreed by contracted parties for:
— vehicles designed only for operation on fully segregated lines and which only use in-cab signalling; or
— vehicles designed only for operation on fully segregated lines and with a windscreen installed at an angle
of more than 60° from the vertical plane.
If there is more than one secondary image, only one secondary image shall be evaluated. The image to be
considered is that which appears brightest to an observer looking through the windscreen from the driving
position.
5.2.2 Optical distortion
Optical distortion is typically evaluated by projecting an array of circular shapes through the glazing material
being tested onto a display screen as represented in Figure 6. The change in shape of the projected image
caused by the glazing material provides a measure of any distortion.
A production windscreen shall be tested. The test optical axis shall be the vehicle body longitudinal axis. The
windscreen shall be positioned to give the correct rake and plan view angles relative to the vehicle body
longitudinal axis. The rake and plan view angles shall be determined in accordance with 4.1.1.
Optical distortion shall be evaluated by testing in accordance with ISO 3538:1997, 5.3. Distance R shall be
4 m and distance R shall be in the range of 2 m to 4 m (see Figure 6). As stated in ISO 3538:1997 Figure 7, the
preferred dimension for R is 4 m.
The undistorted circle diameters projected on the display screen, d, should be 8 mm, corresponding to image
diameters, d , of 4 mm on the windscreen surface.
x
ISO/FDIS 23340:2026(en)
Key
1 projector
2 windscreen
3 display screen
dx diameter of image on the inside of the windscreen, measured on the vertical plane, in millimetres
d undistorted projected image diameter on display screen (without windscreen in the light path), in millimetres
DD maximum diameter of distorted image on the display screen (with windscreen in the light path), in millimetres
α1, α2 angular deviations (anti-clockwise sense positive), in min of arc
R1 distance from light source to windscreen, in metres
R2 distance from the windscreen to the display screen, in metres
ISO/FDIS 23340:2026(en)
Figure 6 — Measurement of optical distortion
For a given position on the windscreen, the optical distortion is considered to be the overall angular deviation
Δα, where Δα = α —− α .
1 2
NOTE 1 In Figure 6, α1 is positive, α2 is negative. In this case, Δα is therefore the sum of the values.
Δα can be determined from the difference between the maximum diameter of the distorted image and the
undistorted image measured on the display screen using the relationship:
Δ𝑑𝑑 = 0,291 ·Δ𝛼𝛼 ·𝑅𝑅 = (𝐷𝐷 𝐷𝐷 − 𝑑𝑑) (1)
2 𝐷𝐷 D
NOTE 2 The constant 0,291 is the conversion from min of arc to radians and from metres to millimetres i.e. 0,291 =
1000 𝜋𝜋
.
180·60
The optical distortion shall not exceed 2,5 min of arc in the primary vision area.
The optical distortion should not exceed 6,5 min of arc in the secondary vision area.
These requirements may be modified if agreed by contracted parties for:
— vehicles designed only for operation on fully segregated lines and which only use in-cab signalling; or
— vehicles designed only for operation on fully segregated lines and with a windscreen installed at an angle
of more than 60° from the vertical plane.
5.2.3 Haze
Maximum value of haze shall be 2,5 %.
Tests to measure haze shall be conducted in accordance with ISO 14782.
When the test is conducted using a complete windscreen , the light source shall come from the outside and the
test shall be conducted on the full glazing composition.
5.2.4 Light transmittance
5.2.4.1 Determination of light transmittance
780 780
∑ ( ) ∑ ( )
𝑆𝑆 𝜆𝜆 · 𝛥𝛥𝜆𝜆 𝑆𝑆 𝜆𝜆 · Δ𝜆𝜆
𝑤𝑤 w
380 380
𝜏𝜏(𝜆𝜆) = (2)
780 780
∑ ( ) ∑ ( )
𝑆𝑆 𝜆𝜆 · 𝛥𝛥𝜆𝜆 𝑆𝑆 𝜆𝜆 · Δ𝜆𝜆
𝐴𝐴 A
380 380
where
τ(λ) is the spectral transmittance of the windscreen;
SΑ(λ) is the relative spectral distribution of CIE illuminant A;
SW (λ)0 is the relative spectral distribution of CIE illuminant A with windscreen in the light path;
λ is the wavelength in nm;
Δλ is the wavelength interval.
The spectral transmittance shall be
...

