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Metrolink south of Charlemont



  • Registered Users Posts: 987 ✭✭✭gjim

    How would that work? Unless they've already decided on and designed the upgrade, there certainly will be more tunnelling required.

    The options include everything from a connection north of Dunville to somewhere around Alex. There is no way to tunnell in advance of picking one of the options.

    To be clear, I'm not talking about stupid stuff like veering off toward UCD or Terenure - just the options to upgrade the Green line.

    The "feck it just build what they'll let us go ahead with" response feels like desperation and worse I completely understand it. "Let's not think about the hard problem we're creating for the future because even drawing attention to it may jeopardise the bit we can probably get support to build."

    On the other hand, it's disappointing to have such an immature approach to infrastructure development even if it is understandable given how starved of funding rail based PT has been historically.

    Even if you're not going to do the entire Sandford to Swords line in one go, surely you should actually have a plan on how you are going to do it so that the bit you do first will fit into the overall plan.

    I find the idea that once the north of Charlemont section is done, the rest of the upgrade will just happen as a matter of course almost naively optimistic.

    To the extend that I'm will to bet - using one of those "long bet" escrow sites - anything to a thousand hard earned euro that there will still be trams running south of Charlemont 10 years after the northern section of ML starts operations.

    This will not be a cheap or easy upgrade - in fact the cost could be astronomical. A TBM will have to be employed to construct a few KM of tunnels, a significant amount of CPOing will be required and maybe even one or two stations have to be expensively mined. The disruption will be horrendous. This is why I'd favour stopping at SSG until there is a realistic plan for the rest of the upgrade. The current approach is ostrich head in the sand stuff.

  • Registered Users Posts: 6,147 ✭✭✭Pete_Cavan

    We don't even know how or where the tunnel will end. Options for connecting to the Green Line were considered and there was a basic plan at an earlier stage which was since dropped, it's possible that or other options remain. Further tunnelling isn't guaranteed and is unlikely to avoid the huge disruption in trying-in to the Green Line.

    If trams are still running south of Charlemont 10 years after the northern section of ML starts operations that will likely be because of refusal to accept the disruption (again). The engineers likely have a basic plan for later tying in to the Green Line even if they aren't made public.

  • Registered Users Posts: 987 ✭✭✭gjim

    I guess I'd like to see the earlier option of a north of the canal/peter place link up (involving some cut n' cover on Earlsford terrace) remaining a possibility as I feel it's one of the few cost-effective options left. This option was included before the sewer issue became know but was dropped in favour of the just-south-of-Charlemont option in that evaluation. When the latter was found to be impossible due to the sewer, the former doesn't seem to have been reconsidered. But tunnelling to an underground station in Charlemont effectively precludes any option except continuing to tunnel at least to Dunville if not almost to Milltown.

  • Registered Users Posts: 6,147 ✭✭✭Pete_Cavan

    Cut n' cover on Earlsford terrace and up through Peter Place is not an option because of the big old church sitting in between, that's why it wasn't reconsidered.

  • Registered Users Posts: 987 ✭✭✭gjim

    The original plan was not to go through the church but through the housing just west of it. But I think we went through this before - I know you prefer CPOing and a portal near Dunville Av.

    The reason the just-past-the-canal link-up (scuppered by the sewer discovery) was preferred initially was because of concerns about disruption on Earlsford Terrace. There was a large commercial block between Dartmouth Road and the canal that would have provided a perfect location for handling the construction of a portal with minimal disruption to traffic or business had the sewer not been there.

    The Peter Place option was ruled inferior at the time because the works would have to occur on a public street - Earlsford Terrace. No other technical obstacles were identified at the time - although the fact that they didn't know about the canal sewer at the time suggests the evaluation was fairly shallow.

    To be honest, I'm not convinced it's the best option. But I would like to see it re-evaluated in light of how much more engineering studies have been done since the first evaluation.

    We're building the northern section without having planned the southern section upgrade. I'd like to know what they have in mind as honestly terminating a newly constructed metro line in the city centre these days seems daft. But I fear that's what we'll be left with for a generation or more. It took 13 years for the original Green line to be extended through the centre of the city.

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  • Moderators, Computer Games Moderators, Recreation & Hobbies Moderators Posts: 9,824 Mod ✭✭✭✭CatInABox

    By the time Metrolink is built, the Greenline will have gone through it's final upgrade. This upgrade will require the closure of all of the road crossings, which will remove most, if not all, the issues surrounding the Metro upgrade.

    Huge question marks over whether the Green line upgrade will buy the time require to do the Metro upgrade, but then I suspect that the NTA knows this too, and are being slightly sly with the projects. They know that images of overcrowded Luas trams are basically the only thing that will get most politicians to care.

