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DART+ (DART Expansion)

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    #6602
    riddlinrussell
    Registered Users Posts: 995 ✭✭✭riddlinrussell


    I think this is going to be a case of time and picking their battles rather than anything else, the options are:
    • Build a new Semi-High Speed line Belfast to Cork with underground section through Dublin
    • Quad track Northern line

    Politically Cork/Belfast High Speed is probably an easier sell to the whole country as its not 'Exclusively for Dublin'

    Price wise we know even semi HS rail is going to be much pricier than the Quad track even with expensive CPOs etc

    Practically will a new HS line solve ALL of the problems with the Northern Line? It can take Intercity service away from the route but can Commuter and Dart happily fit in the 2 track line as population expands?

    Northern line improvement is going to have to be a one and done big job, semi High Speed could feasibly be done more peacemeal, depending on if that means upgrading the current Cork/Dublin and Dublin/Belfast routes or an entirely new line.

    Even with fully new lines you could build Belfast to Dublin Airport, and Cork to... maybe Heuston with a southern Tunnel section (That expense may break this idea...) and then have the Dublin Tunnel presented as a Fait accompli 'no-brainer' to link the two routes.


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    #6603
    riddlinrussell
    Registered Users Posts: 995 ✭✭✭riddlinrussell


    LXFlyer wrote: »
    As I have posted many times, in order to effectively operate the inner stopping DART service operating every 10 minutes, the outer semi-fast DART, and an hourly Enterprise, an overtaking facility is needed between north of Clontarf Road and just before Raheny Station.

    That will allow for an outer DART or Enterprise to overtake a stopping DART at line speed. Otherwise the outer DART/Enterprise will continue to crawl at pedestrian speeds to Clongriffin.

    Loops at Clongriffin In both directions further assist in the ability to overtake.

    The whole line does not need three/four tracks. Just between north of Clontarf Road and Raheny.

    Thanks LX, I think this idea was what I was thinking would be the 'acceptable stopgap' until a possible new High Speed line exists


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    #6604
    Sam Russell
    Moderators, Science, Health & Environment Moderators Posts: 19,453 Mod ✭✭✭✭Sam Russell


    Pete_Cavan wrote: »
    There are many houses less than 30m from the existing tracks. That is not a lot of space to operate large plant. You probably need 3m buffer from the operating tracks. You will need 10m for two tracks, plus another few metres for embankment/retaining wall. At the stations, 8m or more is taken up with platforms, ramps etc. which are need to remain. It may be possible that some properties would be left with up to 10m of a garden but for many, they would have little or nothing left. I doubt they'd be allowed to CPO a full garden and leave the house which is seriously devalued, they would probably be made but the whole lot.

    Even if possible to leave the houses, you have a long linear work site along the tracks with the only access at the bridges crossing the tracks which is not practical. The excavators/trucks cant operate on the embankment, they need to be on level ground which is the gardens. Most of the gardens seem to be less than 15m long, you would need all of that. You then need to dig out the embankment while keeping back from the operational tracks, remove all the material from the site and build replacement embankment/retaining walls in such a way to avoiding subsidence to the houses. The trucks once loaded probably can't continue straight on as that is where the excavation is, they would need to turn or reverse out. It really isn't practical from any point of view.

    This may sound dumb, but can they not use railway trucks to remove the spoil?

    Would working at weekends not allow the rail line work during the week?

    Would they need the third line all the way from Connolly to Howth Junction?


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    #6605
    Pete_Cavan
    Registered Users Posts: 6,789 ✭✭✭Pete_Cavan


    MJohnston wrote: »
    So the 'why' essentially boils down to not being able to close the line while working on the widening?

    I'm just saying that it seems perfectly practical to add a single extra track without having to CPO much more than a few metres of some back gardens IF you accept that the line will have to close for some period.

    You can't be too close the line while working on the widening but you also need a lot of space to do the engineering works required.

    What's a few metres of some back gardens? Looking at Google maps and saying there is Xm of space there means nothing, particularly when much of that space is a steep embankment therefore not available for tracks without major construction works. I'm talking about the practical realities of these construction works.