PROJET FINAL
Norme
internationale
ISO/FDIS 23340
ISO/TC 269/SC 2
Applications ferroviaires —
Secrétariat: AFNOR
Vitres frontales pour véhicules
Début de vote:
ferroviaires
2026-07-15
Railway applications — Windscreens for trains
Vote clos le:
2026-09-09
LES DESTINATAIRES DU PRÉSENT PROJET SONT
INVITÉS À PRÉSENTER, AVEC LEURS OBSERVATIONS,
NOTIFICATION DES DROITS DE PROPRIÉTÉ DONT ILS
AURAIENT ÉVENTUELLEMENT CONNAISSANCE ET À
FOURNIR UNE DOCUMENTATION EXPLICATIVE.
OUTRE LE FAIT D’ÊTRE EXAMINÉS POUR
ÉTABLIR S’ILS SONT ACCEPTABLES À DES FINS
INDUSTRIELLES, TECHNOLOGIQUES ET COM-MERCIALES,
AINSI QUE DU POINT DE VUE DES UTILISATEURS, LES
PROJETS DE NORMES
INTERNATIONALES DOIVENT PARFOIS ÊTRE CONSIDÉRÉS
DU POINT DE VUE DE LEUR POSSI BILITÉ DE DEVENIR DES
NORMES POUVANT
SERVIR DE RÉFÉRENCE DANS LA RÉGLEMENTATION
NATIONALE.
Numéro de référence
ISO/FDIS 23340:2026(fr) © ISO 2026

PROJET FINAL
ISO/FDIS 23340:2026(fr)
Norme
internationale
ISO/FDIS 23340
ISO/TC 269/SC 2
Applications ferroviaires —
Secrétariat: AFNOR
Vitres frontales pour véhicules
Début de vote:
ferroviaires
2026-07-15
Railway applications — Windscreens for trains
Vote clos le:
2026-09-09
LES DESTINATAIRES DU PRÉSENT PROJET SONT
INVITÉS À PRÉSENTER, AVEC LEURS OBSERVATIONS,
NOTIFICATION DES DROITS DE PROPRIÉTÉ DONT ILS
AURAIENT ÉVENTUELLEMENT CONNAISSANCE ET À
FOURNIR UNE DOCUMENTATION EXPLICATIVE.
DOCUMENT PROTÉGÉ PAR COPYRIGHT
OUTRE LE FAIT D’ÊTRE EXAMINÉS POUR
ÉTABLIR S’ILS SONT ACCEPTABLES À DES FINS
© ISO 2026 INDUSTRIELLES, TECHNOLOGIQUES ET COM-MERCIALES,
AINSI QUE DU POINT DE VUE DES UTILISATEURS, LES
Tous droits réservés. Sauf prescription différente ou nécessité dans le contexte de sa mise en œuvre, aucune partie de cette
PROJETS DE NORMES
INTERNATIONALES DOIVENT PARFOIS ÊTRE CONSIDÉRÉS
publication ne peut être reproduite ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique,
DU POINT DE VUE DE LEUR POSSI BILITÉ DE DEVENIR DES
y compris la photocopie, ou la diffusion sur l’internet ou sur un intranet, sans autorisation écrite préalable. Une autorisation peut
NORMES POUVANT
être demandée à l’ISO à l’adresse ci-après ou au comité membre de l’ISO dans le pays du demandeur.
SERVIR DE RÉFÉRENCE DANS LA RÉGLEMENTATION
NATIONALE.
ISO copyright office
Case postale 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Genève
Tél.: [phone]
E-mail: [e-mail]
Web: www.iso.org
Publié en Suisse Numéro de référence
ISO/FDIS 23340:2026(fr) © ISO 2026

ii
ISO/FDIS 23340:2026(fr)
Sommaire Page
Avant-propos .v
1 Domaine d’application . 1
2 Références normatives . 1
3 Termes et définitions . 2
3.1 Termes, définitions et abréviations .2
3.2 Termes abrégés .5
4 Exigences fonctionnelles . 5
4.1 Généralités .5
4.1.1 Classifications des vitres frontales .5
4.1.2 Pare-brises conducteur .7
4.1.3 Vitres frontales passagers et fenêtres d’extrémité du véhicule .8
4.1.4 Accords contractuels .8
4.2 Zones optiques .8
4.3 Exigences d’essai des vitres frontales . .9
4.3.1 Généralités .9
4.3.2 Essais de type .10
4.3.3 Essais de série .11
4.3.4 Essais périodiques .11
4.4 Marquage .11
4.5 Exigences de service .11
4.6 Stockage et manipulation des vitres frontales finies . 12
5 Exigences visuelles et optiques .12
5.1 Défauts apparents . 12
5.1.1 Généralités . 12
5.1.2 Procédure d’examen visuel des défauts apparents . 12
5.1.3 Définition et classification des défauts .14
5.1.4 Critères d’acceptation des défauts .17
5.2 Propriétés optiques .17
5.2.1 Séparation des images secondaires .17
5.2.2 Distorsion optique .18
5.2.3 Diffusion .19
5.2.4 Facteur de transmission lumineuse .19
5.2.5 Chromaticité .21
6 Caractéristiques mécaniques .23
6.1 Résistance à l’impact . 23
6.1.1 Exigences pour l’essai d’impact . 23
6.1.2 Évaluation de la projection d’éclats . 25
6.1.3 Vitesse du projectile pour l’essai d’impact . 25
6.1.4 Procédure pour l’essai d’impact .27
6.1.5 Critères d’acceptation de l’essai d’impact . 28
6.2 Visibilité résiduelle . 29
6.2.1 Généralités . 29
6.2.2 Échantillons d’essai . 29
6.2.3 Méthode d’essai . 29
6.2.4 Critères d’acceptation . 29
6.3 Résistance à l’abrasion . 29
6.4 Résistance à l’impact de petites particules provenant de la voie (gravillonnage) . 30
6.4.1 Généralités . 30
6.4.2 Échantillons d’essai . 30
6.4.3 Méthode d’essai . 30
6.5 Résistance aux tirs de balles .31
6.5.1 Généralités .31
6.5.2 Échantillons d’essai .31

