Identification of systematic faults

Unstad was commissioned by a maintenance company to carry out a structured mapping and analysis of systematic and recurring faults in rolling stock (Type 7, WLAB-2, and EL 18). The work combined historical fault data with inspection reports and technical assessments to identify patterns, weaknesses, and improvement opportunities in both maintenance practices and fault registration.

The project included a review of more than 5,300 reported faults. Data was structured, categorized, and analyzed by vehicle type and system, with prioritization through top-10 analyses. Where the data allowed, faults were further broken down by symptom, component, and functional level. The results were presented with statistics and visualizations that clearly highlighted systematic patterns and potential root causes.

The methodology was based on the principles of EN 50126 (RAMS), with a focus on reliability and maintainability, and supported the need for structured classification in line with EN 15380. The analysis revealed, among other findings, components with high failure frequency, issues related to data quality and fault categorization, correlations between age/wear and fault distribution, and a need for more consistent registration of faults, corrective actions, and root causes.