  • Registered Users Posts: 6,147 ✭✭✭Pete_Cavan

    There is no way you could cut n cover a tunnel down Earlsford Ter, keeping buildings each side, and then swing to avoid that church. That sort of curvature wouldn't work. In any case, the buildings west of the church can't be demolished either. If tunnelling there, if the tunnel is deep enough to avoid undermining the buildings on Adelaide Rd, the incline to get up to the bridge to cross the canal would be way too steep. There are several good reasons why the engineers went away from surfacing north of the canal.

  • Registered Users Posts: 987 ✭✭✭gjim

    Your claims are at odd with the engineering report - none of these objections were raised as issues.

    The Peter Place link-up made it through to a short-list of feasible options but it failed in comparison with locating the portal south of Charlemont on the grounds of increased disruption and a more difficult works environment.

  • Registered Users Posts: 6,147 ✭✭✭Pete_Cavan

    None of thos objections were raised because it simply wasn't possible to construct the portal in that way, which is what I said!

    Look at Section 5.3 here;

    Both Option 2(A) and 2(B) required the demolition of the church, a large retained cut on Earlsfort Ter. plus a ramp over or through Adelaide Rd. It simply ins't possible to get under the church and back up to cross the canal. It also wasn't possible to swerve around the church.

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  • Registered Users Posts: 987 ✭✭✭gjim

    I'm not talking about any of the options 2?

    It's option 3(C) on page 43:

    "From the north, NMN tunnels will be bored to Earlsfort Terrace, at a suitable location between the Conrad Hotel/NCH and Hatch Street junction, where the road is approximately 22m wide. The tunnel portal and TBM receiving shaft will be formed in cut and cover within the public road space, with limited impact on surrounding buildings. During construction, the road will be closed to traffic in both directions and the footpaths will have to be temporarily accommodated within the NCH grounds.

    The tracks will then rise in a cut and cover section beneath the Earlsfort Terrace, Hatch Street and Adelaide Road junctions, to then rise in open retained cut, immediately south of Adelaide Road, on the west side of the Adelaide Road Presbyterian Church, tying in to the existing Luas Green Line ramp, immediately north of Charlemont Stop."

    They explicitly state the church would be avoided. The curvature is not an issue as you can see from the technical drawings.

  • Registered Users Posts: 1,512 ✭✭✭strassenwo!f

    There are a number of possible problems with option 3(C) on page 43.

    Firstly, it appears likely that it would involve acquisition of a number of properties in or around Peter Place, and possibly on Adelaide Road itself (in order to provide at least some gap between the track and the church, as this option would certainly impinge on church grounds without that).

    Secondly, the gradients involved seem to be quite high: a potential metro would have to have its track base about around 5 metres below the road surface on the south side of Adelaide Road - in order to get under the road - before it starts its climb up to Charlemont. (overhead wires, ceiling, road surface). The LUAS can do the Adelaide Road-Charlemont bit quite readily, but it is starting from 0 metres; this option would be starting from around -5 metres, and with a shorter distance to cover.

    Thirdly, it isn't easy to see how this would connect with the LUAS Green in the neighbourhood of Charlemont. Since a metro wouldn't involve an increase in speed between Sandyford and Charlemont, and there would seem to be no way that the LUAS and the metro could both serve the current overground Charlemont stop, this option would make current journeys to/from, say, the Harcourt Centre, slower than they are, as people would have to get out at Charlemont and walk the rest of the way.

    With option 3(C), you would then have no integration with the LUAS around Charlemont and you would basically have to end LUAS passenger services on the expensively built Harcourt Street - Charlemont section, and find some other way to turn those Green line trams around.

  • Moderators, Science, Health & Environment Moderators Posts: 18,544 Mod ✭✭✭✭Sam Russell

    There does not need t be integration at Charlemont. It can occur at SSG. The Green Line could continue down Adelaide Road.

  • Registered Users Posts: 1,512 ✭✭✭strassenwo!f

    Sam, could you clarify what you mean by "the Green Line could continue down Adelaide Road"? (At present, it spends about 150 metres of its journey on Adelaide Road).

    At the moment, the plan is that the Metrolink station on St. Stephen's Green will be on the East side of the Green. The LUAS Green line is on the West. Metro-LUAS integration could not, realistically, be claimed at St. Stephen's Green under that arrangement.

    As I said in my previous post, there doesn't seem to be any way for plausible integration of the LUAS with any overground metro station at Charlemont, even if such an arrangement could be built (with the gradient issues and potential cost of property purchases, etc.).

    Suggesting 'integration' in either of those cases would be even more ludicrous than suggesting that there is 'integration' between the proposed Metrolink and the LUAS Red line in the vicinity of O'Connell Street. At at least a 300 metre gap, as the metrolink plans presently stand, one would have hoped that the planners could have made it better - even if it were to cost a bit more, given that the Red Line carries so many people. More than the DART, I understand.

    But, at least as far as I know, we have so far been thankfully spared anybody telling us that the Red Line and the Metrolink are 'integrated'.

  • Registered Users Posts: 987 ✭✭✭gjim

    What Sam means, I'm guessing, is that there would be a natural (future) extension of the on-street tram system (the green Luas) along Adelaide road - maybe to a terminus in Irishtown or somewhere like that. The 3C option described a turn-back facility just around the corner from the Harcourt St stop on Adelaide Road with a configuration similar to the old SSG stop. Integration between metro and the Green Luas would be provided at SSG.

    Linking ML to the southern section south of Cowper is going to leave us with a Green line tram terminus in a quiet suburban cul-de-sac with no scope for further extension and little scope in the immediate vicinity for densification.

    It will also mean no metro stop between Charlemont and the portal between Cowper and Milltown - maybe a 2km gap, while linking at Peter Place means Ranelagh, Beechwood and Cowper will all have metro stops.

  • Moderators, Science, Health & Environment Moderators Posts: 18,544 Mod ✭✭✭✭Sam Russell


    GL along Adelaide Rd to GCD. - eventually. After that, well I think few of us will see that. I would run the Luas along the SC to join the Red Line at Dolphins Barn.

    Look at how long the Dart expansion has taken - and not even started yet Forty years since the two coach Dart from Howth to Bray, and now goes to Greystones and Malahide = not much after 40 years.

    Connecting to Charlemont would best take place north of the canal, however that can be done. Maybe keep it on stilts to get closer to SSG. Cost is irrelevant, as we can afford the most expensive (children's) hospital in the world.

  • Registered Users Posts: 6,147 ✭✭✭Pete_Cavan

    And immediately after that in the Conclusions it says;

    Option 3(C) delivers a potentially feasible alternative alignment for Stage 1 – Option 3. There are however significant environmental and logistical challenges associated with constructing a TBM receiving shaft and cut and cover section on Earlsfort Terrace. There are also significant technical challenges to be overcome in terms of the design and construction of a cut and cover tunnel section on Earlsfort Terrace and in particular the close proximity of the alignment to Adelaide Road Presbyterian Church and several buildings with basements and lightwells on the northwest corner of the Adelaide Road/Earlsfort Terrace junction. Given the extent of technical difficulties and significant environmental challenges associated with Option 3(C), this option is not brought forward for detailed appraisal. 

    It merely considered that option to be "potentially feasible" but that it had "significant environmental and logistical challenges" which were considered so great that the option was then discounted.

    I don't think it goes into the level of detail to say that the church can definitely be avoided or that the curvature or gradient would not be issues, rather that if they are possible, the level of difficulty would be so great that it just isn't practical.

  • Registered Users Posts: 987 ✭✭✭gjim

    I completely understand why at the time, there would seem to be little need or appetite to explore the 3C option any further given at the time it was believed that option 4B was feasible.

    The 4B option: bringing the TBM out of the ground just south of the canal, in a block of commercial/light industrial land with plenty of room for machinery and the associated works for building a ramp up to GL track level would have looked like a complete winner to me also. Why waste time looking in detail at constructing a portal just 250m away in Peter Place with all the associated on-street disruption and cut n' cover messiness?

    3C is clearly a loser compared to 4B but it's not clear to me, nor was it in the conclusions of that document that it was a clear loser to options involving running the TBM south of beechwood given both those options scored worse than all the others overall.

  • Moderators, Science, Health & Environment Moderators Posts: 18,544 Mod ✭✭✭✭Sam Russell

    They need to start building it, and sort out south of SSG while the TBMs work their way south.

  • Registered Users Posts: 206 ✭✭specialbyte

    One thing that is worth remembering about the original green line tie-in report is that it was done assuming the metro would be twin bored tunnels. The preferred option is now for a single bored tunnel. Single bored tunnels have a larger diameter. General rule of thumb for bored tunnel construction is that you want at least one tunnel diameter of earth above you to reduce the likelihood of tunnel collapse. There's obviously a huge number of factors at play but it's a solid rule of thumb. Single bored tunnels can tend to have longer transitions from below ground to above ground as a result. That might make some of the options north of Charlemont impossible.

