prEN 16729-1

SLOVENSKI STANDARD
01-april-2026
Železniške naprave - Infrastruktura - Neporušitveno preskušanje na progi - 1. del:
Zahteve za ultrazvočni pregled in merila za ovrednotenje
Railway applications - Infrastructure - Non-destructive testing on rails in track - Part 1:
Requirements for ultrasonic inspection and evaluation principles
Bahnanwendungen - Infrastruktur - Zerstörungsfreie Prüfung an Schienen im Gleis - Teil
1: Anforderungen an Ultraschallprüfungen und Bewertungsgrundlagen
Applications ferroviaires - Infrastructure - Essais non destructifs sur les rails de voie -
Partie 1 : Exigences pour l'inspection par ultrasons et les principes d'évaluation
Ta slovenski standard je istoveten z: prEN 16729-1
ICS:
19.100 Neporušitveno preskušanje Non-destructive testing
93.100 Gradnja železnic Construction of railways
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
EUROPEAN STANDARD
NORME EUROPÉENNE
EUROPÄISCHE NORM
February 2026
ICS 93.100 Will supersede EN 16729-1:2016
English Version
Railway applications - Infrastructure - Non-destructive
testing on rails in track - Part 1: Requirements for
ultrasonic inspection and evaluation principles
Applications ferroviaires - Infrastructure - Essais non Bahnanwendungen - Infrastruktur - Zerstörungsfreie
destructifs sur les rails de voie - Partie 1 : Exigences Prüfung an Schienen im Gleis - Teil 1: Anforderungen
pour l'inspection par ultrasons et les principes an Ultraschallprüfungen und Bewertungsgrundlagen
d'évaluation
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 256.
If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations
which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC
Management Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.

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

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2026 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 16729-1:2026 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Basics . 7
4.1 General. 7
4.2 Principle of ultrasonic testing in track . 7
4.3 Ultrasonic testing speed and detection of discontinuities . 7
4.4 Simulation of internal reflectors in reference rails . 7
5 Detection of artificial reflectors . 11
6 Control of positioning accuracy . 16
Annex A (normative) Artificial reflectors in reference rails . 17
Annex B (informative) Ultrasonic test areas in rails tested with test vehicles or manually-
propelled devices . 36
Bibliography . 40

European foreword
This document (prEN 16729-1:2026) has been prepared by Technical Committee CEN/TC 256 “Railway
applications”, the secretariat of which is held by DIN.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 16729-1:2016.
EN 16729-1:2016:
a) Normative references have been updated;
b) Terms and definitions have been revised;
c) General requirements, requirements on testing in track, testing speed and simulation of internal
reflectors have been revised;
d) Requirements on detection of artificial reflectors have been revised;
e) Requirements on detection of artificial reflectors have been revised;
f) Requirements on control of positioning accuracy have been revised;
g) Normative Annex A has been revised;
h) Informative Annex B has been revised;
i) Annex ZA has been removed;
j) Bibliography has been updated.
A list of all parts in the EN 16729 series consists of:
— EN 16729-1, Railway applications — Infrastructure — Non-destructive testing on rails in track — Part
1: Requirements for ultrasonic inspection and evaluation principles;
— EN 16729-2, Railway applications — Infrastructure — Non-destructive testing on rails in track — Part
2: Eddy current testing of rails in track;
— EN 16729-3, Railway applications — Infrastructure — Non-destructive testing on rails in track — Part
3: Requirements for identifying internal and surface rail defects;
— EN 16729-4, Railway applications — Infrastructure — Non-destructive testing on rails in track — Part
4: Qualification of personnel for non-destructive testing on rails;.
— EN 16729-5, Railway applications — Infrastructure — Non-destructive testing on rails in track — Part
5: Non-destructive testing on welds in track;
— CEN/TR 16729-6, Railway applications — Infrastructure — Non-destructive testing on rails in track
— Part 6: Non-destructive testing of manganese cast steel components in switches and crossings.
Introduction
This document represents the actual state of the art of automated ultrasonic testing of rails in track
applied by European railway companies.
1 Scope
This document applies to testing of rails installed in track for detecting internal discontinuities.
This part applies to testing equipment fitted to dedicated test vehicles or manually-propelled devices.
This document does not define the requirements for vehicle acceptance. This part of the series does not
apply to ultrasonic testing of rails in a production plant.
The document specifies the requirements for testing principles and systems in order to produce
comparable results with regard to location, type and size of discontinuities in rails. This document is not
aiming to give any guidelines for managing the result of ultrasonic rail testing.
This document applies only to rail profiles meeting the requirements of EN 13674-1.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 5577:2025, Non-destructive testing – Ultrasonic testing – Vocabulary
EN 13674-1, Railway applications - Track - Rail - Part 1: Vignole railway rails 46 kg/m and above
3 Terms and definitions
For the purposes of this document, the following terms and definitions given in ISO 5577:2025 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
parts of the rail
components that constitute the rail itself as shown in Figure 1

