Talks are continuing at the Labour Relations Commission to avert more strikes at Irish Rail.
Members of SIPTU and the National Bus and Rail Union are to stage two 24-hour work stoppages on Sunday and Monday - over pay cuts.
The workers have already taken part in two strikes last month - with a fifth day of industrial action planned for September 21st.
Owen Reidy from SIPTU says the unions were left with no option but to take the action:
