EN 13146-3: Determination of Resistance to Impact Loads for Rail Fastenings

What is EN 13146-3?

EN 13146-3 is a critical part of the European Standard series titled “Railway applications – Track – Test methods for fastening systems – Part 3: Determination of resistance to impact loads.” This standard focuses on the ability of Rail Fastenings to withstand sudden, high-magnitude forces without failure.

In the Permanent Way (P-Way), fastening systems are the only components keeping the rail secured to the sleepers. They are subjected to severe Impact Loading caused by wheel flats, rail joints, and singularities like switches and crossings. EN 13146-3 provides a standardized laboratory environment to replicate these “hammer-blow” effects.

The Impact Test Methodology

The test defined in EN 13146-3 is designed to simulate the vertical impact of a wheel on the rail. The procedure typically involves:

• Test Assembly: A short section of rail is secured to a concrete sleeper (or other support) using the complete fastening system (clips, pads, and insulators).
• Drop Weight: A specific mass is dropped from a calculated height onto the rail head, generating a massive pulse of energy.
• Repetition: The impact is repeated for a specified number of cycles to check for progressive damage or Component Integrity.
• Evaluation: After the test, the system is inspected for cracks, permanent deformation, or loss of “clamping force” (toe load).

Significance for Track Safety

If a fastening system fails under impact, it can lead to “gauge widening,” where the two rails spread apart, causing a derailment. EN 13146-3 is essential for:

• New System Development: Validating the use of plastic or composite components (like insulators and rail pads) which are more susceptible to brittle fracture than steel.
• System Selection: Helping Infrastructure Managers choose the right fastening category (e.g., Category A for light rail vs. Category E for heavy freight) as defined in EN 13481.
• Reducing Track Maintenance: Identifying systems that can absorb impacts without requiring frequent tightening or replacement.

Dynamic Forces and Attenuation

A key output of these tests is the measurement of how well the “rail pad” (the elastic layer under the rail) attenuates Dynamic Forces. A system that passes EN 13146-3 must demonstrate that it protects the concrete sleeper from the impact, preventing “rail seat deterioration” (RSD) or sleeper cracking.

Comparison: Static vs. Impact Loading Requirements