    Plant can't operate on such a slope, and certainly not one overlooking live rail tracks. So the plant needs to operate from the level gardens at the top of the embankment, which is the gardens. Even the bare minimum 5m strip to allow for single track is very little space for an excavator to operate and movements for trucks for spoil removal would be severely restricted as there are limited access points due to the houses and they have to travel along that same 5m channel which is being excavated and therefore below the level of the road so you also need to facilitate them getting back up to the road. You also need to build a retaining structure to avoid undermining the slope and having everything subside down onto the rail line. The laws of physics apply.

    I doubt 5m is enough to do these works, and even if it was it would be incredibly expensive and drawn out for many years. Taking more land and adding two tracks is an easier job due to the additional working space allowing for more productivity but at that stage you are close to the back wall of the houses and probably have to CPO them. CPOing the houses makes construction much easier as you have a much wider site and continue access the whole way long.


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    #6606
    Brian CivilEng
    Registered Users Posts: 1,020 ✭✭✭Brian CivilEng


    Very quickly ran the exercise south of Raheny as far as east wall road. Again a 25m corridor, so final layout not including for construction. It is very tight, I see at least 20 house that are clipped, multiple houses that would have zero back gardens. And as stated this is just in 2D, a lot of this area is in cut or fill.

    Not saying it's impossible, but it would be a "courageous decision".

    cereiGR.jpg


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    #6607
    lucernarian
    Registered Users Posts: 9,235 ✭✭✭lucernarian


    Pete_Cavan wrote: »
    Where's your sources? Unless you have a link to support, that means nothing. Even if it was said by someone in Irish Rail, it needs context, I mean is the 4 tracks an additional track on either side or two additional on the same side?

    I've spent quite a while digging now.... This Irish Rail document I refer to was back in the day of Sponge Bob et al posting on C&T and with Google de-indexing old pages, I've not found it yet. It's likely over 10 years old also. Very sorry about this, I can try to spend some time looking for this / the thread it was posted in later. I don't remember the report giving any details on the two options, but I suspect the "middle line" passing loop / express line idea was involved, given the price difference. And this is probably all that's needed to make Dart+ or DU a success.


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    #6608
    lucernarian
    Registered Users Posts: 9,235 ✭✭✭lucernarian


    Brian CivilEng wrote: »
    Very quickly ran the exercise south of Raheny as far as east wall road. Again a 25m corridor, so final layout not including for construction. It is very tight, I see at least 20 house that are clipped, multiple houses that would have zero back gardens. And as stated this is just in 2D, a lot of this area is in cut or fill.

    Not saying it's impossible, but it would be a "courageous decision".

    cereiGR.jpg
    There would not be 25 metres needed for a third track, and a lot of space is available to one side (clontarf golf course as an obvious example).


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    #6609
    Pete_Cavan
    Registered Users Posts: 6,789 ✭✭✭Pete_Cavan


    Sam Russell wrote: »
    This may sound dumb, but can they not use railway trucks to remove the spoil?

    Would working at weekends not allow the rail line work during the week?

    Would they need the third line all the way from Connolly to Howth Junction?

    Whats pretty dumb? The laws of physics prevent an excavator from sitting on a steep slope, it would topple over immediately nevermind trying to dig out the slope it is sitting on.

    Using an active railway to remove spoil isn't practical. I'm sure noisy construction works at night would be limited as a planning condition given the proximity of houses so wont be able to work through the night. During the day, you couldn't realistically run any meaningful level of service on the track, the spoil removal train would be sitting there all to fill it.

    It doesn't matter how far it goes, the same problem exists from before Killester going north so anywhere along there is an issue. South of Killester to Connolly would be relatively easy to add track but of lesser benefit.


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    #6610
    Pete_Cavan
    Registered Users Posts: 6,789 ✭✭✭Pete_Cavan


    lucernarian wrote: »
    There would not be 25 metres needed for a third track, and a lot of space is available to one side (clontarf golf course as an obvious example).

    I assume his 25m corridor includes the existing trackbed so space for 3/4 tracks, electrical/signalling infrastructure, embankments, etc. In reality it would probably have to be even wider at the stations though.