iii
ISO/FDIS 23340:2026(fr)
6.5.3 Mode opératoire . .31
6.5.4 Critères d’acceptation .31
7 Aptitude au service .32
7.1 Système de chauffage .32
7.1.1 Généralités .32
7.1.2 Uniformité du chauffage .32
7.1.3 Systèmes de chauffage à couche conductrice .32
7.1.4 Systèmes de chauffage à filaments. 33
7.1.5 Mesure de la résistance . 33
7.1.6 Essai de tenue en tension . 33
7.2 Résistance au vieillissement . 33
7.2.1 Généralités . 33
7.2.2 Essai de conditions climatiques accélérées . 34
7.2.3 Cycles thermiques . 34
7.2.4 Essai d’humidité . 35
7.2.5 Essai de chauffage de la vitre frontale . 36
Annexe A (normative) Détermination des angles des vitres frontales .37
Annexe B (normative) Calcul du facteur de transmission lumineuse d’une vitre frontale inclinée .42
Annexe C (normative) Montage d’essai d’une vitre frontale .45
Annexe D (normative) Projectile pour l’essai d’impact .48
Annexe E (normative) Projectile pour l’essai de gravillonnage .50
Annexe F (informative) Échantillons d’essai . 51
Annexe G (normative) Dispositif de l’essai de résistance aux tirs de balles .52
Annexe H (informative) Méthode alternative pour les essais de résistance aux rayonnements
ultraviolets .53
Annexe I (informative) Liste des informations et exigences à discuter et convenir entre les
parties contractantes .54
Bibliographie .56

iv
ISO/FDIS 23340:2026(fr)
Avant-propos
L’ISO (Organisation internationale de normalisation) est une fédération mondiale d’organismes nationaux
de normalisation (comités membres de l’ISO). L’élaboration des Normes internationales est en général
confiée aux comités techniques de l’ISO. Chaque comité membre intéressé par une étude a le droit de
faire partie du comité technique créé à cet effet. Les organisations internationales, gouvernementales
et non gouvernementales, en liaison avec l’ISO participent également aux travaux. L’ISO collabore
étroitement avec la Commission électrotechnique internationale (IEC) en ce qui concerne la normalisation
électrotechnique. Les procédures utilisées pour élaborer le présent document et celles destinées à sa
mise à jour sont décrites dans les Directives ISO/IEC, Partie 1. Il convient en particulier de prendre note
des différents critères d’approbation requis pour les différents types de documents ISO. Le présent
document a été rédigé conformément aux règles de rédaction données dans les Directives ISO/IEC, Partie 2
(voir www.iso.org/directives).
L’ISO attire l’attention sur le fait que la mise en application du présent document peut entraîner l’utilisation
d’un ou de plusieurs brevets. L’ISO ne prend pas position quant à la preuve, à la validité et à l’applicabilité de
tout droit de brevet revendiqué à cet égard. À la date de publication du présent document, l’ISO n’avait pas
reçu notification qu’un ou plusieurs brevets pouvaient être nécessaires à sa mise en application. Toutefois,
il y a lieu d’avertir les responsables de la mise en application du présent document que des informations
plus récentes sont susceptibles de figurer dans la base de données de brevets, disponible à l’adresse
www.iso.org/patents. L’ISO ne saurait être tenue pour responsable de ne pas avoir identifié de tels droits de
brevets et de ne pas avoir signalé leur existence.
Les appellations commerciales éventuellement mentionnées dans le présent document sont données pour
information, par souci de commodité, à l’intention des utilisateurs et ne sauraient constituer un engagement.
Pour une explication de la nature volontaire des normes, de la signification des termes et expressions
spécifiques de l’ISO liés à l’évaluation de la conformité, ou pour toute information au sujet de l’adhésion de
l’ISO aux principes de l’Organisation mondiale du commerce (OMC) concernant les obstacles techniques au
commerce (OTC), voir le lien suivant: www.iso.org/iso/foreword.html.
Le comité chargé de l’élaboration du présent document est l’ISO/TC 269, Applications ferroviaires, Sous-
comité SC 2, Matériel Roulant.
Il convient que l’utilisateur adresse tout retour d’information ou toute question concernant le présent
document à l’organisme national de normalisation de son pays. Une liste exhaustive desdits organismes se
trouve à l’adresse www.iso.org/members.html.

v
PROJET FINAL Norme internationale ISO/FDIS 23340:2026(fr)
Applications ferroviaires — Vitres frontales pour véhicules
ferroviaires
1 Domaine d’application
Le présent document spécifie les exigences fonctionnelles relatives aux vitres frontales des véhicules
ferroviaires, y compris les essais de type, les essais de série et les méthodes d’examen associées pour les
systèmes ferroviaires de grandes lignes et le transport guidé urbain.
Le présent document s’applique aux vitres frontales composées de verre feuilleté, qui est le matériau le
plus couramment utilisé. Il s’applique également à d’autres matériaux, sous réserve que les exigences de
performance soient satisfaites.
Le présent document s’applique également aux machines empruntant exclusivement les voies ferrées en
mode circulation (automotrices ou remorquées). Les machines empruntant exclusivement les voies ferrées
en mode déplacement et travail ne relèvent pas du domaine d’application du présent document.
Le présent document ne s’applique pas à la détermination des dimensions, de la forme, de l’orientation et de
la position des vitres frontales.
Le présent document ne spécifie pas les exigences relatives aux interfaces entre la vitre frontale et le
véhicule. Le présent document ne traite pas des questions relatives à l’installation, l’intégrité structurelle et
à l’aptitude à la collision.
2 Références normatives
Les documents suivants cités dans le texte constituent, pour tout ou partie de leur contenu, des exigences du
présent document. Pour les références datées, seule l’édition citée s’applique. Pour les références non datées,
la dernière édition du document de référence s’applique (y compris les éventuels amendements).
ISO 48-2, Caoutchouc vulcanisé ou thermoplastique — Détermination de la dureté — Partie 2: Dureté comprise
entre 10 DIDC et 100 DIDC
ISO 3537, Véhicules routiers — Vitrages de sécurité — Essais mécaniques
ISO 3538:1997, Véhicules routiers — Vitrages de sécurité — Méthodes d'essai des propriétés optiques
ISO 3917:2016, Véhicules routiers — Vitrages de sécurité — Méthodes d'essai de résistance au rayonnement, aux
températures élevées, à l'humidité, au feu et aux conditions climatiques simulées
ISO 4892-2, Plastiques — Méthodes d'exposition à des sources lumineuses de laboratoire — Partie 2: Lampes à
arc au xénon
ISO 4892-3, Plastiques — Méthodes d'exposition à des sources lumineuses de laboratoire — Partie 3: Lampes
fluorescentes UV
ISO 6362-2, Aluminium et alliages d'aluminium corroyés — Barres, tubes et profilés filés — Partie 2:
Caractéristiques mécaniques
ISO/TR 8941, Infrastructure ferroviaire — Machines de construction, de maintenance et d'inspection montées
sur rail — Explication du type de machine
ISO/CIE 11664-3, Colorimétrie — Partie 3: Composantes trichromatiques CIE

ISO/FDIS 23340:2026(fr)
ISO 12543-5:2021, Verre dans la construction — Verre feuilleté et verre feuilleté de sécurité — Partie 5:
Dimensions et façonnage des bords
ISO 14782, Plastiques — Détermination du trouble des matériaux transparents
ISO/FDIS 22575, Applications ferroviaires — Freinage — Vocabulaire générique
ISO 22752, Applications ferroviaires — Fenêtres latérales pour le matériel roulant
IEC 60571, Applications ferroviaires — Équipements électroniques utilisés sur le matériel roulant
CIE 15, Colorimétrie
CIE 38, Caractéristiques radiométriques et photométriques des matériaux et leur mesure
CIE 1931, Système colorimétrique normalisé
CIE S 004, Couleurs des signaux lumineux
3 Termes et définitions
Pour les besoins du présent document, les termes et définitions fournis dans l’ISO/FDIS 22575, l’ISO/TR 8941
et les suivants s’appliquent.
L’ISO et l’IEC tiennent à jour des bases de données terminologiques destinées à être utilisées en normalisation,
consultables aux adresses suivantes:
— ISO Online browsing platform: disponible à l’adresse https:// www .iso .org/ obp
— IEC Electropedia: disponible à l’adresse https:// www .electropedia .org/
3.1 Termes, définitions et abréviations
3.1.1
vitrage
matériau qui permet la transmission de la lumière
[SOURCE: ISO 22752:2021, 3.4]
3.1.2
vitre frontale
vitrage (3.1.1) faisant face au conducteur ou aux passagers et à travers lequel l’infrastructure en amont peut
être observée
ISO/FDIS 23340:2026(fr)
Légende
A transport guidé urbain
B grandes lignes
1 pare-brise conducteur (3.1.3)
2 pare-brise latéral (3.1.4)
3 fenêtre latérale
4 vitrages extérieurs (3.1.1) (recouvrant les feux, les panneaux d’informations, par exemple)
Figure 1 — Exemple de vitre frontale, de fenêtre et de vitrage (3.1.1)
Note 1 à l'article: La Figure 1 montre des exemples types de vitres frontales (3.1.2), fenêtres latérales et vitrages
extérieurs (3.1.1).
3.1.3
pare-brise conducteur
vitre frontale (3.1.2) à l’avant d’un véhicule à travers laquelle un conducteur observe l’infrastructure, les
signaux et les obstacles
3.1.4
pare-brise latéral
vitrage (3.1.1) additionnel placé sur le côté d’un pare-brise (3.1.2) dans la cabine
3.1.5
vitre frontale passagers
vitre frontale (3.1.2) à l’avant d’un véhicule faisant face à la zone à passagers
3.1.6
fenêtre d’extrémité du véhicule
fenêtre située aux extrémités du véhicule ou d’une composition de train qui n’est jamais à l’avant du train en
service
Note 1 à l'article: Les fenêtres d’extrémité du véhicule peuvent occasionnellement se trouver à l’avant du train exploité
à vitesse réduite (spécifiée par le client) dans un dépôt.
3.1.7
zone de visibilité principale
zone de la vitre frontale (3.1.2) à travers laquelle la voie et les signaux sont visibles lorsque le conducteur est
en position de conduite
Note 1 à l'article: Voir la Figure 4 pour une illustration de toutes les zones optiques.

