Overview
ISO 22074-8:2022 specifies laboratory test methods for vertical stiffness of rail fastening components. It defines procedures to measure the static stiffness and low-frequency dynamic stiffness of rail pads, baseplate pads and complete rail fastening assemblies. The standard focuses on controlled laboratory tests that simulate the vertical loading experienced in railway track under passing wheels and bogies. It does not cover stiffness testing above 30 Hz.
Key topics and technical requirements
- Scope: Static and low-frequency dynamic stiffness test procedures for pads and full fastening assemblies.
- Test principle: Apply a vertical force and measure resulting vertical displacement to compute stiffness (force per unit displacement).
- Calibration and traceability: Force and displacement instruments must be calibrated in accordance with ISO 7500-1 and ISO 9513 respectively.
- Test environment: Controlled temperature test area at (25 ± 5) °C; additional temperature chambers (−30 to +50 °C ranges) if required by purchaser.
- Apparatus and setup:
- Rigid metal base and load distribution plate(s) with defined dimensions for rail and baseplate pads.
- Abrasive cloth (P120–P400) to ensure consistent contact.
- Actuator with spherical seating capable of applying the required maximum force (typically up to 120 kN).
- At least three independent displacement-measuring instruments located around the load plate perimeter.
- Recording equipment to capture force and displacement vs. time.
- Measurement accuracy:
- Displacement measurement tolerance: ±0.02 mm for pads with declared stiffness ≤ 100 MN/m; ±0.01 mm for > 100 MN/m.
- Force application rate example: (120 ± 10) kN/min (as specified for performance requirements).
- Procedures:
- Static test: cyclic loading/unloading (three cycles) with defined lower/upper force limits and final increase to reference force for measurement.
- Low-frequency dynamic test: cyclic loading at frequencies representative of passing traffic; dynamic stiffness defined for specific frequencies.
Applications and users
ISO 22074-8 is intended for:
- Manufacturers of rail pads, baseplate pads, and fastening assemblies - to validate product stiffness.
- Independent test laboratories and certification bodies - to perform accredited laboratory tests.
- Railway infrastructure owners, designers and procurement teams - to specify and verify component performance for track systems.
- Researchers and consultants working on track dynamics, track support stiffness and vehicle-track interaction.
Use cases include product development, quality control, compliance testing for track performance, and procurement specification.
Related standards
- ISO 22074-1 (vocabulary)
- ISO 7500-1 (force-measuring calibration)
- ISO 9513 (extensometer/displacement calibration)
- EN 15461 and EN 17495 (methods for higher-frequency stiffness assessment)
- Other parts of the ISO 22074 series for rail fastening systems
Keywords: ISO 22074-8:2022, rail fastening systems, vertical stiffness test, rail pads, baseplate pads, static stiffness, low-frequency dynamic stiffness, railway infrastructure, laboratory test procedures.
Open preview (PDF)Railway infrastructure — Rail fastening systems — Part 8: Test method for vertical stiffness