Vandals may have caused yesterday morning's rush-hour DART delays, according to Irish Rail.
A power failure at Killiney shut the line between 6 a.m. and 7.30 and no trains operated between Bray and Dalkey.
Irish Rail has not determined the cause of the power failure but initial investigations indicated that vandalism may have been involved.
A spokesman for the company said: "Extreme weather conditions are normally the only time when we experience power failures of this kind."