ISO/FDIS 23340:2026(fr)
3.1.8
zone de visibilité secondaire
zone de la vitre frontale (3.1.2) située en dehors de la zone de visibilité principale (3.1.7), à travers laquelle le
conducteur peut également regarder lorsqu’il est en position de conduite
Note 1 à l'article: Voir la Figure 4 pour une illustration de toutes les zones optiques.
3.1.9
zone périphérique
zone de la vitre frontale (3.1.2) située en dehors de la zone de visibilité secondaire (3.1.8)
Note 1 à l'article: La zone périphérique comprend les zones d’affichage et les écrans.
3.1.10
séparation des images secondaires
séparation angulaire entre l’image primaire et la plus lumineuse des images secondaires (du fait de la
réflexion interne) d’une source lumineuse distante ou d’un objet visualisé à travers le vitrage (3.1.1)
3.1.11
rayonnement ultraviolet
rayonnement UV
rayonnement optique dont la longueur d’onde est inférieure à celle du rayonnement visible
Note 1 à l'article: La plage entre 100 nm et 400 nm est couramment subdivisée en:
— UV-A: 315 nm à 400 nm;
— UV-B: 280 nm à 315 nm;
— UV-C: 100 nm à 280 nm.
Note 2 à l'article: Il est impossible de définir une frontière précise entre le rayonnement ultraviolet et le rayonnement
visible, car la sensation visuelle à des longueurs d’onde inférieures à 400 nm n’est notée que pour les sources très
lumineuses.
[SOURCE: IEC 60050‑845:2020 ED2, 1‑008, modifiée— Les Notes 3, 4 et 5 à l’article ont été supprimées.]
3.1.12
éclat
petites particules qui se détachent de la surface d’une vitre frontale (3.1.2) sous l’impact d’un choc sur le côté
opposé
Note 1 à l'article: Dans le présent document, l’expression «projection d’éclats» désigne le détachement d’éclats de la
face intérieure d’une vitre frontale (3.1.2) ou d’une fenêtre, lorsque la face extérieure est soumise à un choc.
3.1.13
point chaud
zone très localisée où la température s’écarte considérablement de celle de la région avoisinante
3.1.14
inspecteur
personne qui effectue l’examen technique ou visuel des produits
3.1.15
point de référence du siège
SRP
point de référence à l’arrière d’une nouvelle conception de siège avec une distance horizontale de 135 mm et
une distance verticale de 98 mm du point H selon l’ISO 20176:2020
[4]
Note 1 à l'article: Voir EN 16186-1:2014 , Figure 2 pour des informations générales sur les points de référence du
siège basés sur les caractéristiques anthropométriques.
[SOURCE: EN 16186‑1:2014, 3.1.6, modifiée — La Note 1 à l’article a été modifiée et la Note 2 à l’article a été
supprimée.]
ISO/FDIS 23340:2026(fr)
3.1.16
puissance spécifique
puissance thermique totale divisée par la surface chauffée
Note 1 à l'article: La puissance spécifique est exprimée en W/m .
3.2 Termes abrégés
IRHD (International Rubber Hardness Degree) degré international de dureté du caoutchouc
YI (Yellowness Index) indice de jaunissement
4 Exigences fonctionnelles
4.1 Généralités
4.1.1 Classifications des vitres frontales
Les vitres frontales sont positionnées de manière à permettre l’observation de la voie et des signaux devant
le véhicule. Des pare-brises ou fenêtres latéraux supplémentaires peuvent être montés de part et d’autre de
la vitre frontale (voir Figure 2).

