The DART is being hailed 'an unequivocal success story' for Dublin as it turns 40 today.
The green trains have become synonymous with Dublin life over the last four decades.
Initially, the Dublin Area Rapid Transit (DART) line ran between Howth in Dublin and Bray in Wicklow before it was extended to Malahide and Greystones.
Further extensions are also on the horizon for Drogheda, Hazelhatch and Maynooth as part of DART+.
The DART is 40 today! To our 670 million customers over the last 40 years, thank you!
We'll have lots of memories and surprises today, so stay tuned! #DART40 pic.twitter.com/JSoZOiUmv6— Iarnród Éireann (@IrishRail) July 23, 2024
A specially-commissioned short film written by Roddy Doyle to mark the 40th anniversary will be screened onboard trains for the first time today.
A partnership with Little Museum of Dublin will also be unveiled today, which will turn a DART into a travelling social history museum.
It features a special 'railing in the years' livery outside and images inside from the history of Dublin for the last 40 years - including the likes of the Millennium milk bottle, Rainbow Rapids and Italia '90.
Earlier this month the extension of the DART to Drogheda took a significant step forward when Iarnród Éireann lodged a Railway Order application with An Bord Pleanála.
Irish Rail Corporate Communications Manager Barry Kenny told Newstalk Breakfast the system is "an unequivocal success story".
"Like a lot of public transport investment over the decades, there were people that questioned its need as it was being developed and the approach taken," he said.
"From day one, I think passenger numbers on the DART line doubled within weeks.
"It's continued to grow; it's helped the area that it serves to grow".
Mr Kenny said the DART has "won the argument for investment in high-capacity and high-quality public transport".
"It paved the way for our colleagues in Luas - [who] marked 20 years this year – [and the] investment in bus networks and investments in other aspects of our commuter rail," he said.
"DART shows that when you actually fund - in a serious way - major public transport projects, people will use it and use it in huge numbers".
? The DART turns 40! Reporter @AlexRowley04 gets a behind the scenes look at Fairview DART depot, and meets some of the crew who keep the fleet running. #DART40 pic.twitter.com/Ns8Wp3ODmu
— NewstalkFM (@NewstalkFM) July 23, 2024
Mr Kenny said a railway line was already in place along part of the network.
"Part of the DART line - and the very first railway line in Ireland - [was] between Pearse St and Dún Laoghaire which is in operation 190 years this year," he said.
You did have some very old rail cars or locomotive hauled trains far less frequently.
"It was clear they needed an upgrade and that was the impetus; ultimately I suppose the DART was originally to be part of a far-wider network.
"Of that original plan, it was the Howth to Bray lines that opened 20 years ago today and in the interim years extended to Malahide on the north side and Greystones on the south side".
Mr Kenny said the system is about to undergo another major expansion.
"We are about to embark on the most significant and major expansion with the size of the DART network set to treble under the DART+ programme bringing the DART to Maynooth, Drogheda and to Hazelhatch," he said.
The DART has seen almost 670 million passenger journeys since its inception.
Listen back here: