Iarnród Éireann has confirmed that an unnofficial action involving line inspection and maintenance staff has ended.
The dispute centred around one individual worker, however a number of colleagues stopped work in support of their co-worker at around 3pm.
All services have now returned to normal.
Earlier services between Cork and Cobh and Cork and Mallow were cancelled.
Services between Cork and Dublin were also affected for a time.
Iarnród Éireann has apologised to customers for any inconvenience caused.