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    #6611
    Brian CivilEng
    Registered Users Posts: 1,020 ✭✭✭Brian CivilEng


    lucernarian wrote: »
    There would not be 25 metres needed for a third track, and a lot of space is available to one side (clontarf golf course as an obvious example).

    It's not that there is 25m needed, it's that you need to check the full corridor to allow for curves to avoid obstacles. I'm just doing the 5no. 2.5m offsets either side of the centreline so I can quickly see this when I zoom in. So let's say we need 16m for three tracks, then I can look at 6 lines on one side etc. Apologies that I cant upload in enough detail for everyone to do the same exercise.

    A 1km passing loop through Clontarf Golf Club is feasible. Would need to rebuild the bridge over the Howth Rd. and possibly still need to demolish a couple of houses, or else you are getting down to about a 600m passing loop.


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    #6612
    lucernarian
    Registered Users Posts: 9,235 ✭✭✭lucernarian


    Pete_Cavan wrote: »
    I assume his 25m corridor includes the existing trackbed.
    It does, but firstly the land take for a third track is necessarily lower, and there are easy pickings for that to happen (like along Clontarf golf club). Assuming there's an even 5-8 metres each side of the centerline gobbled up by the plan wouldn't be a realistic prediction.


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    #6613
    crushproof
    Registered Users Posts: 2,753 ✭✭✭crushproof


    I really don't see the point in fussing over quad tracking the northern line because ultimately it is fantasy. Unless Ireland suddenly falls under a dictator infatuated with public transport there is zero political willpower to CPO goodness knows how many homes and properties.

    The current concept of DART upgrade, DART+ (what a genius marketing move) is a step in the right direction and as someone else mentioned makes do with what we currently have. Therefore I'm more hopefully of this being done in comparison to other large infrastructure projects that are rehashed every 5 years.


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    #6614
    ted1
    Registered Users Posts: 23,425 ✭✭✭✭ted1


    bk wrote: »
    Not if it looks to make little difference in the numbers of people using the service.

    Afterall it isn't like people sitting in Malahide and who want to go to Stephens Green are going to say, nah, I won't use this service because it is 5 minutes slower versus some theoretical service that hasn't been built.

    They'll still take it because it is still much faster ...

    Not necessarily, I wouldn’t buy in area if the commute is to long. People might say, no I won’t move to Malahide and further out as it takes to long to get in.

    That 5 minutes is a an hour a week which equates to about 1.5 extra work weeks sitting on a train per year.


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    #6615
    Brian CivilEng
    Registered Users Posts: 1,020 ✭✭✭Brian CivilEng


    Good video here explaining curves on railway tracks. I assumed 400m minimum radius for design. Which means that even though the width of the track bed may only be 16m, a building 15m off the track centreline on one side and another building 10m off the track on the other side but 200m away will still form a pinch point.

    https://youtu.be/a3DahvjOBa4?t=538


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    #6616
    cgcsb
    Registered Users Posts: 9,310 ✭✭✭cgcsb


    bk wrote: »
    Wow, the reports in the ANNEX are a goldmine of their thinking about how all this will fit together, the cost and performance difference between Dart+ versus full Dart Underground and it also gives us the cheaper DART Underground options they were considering!!

    DART+ versus DU

    So first off, the report shows that this DART+ plan carries almost the same number of passengers (just 0.10% less) as full DART Underground, while being about 2 billion cheaper! So obviously this DART+ plan comes out with a significantly better cost to benefit ratio (not that DU's was bad either).

    Other benefits include that it can be rolled out much faster then DU, thus gaining those benefits quicker and supporting the development of West Dublin faster. And the fact that it can be phased, making it overall less risky.

    Of course it also doesn't preclude DU happening in future and most of the cost of this DART+ would be needed for DU anyway.

    It all strikes me as quiet a no brainer to proceed in this manner.

    Alternative Dart Underground plans

    They also looked at 3 other "cheaper" DU plans.

    - Follow the original DU alignment, but with an underground turnback station under Hueston Station. Basically this means people would have to transfer between DARTs at Hueston station coming from the west of the city.

    - Follow the original DU alignment, but with an underground turnback station under Pearse station, underground line does not cross the Liffey. This would mean people coming in from the West and wanting to go North of the Liffy would need to transfer at Pearse Station.

    - A tunnel just between East Wall and Pearse Station. Again would require folks to transfer.

    These 3 options all saved about 400 million (and more for the third one, I forget how much) out of the roughly 4 billion full DU cost. However 400 million isn't that much in the greater scheme of things and they all ended up carrying less passengers and thus had worse benefit to cost ratios compared to both the full DU and the Dart+ plans and thus they were all rejected.

    Modified full DU plan

    They also looked at a slight modification of the full DU plan, which takes into account Metrolink. It saves about 200 million of the full DU plan and looks like so.

    It follows much the same route as original DU, with the same stations, except:

    - Stephens Green DU Station moved closer to the Metrolink station at Stephens Green, an obvious change.

    - The Western DU portal moved closer to Hueston Station and instead an above ground station at Kylemore road. It would require more quad tracking closer into Hueston.

    All seem like sensible changes for a future DU IMO.

    Other tibits

    - They are looking to lengthen station platforms to take 10 carriage DARTs

    - That would be too much capacity off peak, so they are looking to operate 4 carriage DARTs at 2/3'rds frequency off peak.

    - They are thinking of building another turn back at Dun Laoghaire to handle more DARTs coming across the Loop line Bridge.

    - The three lines, Kildare/PPT, Maynooth and Northern will all be able to terminate at either Connolly, Spencer Dock or across the loop line bridge, however the division looks something like this per hour at peak time:

    -- Kildare/PPT line, 16 total, 4 into Hueston, 12 into the PPT and on into Spencer Dock.
    -- Maynooth, 16 total, 6 Connoly, 3 Spencer Dock, 7 Loop line bridge
    -- Northern Line, 19 total, 5 Connoly, 3 Spencer Dock, 11 loop line bridge

    The report is here (warning big PDF):
    https://www.irishrail.ie/Admin/getmedia/d34065cd-6540-4be1-9cb3-bcea61273fdd/Annex-3-3-DART-Expansion-Programme-Options-Assessment.pdf

    All very interesting. Of course some of the above details may have changed since this report (2018) and could change yet as it goes through planning process. But a veery interesting insight into what has been going on.

    To be honest I don't like the service patterns. I'd prefer to have 3 lines interconnected with well defined terminii. Eg:

    - Docklands to Maynooth/M3
    - Hazelhatch to GCD
    - Drogheda to Greystones
    - Howth to Howth junct

    I think this is much easier for commuters to get their head around and easy to represent on a colour codded map. The high frequencies of 16 to 19 trains per hour on each line make any destination convenient even with 2 changes, it's a turn up and go service.


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    #6617
    cgcsb
    Registered Users Posts: 9,310 ✭✭✭cgcsb


    bk wrote: »
    Absolutely, worth stressing again, this report is 2 years old. Very interesting report that shows the overall thinking, but I'm certain some of the details have and will change.

    BTW Another point about the report, they also looked into the quad tracking the Northern line, but they rejected it quickly based on the high cost versus relatively modest gains in passenger numbers.

    The recently announced high speed rail study will likely superceed quad tracking the northern line by moving intercity service to a whole new line. In this scenario the existing Drogheda-Connolly line becomes DART only.


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    #6618
    AngryLips
    Registered Users Posts: 2,687 ✭✭✭AngryLips


    cgcsb wrote: »
    The recently announced high speed rail study will likely superceed quad tracking the northern line by moving intercity service to a whole new line. In this scenario the existing Drogheda-Connolly line becomes DART only.


    If they're really serious about a high speed line Belfast-Dublin-Cork then there's really no need to bring it into the city centre. Just bypass the whole city and build a station out at Dublin Airport, this would be a similar approach to what's done in Paris and other parts of France.


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    #6619
    cgcsb
    Registered Users Posts: 9,310 ✭✭✭cgcsb


    bk wrote: »
    Not if it looks to make little difference in the numbers of people using the service.

    Afterall it isn't like people sitting in Malahide and who want to go to Stephens Green are going to say, nah, I won't use this service because it is 5 minutes slower versus some theoretical service that hasn't been built.

