SIST EN ISO 24478:2024/kFprA1:2026

• Status: Not Published
• Public Enquiry End Date: 31-Jan-2026
• ICS: 01.040.45 - Railway engineering (Vocabularies)
• ICS: 45.020 - Railway engineering in general
• ICS: 45.040 - Materials and components for railway engineering
• Technical Committee: IŽNP - Reilway applications
• Current Stage: 5020 - Formal vote (FV) (Adopted Project)
• Start Date: 28-Oct-2026
• Due Date: 16-Dec-2026
• Completion Date: 30-Oct-2026
• Ref Project: EN ISO 24478:2024/FprA1:2026 - Railway applications - Braking - General vocabulary - Amendment 1 (ISO 24478:2024/FDAmd1:2026)

• Referred By: SIST EN ISO 13473-5:2025 - Characterization of pavement texture by use of surface profiles - Part 5: Determination of megatexture (ISO 13473-5:2025)
• Effective Date: 28-Jan-2026
• Amends: SIST EN ISO 24478:2024 - Railway applications - Braking - General vocabulary (ISO 24478:2023, including corrected version 2024-04)
• Effective Date: 11-Sep-2024

SIST EN ISO 24478:2024/kFprA1:2026 is the Slovenian draft Amendment 1 to the railway braking general vocabulary. It updates the terms, notes, and explanatory figures used for braking systems in railway applications, so designers, testers, and document writers can use the same braking language.

What does SIST EN ISO 24478:2024/kFprA1:2026 specify?

SIST EN ISO 24478:2024/kFprA1:2026 updates the vocabulary for railway braking. The amendment focuses on how brake systems, brake subsystems, braking demands, forces, and component relationships are named and shown in figures.

The document is organized as an amendment to the vocabulary clauses and illustrative annexes. The main changes touch the Introduction and clauses 3.1, 3.5, 3.6, 3.7, 3.8, 3.9 and 3.10, plus Annexes C, D and E and the Bibliography.

Annex	What it covers
Annex C	Examples linked to increasing, equivalent, and decreasing braking deceleration
Annex D	Relationship among brake devices/signals and brake system/subsystem(s)
Annex E	Disc and tread brake unit, and stationary braking/braking figures

What are the key requirements of SIST EN ISO 24478:2024/kFprA1:2026?

SIST EN ISO 24478:2024/kFprA1:2026 mainly changes terminology, but those changes matter in specifications, calculations, drawings, and test documentation. The most important updates are the ones that separate whole-train functions from local brake parts and make the braking vocabulary more precise.

Brake system and subsystem terms

Clause 3.1 adds brake application as an admitted term, changes brake system to the preferred term, and keeps brake as an admitted term. It also adds main brake system and brake subsystem. In practice, this helps writers distinguish between a trainwide braking function and a local set of brake units and controls.

Clause 3.1.2 adds a note saying one braking demand is handled by only one brake system. That matters when allocating responsibility between service, emergency, and parking functions.

Mass, payload, and deceleration vocabulary

Clause 3.5 adds maximum braking payload and design mass under maximum braking payload (MXB), with the note that MXB is also known as maximum braking load. This gives designers a named basis for braking calculations when payload changes affect stopping performance.

Clause 3.6 revises the wording for increasing braking deceleration, equivalent braking deceleration, and decreasing braking deceleration. This keeps braking curves and performance descriptions consistent in reports and specifications.

Brake forces and component terms

Clause 3.7 adds notes and terms tied to tread and disc brake forces, including mean swept radius. It also clarifies the use of single brake block force and clamping force in notes to entry. In practice, these terms support consistent calculation and comparison of brake forces for disc and tread brake designs.

Brake blending and related functions

Clause 3.9 defines brake blending and adds four types: substitution blending, fixed blending, programmed blending, and continuous blending. These terms describe how braking demand is shared between friction brakes and dynamic brakes, which is important when specifying control logic and expected brake allocation.

