EN ISO 24478:2024/FprA1:2026
(Amendment)Railway applications - Braking - General vocabulary - Amendment 1 (ISO 24478:2024/FDAmd1:2026)
- Status
- Not Published
- Publication Date
- 03-Mar-2027
- Technical Committee
- CEN/TC 256 - Railway applications
- Drafting Committee
- CEN/TC 256/SC 3/WG 47 - Braking
- Current Stage
- 5020 - Submission to Vote - Formal Approval
- Start Date
- 22-Oct-2026
- Completion Date
- 22-Oct-2026
EN ISO 24478:2024/FprA1:2026 is the draft Amendment 1 to the Railway applications - Braking - General vocabulary. It updates the terminology used for railway braking, so designers, integrators, test teams and maintainers can use the same definitions for brake systems, brake subsystems, braking demands and brake blending.
What does EN ISO 24478:2024/FprA1:2026 specify?
EN ISO 24478:2024/FprA1:2026 specifies changes to the vocabulary of railway braking rather than a new braking method or performance level. The amendment revises terms, definitions, notes and figures in clause 3 and the related annexes, so the language used in specifications, drawings and technical documentation stays consistent.
The document is organized as amendment instructions that point to individual clauses and annex figures. The main updates are in clause 3, with supporting changes in Annex C, Annex D and Annex E, plus a bibliography correction.
| Annex | What it covers |
|---|---|
| Annex C | Updated figure keys for braking deceleration terms |
| Annex D | Relationship among brake devices/signals and brake system/subsystem(s) |
| Annex E | Disc brake and tread brake unit figures, and stationary braking / braking figures |
What are the key requirements of EN ISO 24478:2024/FprA1:2026?
The amendment mainly standardizes terminology used in railway braking. In practice, that means people writing requirements, producing diagrams or reviewing test documents should use the preferred terms and the updated definitions below.
Clause 3.1 tightens the core vocabulary. It adds brake application as an admitted term, makes brake system the preferred term in 3.1.2, and adds a note that one braking demand is handled by one brake system. This matters when a vehicle has more than one braking function and the designer must assign each demand clearly.
Clause 3.1.4 and 3.1.5 add main brake system and brake subsystem. The main brake system is the trainwide continuous brake system used for emergency braking, service braking and parking, while a brake subsystem is a combination of brake units and local control devices. This helps separate whole-train functions from local equipment.
Clauses 3.5.8 and 3.5.9 add maximum braking payload and design mass under maximum braking payload (MXB). MXB is the design mass in working order plus maximum braking payload. This is important for mass-based braking calculations and for choosing the right design case.
Clauses 3.6.28, 3.6.32 and 3.6.33 refine the terms for increasing, equivalent and decreasing braking deceleration. Annex C updates the figure keys to match. That matters because deceleration terminology appears in performance curves and braking explanations.
Clauses 3.7 and 3.10 clarify forces and components in friction braking. The amendment updates terms such as brake application force, brake pad force, clamping force, mean swept radius and friction brake subsystem components. In practice, this helps engineers distinguish actuator force, contact force and resulting braking force.
Clause 3.9.4 defines brake blending and adds substitution blending, fixed blending, programmed blending and continuous blending. These terms describe how braking effort is shared between brake units or subsystems, usually to reduce friction brake use when dynamic braking is active.
Clause 3.10.11.4 and 3.10.11.5 add or clarify terms for scotch block and brake slipper. These are practical terms for securing or stopping a rail vehicle when it must remain immobile.
What terms does EN ISO 24478:2024/FprA1:2026 define?
- Brake system - the preferred term for the braking system entry updated in clause 3.1.2.
- Main brake system - the trainwide continuous brake system used for emergency, service and parking braking.
- Brake subsystem - a combination of brake units and 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) - the design mass in working order plus maximum braking payload.
- Brake blending - the process of reallocating braking force among brake units or subsystems to meet the demanded train braking force.
- Continuous blending - a blending method where the friction brake is adjusted to 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.
Who uses EN ISO 24478:2024/FprA1:2026?
EN ISO 24478:2024/FprA1:2026 is used by railway applications specialists who need consistent braking terminology. That includes rolling stock engineers, braking system designers, vehicle integrators, maintenance teams, technical writers and test or certification personnel.
It is especially useful when drafting requirements, preparing manuals, reviewing diagrams, translating technical documents or checking that braking functions are named consistently across a project. For buyers and quality managers, it helps align supplier documents and internal specifications.
What changed in EN ISO 24478:2024/FprA1:2026 from the previous edition?
This amendment updates the general braking vocabulary by revising terms, notes and figures. The main changes stated in the document are:
- Introduction wording changed from may to can.
- New or revised terms were added for brake system, brake subsystem, main brake system, maximum braking payload, MXB and brake blending.
- Several existing entries were reworded, including terms for braking deceleration, brake actuator-related forces and parking brake subsystem.
- Annex C figure keys were updated to match the renamed braking deceleration terms.
- Annex D was retitled and given a new figure showing relationships among brake devices/signals and brake system/subsystem(s).
- Annex E figures were replaced for disc brake and tread brake units, stationary braking and braking.
- The bibliography numbering was corrected.
What does the EN ISO 24478:2024/FprA1:2026 document contain?
EN ISO 24478:2024/FprA1:2026 is a terminology amendment, so its content is concentrated in edited entries, notes and figure captions rather than in test methods or calculations. It updates clause 3 entries across the braking vocabulary and aligns the annex figures with those terms.
The annex material shows how the vocabulary is meant to be read in context. Annex C supports braking deceleration terminology, Annex D maps braking demands to brake systems and subsystems, and Annex E illustrates disc and tread brake units plus stationary braking and braking force relationships.
For users, the document is mainly a reference for writing, checking and translating braking-related technical language. It is not a design handbook, but it is the source to consult when naming brake functions, component types or braking-force relationships consistently.
Relations
- Effective Date
- 28-Jan-2026
- Consolidated By
ISO 24478:2023/FDAmd 1 - Railway applications — Braking — General vocabulary — Amendment 1 - Effective Date
- 12-Feb-2026
- Effective Date
- 11-Sep-2024
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Frequently Asked Questions
EN ISO 24478:2024/FprA1:2026 is a draft published by the European Committee for Standardization (CEN). Its full title is "Railway applications - Braking - General vocabulary - Amendment 1 (ISO 24478:2024/FDAmd1:2026)". This standard covers: Railway applications - Braking - General vocabulary - Amendment 1 (ISO 24478:2024/FDAmd1:2026)
Railway applications - Braking - General vocabulary - Amendment 1 (ISO 24478:2024/FDAmd1:2026)
EN ISO 24478:2024/FprA1:2026 is classified under the following ICS (International Classification for Standards) categories: 01.040.45 - Railway engineering (Vocabularies); 45.020 - Railway engineering in general. The ICS classification helps identify the subject area and facilitates finding related standards.
EN ISO 24478:2024/FprA1:2026 has the following relationships with other standards: It is inter standard links to EN ISO 13473-5:2025, ISO 24478:2023/FDAmd 1, EN ISO 24478:2024. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
EN ISO 24478:2024/FprA1:2026 is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.
Standards Content (Sample)
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
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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
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BE CONSIDERED IN THE LIGHT OF THEIR
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POTENTIAL TO BECOME STANDARDS TO
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NATIONAL REGULATIONS.
ISO copyright office
RECIPIENTS OF THIS DRAFT ARE INVITED
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TO SUBMIT, WITH THEIR COMMENTS,
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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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This document was prepared by Technical Committee ISO/TC 269, Railway applications, Subcommittee SC 2,
Rolling stock.
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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(
...