ISO/FDIS 23340:2026(fr)
Légende
1 vitre frontale
2 pare-brise latéral
3 pare-brise latéral (fenêtre de cabine devant le point de référence du siège, voir 4.1.2)
4 fenêtre latérale
5 siège de conduite (ou sièges passagers, par exemple dans les véhicules automatiques)
6 point de référence du siège (SRP)
Θ , Θ angles dans le plan (pour les pare-brises courbes, les valeurs varient en fonction de la position)
i n
Figure 2 — Pare-brise conducteur, pare-brises latéraux et fenêtres latérales
La classification des vitrages utilisés sur les véhicules ferroviaires (pare‑brises conducteur, pare‑brises
latéraux ou fenêtres latérales) affecte les caractéristiques requises et dépend essentiellement de leur
orientation par rapport à la voie.
Pour déterminer l’orientation d’une vitre frontale, seules les parties du vitrage qui, si elles sont retirées, sont
susceptibles de créer une ouverture et d’exposer les occupants d’un véhicule à l’extérieur, doivent être prises
en compte.
Les vitrages recouvrant les feux, les panneaux d’informations, etc. ou s’étendant sur toute la longueur de la
structure à des fins esthétiques sont donc exclus.
Sauf si les prescriptions applicables aux cabines de conduite s’appliquent (voir 4.1.2), lorsque la zone projetée
faisant face à la voie déterminée conformément à l’Annexe A est inférieure ou égale à 0,065 m , le vitrage
doit être considéré comme une fenêtre latérale et doit être conforme à l’ISO 22752.

ISO/FDIS 23340:2026(fr)
Pour les vitres frontales pouvant être considérées comme faisant face à la voie qui ne sont pas nécessaires
ou destinées à l’observation directe de la voie et des signaux, les angles dans le plan minimaux et maximaux
Θ (voir Figure 2) doivent être déterminés conformément à l’Annexe A.
Pour les pare-brises conducteur, avec une position de conduite centrée, l’angle dans le plan Θ peut être
supposé égal à 0°.
Les angles d’inclinaison Φ minimaux et maximaux doivent être déterminés conformément à l’Annexe A.
Pour les pare-brises courbes, il convient de suivre la méthode décrite à l’Annexe A pour la détermination des
angles dans le plan et d’inclinaison.
Les angles de montage minimaux et maximaux Ψ doivent être déterminés d’après les angles dans le plan
minimaux et maximaux Θ et les angles d’inclinaison minimaux et maximaux Φ en utilisant la relation
cos(Ψ) = cos(Θ)·cos(Φ).
Les angles dans le plan, d’inclinaison et de montage minimaux et maximaux de la vitre frontale doivent être
indiqués dans la spécification technique de fabrication et d’essai.
Lorsque des échantillons sont utilisés pour déterminer les propriétés optiques, l’angle de montage maximal
doit être utilisé (voir 5.2 par exemple).
Lorsque des échantillons sont utilisés pour déterminer les propriétés mécaniques telles que la résistance à
l’impact, l’angle de montage minimal doit être utilisé (voir 6.1 par exemple).
La Figure 3 montre différents types de vitres frontales et de fenêtres.
Légende
X sens de marche
1 véhicule de tête (la figure montre deux types de cabines)
2 siège de conduite dans le sens de marche vers l’avant
3 pare-brise(s) conducteur
4 vitre frontale passagers
5 fenêtres d’extrémité du véhicule
6 paroi de séparation de la cabine du conducteur
Figure 3 — Exemples de vitres frontales et de fenêtres d’extrémité du véhicule
4.1.2 Pare-brises conducteur
Toutes les vitres des cabines de conduite qui sont situées partiellement ou complètement devant le point
de référence du siège (SRP) conducteur, mesuré dans l’axe longitudinal, doivent être considérées comme

