DIN 25201
DIN 25201 was a national design guideline for bolted joints in rail vehicle construction, consisting of seven parts systematically organized by application area, including mechanical and electrical design, fastening, corrosion protection, connection dimensions, and assembly.
Part 1 classified bolted joints into risk categories and loading cases, which significantly influenced safety-related design.
Parts 2 and 3 provided design specifications for mechanical and electrical screw connections, addressing different requirements for contact and force transmission principles.
Part 4 formed the core of the standard in terms of safety engineering and focused on measures to prevent the spontaneous loosening of high-strength bolted joints under dynamic loads.
Parts 5, 6, and 7 contained technical guidelines for preventing corrosion damage, ensuring geometric interface compatibility, and ensuring quality-compliant assembly.
Key differences and new features introduced by DIN EN 17976:
- Holistic approach: The new standard takes a comprehensive view of the loosening of bolted joints, including the loosening and unscrewing phases.
- Preventive loosening protection: Specific requirements and test methods are defined to ensure protection against loosening.
- Spring-loaded fasteners: The standard emphasizes the importance of spring-loaded fasteners for increasing elastic resilience and slip resistance.
- Electrical contact glands: Specific requirements for securing elements are defined for electrical applications, although adhesives are still not permitted as securing agents.
Conclusion:
The replacement of DIN 25201 by DIN EN 17976 represents a significant step toward harmonizing and improving the safety of bolted joints in rail vehicle manufacturing. The introduction of precise requirements and test procedures increases the reliability and lifetime of bolted joints, which is particularly important in light of lightweight design concepts and the reduction of the CO₂ footprint.