Iarnód Eireann has confirmed a fatality in the vicinity of Sallins Train Station in county Kildare.
It happened at around 3.30pm and Irish Rail says the line has been closed.
Commuters are being advised there is no service to-and-from Cork, Kerry, Limerick, Waterford, Westport and Galway.
There are also major delays to services to-and-from Heuston Station this evening.
A limited service is operating to Hazelhatch.