Devices, signals, and brake components

Clause 3.10 updates the relationship among brake devices/signals and brake system/subsystem(s) and points readers to Annex D, Figures D.1 and D.2. It also revises terms for friction brake subsystem components, updates the definition of brake actuator-related parts, and introduces scotch block and brake slipper. That helps align control diagrams, maintenance language, and component naming.

What terms does SIST EN ISO 24478:2024/kFprA1:2026 define?

SIST EN ISO 24478:2024/kFprA1:2026 defines and revises a large set of braking terms. The most useful ones for day-to-day use are:

• main brake system - the trainwide continuous brake system that enables emergency, service, and parking braking.
• brake subsystem - a combination of brake units and their local control devices, usually grouped by brake unit type.
• maximum braking payload - the typical payload used for maximal braking conditions.
• design mass under maximum braking payload (MXB) - design mass in working order plus maximum braking payload.
• brake blending - the process of distributing demanded train braking force among different brake units or subsystems.
• continuous blending - adjusting friction brake force to match the achieved braking force of the dynamic brake.
• scotch block - a device placed between a wheel and the rail to prevent movement for an indefinite period.
• pressure gauge - also known as a manometer.

Who uses SIST EN ISO 24478:2024/kFprA1:2026?

SIST EN ISO 24478:2024/kFprA1:2026 is used by railway rolling stock engineers, braking system designers, test laboratories, maintenance teams, and quality managers. It is also relevant to buyers and specifiers who need consistent wording in technical documents, contracts, and acceptance criteria.

The standard is especially useful when teams write brake system descriptions, compare disc and tread brake solutions, document braking force calculations, or prepare diagrams showing how braking demands are handled across brake systems and subsystems.

What changed in SIST EN ISO 24478:2024/kFprA1:2026 from the previous edition?

SIST EN ISO 24478:2024/kFprA1:2026 is Amendment 1 to the railway braking general vocabulary. It revises terminology, adds new terms such as main brake system, brake subsystem, MXB, and the four types of brake blending, and updates the wording and figure keys in Annexes C, D and E.

What does the SIST EN ISO 24478:2024/kFprA1:2026 document contain?

SIST EN ISO 24478:2024/kFprA1:2026 contains revised vocabulary entries, notes to entries, and updated figure references. Annex C provides figure keys for braking deceleration terms, while Annex D shows the relationship among brake devices, signals, and brake system/subsystem(s).

Annex E includes figures for disc and tread brake units, plus stationary braking and braking diagrams. These figures support consistent interpretation of brake architecture and force paths in design, testing, and documentation.

SLOVENSKI STANDARD
SIST EN ISO 24478:2024/oprA1:2026
01-januar-2026
Železniške naprave - Zavore - Splošni slovar - Dopolnilo A1 (ISO 24478:2023/DAM
1:2025)
Railway applications - Braking - General vocabulary - Amendment 1 (ISO
24478:2023/DAM 1:2025)
Bahnanwendungen - Bremsen - Fachbegriffe - Änderung 1 (ISO 24478:2023/DAM
1:2025)
Applications ferroviaires - Freinage - Vocabulaire général - Amendement 1 (ISO
24478:2023/DAM 1:2025)
Ta slovenski standard je istoveten z: EN ISO 24478:2024/prA1:2025
ICS:
01.040.45 Železniška tehnika (Slovarji) Railway engineering
(Vocabularies)
45.040 Materiali in deli za železniško Materials and components
tehniko for railway engineering
SIST EN ISO 24478:2024/oprA1:2026 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

