DART underground - options

gjim

I hadn't seen it mentioned here but the original DART underground route selection has been revised in line with the current plans for DART+, ML and other PT improvements. The document is quite interesting as it covers a range of options for DU (including the fetish for a College Green stop promoted endlessly by one particular poster). The document was published last year: https://www.nationaltransport.ie/wp-content/uploads/2021/11/DART-Tunnel-Route-Options-and-Feasibility.pdf

TLDR; the preferred route is very similar to the the previous (2014) one with a few minor changes. No surprise really. The western tunnel portal would be moved a bit further east. The TBM would be started at the Eastern (docklands) tie in. The positioning of the underground stations have been moved a little bit but in ways that all seem like improvements to me. Hueston underground would be directly below the existing building rather than further east. The docklands underground station will be directly below the planned DART+ docklands station although the platforms will start and end further south than the overground platforms allowing an entrance at the quays.

It also evaluates a bunch of fairly crazy looking alternatives - including linking the Kildare line to the Northern by swinging under the Liffey just east of Hueston, and linking the Kildare line to the Southern coastal line without crossing the Liffey at all (from page 24):

There is a lot of interesting stuff about demand modelling, geology, avoiding historical monuments/sewers/etc, station access and design and the like - the sort of thing the crayon experts generally don't consider. For example a station at Tara is more or less ruled out because of a large sewer which Irish Water say would be very difficult to move.

I know this stuff is all fantasy for now but apparently the preferred route will be "protected" in some way although I don't know what this means in practice.

There was a previous thread (https://www.boards.ie/discussion/2057289979/dart-underground-alternative-routes) which I would have liked to post to but it's been closed/re-opened/closed a few times and is currently closed. Mods - feel free to move this discussion to the older thread. I think it might make sense to do so as this is quite relevant.

donaghs

With the Metrolink back in the news, Trains every 3 minutes at peak times in MetroLink plan (rte.ie), I noticed the "DART Underground" got no mentions at all.

Is this project effectively dead for now?

bennyineire

Would it not be better to create a circle route using the exiting Phoenix park tunnel to Docklands line then swinging back through the inner South Side. That and the new Metro coupled with a future South line would truly interconnect the whole city.

Pie in the Sky stuff I know but really would make the city much easier to travel around by train/metro

gjim

https://www.boards.ie/discussion/comment/119304033#Comment_119304033

No I don't think so. Circle lines are overrated unless they link high demand destinations all along the route. I doubt any city has bothered to construct a new one recently with a radius as large as the one you are suggesting. Not sure even if there is a heavy rail circle line operating anywhere? Common practice these days is to provide increased axial capacity by building lines that criss-cross the city centre with as much interconnection as possible.

For capacity and frequency, you want only want through-stations in the centre which is the fundamental issue with the way the DART and even DART+ will operate with effectively a bunch of terminus' in the centre. This kills frequency and capacity - DART Underground would fix this by allowing nearly all DARTs to through-run.

When you think about the kind of trips facilitated by a circle line, using axial routes, even with an interchange, will often get you to your destination faster. For Dublin in particular, I believe buses could easily meet all the demand for circle-like journeys.

donaghs

https://www.boards.ie/discussion/comment/119304784#Comment_119304784

So what next for DART underground or a similar plan? A fast link from town to the airport will be great (and other locations which can connect to it). But there does seem to be some gaps there still. i.e. no fast link from Heuston to Pearse or the south side, the existing bottleneck and Connolly with the Maynooth Line and Belfast/Malahide/Howth all converging there.

Brian CivilEng

DART Underground is hampered by the conception of it being a Heuston to Connolly link, and therefore the reopening of the Phoenix Park Tunnel in DART+ has made it look like it is no longer needed. In reality the utility of DART Underground was going to be an East West rail link serving multiple city centre destinations, the existing train stations are all a long way the busiest areas of town. I think there will come a time in the not too distant future that we will need to remove a lot of buses from the city centre when pedestrianisation is increased and plazas constructed. DART Underground will probably come back on the agenda then.

pigtown

An NTA presentation to the Dublin Commuter Coalition this week effectively said that the DU would only increase the no. of passengers making an east-west trip by c.10k above the planned DART through the Phoenix Park tunnel. Its not worth spending the billions on any time soon

strassenwo!f

As I recall, when most of the discussion on the 'DART Underground - Alternative Routes' thread happened, the major issue was the St. Stephen's Green station.

Pretty much nobody expressing an opinion on that thread expressed an opinion that the project was not a desirable one, and the fact that it went to ABP and got a railway order in 2010 showed that it was deemed to be an important and desirable project, for the State, at the highest levels.

Although it still, theoretically, remains in various extant official transport plans for the years to 2040, or 2020-2070, etc., such as the one mentioned in the opening post, it has effectively disappeared.

At the time, my major concern was that it was being routed through St. Stephen's Green unnecessarily, as the LUAS was stuck there due to Mary O'Rourke's inability to make a decision and, while it was going to achieve integration of everything, it was thus going to miss the highest demand points in the city. A very useful link, now seemingly inactive, provided by the excellent poster Monument, showed that the two highest locations of work activity in Dublin were indeed between St. Stephen's Green and College Green and just across the river between Abbey Street and the river itself.

St. Stephen's Green is at the tip of one of those areas, while College Green is right in the middle, adjacent to both.

We have now seen the Green LUAS extended across the city, beyond St. Stephen's Green, as I said on that thread that it would most probably be. The work patterns in that part of the city haven't broadly changed - as far as I know - the city wants to pedestrianise the area, which is currently a 6-8 lane road, and we are told that there is a sewer issue at Tara Street which would make it a very difficult location for an East-West line.

Were Dublin to go, broadly, with the original plan, no metrolink detour to Tara Street would be necessary.

I haven't seen persuasive arguments against College Green being used - long-term in its hopefully pedestrianised era - as an underground hub which could replace its current massive contribution to Dublin's public transport.

I do think it is unfair of the OP to describe my belief in College Green as a future location of a major station as a fetish. If the OP has a better idea, please bring it on.

D.L.R.

https://www.boards.ie/discussion/comment/119305119#Comment_119305119

DU ought to be a second Metrolink line. There's no real need for this Crossrail scale in a city of Dublin's size. Much as I'd love to see it, I believe the state incapable of delivering it.

A Metrolink format single bore would do much the same job for a fraction of the cost, and I predict this penny will drop once the first line starts taking shape.

gjim

"I do think it is unfair of the OP to describe my belief in College Green as a future location of a major station as a fetish. If the OP has a better idea, please bring it on."

I'm going to come across as an asshole but why would I bother? You've been banging this same College Green underground drum for at least 15 years on various fora. I've already made the mistake of responding with counter-arguments years ago. And I've read countless responses from others over the years - now going on decades - presenting careful and considered rebuttals but they're like water off a ducks back. You've never convinced anyone to change their mind in the 15 odd years - it's time to move on, dude.

murphaph

The original plan had and still has the advantage of linking up the more similar alignments. The MGWR & D&SER alignments are very similar. They are unlikely to be widened and will always share the space with IC and outer suburban services. The GNR and GS&WR are or could be very similar if the GNR was widened to allow IC services to leave the DART in peace. There's only a few real pinch points that make quad tracking tricky. The GS&WR is mostly quad tracked to Hazelhatch already. DU wouldn't be comparable to Crossrail. It would require a relatively short tunnel to deliver huge benefits. The bang for our buck from DU was always way higher because it sweats existing assets as much as creating new ones. It would be a tragedy if it were never to appear.

Sam Russell

The Clongriffin to the airport was a good solution, but it would compete with the metro airport project. Clongriffin would complement the Interlink, or DU tunnel. Now both Metro and Dart serving the airport would make sense if they were already built. Instead we go three platforms at Clongriffin and no track to the airport.

The use of the Phoenix Park Tunnel was not favoured by Irish Rail because it would compete with Dart Underground and make DU too expensive in comparison. So we got the Phoenix Park Tunnel with a tiny service and no Dart Underground.

Metro had to be kept away from CIE for whatever reason, as did Luas. No metro yet but Luas has been kept away from CIE.

