There was major disruption on the 3.04pm rail service from Galway to Dublin Heuston yesterday.
Shortly after 5pm, a woman went into labour on board as the train approached Kildare.
The baby girl was delivered safely within around half an hour, thanks to the quick thinking of passengers and staff.
An off duty doctor was on board and was able to assist the woman as ambulance crews made their way.
The brand new baby and her mum are said to be doing well.