As of 2018, the Green line is operating at near maximum capacity during the morning and evening rush hours, and it experiences mass overcrowding and congestion at these times.

Between Harcourt Street and Charlemont, the Green Line takes a large loop east around buildings which did not exist between 1859 and 1959.

The route deviation was seemingly intended to serve the new properties that would have been built during the "Celtic Tiger" boom, before the Extension was open.

The Carrickmines/Bride's Glen section was also intended to have terminated into what should have a "Celtic Tiger" town centre, similar to the Tallaght area stops, until the Line B2 extension to Fassaroe/Bray was built.

The new section begins at the former city centre terminus, St. Stephen's Green, crosses the Red Line near the Abbey stop, and continues northwards, terminating at Broombridge station.

The Green line initially was provisioned with a works depot just past the Sandyford terminus and opposite the old Stillorgan railway station building.

Following a storm damage incident in October 2017 at Red Cow it was found the depots at Broombridge and Sandyford were not able to take over the function and the whole Luas system was suspended for two days.

[8] The section of the Luas Green Line between Charlemont and Sandyford was built with the eventual intention that it be upgraded to carry metro services.

The proposal included the construction of a tunnel extension from the Ranelagh area to St. Stephen's Green, where it would have linked with Metro North.

At the time, it was planned that trains could either enter the tunnel at Ranelagh to run on the Metro North route towards Swords, or continue at street level on the Luas tracks towards Broombridge.

[14] During the public consultation process for this proposal, Dublin City Council submitted that a large sewer was blocking the path of where the tunnel was planned to emerge, just south of the existing Charlemont tram stop.

In May 2019, an executive of Transport Infrastructure Ireland reaffirmed their commitment to extend the metro to Sandyford, though it would not proceed "now, or in the short term.