She has been named locally as Jessica McLoughlin from Sligo town who was aged in her 40’s.
A second woman aged in her 20’s is still in a serious condition in hospital.
Investigations are underway into how the incident involving the 3.05 pm service from Sligo to Dublin happened.
Around 100 passengers were on board the Irish Rail carriages at the time, and the Dublin to Sligo service will operate bus transfers between Boyle and Sligo in both directions until the line is full reopened.
Local Councillor in the area Thomas Healy says people there are numb:
