Technical Resources
Official guidelines and technical documents for HSFG torquing on Indian Railways
Technical GuidelinesDownload PDF
RDSO Report BS-111
Guidelines for use of High Strength Friction Grip (HSFG) bolts on bridges on Indian Railways
The official technical reference document published by Research Design and Standards Organisation (RDSO), Lucknow in June 2012. This is the foundational guideline that mandated HSFG bolts as the replacement for traditional rivets on Indian Railways bridges.
Key Topics Covered:
- • Why HSFG bolts replaced rivets on Indian Railways
- • Property classes 8.8 and 10.9 specifications
- • Mandatory minimum bolt tensions (M16 to M36)
- • Two-stage tightening procedure
- • Torque wrench calibration requirements (±10% accuracy)
- • Direct Tension Indicator (DTI) verification method
- • Surface preparation and metallisation standards
- • Compliance documentation requirements
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Our technical team can help you understand and implement RDSO BS-111 requirements on your project. We provide complete HSFG torquing services with full compliance documentation.
Reference: RDSO Report BS-111, June 2012, Research Design and Standards Organisation, Lucknow