Updated 10.20

An investigation is underway into what caused a DART train to partially derail in Co. Wicklow last night.

The four carriage train from Greystones to Connolly hit rocks on the tracks between Bray and Greystones just after 11 O'clock last night, but no-one on board was injured.

The impact knocked two sets of wheels on the four carriage train off the track. 

33 DART passengers escaped injury in the incident, and Irish Rail organised transport for their onward journeys.

Irish Rail spokesman Barry Kenny told Newstalk's Breakfast an investigation into what happened is underway:

Meanwhile, Iarnród Éireann has reopened the line.

Bray to Greystones line reopening, full services resuming.

— Iarnród Éireann (@IrishRail) July 9, 2014