DART underground - options

jwwb · 07-08-2022 6:38pm

Been having a look at the document linked earlier. The study area (drawing 2-2 on pg14)seems to skirt around The Coombe Hospital in Dolphins Barn and Griffith College - I would have thought both would be big public transport destinations

D.L.R. · 08-08-2022 5:15pm

The Coombe and Griffith are not the city centre though, which kind of misses the point.

Heuston - City Centre - Northern line. That's it. Its not rocket science. And we have a solution. We've had a solution for 15 years.

The issue isn't the route, the issue is the Irish state's unwillingness to build it.

brianc89 · 09-08-2022 1:42pm

When DU was designed, it had two main purposes, if I'm correct, which was to improve East-West travel through the city centre and free up Connolly station to increase capacity on the Dart Coastal line.

The Phoenix Park tunnel and Dart+ has provided new East-West capacity and the new Spencer Dock will free up Connolly station. All Dart+ W and SW passengers will change to the Metro at Glasnevin or Green Luas at Spencer. Dart+ W also has Green Luas connection at Broombridge.

We also shouldn't forget Bus Connects which is costing $3B+. A huge goal of Bus Connects is frequent on-time services to maximize connectivity and increase capacity.

The two main arguments for DU have now been severely reduced. The solution that was designed 20years ago has to be re-examined, which will include the route.

murphaph · 09-08-2022 2:54pm

Personally I think the original route still stands up to scrutiny and is probably the best one but with Tara seemingly (and inexplicably for me) ruled out as an interchange with metrolink then it has to be the Green or (far less likely) O'Connell St. It would be completely unacceptable to build DU with no interchange to metrolink IMO.

DU as originally planned creates an X shaped DART network with Pearse the crossing point. DU must interchange with the other DART line as much as it must interchange with metrolink. Leaving either off would be massive folly.

The north of the quays "replicate the red line" idea has merit as the actual red line could go underground at Dolphin's Barn and ultimately be upgraded to pre-metro or metrolink some day with the on street section running just from Dolphin's Barn to Docklands and serving a local distributor function. In this case interchange with metrolink would be at O'Connell St. and interchange with overground DART would need to be in the vicinity of Connolly.

I think the proposed Spencer Dock station may so hobble the original DU plan that a radical redesign such as a north of the quays alignment is chosen. It seems largely like rolling dice because a long term plan does not exist. Every change of government brings a risk of cancellation or "review".

D.L.R. · 09-08-2022 4:27pm

Clueless country will never have a long term plan. It will continue to build piecemeal, small time measures upon small time measures, resulting in our garbled, messy network becoming a slightly larger garbled, messy network.

Look at Spencer Dock, perfect example. Nobody even mentioned that project until recently, now its a hot topic. Why? Because its cheap. Great way to avoid the big calls like DU or Metro. "Look at us building things".

Why would any sane person expect anything different from this state. Its track record speaks for itself.

gjim · 09-08-2022 10:53pm

I've yet to hear a reasonable alternative to Spencer Dock - except vague claims that "they should just do it properly". The problem is that no-one has managed to explain what "doing it properly" means which works from an engineering perspective.

Spencer Dock was always going to be required for DART+ - there's simply no way around it except to spend nearly a billion for an upgrade to Connolly which would become defunct when/if DU becomes operational. I don't see the relative "cheapness" of Spencer Dock as a problem - because long term, post DU - it will have a limited role. According to the Jacobs report, it's unlikely to support terminating more than 3 trains/hour from either DART S or DART SW post DU. Regardless it's going to be a great addition to the network for the decades before DU.

@murphaph - the Jacob report agrees with you and having evaluated all options recommends the 2014 plan (for which the RO was granted) with very minor changes as the preferred next step after DART+. I.e. the X-shaped DART network crossing at Pearse with ML integration at Stephen's Green.

murphaph · 09-08-2022 11:24pm

Here's a reasonable alternative to the planned 4 platform SD station then that involves building less than is currently planned...

Firstly, don't close the existing Docklands station as is currently planned. That gives you two terminating platforms in the Docklands straight away. Yes they can only be reached from the MGWR line but the junction at Glasnevin used to face the other way before about 1925, ie before the GSWR built the route through Drumcondra. Reinstate the junction at Glasnevin so that trains from the GSWR (DART SW) can reach the MGWR line again if needs be. Then you can terminate DART W and DART SW trains at the existing Docklands station, which provides half the termination capacity of SD and that station already exists!

Secondly, slim the proposed SD station down to a single island platform, half the width of the proposed station, a cheap clone of the existing Docklands station and keep it tight to the west side of the proposed SD site. This provides the other two termination platforms in the Docklands. That is all the capacity the proposed SD station would have. Almost no passengers would ever transfer from a terminating DART SW train to a departing DART W one or vice versa as these commuting patterns currently do not really exist, so it is not a penalty to terminate the trains in separate locations (like Kings Cross and St. Pancras in London).

Why do this? Because then you have the other eastern half of the site to run your TBM in, build your 2 platform DU station etc. all without disrupting DART+ services into the Docklands during DU construction.

AngryLips · 10-08-2022 6:40am

I just fail to see how a ten minute all-day frequency to Spencer Dock can be justified in the Dart+ project when the current Docklands station can't even justify services outside of peak periods - like where's the proof of concept?

brianc89 · 10-08-2022 10:53am

https://www.boards.ie/discussion/comment/119451962#Comment_119451962

https://www.boards.ie/discussion/comment/119452233#Comment_119452233

I think the trains need to terminate right next to the Luas stop otherwise the demand won't be there. I've done that walk from the current SD platform to the Luas and it's PAINFUL. You just get to the station and miss Luas. You end with a 15minute connection.

How about they kept the platforms for new SD tight in on the left and actually built two levels. One platform over the other.

This would keep the eastern side of the entire site, North and South of Sheriff Street, free for future use in DU.

Apologies for my crude diagram but hopefully it illustrates my suggestion.

murphaph · 10-08-2022 12:59pm

I'm more convinced than ever that the DART+ SD station is folly. Just expand the existing Docklands station to 4 platforms (western 2 for MGWR line as at present, eastern two for GSWR line from Drumcondra) and create a public right of way along the canal (if one does not exist already). Then relocate Spencer Dock Luas stop to the end of that footpath beside the bridge. That's no more than 3 minutes walk in a straight line. You could even put a nice glass roof over the path and stick a security guard on it so nobody gets wet in the rain or feels unsafe at night. Rename the Luas stop to "Docklands" or whatever to match the IE station and hey presto job done. There are significantly longer interchange walks in London in stations with the same name!

Leave the SD site completely vacant (better yet build the damn DU station box in full now and allow construction of offices above the station to get some serious rent flowing to go towards completing DU later) and don't hobble DU at all. And all for less money!

SD station is completely unnecessary at that precise location. In fact, isn't the fact it would have blocked DU at least partially why the existing Docklands station was built where it is??

brianc89 · 10-08-2022 1:58pm

https://www.boards.ie/discussion/comment/119453598#Comment_119453598

This is a fantastic idea. Love it. Move the Luas stop closer to the canal. Job DONE. Even cheaper than the current proposal.

murphaph · 10-08-2022 5:27pm

Aye and a Luas stop is little more than a raised kerb and a ticket machine! That is literally all you need to do to provide decent connectivity to Luas. Who on earth came up with the idea of plonking a flashy and disruptive (and temporary) station in there rather than working with the existing Docklands one which has lands to the east to add at least another 2 platforms, possibly more!

You would really have to wonder is the plan to intentionally hobble DU when you see what's going on here.

gjim · 10-08-2022 10:13pm

@murphaph - repeating this "hobble the DU" claim over and over doesn't make it true.

Just read the short section in the Jacob's report on the DU Docklands station. The DU Docklands station was always (even in the 2014 RO) planned to use mining - to get under the Luas and Mayor street - and to only use cut and cover construction on the North Wall Quay site. In the 2014 RO, there was going to be a shaft on the proposed Spencer Dock site, but the Jacob's report suggests that it's not required because of the proximity to the portal and recommends it should be removed from the plan in light of the planned DART+W station on the site.

And I don't see how your proposal is any better than the Spencer Dock one in terms of avoiding disruption. If you look at the eastern tie-in section of the Jacob's report, the area you are proposing to be used for new platforms would have to be levelled for DU construction - as it's needed for spoil management.

