It was an overhead line fault, there seems to be a lot of them in the Dalkey area for some reason
About a third of the DART fleet is based in Bray so without that available things get messy, normally the fault arises during the rush hour when most of the trains have left Bray, that wasn't the case today
Of course it had nothing to do with this
http://www.irishrail.ie/news_centre/...ew&news_id=480