FprEN IEC 63341-2:2025/prAA:2025

Railway applications - Hydrogen and fuel cell systems for rolling stock - Part 2: Hydrogen fuel system

This document amends EN IEC 63341-2 which applies to onboard hydrogen fuel systems used to supply the fuel cells for the traction power and the auxiliaries supply of rolling stock vehicles (such as hybrid vehicles as defined in EN IEC 62864-1). NOTE 1 This document may also be used as informative recommendations for applications with hydrogen internal combustion engines. EN IEC 63341-2 applies to hydrogen storage in gaseous form. Other means of storage (such as liquid, liquid cryo-compressed, metal hydrides) are not covered in this document. EN IEC 63341-2 applies to any rolling stock type (e.g. light rail vehicles, tramways, streetcars, metros, commuter trains, regional trains, high speed trains, locomotives). EN IEC 63341-2 addresses the mechanical, fluidic and electrical interfaces between the on-board hydrogen fuel system and fuelling station. The fuelling station, fuelling protocol and communication for the fuelling protocol are not in the scope of this document. EN IEC 63341-2 defines: – the scope of supply of hydrogen fuel system (HFS) and the description of the interfaces with sub-systems internal and external to the rolling stock such as fuel cell power system, fuelling station systems; – the environmental constraints; – the design requirements to support HFS compliance with railway applications; – the safety and reliability requirements to design and install the HFS for railway applications; – the marking and labelling requirements; – the requirements related to storage, transportation, installation and maintenance; – the validation (type, routine and investigation tests) requirements

Applications ferroviaires - Systèmes à hydrogène et à pile à combustible pour le matériel roulant - Partie 2: Système à hydrogène

Železniške naprave - Vozna sredstva - Sistemi gorivnih celic za vozna sredstva - 2. del: Sistem za shranjevanje vodika - Dopolnilo AA

General Information

• Status: Not Published
• Publication Date: 30-Aug-2026
• Technical Committee: CLC/TC 9X - Electrical and electronic applications for railways
• Drafting Committee: WG 40 - Survey Group on the parallel vote of IEC 63341-2 ED1
• Current Stage: 4020 - Enquiry circulated - Enquiry
• Start Date: 07-Nov-2025
• Due Date: 10-Aug-2025
• Completion Date: 07-Nov-2025
• Ref Project: SIST FprEN IEC 63341-2:2025/oprAA:2026 - Railway applications - Hydrogen and fuel cell systems for rolling stock - Part 2: Hydrogen fuel system

Relations

• Amends: FprEN IEC 63341-2:2025 - Railway applications - Hydrogen and fuel cell systems for rolling stock - Part 2: Hydrogen fuel system
• Effective Date: 14-Jan-2025

Overview

FprEN IEC 63341-2:2025/prAA:2025 is an amendment to the European standard for onboard hydrogen fuel systems in railway rolling stock. Developed by CLC/TC 9X, this standard specifically addresses hydrogen fuel systems (HFS) supplying fuel cells for traction power and auxiliary uses in various types of rolling stock, including hybrid vehicles. Importantly, it applies exclusively to gaseous hydrogen storage, excluding liquid or metal hydride storage methods.

This amendment refines and updates safety, design, maintenance, and interface requirements essential for integrating hydrogen fuel systems in railway applications. It aligns with existing European regulations to promote reliable and safe use of hydrogen technologies in rail transport.

Key Topics

• Scope and Application
  Covers hydrogen fuel systems used onboard trains such as trams, metros, commuter, regional and high-speed trains, and locomotives. It focuses on gaseous hydrogen storage and excludes fueling station protocols, which remain out of scope.

• Design and Structural Requirements
  Specifies compliance with standards such as EN 12663-1 for structural design and EN 15085-4 for welded joints. This ensures the mechanical integrity and safety of hydrogen fuel system installations on rolling stock.

• Safety and Fire Protection
  Mandates adherence to EN 45545-2 concerning fire protection materials and components. It introduces reinforced requirements for fire barriers with performance levels E15, I15, tested in accordance with EN 1363-1 and related standards.

• Maintenance and Inspections
  Establishes requirements for regular leak inspections, container integrity verification, valve and sensor calibration, and system functional checks. It advises maintenance records and non-destructive testing aligned with recognized methods like EN 1779 and ISO 19078 guidelines.

• Marking and Labelling
  Details are included to ensure proper labeling for safety and identification consistent with railway operational standards.

• Interfaces
  Addresses mechanical, fluidic, and electrical interfaces between onboard systems and external elements such as fueling stations, enhancing compatibility and operational reliability.

Applications

• Railway Rolling Stock
  Used in the design and operation of hydrogen-powered trains, including hybrid rolling stock, trams, commuter services, and high-speed trains, enabling cleaner, sustainable rail transport.

• Hydrogen Fuel Cell Integration
  Facilitates proper hydrogen fuel supply to fuel cell power systems, promoting zero-emission traction power solutions.

• Safety-Critical Systems Design
  Guides railway manufacturers and operators in constructing hydrogen systems that meet stringent mechanical, fire protection, and maintenance standards to ensure passenger and equipment safety.

• Maintenance Protocol Development
  Helps asset managers implement maintenance regimens focused on hydrogen system reliability, leak detection, and periodic inspections, crucial for preventing incidents.