Oh what a complex web we weave when politics and vested interests get involved.

brianc89

I've been banging my head against a wall on the Dart+ forum regarding the DU. So I'm gonna move here and hopefully get more sympathy 😂

Regarding the Eastern tie-in at Docklands, I am suggesting that the proposed new Spencer Dock station for Dart+ makes future development of the DU highly unlikely.

The DU feasibility study says the following which lines up with my initial thoughts. My main argument is that it is highly unlikely that the new Spencer Dock station will ever be dug up once built.

The added complexity of the proposed DART+ West shallow station at Spencer Dock has not been considered on the understanding that it would need to be temporarily relocated during the construction of the DART+ Tunnel and, afterwards, be reinstated and integrated with the new underground heavy rail station.

murphaph

They could still connect the Northern line into the tunnel but nothing else. This would require a mined station south of the planned DART West one. In short, this planned station is going to seriously hobble DU.

If they absolutely must have temporary termination capacity then build a clone of the existing cheap and cheerful docklands station on the western side of the Spencer Dock site, leaving room to drop down into a future DU station on the other half of the site. Use the existing docklands station + clone to create your 4 terminal platforms. 2 original station platforms accessible only from the MGWR, the 2 cloned ones accessible from the GSWR also. Preferably the sheet piling should go in already to enable excavation for DU without major interruption to services at the clone station, should DU ever be built.

brianc89

How would they connect the Northern line? On the right hand side / to the north-east of proposed new platforms? Or further west?

I'm no engineer, but you'd imagine they could make it work. There is a lot of space to work with in that area.

What I'm hot happy about, is diving into building the new Spencer Dock station without fully considering how it'll impact construction of DU.

See my crude diagram. Would there be space on the west side for a TBM? One way or another, this would leave you with 3 lines crossing over to continue down DU or terminate at SD, which is far from ideal.

murphaph

I suppose with enough money thrown at it anything is possible but that's our money. I think it would be relatively trivial at this stage to build the new station as if DU was going to use it from day 1. It would be more expensive than what is currently planned but IMO significantly cheaper in the long run. Tens of if not low hundreds of millions cheaper. That's a lot of waste.

The idea of building a second docklands station that will be discarded in the event of DU just does not sit well with me at all. The original disposable Docklands station didn't sit well with me but this one is going to cost significantly more.

cgcsb

Is there a reason why we shouldn't have DART Underground going into tunnel at Heuston, a stop at Smithfield at the current hole in the ground near the luas stop. A stop at the O'Connell St Metro station /Carlton site and then emerge from tunnel at Fairview Park and join the northern line at Clontarf Road Station?

murphaph

I could certainly live with it. I could live with just about any east west alignment that connected up the DART lines, which is the primary goal. The major advantage of going under at Spencer Dock was the at least potential ability to run some DARTs from Maynooth through the tunnel but in reality I don't see a practical benefit to that option as many people would cut the corner by transferring to metro at Glasnevin and again at St. Stephen's Green (or in your case at O'Connell St. It would completely replicate the red line from Heuston to O'Connell St. of course. In some ways that could be a benefit as the red line along there is at capacity. Passengers could change to red line at Heuston, Smithfield or O'Connell for stops in between. A bit like local and express trains on some networks. Still leaves the south inner city with no rail but could open up options to extend the red line underground before it turns into James' and follow the canal roughly around to Charlemont.

Dublin is such a blank canvas it's hard to build an alignment that wouldn't be useful.

loyatemu

https://www.boards.ie/discussion/comment/119432270#Comment_119432270

that option is in the report linked in the OP. It doesn't score well.

cgcsb

https://www.boards.ie/discussion/comment/119432466#Comment_119432466

Thanks must have a read in detail

brianc89

A metro line along the full length of the Grand Canal I believe would be a fantastic solution.

Heuston West, Suir Road, Dolphins Barn, Harold's Cross, Rathmines, Charlemont, Mespil / Wilton Park, Grand Canal Dock, Ringsend, Irishtown.

This would interchange with Red Luas twice (Suir Road, Ringsend - assuming an extension from Point), Metro / Green Luas at Charlemont, Dart line twice (Heuston West, Grand Canal Dock).

