By law, the California High-Speed Train System (CHSTS) must be designed and built along established transportation corridors, includes adjacent to or in shared right-of-ways with Class 1 freight railroads. The Adjacent Railroad Hazard Risk Assessment Model (ARHRAM) has been developed as a tool to assist the California High-Speed Rail Authority (Authority) in the assessment of hazard risk posed by adjacent freight railroads. This assessment assists the Authority in the risk-based prioritization of resources meant to mitigate the hazards presented by the adjacency of freight railroad operations. Use of the ARHRAM allows the Authority to apply consistent, objective assessment techniques across the entire system and throughout the various developmental phases.
ARHRAM uses both quantitative and qualitative techniques to develop a characterization of the hazard risk at a particular location, as opposed to an exact probability of the occurrence of a derailment. FRA-reportable derailment data is used to establish the frequency of a derailment on the adjacent railroad at any location, normalized against the performance over a 10-year period. A review of characteristics at a particular location is then conducted, examining for the presence of sixteen separate site characteristics including alignment geometry, train control methods, speed, access, grade crossings, special trackwork, and operational modes. Each characteristic is given a value according to its presence (or not) and the total multiplied by the derailment factor for the railroad and volume of trains operated at the location.
The result is a characterization of the levels of site-specific hazard risk that allows the Authority to prioritize mitigations (resources) in order to reduce risk to an acceptable level. The model is dynamic in that it can be modified if new characteristics need to be introduced or existing characteristics modified, and the model can be re-run should physical or operational conditions change in the future.
This paper applies the model to an existing rail corridor adjacent the CHSTS, demonstrating how appropriate mitigations can be determined and residual risk accepted. The paper also identifies future applications of the ARHRAM in the development of the CHSTS, and potential applications for other systems or modes.
