Dublin - Metrolink (Swords to Charlemont only)

If you search online, you can find the 2018 report on converting Green line to Metro. The recommendations in that report are being followed. First step is Green line frequency and capacity improvements, and some of that is done; they're is still more capacity available for future growth.

The big, big problem with conversion is that the upgrading works will sever the Green line corridor for three years, forcing a change of mode south of Charlemont. I think that nothing will be started until there's a second alignment for Green Luas here, because there's no way that the bus infrastructure could absorb replacement passengers on a closed Green line.

Interesting how one could read the thread from 2010 and pass it off word for word today.

The modern approach to metro design dictates through-running in the core. A terminus in/near the centre is a frequency and capacity killer as effectively incoming trains and outgoing trains have to cross each other at-grade limiting headway at a point in the system where demand is highest. Metrolink ticks nearly all the boxes as far as a checklist of modern metro design is concerned: driverless, platform screen doors, frequency over length, no-interlining/dedicated tracks for a single service, barrier-less, shallow/accessible underground stations, multiple trip-generating destinations along the route, etc.

It ticks all the boxes except the fact that it terminates so close to the centre of the city.

I know how we ended up here but when you consider the end result, I can't help feel it's going to look somewhat ludicrous.

Two high-capacity, high-frequency rail alignments - perfectly lined up but both terminating at the point where they meet. It's analogous to having two stretches of motorway that meet but have a line of bollards blocking travel from one to the other - one coming to a dead stop while the other veers off and continues as a boreen.

It's being childish and spiteful, but I'd almost like to see the Greenline capacity upgrade postponed and have the resources diverted towards other PT infrastructure projects around the city where the investment would be welcomed. Let the greenline NIMBYs sweat (literally) for a few years and reflect on what they've achieved.

Metrolink extension along the Green Line south of Ranelagh is really the only game in town, they just aren't allowed to say it as it would poke every bear of a NIMBY in south Dublin. The 3 year closure thing was convenient as a front for dropping the Green Line upgrade, it was just going to be more hassle than it was worth to be dealing with all that on top of the monster than is Metrolink. A workable solution will be put forward when the time is right.

Once Metrolink is operational, Green Line users will be screaming for it to be linked up so they can shoot through straight to the airport/Mater/DCU/wherever. When it dawns on them that the level of service from Metrolink is far superior to Luas (speed, frequency, rolling stock, not getting regularly curtailed, etc.), they'll demand it. They certainly won't be happy seeing property values shooting up on the northside thanks to Metrolink while the gleam will be long gone from the jewel which the Green Line once was.

Again, before any green line conversion can start, they're needs to be a new Luas routing in place. Otherwise, you will inflict absolute chaos on Dublin for three years while there is neither a Luas nor a Metro allowing travel into the City Centre.

This disruption, as well as the marginal benefit, was one of the reasons that the Southern extension was dropped from Metrolink.

Future capacity improvements on Green Line will keep it up with demand for close to 20 years. That's time to get things in order for a painless conversion to Metro.

Th tunnel portal will have to be not directly on the Luas line, then it is just a tie-in and stations upgrade which would take a few months.

Read the documents. The upgraded section must be closed completely for nine months, but the Green Line itself would be broken into two sections for a period of three years. Even if the break is only a single station gap, that's still a gap in the middle of someone's journey that needs to be accommodated by changing to other modes, and the most likely effect of changing a direct connection into a two-change connection (Luas to bus/foot, bus/foot back to Luas) will be to shift passengers to bus or, worse, private car.

The tunnel portal has to tie to the existing rail line at some point, so you have to suspend Luas services on that line section while these works are being done. There's no way around this, as there is no space to build a parallel track to minimise the time that Luas needs to be suspended.

This is a job that looks simple until you start planning on how to actually do it...

I think you all underestimate how disruptive that one stop break will be to Green Line usage. It's easy to write "9 minute walk" on an infographic, but everything we understand about public transport says that putting a forced walk like this into the service will cause ridership to plummet for journeys that need to cross the breakpoint... and where will those displaced passengers go?

I don't disagree about this being inevitable, I just believe it would be stupid to start it without at least beginning an alternative routing of the Green Line south of Charlemont.

(incidentally, that infographic is misleading: the engineering report says that the Ranelagh Luas stop cannot reopeen afterwards, as it will be north of the only practical location of the metro portal)

Would the track be replaced when the metro is being built out that way? What happens to the Sandyford depot. Does it become a metro depot?