    They'll still take it because it is still much faster then the alternatives.

    And 2 billion extra is a ton of extra money to have in your pocket. With that extra money you could do the more expensive Green Line Metro upgrade and say a second South-West Metro branch line.

    I mean that would get you far more extra people into the city, then just taking a few minutes off a DART journey.



    Because they are looking at the bigger picture. The goal isn't to get more people on heavy rail, the goal is to get more people using public transport in all it's forms. To increase public transports share of all transport into the city.

    There is no point in spending billions extra, just to cannibalise people off bus/tram/metro, if it then leaves those other services half empty.

    Specially as I mentioned above, those billions extra can be put to better use increasing public transport elsewhere, where the demand actually exists.
    DARTU provides relief for the central part of the luas red line which is under enormous and growing pressure. That capacity is still needed.


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    #6620
    cgcsb
    Registered Users Posts: 9,310 ✭✭✭cgcsb


    bk wrote: »
    To be clear, you are talking about spending 2 Billion extra just to reduce a journey time by a few minutes!

    15 to 20 thousand people an hour saving 5 minutes for 100 years is a massive win. In economic terms that's € billions


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    #6621
    cgcsb
    Registered Users Posts: 9,310 ✭✭✭cgcsb


    AngryLips wrote: »
    If they're really serious about a high speed line Belfast-Dublin-Cork then there's really no need to bring it into the city centre. Just bypass the whole city and build a station out at Dublin Airport, this would be a similar approach to what's done in Paris and other parts of France.
    I expect an airport station will be included but there will almost certainly also be a central station also. Whether that's Heuston or somewhere else, who knows. French high speed terminates at the traditional central Paris stations. It's China where the high speed stations are suburban.


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    #6622
    riddlinrussell
    Registered Users Posts: 995 ✭✭✭riddlinrussell


    cgcsb wrote: »
    To be honest I don't like the service patterns. I'd prefer to have 3 lines interconnected with well defined terminii. Eg:

    - Docklands to Maynooth/M3
    - Hazelhatch to GCD
    - Drogheda to Greystones
    - Howth to Howth junct

    I think this is much easier for commuters to get their head around and easy to represent on a colour codded map. The high frequencies of 16 to 19 trains per hour on each line make any destination convenient even with 2 changes, it's a turn up and go service.

    I think you'll still want a few an hour Hazelhatch to Heuston, but apart from that I'd agree


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    #6623
    eguiney
    Registered Users Posts: 53 ✭✭eguiney


    cgcsb wrote: »
    To be honest I don't like the service patterns. I'd prefer to have 3 lines interconnected with well defined terminii. Eg:

    - Docklands to Maynooth/M3
    - Hazelhatch to GCD
    - Drogheda to Greystones
    - Howth to Howth junct

    I think this is much easier for commuters to get their head around and easy to represent on a colour codded map. The high frequencies of 16 to 19 trains per hour on each line make any destination convenient even with 2 changes, it's a turn up and go service.

    Except that each required change is still likely to add at least 5 mins to the journey.
    Given that they appear to be planning to do almost nothing at Connolly, the best operational solution would be to move closer to the Maynooth-Bray service planned under DU.


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    #6624
    Sam Russell
    Moderators, Science, Health & Environment Moderators Posts: 19,453 Mod ✭✭✭✭Sam Russell


    cgcsb wrote: »
    To be honest I don't like the service patterns. I'd prefer to have 3 lines interconnected with well defined terminii. Eg:

    - Docklands to Maynooth/M3
    - Hazelhatch to GCD
    - Drogheda to Greystones
    - Howth to Howth junct

    I think this is much easier for commuters to get their head around and easy to represent on a colour codded map. The high frequencies of 16 to 19 trains per hour on each line make any destination convenient even with 2 changes, it's a turn up and go service.

    I would have thought:

    - Bray to Maynooth
    - Greystones or Dun Laoghaire to Drogheda
    - Howth to Howth Junction
    - Hazelhatch to GCD or Docklands

    Frequency would be driven by demand. Four coach trains off peak.


