Route Optimization of Hazardous Material Railway Transportation Based on Conditional Value-at-Risk Considering Risk Equity

Rail transportation of hazardous material (Hazmat) involves low-probability, and high-consequence risks, requiring strategies that mitigate extreme accident impacts while ensuring fair risk distribution. To address this, we introduce conditional value-at-risk with equity (CVaRE) into railway Hazmats risk assessment, enabling flexible decision-making that balances risk minimization and equity considerations. Unlike conventional models that focus solely on risk reduction, CVaRE incorporates a risk equity goal, ensuring a more balanced distribution of risk across transportation routes. This study develops a novel CVaRE model that replaces fixed threshold constraints with a dynamic risk equity goal, providing greater flexibility in risk distribution adjustments. A k-shortest path-based algorithm was designed to balance extreme risk minimization with equitable risk allocation in route selection. A case study on the Yangtze River Delta railway network validates the model, demonstrating that moderate cost increases can significantly reduce extreme accident risks while achieving fairer risk distribution. Findings also show that direct transportation improves risk equity over transfer-based routes, highlighting the importance of strategic route planning. This research offers practical decision support for transport companies and regulators, helping optimize routes while ensuring cost efficiency and regulatory compliance. It also provides a scientific foundation for risk-equity-based policies, promoting safer, more sustainable Hazmat railway transportation.