So in terms of wasting money your proposal is actually worse as the station you are proposing would have to be bulldozed for DU construction. At least with Spencer Dock station, the disruption caused by DU construction doesn't require the new station to be destroyed - it would just be cut off during the portal works. But afterwards there will be a working and useful terminal station still standing.

The existing Docklands station is nasty - and was only ever intended to be temporary. It's wind-swept and has poor access as it's surrounded on three sides by inaccessible industrial brown-field - mostly railway works but also an unused canal. In contrast, Spencer Dock has direct access from both Major St - the "high street" of the north docklands - and Sheriff St and is fully covered. It reflects the fact that we've a bit more ambition when it comes to station design and utility these days than we had in 2006.

murphaph · 10-08-2022 10:47pm

So to summarise, my plan can't work because spoil for DU absolutely must be heaped up at that location (and not say railed out promptly - a TBM isn't going to be removing more than a couple of train loads of spoil a day) and because Docklands station isn't as "nice" as SD would be?

gjim · 10-08-2022 11:33pm

Honestly I don't know what your plan is? You're all over the shop with ideas, suggestions and concerns. I thought you were arguing to build 4 deep terminal platforms under the old North Wall station site? You also seem to be arguing to build a completely different DU underground station (under the SD site) than the one which was planned (under the North Wall station site) - decades before it might be used? Your concerns flip and flop between the idea that SD will block construction of DU and that it won't but that DART+ S and SW services would be disrupted more during DU construction. Or that money is being wasted by building SD ? You suggest a temporary station north of Sherrif St would be superior even though current DU plans need that land for TBM and portal works. You seem to be redesigning DU as you go so I don't really know what to argue with - it's all a bit too fluid for me.

brianc89 · 11-08-2022 7:10am

https://www.boards.ie/discussion/comment/119456694#Comment_119456694

Okay now you genuinely are being rude and indignant.

You blatantly ignore real issues and unanswered questions which we have raised such as where exactly the new Spencer Dock station can be "temporarily relocated" during DU construction, if this happens.

You keep referring to this legendary Jacobs report which has one paragraph written about the "eastern tie-in". It omits any detail whatsoever about how this these two projects could ever work together. If I didn't know better, you might have written it.

And DON'T DARE tell us to offer real solutions and then pick them all apart as proof we are talking nonsense and rambling. We are trying to be constructive.

murphaph · 11-08-2022 8:01am

Yeah I'm out too. I made suggestion A and it was discounted for reason x. I then suggested B and it was discounted for reason y. I then made a final suggestion C and the only grounds gjim can find to discount that one are that a single paragraph in the Jacobs report suggests that spoil needs to be heaped exactly where the existing Docklands station is (necessitating its demolition) and that a new SD station would be nicer than the existing Docklands station. That's it. Those are gjim's arguments against adding two platforms to Docklands and leaving the SD site in peace.

I didn't stick with my original suggestion and doggedly defend it like some posters here. If that's "too fluid" then I'm sorry but I'm looking for a way to make sure DU isn't scrapped later because quite frankly there is no way any government will sanction the kind of suspension of services gjim suggests would be required to build DU after SD station becomes operational.

gjim · 11-08-2022 11:10pm

Yeah I'm kinda running out of energy for this argument also.

Regarding your suggestion C, I accept that it would probably be possible to change the DU construction plans so that such a new north-of-Sheriff-St station would not need to be demolished but I fail to see what problem such a station station solves. The line from Drumcondra enters the docklands in a gullet meters from the Northern line spur and right through the area required to build the portal so it doesn't matter where you locate the terminal platforms for this line, it will be inoperable during DU construction.

I sort of agree with one aspect of your suggestion C, in the sense that I think that the current Docklands Station should probably be kept in a shuttered state, even after Spencer Dock is built, in case it turns out to be possible to terminate canal line trains there during DU construction.

But I don't agree with the other part of your suggestion (build new temporary platforms north of Sheriff St) as it does nothing to avoid the disruption issue and at the same time we'd have DART+ W and SW users expected to use a poorly located "temporary" station for 20 odd years.

I don't get the opposition to Spencer Dock - it will be a modern, fully covered, 4 platform integrated station, in the heart of a high density area, providing dual access/entrances hundreds of metres apart, opening onto the "main street" of the north docklands. After spending 3 billion odd on the rest of DART+, it just seems the worst sort of penny pinching to expect users to use a cheap nasty "temporary" and poorly located platforms for 20 years or so.

CatInABox · 25-07-2023 3:58pm

Looks like we've got a direction for Dart Underground from the All Ireland Rail Report.

− A modified line linking Heuston and Drogheda. This consists of a new tunnel connecting Heuston and Spencer Dock via Temple Bar and Tara Street, four-tracking the northern line between Spencer Dock and Clongriffin, and a new line inland from Clongriffin to Drogheda. A spur to Dublin Airport from Clongriffin is included.

Temple Bar and Tara Street look to be the new desired stations, which is interesting.

All of this seems to be connected as well. I can't imagine Dart Underground going ahead without four tracking, or the new inland line, or the spur to the Airport.

bk · 25-07-2023 6:44pm

Reading the report today, I'm now certain that DART Underground is dead and gone!

They now instead want to build "Crossrail Dublin" which will be like the Crossrail line (Elizabeth Line) in London.

They only mention the tunnel taking Intercity and long distance commuter trains, no mention of DART in the tunnel at all!

So that is that, DART Underground is gone.

I guess they plan instead for DART to continue to use the PPT, while they build this Crossrail tunnel for intercity instead.

I think it is a terrible idea as I don't see this Crossrail tunnel happening in any of our lifetimes. Dart Underground might have been justified, but this just doesn't make sense and even in their report it has a pretty poor cost benefit ratio!

EDIT: They call is "cross-Dublin Tunnel" rather then Crossrail.

CatInABox · 25-07-2023 7:48pm

Yes, it's honestly bizarre. I wonder what the passenger projections would be for each option, a Dart tunnel Vs a commuter tunnel.

Personally, I just don't think a cost benefit ratio for any tunnel will work anymore.

cgcsb · 25-07-2023 9:59pm

Spur to the airport seems silly when you're building from scratch and can easily have it as a through station

donaghs · 26-07-2023 12:03pm

As someone who commuted on DART from Kilbarrack to town for a few years, I wouldn’t fancy getting to airport on DART from town to Clongriffin, and then switching to another train to the airport.

It would just take too long. And you’d want to leave a LOT of extra time also for all those unknown eventualities (train breakdown at station ahead, scumbags fighting and guards called, etc).

Geuze · 26-07-2023 12:25pm

I admit that I have not read all the posts here.

I also admit that I don't know all the sewer/geology constraints.

However, I still make some key points that I feel strongly about:

(1) Dublin airport should have a station on the intercity network (which should be close to / linked to the metro station)

(2) Dublin airport should preferably be a through station on the intercity line to Belfast, not a stub terminus

(3) I suggest that all IC and regional trains from Belfast/Dundalk/Drogheda stop at the airport

(4) the line should leave the existing line somwhere south of Drogheda or south of Balbriggan, it should be 4-track electrified

(5) there should be a station in Swords (as well as the metro station)

(6) the existing line through Malahide becomes DART-only

Where the line should go south of the airport, I am less sure about, however, I make the following points:

(7) Under SSG jumps out to me as a good place for a through IC station: it is central, plus access for construction equipment is not too bad

(8) Trains from Cork/LK/WD/GY should be able to go to the airport, so there should be a link from the existing southwest line to the new airport line.

I realise something I have not mentioned is the issue of 1500 V DC versus 25kV AC, I will leave that to the experts.

Pete_Cavan · 28-07-2023 8:35pm

The AIRR is just a report which looked at options for a potential future rail network but crucially the commuter network in cities is apparently outside its scope. That means it won't have considered that any future tunnel under Dublin would likely be exclusively for DARTs.

I assume the mention of "via Temple Bar" because someone thought it would be good for tourists rather than technical analysis. It seems most of the report is written from the pov of "wouldn't it be great if...".

The report really has no bearing on a future DART tunnel which will be the subject of much stricter analysis with a very different scope.

Paul2019 · 29-07-2023 9:41am

"The report really has no bearing on a future DART tunnel which will be the subject of much stricter analysis with a very different scope."

Indeed, a future DART tunnel taking in Temple Bar and Tara St would have a west to east alignment. The next stop, Spencer Dock, would need a very hard left turn to create a south to north alignment.