ISO/FDIS 23340:2026(fr)
des pare-brises conducteur ou des pare-brises latéraux (voir Figure 2). Les exceptions prévues en A.1 sont
acceptables si l’angle Ɵ est supérieur à 70° et si convenu entre les parties contractantes.
Lorsque le véhicule est équipé de deux vitres frontales ou plus, mais qu’une seule d’entre elles doit être
un pare-brise conducteur, les exigences relatives aux pare-brises conducteur s’appliquent à l’ensemble des
vitres frontales (voir Figure 3).
Pour les pare-brises conducteur, l’angle dans le plan doit être déterminé à l’aide des points qui délimitent la
zone de visibilité principale (voir 4.2; Figure 4, zone A).
4.1.3 Vitres frontales passagers et fenêtres d’extrémité du véhicule
Les vitres frontales ou vitres latérales aménagées dans le seul but de permettre aux passagers de regarder
dehors sans être utilisées par un conducteur ou un membre de personnel occasionnel (par exemple en mode
dégradé, en phase d’entraînement ou d’essai) doivent être appelées vitres frontales passagers (voir Figure 3).
Si convenu entre les parties contractantes, les éléments suivants peuvent être considérés comme étant
équivalents à des fenêtres latérales (voir ISO 22752) et ne relèvent donc pas du domaine d’application du
présent document:
— fenêtres d’extrémité du véhicule faisant face à la voie, situées à l’extrémité arrière d’un véhicule, si elles
sont protégées du risque d’impact longitudinal direct par un véhicule contigu (voir Figure 3);
— fenêtres d’extrémité du véhicule faisant face à la voie, par exemple au niveau des portes d’extrémité, où
les personnes ne sont pas présentes pendant le service;
— fenêtres d’extrémité du véhicule faisant uniquement face à l’arrière en conditions de service normal (voir
Figure 3).
4.1.4 Accords contractuels
Lorsque le présent document propose des options, il convient que les parties contractantes consignent les
choix effectués. L’Annexe I fournit la liste des éléments qu’il convient d’enregistrer.
Les exigences spécifiées tout au long du présent document et les options formulées à l’Annexe I doivent être
satisfaites avant de pouvoir revendiquer et vérifier la conformité au présent document.
4.2 Zones optiques
Une vitre frontale peut être divisée en trois zones optiques maximum (voir Figure 4).
Une zone de visibilité principale doit être définie pour les pare‑brises conducteur. La limite entre les zones
secondaires et périphériques doit être indiquée dans la spécification technique de la vitre frontale.
Pour les vitres frontales autres que le pare-brise conducteur, une zone de visibilité principale peut être
facultative. Dans ce cas, les limites entre les zones optiques doivent être indiquées dans la spécification
technique de la vitre frontale.

ISO/FDIS 23340:2026(fr)
Légende
A zone de visibilité principale
B zone de visibilité secondaire
C zone périphérique
0 position supposée de l’œil
1 épure de visibilité
W, X, Y, Z points d’intersection des lignes de visée
Figure 4 — Zones optiques d’une vitre frontale
Les quatre points W, X, Y et Z (voir Figure 4) représentent les intersections entre la vitre frontale et l’épure de
visibilité du conducteur. Ces points sont reliés par des lignes afin de délimiter la zone de visibilité principale
(voir Figure 4).
La définition de l’épure de visibilité (pour l’observation de la voie et des signaux) ne relève pas du domaine
d’application du présent document. Les données permettant de définir ces points doivent être indiquées
dans la spécification technique de la vitre frontale.
NOTE L’ISO 26053‑1, actuellement en cours de développement, définira ces critères de visibilité.
La zone périphérique peut être volontairement obscurcie (en partie ou en totalité) par une sérigraphie pour
les raisons suivantes:
— élimination des sources de distraction du champ de vision;
— dans le cas des vitres frontales qui sont collées, protection de la zone collée contre l’action des
rayonnements ultraviolets (UV);
— fins esthétiques.
4.3 Exigences d’essai des vitres frontales
4.3.1 Généralités
La conception des vitres frontales doit être validée par l’obtention de résultats satisfaisants lors des
évaluations et des essais décrits dans le présent document. Le Tableau 1 contient un résumé des essais
définis dans le présent document.

ISO/FDIS 23340:2026(fr)
Tableau 1 — Essais
Propriété à soumettre à essai Essai de type Essai de série Essai périodique
Aspect (voir 5.1) W W
Images secondaires (voir 5.2.1) W
Distorsion optique (voir 5.2.2) W W
Diffusion (voir 5.2.3) S ou W
Facteur de transmission (voir 5.2.4) S ou W S ou W
Chromaticité (voir 5.2.5) S ou W
Impact (y compris projection d’éclats) (voir S ou W
6.1)
Visibilité résiduelle (voir 6.2) S
Résistance à l’abrasion (voir 6.3) S
a
Gravillonnage (voir 6.4) S
a
Résistance au tir à balles (voir 6.5) S
Chauffage (voir 7.1) W W
Vieillissement (voir 7.2) S ou W
Tenue en tension W W
Légende
S échantillon
W vitre frontale complète
a
Si la spécification technique de la vitre frontale l’exige.
4.3.2 Essais de type
Tous les essais de type sont répertoriés dans le Tableau 1.
Si une vitre frontale est équipée d’un système de chauffage, les essais suivants doivent être répétés avec le
système de chauffage en fonctionnement:
— images secondaires (voir 5.2.1);
— distorsion optique (voir 5.2.2).
Lorsque les essais de type sont répétés avec le système de chauffage en fonctionnement:
— le système de chauffage doit fonctionner à sa tension nominale;
— la stabilisation thermique doit être atteinte avant le début des mesures.
Cette exigence ne doit pas s’appliquer aux systèmes de chauffage rapide utilisés sur des véhicules à l’arrêt
dans le but d’accélérer l’élimination du givre ou de la neige.
Les propriétés des échantillons d’essai sont résumées à l’Annexe F.
Si une vitre frontale validée conformément au présent document est modifiée et qu’il peut être démontré,
pour un essai de type donné, que les performances requises ne sont pas affectées, un nouvel essai de type
peut être omis.
Pour les vitres frontales passagers, les essais suivants sont facultatifs:
— images secondaires (voir 5.2.1);
— diffusion (voir 5.2.3);
— facteur de transmission (voir 5.2.4), un facteur de transmission minimal de 40 % peut être accepté;