Key
1 field side
2 gauge side
3 rail head
4 rail web
5 rail foot
running surface
gauge corner area
rail head side area
rail head fillet radius area
rail web area
rail foot fillet radius area
rail foot area
Figure 1 — Parts of the rail
3.2
artificial reflector
artificial feature designed to represent a discontinuity of a known size, orientation and position to test an
ultrasonic system
4 Basics
4.1 General
In order to verify the performance of the automated ultrasonic systems for rail testing there shall be
defined artificial reflectors in a test track. These artificial reflectors shall be recorded and reported at the
normal operational speed of the test vehicle/system.
The reference rail in the test track shall be constructed from new rail to provide the correct head profile
and running surface condition. Rails with corrosion on the running surface shall be cleaned to allow the
transmission of ultrasound prior to any testing, for example using a powered steel wire brush.
A signal shown on the display of an ultrasonic instrument or system as a result of received ultrasonic
pulse is called an indication. Evidence obtained by non-destructive testing.
In test systems according to this document ultrasound at a frequency range of 2 MHz to 5 MHz is used.
A flat-bottom hole (FBH) shall be machined using a twist drill at the appropriate diameter followed by a
slot drill hole of the same diameter to the required depth to generate the flat end of the hole.
The accuracy of the diameter and the vertical depth shall be within 0,1 mm and 1,0 mm respectively. The
accuracy of the angle shall be within 1,0°.
Due to wear of the rail, dimension might vary. If the rail is used for distance and sensitivity setting of
Ultrasonic Testing (UT) inspection devices this needs to be taken into account.
4.2 Principle of ultrasonic testing in track
Ultrasonic waves transmitted into the rail will be reflected from the surfaces of the rail body. Fractures
and other discontinuities within the rail, as well as the boundary of the rail will act as reflecting surfaces.
By receiving, recording and interpreting the returned ultrasonic signals, it is possible to detect
discontinuities within a rail installed in track before they present an unacceptable risk to the integrity
and strength of the rail. Annex B gives examples of test areas in rails tested with test vehicles or manually
propelled devices.
4.3 Ultrasonic testing speed and detection of discontinuities
Ultrasonic beams have a width which is determined by the size of the transducer and the frequency. All
reflectors interact with the ultrasonic beam. The beam sweeps across the reflector when the vehicle and
/ or manually-propelled device travels along the track. Ultrasound will be reflected and detected by the
transducer. All ultrasonic systems use a threshold level in a gate and the system will record a response
when the reflection is above the threshold level. By controlling the gain in the ultrasonic system and the
gate threshold level the number of responses for a given size of reflector can be defined.
A reflector can be sized by setting the system parameters so that a known number of responses are
received from a known sized artificial reflector. The relationship of the number of responses and the size
of the artificial reflector is known. This applies to all the reflectors in Annex A.
The maximum testing speed depends upon the rail profile (longitudinal and transverse), reflector size to
be detected, the beam width, sampling frequency and the number of responses required for an indication
to be recorded.
In semi- and full automatic systems, the inspection results shall be documented so that the evaluation can
be reviewed.
4.4 Simulation of internal reflectors in reference rails
Reference rails incorporating sets of artificial reflectors selected from Annex A shall be created. They shall
be installed in the left and right rails of a section of track if test vehicles are used. If only trolleys or
manually-propelled devices are used, the reference rails may be installed out-of-track. The length of the
reference rails is not defined by this document. When in track carrying traffic, the distance between the
artificial reflectors should be assessed by the Infrastructure Manager with consideration to the structural
integrity of the rail. Artificial reflectors shall be orientated to check probes scanning in both directions.
To prevent the influence of water and dirt on the ultrasonic responses, reference holes and notches shall
be plugged with a synthetic compound.
Where the reference rails carry traffic, the Infrastructure Manager shall carry out a risk assessment to
determine if reinforcement of the artificial reflectors is necessary (fishplates or similar) and determine
the maintenance regime of the reference rails.
Table 1 — Artificial reflectors in reference rails (normative references)
No. Set Figure, shown Description Dimensions
in Annex A
mm
01.1 A Figure A.1 Volumetric reflector in rail head a = 7
d = 6
01.2 A Figure A.1 Volumetric reflector in rail head a = 10
d = 6
01.3 A Figure A.1 Volumetric reflector in rail head a = 20
d = 6
02.1 A Figure A.2 Central transverse reflector (20°) in rail head a = 10
d = 5
l = 20
02.2 B Figure A.2 Central transverse reflector (20°) in rail head a = 15
d = 10
l = 20
03.1 A Figure A.3 Gauge transverse reflector (20°) in rail head a = 10
b = 15
d = 5
l = 20
03.2 B Figure A.3 Gauge transverse reflector (20°) in rail head a = 15
b = 15
d = 10
l = 20
03.3 A Figure A.3 Field transverse reflector (20°) in rail head a = 10
b = 15
d = 5
03.4 B Figure A.3 Field transverse reflector (20°) in rail head a = 15
b = 15
d = 10
04 B Figure A.4 Full width transverse reflector (20°) in rail a = 20
head
d = 3
l = 7
No. Set Figure, shown Description Dimensions
in Annex A
mm
05 B Figure A.5 Full width transverse reflector (35°) in rail a = 20
head
d = 3
l = 7
06 B Figure A.6 Full width transverse reflector (53°) in rail a = 20
head
d = 3
l = 7
07.1 B Figure A.7 Volumetric reflector gauge side of rail head a = 25
b = 20
d = 6
07.2 A Figure A.7 Volumetric reflector gauge side of rail head a = 25
b = 25
d = 6
07.3 B Figure A.7 Volumetric reflector gauge side of rail head a = 25
b = 30
d = 6
07.4 B Figure A.7 Volumetric reflector gauge side of rail head a = 25
b = 36
d = 6
08.1 B Figure A.8 Volumetric reflector field side of rail head a = 25
b = 20
d = 6
08.2 A Figure A.8 Volumetric reflector field side of rail head a = 25
b = 25
d = 6
08.3 B Figure A.8 Volumetric reflector field side of rail head a = 25
b = 30
d = 6
08.4 B Figure A.8 Volumetric reflector field side of rail head a = 25
b = 36
d = 6
09.1 B Figure A.9 Horizontal reflector in rail head a = 20
d = 5
e = 10
09.2 A Figure A.9 Horizontal reflector in
...