Conference Agenda

Third-party conformity assessment under ISO/IEC 17065 represents a pivotal governance mechanism for railway safety assurance. While non-accredited assessments may overlook critical system hazards leading to catastrophic failures and losses, mandating rigorous ISO-compliant processes demands additional financial overhead and procedural burdens. Thus, evidence guiding these accreditation mandates remains scarce, particularly in emerging railway markets. To address this gap, this study proposes a comprehensive probabilistic framework that quantitatively evaluates the systemic and economic impacts of accreditation rigour conditioned by institutional enforcement quality across four Safety Integrity Levels (SILs) and a Basic Integrity baseline.

Employing a quantitative risk evaluation methodology with stochastic parameter ranges, the framework can determine residual hazard rates as a function of SIL-specific baselines, an Intrinsic Rigour Score (K₀), the instructional effectiveness of the railway authority (β) and enforcement-conditioned certification effectiveness. , extracted from ISO/IEC 17065, critically imposes verifiable requirements for technical competence, impartiality and procedural rigour on certification bodies. serves as a weight-sum representation of the railway regulatory maturity index, government effectiveness and control of corruption. Finally, to translate technical safety outcomes into an economic justification metric, the derived residual hazard rates are converted into lifecycle expected losses by factoring in total operational hours and heavy-tailed consequence costs per event.

A 2 × 2 × 5 factorial design (accreditation status, enforcement profile, and SILs) was evaluated through extensive computational simulations. The proposed framework establishes a quantitative link between institutional regulatory inputs and high-consequence safety outcomes. The model is formulated, demonstrating how variations in safety integrity requirements alter the financial breakeven financial thresholds for mandatory accreditation and technical competence for certification bodies. By capturing the divergence between expected-value economic metrics and heavy-tailed risk distributions, the model directly supports the ALARP principle and precautionary regulatory decision-making. Ultimately, this research delivers a replicable, multi-tiered evaluation methodology. It provides policy-makers and railway authorities with a robust, evidence-based structural tool to confidently justify and integrate mandatory ISO/IEC 17065 technical qualification directly into infrastructure procurement specifications.