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Luas Tunnels?

  • 06-11-2024 10:10PM
    #1
    Registered Users, Registered Users 2 Posts: 170 ✭✭


    I was just thinking about the Luas network and it’s inevitable exponential expansion over the coming years, and with all the spinal trunk routes (orbital routes aside) that will be converging on, and likely running through and out the far side of, the city centre, there will be a lot of potential grade crossings on what will be high capacity, high frequency lines. As it is, the single crossing of the Green and Red lines in the O’Connell Street area is a big problem and trams are regularly left waiting to cross. And trams crossing other trams isn’t the only problem, with the roll-out of Bus Connects over the next few years, there are going to be heavy and frequent bus corridors in and out of the city centre which the equally if not more frequent Luas lines will need to cross, and doing so at-grade is asking for trouble.

    I am wondering therefore if grade-separated Luas crossings would be possible in certain places in the city centre. Where lines cross, one of them could be dropped so as to dip under the other and avoid a grade crossing entirely. For example, the Red Line could be sunk outside the Oval Bar so as to cross under O’Connell Street and the Green Line. This would be the perfect opportunity to create a far better interchange between the two lines here, with the "underground" nature of the stop providing opportunity for a direct underground pathway link between Marlborough, O'Connell GPO, and Abbey for a more direct Red and Green Line and Metro connection. This area of below street-level Luas between the two Green Line branches which currently houses Abbey Street stop could also be covered over and regenerated as an urban park.

    Another example of where this could be used in the tangible future is with Luas Lucan/South City. If a route through the Liberties and down Cork Street/Kevin Street is used, then the new line could dive under the Green Line at Stephens Green to avoid a grade crossing and allow the line to continue running towards Irishtown/Ringsend (although it could also turn left upwards to run aloneside the Green Line with two new terminating platforms being built for the line at the existing Stephens Green stop, though I think through running would be preferable… we should've leaned our lesson with terminating light rail in the city centre at this stage…)

    However if a Christchurch/Dame Street route is used (much preferable operationally in my opinion) then a larger dive-under could be built as part of the College Green pedestrianised plaza revamp, with a cut and cover station linking with the Green Line, before continuing under College Street and emerging out on Pearse Street or, preferably Townsend Street to link with DART and Metro at Tara.

    This is not something uncommon either, many German cities with intertwining tram networks, like Karlsrühe, Gelsenkirchen, Essen, and many many more have tram lines that go underground for compete sections of city centre running, so small dive-unders to avoid grade crossings shouldn’t be a hard task in any way. I do believe however that College Green is a perfect candidate for a short through-running tunnel beneath the plaza, under College Street and onto Townsend Street where it would rise back out of the tunnel to run on-street past Tara (Metro and DART interchange) and onwards to Ringsend/Poolbeg.

    Looking at similar tram tunnels, a run of only about 75 metres is required to drop below street level, so the rise back up to Townsend Street should be done after the junction with Luke Street, avoiding Tara Street - a heavy bus corridor, allowing for further grade-separation (and therefore value for money) - and keeping the road outside of the fire station clear. This has the added benefit of having the tram line pass beneath the DART bridge at Tara while still on its incline, meaning more headroom for the tall catenary wires beneath the bridge. A Tara Street link station could then be built either at the junction with Moss Street or cut and cover before the incline allowing a better connection to the DART and ML station and the new Plaza being built here.

    Just a few thoughts, and I'm wondering how realistic and feasible a plan it is... Definitely grade-separating the line crossings seems like an easy win but I know that a College Green tunnel, while still very much a win, is a lot less easy... Any thoughts on this at all?



Comments

  • Registered Users, Registered Users 2 Posts: 14,111 ✭✭✭✭Zebra3


    I think most here would support the end result.

    But cost, planning, delays, construction period, opposition, etc, all these things can’t happen in a short period.



  • Registered Users, Registered Users 2 Posts: 4,382 ✭✭✭goingnowhere


    Was looked in the late 1990's before Luas was built and seems to be accepted as the right thing to do but wasn't done

    Something like the German Stadtbahn system with the trams undergound in the core city area and on surface elsewhere, works super good in Dusseldorf, Duisburg, Koln, Essen etc

    Too late now, focus on getting Metro and DART underground built which would help a lot in reducing on street traffic in the city centre



  • Registered Users, Registered Users 2 Posts: 151 ✭✭knockoutned


    Prior to the extension from Connolly to the Port, we had a perfect setup of four rail terminals, located just outside the core city centre on the North, South, East and West side of the city that should have been used as the point where the Luas went underground. So from Broadstone to Harcourt, and Heuston to Connolly. This is what they have in Newcastle! Complete the DART underground to circle around these stations and along with the Metro North, you would have had gone a long way to sorting out the traffic issues in the city, instead of adding to them!

    I really hope when they start Metro North, they keep the boring machines on the island so that once that work is completed, they can redo the city centre section of the tracks properly, in addition to going to Cork, Limerick and Galway. The Port tunnel works, why can we not have more.



  • Registered Users, Registered Users 2 Posts: 1,192 ✭✭✭riddlinrussell


    Luas as it stands is never going to be a deep bore job. I reckon if done as 'small' jobs you could work your way along the red line core stubbing off all minor road crossings and handling the major ones piecemeal, obviously bigger job would be the crossover at O Connell.



  • Registered Users, Registered Users 2 Posts: 18,991 ✭✭✭✭murphaph


    Red Line is absolutely crying out to be upgraded to cut and cover pre-metro. It's a no-brainer but I doubt it would happen due to the disruption. It was hard enough to get it built at street level. That was the time to go cut and cover from Heuston to Connolly really. The disruption was severe due to all the diversion works anway.



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  • Registered Users, Registered Users 2 Posts: 170 ✭✭OisinCooke


    How long would it take roughly to sink Museum - Busáras/Georges Dock? Theoretically the Connolly spur could be cut out with an “underground” station at Busáras using an underground passage connecting to outside Connolly avoiding the busy and dangerous pedestrian crossing at Amiens Street. It would be fantastic to have done but I presume the full Red Line closure would be in excess of a year… Likely something that’ll only be even considered when DART Tunnel and Lucan - South City/Ringsend are complete…



  • Registered Users, Registered Users 2 Posts: 14,111 ✭✭✭✭Zebra3


    Far too much other stuff to do first.



  • Registered Users, Registered Users 2 Posts: 18,991 ✭✭✭✭murphaph


    It would take a lot longer than a year to put the Red Line in a cut and cover trench from Museum to Connolly. The Red Line is sadly really hamstrung by this section and to a lesser extent between Heuston and James'. Once you get out past James' you're on a largely segregated alignment or one that could be largely fully segregated bit by bit for modest sums. A flyover here, an underpass there. It's exactly the reason so many European cities undergrounded their core tram routes but they had denser networks and could probaly live with some disruption. It would be very difficult to shut the Red Line from Heuston for a prolonged period of time unless DART Underground was in place to offer an alternative East-West corridor. If the Red Line is to go pre-metro without DART Underground it would need to be on a parallel alignment that allowed the current Red Line to remain open. Of course if DART Underground is ever built there will be claims that putting the Red Line underground is superfluous. I would contest that if DART Underground was built as originally planned but if it is built close to the Liffey then it would be really difficult to justify a parallel tram tunnel when people could just change from Red Line to DART at Heuston.

    If DART Underground is built then I would foresee the grade separation and segregation of the section from Heuston to Tallaght as the priority really. Get people in from the suburbs to Heuston as speedily as possible and allow them to change there. We may never need to put the Red Line underground if we can build the other things that allow us to effectively ban the private car from the city centre anyway and that's the other way to solve the issue of conflicts. As an alternative to fixing the Red Line between Heuston and James', just build a branch off the Red Line at Kylemore and take it up to the railway and build an interchange station there. You'd be in town way faster coming in from Tallaght if you changed at Kylemore onto a DART.

    All pie in the sky for now of course.



  • Moderators, Science, Health & Environment Moderators Posts: 20,378 Mod ✭✭✭✭Sam Russell


    Why not divert the Red Line down High St - Lord Edward ST College Green - Rings End?

    It would allow the Museum to Abbey to be tunnelled by taking pressure off the route.



  • Registered Users, Registered Users 2 Posts: 12,138 ✭✭✭✭tom1ie


    Grade separate:

    Belgrade road

    Naas road

    Walkinstown avenue


    and you knock a few mins of total journey times into cc and improve road traffic flow on these main arterial routes.
    Not grade separating these junctions was insane.



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  • Registered Users, Registered Users 2 Posts: 870 ✭✭✭csirl


    The Belgard Road Luas crossing is a complete mess at busy times. There should be a overpass........like those already in place on the Green line in Leopardstown and Cherrywood. Funny how the more affluent areas seem to get these things.



  • Moderators, Science, Health & Environment Moderators Posts: 20,378 Mod ✭✭✭✭Sam Russell


    Those were constructed after the Red Line was built. Perhaps lessons learnt.



  • Registered Users, Registered Users 2 Posts: 170 ✭✭OisinCooke


    Currently one of two options being considered for Luas Lucan, and even when that’s open, it could prove very helpful to divert Red Line trams onto while the current alignment was sunk sub-surface. However I think @murphaph is right, with DU, Luas Lucan (which itself will have an interchange station with the mainline at Kylmore/Ballyfermot like suggested),a more grade separated Heuston-Tallaght section, and the banning of the private car from the city centre, it is probably not needed to sink the Red Line

    Out of interest though, is there any sense in building the new Lucan Line cut and cover in the city centre given it is a new line from scratch…? This would certainly up the price but would get rid of every NIMBY concern for the Christchurch/Liberties area and the Dame Street/College Green plaza…? If it is done outright, it would also take congestion off the Red Line. Then again though, would probably give a lot of ammo to the anti-DU group…



  • Registered Users, Registered Users 2 Posts: 18,991 ✭✭✭✭murphaph


    I would argue that if we are going to build any east-west rail tunnel under the city streets it should be a bored tunnel for DU. A cut and cover tunnel for Luas might be a little cheaper but it might not be cheaper at all when you factor in the disruption and hence the cost to the economy during construction. If Lucan Luas was built in a tunnel DU would be even deader than it is now.



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