EN 13146-8: Railway Applications – Track – Test Methods for Fastening Systems – Part 8: In-Service Testing

What is EN 13146-8?

EN 13146-8 is a specialized testing standard titled “Railway applications – Track – Test methods for fastening systems – Part 8: Influence of exposure to severe environmental conditions.” As a part of the broader EN 13146 series, it focuses on the durability of the components that secure the rail to the Sleeper.

In Infrastructure Management, fastening systems are exposed to harsh elements for decades. Part 8 specifically evaluates how corrosion and environmental degradation affect the ability of the fastening to maintain Track Geometry and Operational Safety.

Test Methodology: The Salt Spray Challenge

The core of the EN 13146-8 test is a simulated accelerated aging process. Unlike mechanical fatigue tests, this is a chemical and environmental stress test:

• Salt Spray Exposure: The complete fastening assembly is placed in a test chamber and subjected to a neutral salt spray (NSS) for a specified duration (typically 300 to 500 hours).
• Pre-Stressing: The system is tested in its assembled state, meaning the components are under the actual tension they would experience on a real track. This is vital because stress-corrosion cracking can occur in tensioned metal.
• Post-Exposure Inspection: After removal from the chamber, the system is disassembled to check for rust, pitting, or degradation of the coating.

Key Performance Criteria

The Technical Delivery Conditions for fastening systems require that, following the environmental exposure, the system must still meet several functional benchmarks:

• Clamping Force: The clips must still exert sufficient pressure on the rail foot to prevent longitudinal movement.
• Electrical Resistance: Corrosion must not create a “conductive bridge” that would interfere with Signalling and track circuits.
• Ease of Maintenance: Crucially, it must still be possible to remove the bolts or clips using standard tools. If corrosion “welds” the parts together, it fails the test.

Impact on Lifecycle and Safety

Fastenings that fail EN 13146-8 testing can lead to “gauge widening,” where the rails push apart under the lateral forces of Rolling Stock. By ensuring high corrosion resistance, Infrastructure Management can extend Maintenance Intervals and reduce the risk of derailment in coastal or industrial areas where the air is high in chlorides or pollutants.

The EN 13146 Series Context