A plan to extend the DART to Maynooth in County Kildare has finally been approved by An Bord Pleanála.

The green light for the DART+ West project comes more than two years after Irish Rail first sought permission.

The company says it "warmly welcomes" the decision by An Bord Pleanála.

Irish Rail says it will provide a sustainable, electrified and more frequent rail service to customers, improving capacity on the Maynooth and M3 Parkway to city centre rail corridors.

DART+ West will increase train capacity from the current six trains per hour per direction up to 12 trains per hour per direction, subject to demand.

Passenger capacity is expected to increase to 13,200 passengers by 2025 – up from 5,000 in 2019.

DART+ West Route Map

"Delivery of this DART+ West will support existing communities and support future sustainable development," Irish Rail says.

"It will serve all existing stations along the railway corridor between Maynooth Station and M3 Parkway Station to Connolly Station and to the proposed Spencer Dock Station using electrical power, which has a lower carbon footprint than the current diesel trains.

"The frequency and quality of service will provide a viable transport alternative for surrounding communities other than private car travel."

The electrification of the rail line will mainly follow the existing railway corridor.

The Railway Order gives Iarnród Éireann the authority to proceed with the electrification and infrastructure upgrades.

"This is a crucial milestone in a programme which will ultimately double the capacity of the Greater Dublin Area rail network, and treble the electrification of the network," a spokesperson told Newstalk.

Iarnród Éireann, in collaboration with the National Transport Authority (NTA), will now progress the delivery of the DART+ West project to its construction stage which involves procurement processes to engage contractors.