The expansion programme, rebranded “DART+”, aims to double peak-hour capacity by 2028 with more trains and new stations.
The proposals would create a “full metropolitan area Dart network for Dublin”, the NTA said.
The project will see the electrification of services on the three commuter lines, new Dart trains, and the upgrade of the existing southern line to Greystones.
Under the plans, the Maynooth line will be the first to progress, with Minister for Transport Eamon Ryan opening the first round of consultation on the route on Wednesday.
DART+ is a radical plan to transform the frequency and capacity of all rail lines in the Dublin area.
DART+ West is the first phase - bringing the DART to Maynooth and M3 Parkway.
Have your say in public consultation on DART+ West which begins today https://t.co/HCnLQyFQgH pic.twitter.com/ZEpukHTrSc— Iarnród Éireann (@IrishRail) August 26, 2020
The NTA plans to seek a railway order, the planning application for rail infrastructure, from An Bord Pleanála in the first half of next year.
Construction is due to begin in 2022 and it is hoped it will be finished by 2024.
