Overview
IEC 62128-2:2013 - "Railway applications - Fixed installations - Electrical safety, earthing and the return circuit - Part 2: Provisions against the effects of stray currents caused by d.c. traction systems" - is an internationally recognized standard published by the International Electrotechnical Commission (IEC). This standard establishes essential requirements to prevent and control the adverse effects of stray currents generated by direct current (d.c.) traction systems in railway infrastructure.
Stray currents can lead to significant corrosion and operational risks in both railway assets and nearby metallic structures. IEC 62128-2:2013 outlines protective measures for metallic fixed installations forming part of the traction system as well as other metallic components in the ground that could carry stray currents. The scope primarily covers new d.c. railway lines and major modifications to existing lines and provides principles that are also valuable for evaluating and upgrading existing installations.
Key Topics
- Stray Current Hazards: Identification and assessment of hazards associated with stray currents, such as corrosion of metallic structures and safety risks from overheating, arcing, or fire.
- Assessment and Acceptance Criteria: Parameters for evaluating stray current impact, including conductance per length of tracks, rail-to-earth potentials, and acceptable thresholds for safety and asset protection.
- Design Provisions: Recommendations for the design and installation of return circuits, return conductors and cables, electrical separation practices, cross-bonding, and insulation methods.
- Protection of Structures: Specific provisions for protecting tunnels, bridges, viaducts, reinforced concrete, and adjacent metallic installations from stray current damage.
- Testing and Monitoring: Guidelines for testing, validating, and monitoring stray current controls, including continuous supervision and periodic assessment of rail potentials and system insulation.
- System Integration: Considerations for integration with non-traction electrical systems, substations, and scenarios such as tram and trolleybus shared infrastructures.
Applications
IEC 62128-2:2013 is relevant to a variety of rail and mass transit applications that utilize d.c. traction systems, including:
- Mainline railways
- Tramways and light rail systems
- Underground and elevated metro systems
- Mountain railways and trolleybus networks utilizing d.c. traction
- Material transportation systems (excluding underground mine railways, cranes, and similar equipment)
- Infrastructure projects involving major upgrades or extensions to existing d.c.-powered lines
By implementing the provisions of IEC 62128-2:2013, railway infrastructure designers, operators, and maintainers ensure:
- Enhanced electrical safety across all relevant fixed installations
- Prolonged equipment lifespan through effective control of corrosion risks
- Safety for personnel and the public from electrical hazards
- Compliance with international best practices for electrical earthing and return circuits in railway systems
These measures are essential for sustainable operation, reduced maintenance costs, and protection of both railway assets and nearby third-party infrastructure from electrical interference and corrosion.
Related Standards
To ensure holistic compliance and optimal integration, IEC 62128-2:2013 should be referenced alongside other key railway standards, such as:
- IEC 62128-1: Railway applications - Fixed installations - Electrical safety, earthing and the return circuit - Part 1: Protective provisions against electric shock
- IEC 60850: Railway applications - Supply voltages of traction systems
- IEC 62128-3: Railway applications - Fixed installations - Electrical safety, earthing and the return circuit - Part 3: Mutual interaction of a.c. and d.c. traction systems
- EN 50122-2 (for European contexts): Railway applications - Fixed installations - Electrical safety, earthing and the return circuit - Part 2: Provisions against the effects of stray currents caused by d.c. traction systems
- EN 50162: Protection against corrosion by stray current - Criteria and protective measures (European guidance on permissible voltage shifts and corrosion prevention)
IEC 62128-2:2013 plays a vital role in supporting electrical safety, asset protection, and the reliable operation of modern d.c. traction railway systems worldwide.