Not sure how or even if that could be pulled off.

bk · 29-07-2023 1:26pm

The inclusion of this cross rail Dublin tunnel in the report really throws the whole idea of DU up in the air and I feel makes it much less likely to happen.

There are now two competing ideas for an East - West Tunnel.

So what are we going to end up with now from the following:

1) Original DART Underground, two tracks, DARTs only. The cheapest and simplest option

2) Crossrail Dublin, 2 tracks, only intercity and long distance commuter in the tunnel, no DARTs, they stay in the PPT. Will be more expensive as you need much bigger stations for intercity trains. I’d guess it would have a poor CBA

3) Crappy option, two tracks and trying to mix DART, long distance commuter rail and intercity into the same two tracks. Repeats the mistakes of current DART line mixing different types of services on one line. Will be more expensive then option 1 or 2. I’d guess it would be extremely simplified to just one underground station at Stephen’s Green or similar.

4) DU + Crossrail. 4 tracks somehow (2 or 4 tunnels), separated 2 tracks for DART’s + 2 tracks for intercity. Obviously by far the most expensive option, but at least it separates services. CBA might be very poor.

I don’t know, non of them seem likely. Maybe they are thinking of going for option 3, because while crappy, it might have the best CBA.

Im not saying we won’t get something, but looks less likely now before 2050 then ever unfortunately.

gjim · 29-07-2023 6:40pm

I'm confused by the crossrail analogy - inter-city trains don't travel through the crossrail tunnels as far as I know? The Elizabeth line has dedicated rolling stock and runs an S-Bahn/DART/RER/etc. style service.

Tunnels through city centres are incredibly expensive. So unless you're going to carrying tens of thousands of passenger peak per hour per direction, the CBA hasn't a chance - that's why intercity rail "interconnector" projects are rare across Europe - nearly all the interconnectors around Europe built in the last few decades are used exclusively for S-Bahn/DART/commuter (in the general sense) type high-frequency services.

Considering digging tunnels under Dublin for Irish inter-city traffic is crazy talk. About 3000 a day use the enterprise to get to Dublin, how many of this share would be interested in continuing on to Cork - 10% - optimistically? How about prioritising the 25,000 per HOUR (not per day) peak DART passengers if there's money to be spent on bringing heavy rail tracks through tunnels under the city?

Any tunnels (after ML) under the streets of central Dublin had better be either for metros or if heavy-rail, for DARTs.

Pete_Cavan · 29-07-2023 8:17pm

https://www.boards.ie/discussion/comment/120911938#Comment_120911938

There aren't really two competing ideas for an East - West Tunnel. There is one idea which previously advanced as far as Railway Order stage and a version of the idea still appeas in official strategies, the other is a paragraph in a report which also proposes creating a rail line between Portadown and Mullingar to serve a couple of smallish towns. There is only one idea.

bk · 30-07-2023 2:19pm

https://www.boards.ie/discussion/comment/120913470#Comment_120913470

I agree with what you are saying, but it is an official report, a strategic Rail review commissioned by two governments. And the tunnel stuff isn’t just one paragraph, it is mentioned multiple times and seems to have been priced out and modelled as part of the review.

Of course, we all know that non of that means it will actually happen, but it does seem to be an idea that is floating around Irish Rail and government departments. It wouldn’t have been included if some high ups in IR didn’t support the idea. I’m interested in what they are thinking.

“I'm confused by the crossrail analogy - inter-city trains don't travel through the crossrail tunnels as far as I know? The Elizabeth line has dedicated rolling stock and runs an S-Bahn/DART/RER/etc. style service.”

You are right, no intercity trains, though it is more a commuter type train than DART, though obviously the difference is blurry, DART+ seems to be moving away from the original DART design itself to a more commuter type service, at least on the new lines.

Having said that the ICR’s aren’t all that different from the class 345, other than seating arrangements. The report also mentions long distance commuter trains in the tunnel and that would be closer to Crossrail.

I think they were inspired by Crossrail, but obviously we don’t have enough long distance commuter trains to justify a CBA for a tunnel like that, so they want to add the intercity in too to improve the CBA. So Option 2 above, no dart (they stay in the PPT), just intercity + long distance commuter in a new tunnel.

So yes, I’ll stop calling it Crossrail Dublin, as it doesn’t perfectly match, they call it the “Cross Dublin Tunnel”

DART underground - options

Comments