IEC 63341-2:2025

Overview

IEC 63341-2:2025 - "Railway applications - Hydrogen and fuel cell systems for rolling stock - Part 2: Hydrogen fuel system" specifies requirements for on-board hydrogen fuel systems (HFSs) that supply fuel cells for traction and auxiliary power on railway vehicles. The standard applies to gaseous hydrogen storage only (liquid, cryo-compressed, metal hydrides are excluded) and covers all rolling stock types (trams, metros, commuter, regional and high-speed trains, locomotives, light rail). It defines the scope of supply, interfaces, environmental constraints, design, safety, maintenance, marking and validation (type, routine and investigation tests).

Key topics and technical requirements

• System description and modules: compressed hydrogen storage system (CHSS), hydrogen handling system (HHS), monitoring and control system (MCS), on-board fuelling interface, fuel/purge/discharge lines.
• Interfaces: mechanical, fluidic and electrical interfaces between HFS and fuelling station; on-board fuelling receptacle; fluidic interfaces for supply, purging and discharge. Fuelling station protocols and fuelling-station communication are out of scope.
• Environmental and mechanical requirements: ambient temperature, humidity, altitude, air movement, corrosion/pollution degree, shock, vibration, degree of protection and structural integration.
• Design and performance: hydrogen quality, pressure ranges (high/medium), flow rates, temperature, material compatibility and electrical/EMC principles.
• Safety, RAMS and maintenance: reliability, availability, hazard identification, explosive-atmosphere management, maintenance documentation, leak testing, flushing and inertizing procedures.
• Marking, labelling and documentation: safety signs, nameplates and required documentation for operation, installation, transportation and maintenance.
• Validation and testing: type, routine and investigation tests for mechanical, electrical, gas, control, communication and EMC performance; tests at system and container level (informative annex covering container cycling, hydrostatic, drop, fire and permeation considerations).

Practical applications

• Ensures safe, interoperable on-board hydrogen fuel systems for rail vehicles using gaseous hydrogen.
• Guides design and integration of CHSS modules and HHS into rolling stock, including mounting, cabling, piping and control interfaces.
• Supports certification, safety assessments and acceptance testing of hydrogen-powered trains.
• Informs maintenance procedures, labeling and lifecycle requirements for operators and maintainers.

Who should use this standard

• Rolling stock manufacturers and integrators
• Fuel cell system and hydrogen-storage suppliers
• Railway system engineers and safety/RAMS specialists
• Test laboratories, certification bodies and infrastructure planners
• Maintenance teams and depot managers

Related standards

• IEC 62864-1 (referenced for hybrid vehicles and fuel cell traction concepts)
• See other IEC hydrogen and fuel cell standards for complementary guidance on fuel cell systems and fuelling infrastructure.

Keywords: IEC 63341-2:2025, hydrogen fuel system, on-board HFS, compressed hydrogen storage, railway applications, rolling stock, fuel cell systems, CHSS, HHS, MCS.