    Effectively that original green line tie-in report is out of date on many design parameters. So while it might be useful / interesting to look at, it shouldn't be interrogated on all details.

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  • Registered Users Posts: 6,147 ✭✭✭Pete_Cavan

    The report then was fairly high level. The fact that Option 4(B) was identified as the preferred option and the sewer issue then came to light which meant that wasn't possible shows that no option should automatically be considered possible. 4(B) was considered impractical at best and possibly would have been found to be impossible with further assessment. I don't think it solves any problems, likely only creating more.

  • Registered Users Posts: 987 ✭✭✭gjim

    I agree - yes the report was quite superficial. Which is why I'd like them to have done a more detailed study, once the 4B option was found to be impractical/impossible. Obviously without delaying the rest of the project - going ahead (as fast as possible) with the rest (north of SSG).

    You might be right - on-street cut n' cover - might have turned out not to have been possible - given a huge sewer was overlooked for the 4B option.

    But I think that joining north of the canal solves a number of important problems.

    The most important is that it will allow metro stations at Charlemont, Ranelagh, Beechwood and even Cowper at relatively little cost and with minimal disruption. This option scored the highest on the accessibility category in that document because of this. The cost of providing stations underground at these locations would be astronomical.

    Secondly, it terminates the on-street Green line in a location - Harcourt St./Adelaide Rd. - which offers good scope for obvious future extension, whether southwest (say towards Terenure) or east/sout east (toward GCD or Irishtown or UCD) instead of having a tram terminus at the end of a cul-de-sac in a quiet mature low-density inner suburb with nowhere to go.

  • Moderators, Science, Health & Environment Moderators Posts: 18,544 Mod ✭✭✭✭Sam Russell

    That is a good summary of my thoughts.

    The Charlemont bridge/station structure could continue north as an elevated line until the possible transition to underground could be achieved.

    As for the Green Line, I think the line should continue east towards GCD. The GCD extension could be continued west, past Harcourt onto the South Circular as far as Dolphins Barn, which would allow trams to go GCD to the Red Line and go towards Tallaght or north towards Connolly or The Point, but also network with the Green Line. We would then have a comprehensive tram network allowing orbital travel avoiding the City Centre if required.

  • Registered Users Posts: 2,545 ✭✭✭AngryLips

    I dunno about this suggestion, but you raise a good point insofar as once Metrolink is built, we're going to be left with a green line that travels no further south than Harcourt or Charlemont - there's no way that a line as short as Broombridge-Charlemont should be allowed to terminate so close to the city centre. They should at least extend it, even by a short distance to serve Rathmines or Harold's Cross ...and because it's just a Luas line, it's not going to break the bank to do that.

  • Registered Users Posts: 93 ✭✭densification

    I don't really see the point in extending it 1-2km to Rathmines or Harolds Cross. How does that fit into the transport network for the city? It's not nearly long enough to replace a BusConnects spine, doesn't unlock new TOD, and both areas are a short cycle or walk from the South City centre. If you extended it 2km South West, people 5-10km south west would also want it extended there.

    A connection to GCD enhances the PT network but duplicates the O bus route.

  • Registered Users Posts: 6,147 ✭✭✭Pete_Cavan

    Joining the Green Line north of the canal would solve a number of important problems but one major problem would remain - Dunville Ave. Metro can't have a Level Crossing, there is huge opposition to severing the street, an overbridge would be fought by the residents and going under wouldn't be an option.

    This predicament has been set in stone since the decision was made for Luas to cross Dunville Ave at grade. From Dublin Commuter Coalition a few months ago, there seems to be a plan now for Metro to be extended under Dunville Ave. This fits nicely with it emerging from the tunnel north of there, therefore being low enough to go under.

    While there are benefits to surfacing north of the canal, ending the tunnel south of Charlemont allows for tying in to the Green Line without further tunnelling, which I think is the most realistic way of Metrolink being extended south.

  • Registered Users Posts: 6,147 ✭✭✭Pete_Cavan

    On the future Green Line, it should continue east towards GCD and on to the Glass Bottle Site at Poolbeg. I know there is a basic plan to extend the Red Line from The Point over to there but that would require an extremely expensive opening bridge at the widest end of the Liffey.

  • Registered Users Posts: 994 ✭✭✭Viscount Aggro

    The site planned for metro station at Charlemont, its being built on currently. I'm surprised by this.

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  • Moderators, Science, Health & Environment Moderators Posts: 18,544 Mod ✭✭✭✭Sam Russell

    I doubt that Dunville Ave will be an issue that will kill the Metrolink project. They may complain vociferously, but that would be all.

    St Raephaella's Road is another project that needs sorting, but that could be done now if they wanted.