Irish Rail says all services to and from Dublin's Docklands station are suspended until Friday.
It's due to low rail adhesion caused by leaves on the tracks.
A number of service alterations are in place.
Spokesperson Barry Kenny says it's an unavoidable seasonal issue: "It is a seasonal issue, but the impact of it varies in each location.
"We do extensive works - we treat the rails every single night. But this is particularly severe now."
Until Fri 30th Oct, due to severe low rail adhesion:
-M3 Parkway services will operate to/from Clonsilla only, and will connect with Maynooth/Connolly.
-Services will not operate to/from Docklands (please use Connolly).— Iarnród Éireann (@IrishRail) October 28, 2020