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    #6625
    IE 222
    Registered Users Posts: 1,670 ✭✭✭IE 222


    Quad tracking between Connolly and Brookwood Ave (Harmonstown) and Grange rd - Malahide should avoid most of the CPO's and curved sections of the line while releasing most of the capacity issues.

    Cant see treble tracking been a major saving. It would still require a lot of work such as station rebuilding, clearance works and over head line replacements.

    Has the issue of capacity on the Maynooth line been looked into. Did they look into any quad or loop sections on the line. They really need to look into adding a bay at Maynooth or they'll create another Malahide problem with Sligo.


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    #6626
    cgcsb
    Registered Users Posts: 9,310 ✭✭✭cgcsb


    eguiney wrote: »
    Except that each required change is still likely to add at least 5 mins to the journey.
    Given that they appear to be planning to do almost nothing at Connolly, the best operational solution would be to move closer to the Maynooth-Bray service planned under DU.

    Nope. At 16 trains an hour you're talking a train every 4 minutes or less. That's an average wait time under 2 minutes.


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    #6627
    cgcsb
    Registered Users Posts: 9,310 ✭✭✭cgcsb


    Sam Russell wrote: »
    I would have thought:

    - Bray to Maynooth
    - Greystones or Dun Laoghaire to Drogheda
    - Howth to Howth Junction
    - Hazelhatch to GCD or Docklands

    Frequency would be driven by demand. Four coach trains off peak.

    Also good but you get the idea. I'd rather have it as well defined lines like the RER in Paris rather than the mess of suburban rail doing all sorts of routes in London.


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    #6628
    lucernarian
    Registered Users Posts: 9,235 ✭✭✭lucernarian


    AngryLips wrote: »
    If they're really serious about a high speed line Belfast-Dublin-Cork then there's really no need to bring it into the city centre. Just bypass the whole city and build a station out at Dublin Airport, this would be a similar approach to what's done in Paris and other parts of France.
    Similar except for the most important part, TGVs still mostly serve central Parisian stations.


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    #6629
    lucernarian
    Registered Users Posts: 9,235 ✭✭✭lucernarian


    How will Dart+ work with the envisioned train station in the northern part of Drogheda?


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    #6630
    bk
    Moderators, Motoring & Transport Moderators, Technology & Internet Moderators Posts: 22,597 Mod ✭✭✭✭bk


    cgcsb wrote: »
    To be honest I don't like the service patterns. I'd prefer to have 3 lines interconnected with well defined terminii. Eg:

    - Docklands to Maynooth/M3
    - Hazelhatch to GCD
    - Drogheda to Greystones
    - Howth to Howth junct

    I think this is much easier for commuters to get their head around and easy to represent on a colour codded map. The high frequencies of 16 to 19 trains per hour on each line make any destination convenient even with 2 changes, it's a turn up and go service.

    That is from a 2018 report and they now seem to be considering different options.

    From what others have said, they seem to be now considering:
    - Hazelhatch to Spencer Dock (All trains except the 4 that go to Hueston).
    - Maynooth/M4 - All trains go to Connolly, either terminate at Connolly or cross river.
    - Northern Line - All trains go to Connolly, either terminate at Connolly or cross river.

    Of course that may change again before the project all goes live.
    Equium wrote: »
    A small point in the grand scheme of things, but I would hope and imagine that a higher standard of station design will be forthcoming. The Option B location in particular offers IE/IR a fantastic opportunity to make use of air rights above the tracks for commercial/residential development right in the heart of the Docklands.

    Yes, I agree. The Spencer Dock station looks quiet different in the pictures shown on the current DART+ site, versus the pics in the 2018 report. So I think it will possibly be more substantial. Bigger station building, 3 platform islands, etc.


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    #6631
    LXFlyer
    Registered Users Posts: 17,602 ✭✭✭✭LXFlyer


    cgcsb wrote: »
    The recently announced high speed rail study will likely superceed quad tracking the northern line by moving intercity service to a whole new line. In this scenario the existing Drogheda-Connolly line becomes DART only.

    That does not solve the issue of inner stopping DART services holding up outer semi-fast DART services between Connolly and Clongriffin and forcing them to crawl.

    You still need the ability to overtake on the northern line between Connolly and Howth Junction in either direction as I outlined above.


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