ISO/FDIS 23340:2026(fr)
— chromaticité (voir 5.2.5).
4.3.3 Essais de série
Lors de la production, toutes les vitres frontales doivent être soumises aux essais de série suivants:
— aspect (voir 5.1);
— distorsion optique (voir 5.2.2);
— chauffage (voir 7.1);
— tenue en tension.
4.3.4 Essais périodiques
Le facteur de transmission (voir 5.2.4) doit être soumis régulièrement à essai à la fréquence indiquée dans la
spécification technique de la vitre frontale.
4.4 Marquage
La vitre frontale doit être marquée de manière permanente, de manière à afficher au minimum les
informations suivantes:
— le nom ou le logo du fournisseur de la vitre frontale;
— la date de fabrication (le mois et les deux derniers numéros de l’année ou un code permettant d’identifier
cette information);
Il convient d’inclure dans le marquage les aspects suivants:
— un numéro d’identification unique (numéro de référence et numéro de série);
— la tension nominale et le type de courant (alternatif ou continu) du chauffage (s’il y a lieu);
— la puissance totale du chauffage (s’il y a lieu);
— la version applicable du présent document.
Le marquage doit se situer en dehors de la zone de visibilité principale. Sauf exigences contradictoires, il
convient de placer le marquage dans le coin supérieur droit de la vitre frontale.
Le marquage doit être lisible et visible de l’intérieur de la cabine. Le marquage doit être lisible sans dispositifs
d’aide visuelle. Il convient que la hauteur minimale des caractères soit de 3 mm.
4.5 Exigences de service
Les vitres frontales installées sur des véhicules ferroviaires doivent être conçues pour résister aux
conditions d’exploitation normales, notamment les charges statiques et dynamiques induites ainsi que les
conditions environnementales telles que la température et l’humidité.
Si des exigences relatives à l’utilisation dans un environnement spécifique s’ajoutent aux exigences établies
dans le présent document, alors celles‑ci doivent être indiquées dans la spécification technique de la vitre
frontale.
Il convient d’intégrer un système de chauffage au pare-brise conducteur pour assurer le dégivrage/
désembuage de la vitre et ainsi permettre au conducteur de garder une visibilité optimale dans la plupart
des conditions météorologiques et de conduite. Si un tel système de chauffage intégral est présent, ce dernier
doit satisfaire aux exigences établies au 7.1.

ISO/FDIS 23340:2026(fr)
Lorsqu’ils sont impactés ou fissurés, les pare‑brises conducteur doivent garantir une visibilité résiduelle
suffisante pour que le train puisse circuler dans le respect des règles d’exploitation. Cette exigence doit être
considérée comme satisfaite par la réalisation des exigences de visibilité résiduelle établies au 6.2.
NOTE Pour les vitres frontales passagers, la spécification technique peut exiger un essai au pendule et un essai de
confinement des passagers selon l’ISO 22752:2021.
4.6 Stockage et manipulation des vitres frontales finies
Il convient que les vitres soient stockées dans un endroit bien aéré, à l’abri des intempéries et des rayons
directs du soleil.
Il convient que les vitres planes soient stockées verticalement sur un support solide, selon un angle
d’inclinaison de 6° environ. Il convient que les vitres soient constamment soutenues par des supports
sur chaque bord. Il convient que les supports soient recouverts d’un matériau souple pour éviter tout
endommagement des vitres.
Pour les vitres bombées, il convient que le stockage suive les mêmes principes en fonction de la géométrie
spécifique du produit.
Les bords des vitrages doivent être façonnés conformément à l’ISO 12543-5:2021, 5.3.2, 5.3.3 ou 5.3.4.
NOTE L’objectif des bords façonnés est d’éviter des blessures par arêtes vives aux personnes manipulant les
vitrages.
5 Exigences visuelles et optiques
5.1 Défauts apparents
5.1.1 Généralités
Les défauts apparents (imperfections) sont caractéristiques de l’un des élém
...