Related Standards

• EN IEC 63341-1
  Railway applications - Fuel cell power system for rolling stock, complementing hydrogen fuel system requirements.

• EN 12663-1
  Structural requirements for railway vehicle bodies, ensuring mechanical compliance for hydrogen fuel system fixation.

• EN 15085-4
  Welding of railway vehicles and components - production requirements relevant to structural parts of hydrogen systems.

• EN 45545-2
  Fire protection on railway vehicles - materials and components requirements for fire behavior.

• EN 1779
  Non-destructive testing - guidelines on leak testing methods for safety checks.

• ISO 17268-4
  Specifies hydrogen refueling receptacles such as the preferred "H35VFH" standard connector.

• ISO 19078
  Provides guidance on in-service inspection and acceptance criteria for hydrogen fuel containers based on CNG standards until dedicated hydrogen inspection standards are finalized.

This amendment supports the adoption of sustainable hydrogen technology in rail transport - enhancing safety, environmental performance, and interoperability. It is essential for railway manufacturers, operators, safety engineers, and maintenance personnel involved in hydrogen fuel system integration and stewardship.

Standards Content (Sample)

SLOVENSKI STANDARD
01-januar-2026
Železniške naprave - Vozna sredstva - Sistemi gorivnih celic za vozna sredstva - 2.
del: Sistem za shranjevanje vodika - Dopolnilo AA
Railway applications - Hydrogen and fuel cell systems for rolling stock - Part 2: Hydrogen
fuel system
Applications ferroviaires - Systèmes à hydrogène et à pile à combustible pour le matériel
roulant - Partie 2: Système à hydrogène
Ta slovenski standard je istoveten z: FprEN IEC 63341-2:2025/prAA:2025
ICS:
27.070 Gorilne celice Fuel cells
45.060.01 Železniška vozila na splošno Railway rolling stock in
general
SIST FprEN IEC 63341- en
2:2025/oprAA:2026
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD DRAFT
FprEN IEC 63341-2:2025
NORME EUROPÉENNE
EUROPÄISCHE NORM
prAA
November 2025
ICS  -
English Version
Railway applications - Hydrogen and fuel cell systems for rolling
stock - Part 2: Hydrogen fuel system
Applications ferroviaires - Systèmes à hydrogène et à pile à To be completed
combustible pour le matériel roulant - Partie 2: Système à
hydrogène
This draft amendment prAA, if approved, will modify the European Standard FprEN IEC 63341-2:2025; it is submitted to CENELEC
members for enquiry.
Deadline for CENELEC: 2026-01-30.

It has been drawn up by CLC/TC 9X.

If this draft becomes an amendment, CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which
stipulate the conditions for giving this amendment the status of a national standard without any alteration.

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

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Türkiye and the United Kingdom.

Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are aware and to
provide supporting documentation.

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

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2025 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Project: 81192 Ref. No. FprEN IEC 63341-2:2025/prAA:2025 E

Contents Page
1 European foreword . 3
2 1 Modification to Clause 2, “Normative references” . 4
3 2 Modification to 8.8.3, “Structural design” . 4
4 3 Modification to 8.9, “Fire protection” . 4
5 4 Modification to 9.6.1, “On-board hydrogen receptacle” . 4
6 5 Modification to 11.3.1, “Maintenance requirements” . 4
7 6 Modification to 11.3.4.2, “Regular leakage inspection” . 4
8 7 Modifications to Annex D, “Standards, laws and regulations applicable in specific
9 countries or regions” . 4
10 8 Modifications to Annex E, “Recommendations for fire protection of the HFS” . 5
11 9 Modifications to Annex F, “Recommendations for minimum maintenance checks and
12 tasks” . 5
13 Annex ZA (normative) Normative references to international publications with their
14 corresponding European publications . 7
15 European foreword
16 This document (FprEN IEC 63341-2:2025/prAA:2025) has been prepared by CLC/TC 9X “Electrical and
17 electronic applications for railways”.
18 This document is currently submitted to the Enquiry.
19 The following dates are proposed:
• latest date by which the existence of this (doa) dav + 6 months
document has to be announced at national
level
• latest date by which this document has to be (dop) dav + 12 months
implemented at national level by publication of
an identical national standard or by
endorsement
• latest date by which the national standards (dow) dav + 36 months
conflicting with this document have to be (to be confirmed or
withdrawn modified when voting)
20 1 Modification to Clause 2, “Normative references”
21 Add the following references:
22 EN 12663-1, Railway applications - Structural requirements of railway vehicle bodies - Part 1: Locomotives
23 and passenger rolling stock (and alternative method for freight wagons)
24 EN 15085-4, Railway applications - Welding of railway vehicles and components - Part 4: Production
25 requirements
26 EN 45545-2, Railway applications - Fire protection on railway vehicles - Part 2: Requirements for fire
27 behaviour of materials and components
28 EN 1779, Non-destructive testing - Leak testing - Criteria for method and technique selection
29 EN 1363-1:2020, Fire resistance tests - Part 1: General requirements
30 EN 1364-1, Fire resistance tests for non-loadbearing elements - Part 1: Walls
31 EN 1364-2, Fire resistance tests for non-loadbearing elements - Part 2: Ceilings
32 2 Modification to 8.8.3, “Structural design”
33 Replace the content of the subclause with the followi
...