The Luas Green Line is a very popular piece public transport infrastructure. This presents a problem. Transport engineers predict that the Luas Green Line will run out capacity by 2027. This is even with the current capacity enhancement programme, which will add 8 new trams and lengthen 26 existing trams to their full length. Even with these near-term improvements the Luas Green Line will be over capacity by 2027. Passengers will left behind on the platforms.

The growth in passengers numbers is driven by two factors. The Luas Green Line is now more useful to more people since the Luas Cross City has opened. As a result more people are using it. The other is that Dublin is a growing city. There are simply more people who need to use public transport.

Future growth in passengers will come from new housing developments all along the Luas Green Line. In particular at Sandyford, Carrickmines and most notably Cherrywood, which will become home to 25,000 people.

If the Luas Green Line is over capacity it will also be impossible to extend the Luas Green Line to Finglas in the north or to Bray in the south. Otherwise, new passengers from these extensions would simply overwhelm the existing Luas Green Line.

How do you increase capacity?

The capacity on the Green Line will be 8,000 people per direction at peak times after the current upgrade works. This would make the Luas Green Line would of the highest capacity trams systems in Europe.

There are two ways to increase the capacity of the Luas Green Line:

  • Use trams that can take more people
  • Run the trams more frequently

To fit more people you need more space.

First option is to remove seats inside the tram. There are few seats inside the Luas that could be removed as most are on top of the Luas tram's wheels.

The other option, but harder option is to use bigger trams. The length of the Green Line trams has already been increased twice to 55 meters long, up from 33 meters originally. It would be very difficult to increase the length of the Green Line trams again without causing further traffic congestion in the city center. The 55 meter trams were specially made for Dublin by the tram manufacturer and they are now the longest on-street trams in Europe.

Luas in mixed traffic at College Green

The other option to increase capacity is to run the Green Line trams more frequently. This means more trams on the tracks at the same time. At peak-times Green Line trams can run every three to four minutes. The Green Line struggles to maintain this frequency and is unlikely to be able to increase it further. An increase in frequency would require the closure of road crossings along the line as trams would be passing by in both directions so frequently the road would hardly ever be open. More trams on city centre streets would negatively affect the pedestrians, cyclists, buses and taxis that the Luas Green Line shares space with.


So how do we increase the capacity of the Green Line?

The issue that stops further Green Line capacity improvements is the on-street section of the Luas Green Line north of Charlemont in the city centre. The only option left is to run the Luas underground in the city center so it is not competing for space. If the trams were underground they could be wider, longer and more frequent.

The idea of connecting the Green Line into the MetroLink tunnels makes sense in this context. The Green Line needs further capacity enhancements, which will require underground tunnelling. The government is planning to build a metro from Swords to Stephen's Green. As a result there will be tunnel boring machines under the city. The logical solution is to tunnel another 900 meters so that the Luas Green Line could be connected into the new metro tunnels.


This is an upgrade that has been planned for the Luas Green Line since the year 2000. By connecting the Luas Green Line into the MetroLink tunnels and a few other upgrades to the Luas Green Line the capacity would be increased from 8,000 to 15,000+. This upgrade would also allow for even further upgrades that might be necessary after 2050.

The metro upgrade of the Luas Green Line as part of MetroLink is exactly the answer to this capacity problem. If we act now to build MetroLink we can avoid the Luas Green Line getting over-crowded again.

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