JVAT first conducted a desktop study on the system hazards, causal factors and safety functions. This, coupled with “day-in-the-life of” (DILO) scenarios, helped guide very effective workshop discussions. Following the identification and capture of various hazardous states by the workshops, each was assessed with the severity criteria. The System-Level PHA considered the route and operations, rolling stock, stations and infrastructure when undertaking its analysis. JVAT facilitated three workshops to assess four operational contexts:
Maintenance and network control centre
These workshops promoted both subject matter expert and stakeholder interaction in order to collectively identify hazardous states, associated top level events and causal factors.
JVAT’s team developed a systems definition for the MTP System-Level PHA, ensuring a clear and consistent context for the PHA workshops. The PHA activity utilised the bowtie diagram to represent potential accident sequences. This diagrammatic approach involves identifying top-level events leading to a hazardous system state, which has a number of potential causal factors preceding a specific outcome (i.e. injury or death).
JVAT identified MTP-specific observations to flag for further investigation. These hazardous states focus further work in the development and refinement of controls to eliminate or mitigate the identified hazards. In addition, the PHA provided a basis for a more detailed safety analysis of MTP systems and organisational interfaces. The JVAT team analysed the workshop finding and documented the hazardous states, associated top level events and causal factors through a detailed report,