SIST EN ISO 24478:2024/oprA1:2026

SIST EN ISO 24478:2024/oprA1:2026
DRAFT
Amendment
ISO 24478:2023/
DAM 1
ISO/TC 269/SC 2
Railway applications — Braking —
Secretariat: AFNOR
General vocabulary
Voting begins on:
AMENDMENT 1
2025-11-17
Applications ferroviaires — Freinage — Vocabulaire général Voting terminates on:
2026-02-09
AMENDEMENT 1
ICS: 01.040.45; 45.020
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document is circulated as received from the committee secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
ISO/CEN PARALLEL PROCESSING
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS.
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.
Reference number
ISO 24478:2023/DAM 1:2025(en)
SIST EN ISO 24478:2024/oprA1:2026
DRAFT
ISO 24478:2023/DAM 1:2025(en)
Amendment
ISO 24478:2023/
DAM 1
ISO/TC 269/SC 2
Railway applications — Braking —
Secretariat: AFNOR
General vocabulary
Voting begins on:
AMENDMENT 1
2025-11-17
Applications ferroviaires — Freinage — Vocabulaire général
AMENDEMENT 1
Voting terminates on:
ICS: 01.040.45; 45.020
2026-02-09
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document is circulated as received from the committee secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
© ISO 2025
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
STANDARDS MAY ON OCCASION HAVE TO
ISO/CEN PARALLEL PROCESSING
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
BE CONSIDERED IN THE LIGHT OF THEIR
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
or ISO’s member body in the country of the requester.
NATIONAL REGULATIONS.
ISO copyright office
RECIPIENTS OF THIS DRAFT ARE INVITED
CP 401 • Ch. de Blandonnet 8
TO SUBMIT, WITH THEIR COMMENTS,
CH-1214 Vernier, Geneva
NOTIFICATION OF ANY RELEVANT PATENT
Phone: [phone]
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION.
Email: [e-mail]
Website: www.iso.org
Published in Switzerland Reference number
ISO 24478:2023/DAM 1:2025(en)
ii
SIST EN ISO 24478:2024/oprA1:2026
ISO 24478:2023/DAM 1:2025(en)
Foreword
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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
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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.

iii
SIST EN ISO 24478:2024/oprA1:2026

SIST EN ISO 24478:2024/oprA1:2026
ISO 24478:2023/DAM 1:2025(en)
Railway applications — Braking — General vocabulary
AMENDMENT 1
Introduction, second paragraph
Replace “may” with “can”
3.1.1
Add “brake application” as admitted term

3.1.2
Change “brake system” to preferred term and “brake” to admitted term

Add note 2 to entry as follows:
“Note 2 to entry: One braking demand is managed by only one brake system.”

3.1.3
Change definition as follows:
“device or assembly of components, that is the origin of the braking force/torque”

Change note 2 to entry as follows:
“Note 2 to entry: For tread brake and disc brake, it consists of the brake actuator and the friction couple
(pads or block), but the disc/wheel tread are part of the brake system.”

3.1.4
Add new 3.1.4 as follows:
3.1.4
main brake system
trainwide continuous brake system which enables emergency braking, service braking and parking
Note 1 to entry: The main brake system can also ensure holding function and immobilizing function.

3.1.5
SIST EN ISO 24478:2024/oprA1:2026
ISO 24478:2023/DAM 1:2025(en)
Add new 3.1.5 as follows:
3.1.5
brake subsystem
combination of brake units and their local control devices, usually per type of brake units (e.g. friction brake
subsystem)
3.5.4
In the definition, replace “hold” with “keep”

3.5.8, 3.5.9
Add the following new terms and definitions and renumber former 3.5.8 to 3.5.10 and former 3.5.9 to 3.5.11:
3.5.8
maximum braking payload
typical payload for maximal braking conditions which is lower or equal to exceptional payload
3.5.9
design mass under maximum braking payload
MXB
design mass in working order plus maximum braking payload
Note 1 to entry: The “design mass under maximum braking payload” is also known as “maximum braking load”.

3.6.28
Change term to “increasing braking deceleration”
In the definition, delete “variation in”

3.6.31
Replace “brake deceleration” with “deceleration”

3.6.32
Change term to “equivalent braking deceleration”
In the definition replace “brake deceleration” with “deceleration”

3.6.33
Change term to “decreasing braking deceleration”
In the definition delete “variation in”

3.7.1
Replace “brake system” with “brake subsystem”

SIST EN ISO 24478:2024/oprA1:2026
ISO 24478:2023/DAM 1:2025(
...