2. Experimental procedureInitial close visual inspection was carried out onsite. The failed component was identified and removed to the laboratory forfailure investigation. A photographic survey was carried out on the as-received component and also at various stages throughout theproject. Copper wire samples were removed for fractography and, after initial examination, cleaned using 5% Quadralene QIC/2instrument cleaner in water for 5 min in an ultrasonic bath. The contact clip was ground in two places to remove any coatings forchemical analysis of the underlying material. Fractography was carried out using an FEI environmental scanning electron microscopewith a 2 nm resolution capability. Chemical analysis was carried out using a Bruker Energy Dispersive spectrometer. Preparation formetallographic analysis was involved sectioning with a diamond saw, mounting the wire within conductive phenolic resin, grindingto 2500grit silicon carbide paper, polishing to 1μm diamond pastefinish,final polishing with colloidal silica suspension and etchingusing 10% alcoholic ferric chloride solution.Fig. 1.Motor Operation Contact showing fractured copper wires and connection point (Inset).Fig. 2.Position of contact within trackside assembly.Fig. 3.Trackside casing for contacts.N. Brewitt, et al.Engineering Failure Analysis 108 (2020) 1042142