CIÉ says it will net around €1m from new pay and display parking charges at 37 stations on the greater Dublin rail network.
A spokesman for Iarnród Éireann says that the revenue it collects from commuters will be reinvested in parking spaces.
Commuters will be charged €2 a day or a discounted rate of €8 a week. Clamping will be introduced to enforce the new fees.
There are 4,500 parking spaces at the stations in question.
Most of the money collected from these will go to CIÉ with servivce provider Nationwide Controlled Parking Systems receiving a percentage for managing the car parks.
The stations affected are on lines from Athlone and Longford including the stations on the Portlaoise and Coolmine Arrow routes, the Dundalk line, the Dart routes, the Arklow and Gorey lines.