You could avoid the Spencer Dock difficulty, as people could connect to Metro at Glasnevin or use the Red Luas to continue from SD to Irishtown.

Sam Russell

Even a Luas along the Grand Canal would be a good option.

Red line at Dolphins Barn to GCD, and allow branch at Charlemont to SSG, so there could be GCD to Broombridge, GCD to Tallaght, Tallaght to Charlemont and onto SSG, Parnell and Broombridge.

This would make a network that would allow a huge number of connections.

Dart Underground is still a good option for fast east west traffic.

L1011

https://www.boards.ie/discussion/comment/119432270#Comment_119432270

It wouldn't provide any connection to the Maynooth-Bray line that way. Also that hole in the ground is going to have something built on in Any Day Now (for the last decade). It is/was being used for site facilities for other developments.

cgcsb

https://www.boards.ie/discussion/comment/119437428#Comment_119437428

The opw owns it so doubt you'll ever see anything on it. There could be a new station somewhere around Croke Park or a 'Connolly North' could provide interchange between the two lines.

L1011

https://www.boards.ie/discussion/comment/119438059#Comment_119438059

It has a specific plan. New station to create interchange is sub-par to doing it at an existing one; albeit it is already being done at Glasnevin.

strassenwo!f

https://www.boards.ie/discussion/comment/119432270#Comment_119432270

One of the places that the original route for DU was selected to serve was Christchurch, and the much-trumpeted 'Digital Hub' in the vicinity.

Around 2005-8, no statement about DU was complete without a mention of how it would 'go via St. Stephen's Green to connect with the LUAS....and via Christchurch to serve the Digital Hub...'

How is that Hub doing?

murphaph

Ah now if it doesn't go through Christchurch there isn't a snowball's chance in hell of it going through College Green ;-)

Seriously what I like about the idea of simply running under the red line is that the red line is basically crap along there with all the junctions it has to negotiate. I've long thought that putting it underground would eventually be required but there's more than one way to skin a cat and the idea of using the interconnector as a direct underground replacement for red line north of the quays has a certain appeal as you can look at diverting the red line underground at Dolphin's Barn to run roughly along the grand canal to Charlemont, and then closing the few remaining gaps of on street running through cut and cover (longest section is Bluebell to Black Horse, remaining bits are all individual junctions - the red line actually runs off street/on its own alignment for much of its length but is let down by the on street bits). This could remain pre-metro or be upgraded to full metro.

I'd probably slightly adjust the proposal to swing into an underground station at Connolly before emerging onto the northern line. Then you interchange with the other DART and mainline rail and Luas and bus at one point.

strassenwo!f

Don't get me wrong - Christchurch and its environs always made eminent sense to me for an underground line across the city. The focus on the 'Digital Hub' was, to my mind, taking away from the natural regeneration possibilities that were and are there, in that part of the city, Digital Hub or not.

It is on a significant hill, and some of the plans for that area in, e.g., the DTO's 'Platform for Change' scheme, were mad - for example, the tramline along Bridge Street, where the proposed gradients would have been way beyond anything currently achieved. A funicular might perhaps have worked.

It will be interesting to see if the proposed Lucan LUAS can manage the gradients in that area. Underground through Christchurch, with an East-West line, always made sense to me as the best way to serve that area.

We shall see if the proposed Lucan LUAS - and we haven't heard much here about that in the last few years - can handle the gradients involved.

strassenwo!f

And, one good thing is that nobody is expending any effort suggesting that the DU project needs to be built via St.Stephen's Green.

That ship has sailed.

noelfirl

Right... that ship has sailed, despite the most recent commissioned report from Jacobs saying it should go via... St. Stephen's Green.

murphaph

If I had a choice I'd take the original plan via the south inner city but more or less any east west alignment would deliver. St. Stephen's Green, College Green, O'Connell Street. Tara would have been great as you'd have interchange to metro and the other DART but (and I'm sorry this is utterly pathetic) Irish Water says a large sewer would be in the way and difficult to relocate. Tragic stuff really. Can't they go above or below the sewer even if it is some immovable, irreplaceable jewel in the crown of sewers? A Crossrail engineer would find such an argument against Tara quite humourous I'm sure.