I've noticed on British forums that electrification to the British MkIII system built in the mid-80s (ie the Bedpan line) now seems to be suffering from Overhead Line failures, not unlike the problem last year near Stirling. The WA system is of the same type and era as the system causing cancellations and delays to Thameslink trains in Britain. NR has intimated that substandard components chosen for lowest project cost, rather than lowest whole-life cost may be the underlying cause of the problems.
I hope The PTA is liaising with their Network Rail colleagues in Britain. It would be smarter for all concerned to plan and budget for a preventative programme than suffer ongoing failures then undertake ad hoc
HTH somebody in the "system"
DW in Devonport