The 7.15am morning train from Westport to Heuston station in Dublin is running almost an hour late this morning.
The train was found to have a mechanical fault on the platform this morning.
Irish Rail brought in a replacement train, which left Westport at 8.10 - almost an hour behind schedule.
This is also a shorter train, and therefore has reduced capacity.
An Irish Rail spokesman told Midwest News that they're endeavouring to get an additional train to bring passengers from stations further along the line.