It follows an incident in that area.
Maynooth and Sligo rail services through Castleknock station in Dublin are suspended following an incident.
Dublin Bus will honour tickets in the meantime, and a shuttle train is operating temporarily.
It's serving stops between the M3 Parkway, Clonsilla and Maynooth.
Update: Maynooth / Sligo services remains suspended. Dublin bus are honouring rail tickets. Shuttle service operating M3 Parkway / Clonsilla / M3 Parkway & Maynooth / Clonsilla / Maynooth. Update to follow. -AB https://t.co/xrqXDWGGgf— Iarnród Éireann #StaySafe (@IrishRail) September 9, 2021