The purpose of this paper is to describe a risk-based scenario analysis, by use of an Event Tree Analysis approach, which will support testability considerations and test level integration in the design or dependability improvement phases of technical systems. The proposed scenario analysis includes fault recognition and fault localization efforts and their associated hazards of false alarms, unrecognized faults, and un-localized faults. The combination of these single hazards into the hazard of NFF events and the consequences to safety, dependability, and cost are also discussed. It should be noted that the paper focuses on Built-in-Test (BIT), i.e., the capability of a test system of performing automatic fault recognition and fault localization. The hardware aspects, related to Built-in-Test Equipment (BITE), are not specifically considered. An earlier version of this paper has previously been presented at the IAI2023 Congress. 

This paper describes results from a research and development (R&D) project at Trafikverket (Swedish transport administration). The purpose of the study was to systemize dependability improvements of Trafikverket’s Control Command and Signalling (CCS) assets considering all phases of its life cycle. A case study was conducted on level crossings that represent a critical part of the CCS system. The results of the study show that the systemic approach contributes to asset management by short-term dependability and productivity improvements as well as by medium term specifications for system modifications and long-term specifications for next generation of level crossings. The approach is based on a combination of methodologies and tools described in dependability standards, e.g., Failure Modes, Effects and Criticality Analysis (FMECA). However, the approach also considers aspects from Design of Experiments (DoE) to support field tests aligned with other tasks in the railway infrastructure. Besides contributing to improvements, the approach complies with regulations and mandatory standards. Examples of these are Common Safety Method for Risk Evaluation and Assessment (CSM-RA, EU 402/2013) and EN 50126—RAMS (Reliability, Availability, Maintainability and Safety) for railway applications. In addition, the approach complies with regulatory requirements related to enterprise risk management and internal control, i.e., effectiveness, productivity, compliance and documentation. The approach also supports asset management in accordance with the ISO 55000-series.

Infrastructure projects undergo multiple changes throughout their lifecycle, adapting to new mobilities, technologies and environments. We build on the System of Systems (SoS) theoretical concept to understand the implications of such infrastructure transformations, specifically when projects move from a single purpose to hosting multiple functions. Using multiple case studies in Europe, we investigate which functions will likely be added to the original infrastructure and the rationale for adding these functions. Therefore, we expand upon the theoretical concepts of circularity, resilience, and social sustainability, wherein multifunctional infrastructure adapts, renews, and complements existing infrastructure.