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M50 and Luas

  • 30-04-2022 12:49pm
    Registered Users Posts: 106 ✭✭

    With the immense amount of work done on the M50 in recent years and the space available and made available to the upgraded motorway was there ever any consideration given to running light rail along the route and into the city via the Phoenix Park? What would have prohibited it from happening? Could it have worked?

    Strikes me that at a glance it's a lost opportunity, you could have linked Dublin Airport to the city, take a significant number of cars off the road and take in many areas of the city not well served by public transport providing relatively rapid connections between those points. It could have been done, comparative to metro and other plans in the works, quickly, cheaply and with relatively little disruption. It may be that it's something that could never have been done at all but I'd be interested to hear informed opinion on the subject.


  • Registered Users Posts: 19,385 ✭✭✭✭road_high

    Where would it fit on the M50 exactly? Overhead? Imagine the cost and disruption alone

  • Registered Users Posts: 106 ✭✭47akak

    I'm talking past tense, to have been built when there was already considerable disruption. Tracing the route north from the bridge I doesn't appear as if space would have been the critical issue, adjacent to the road. And perhaps if you were moving tens of thousands of passengers per day between the city and airport/suburbs it would have reduced the demand for the M50. Road demand is fairly elastic too, if you build it they will drive on it.

  • Moderators, Science, Health & Environment Moderators Posts: 19,357 Mod ✭✭✭✭Sam Russell

    The lost opportunity was not incorporating a Luas/metro tunnel into the port tunnel, either within the existing tunnel or as a third tunnel, and going onto the airport.

    Mind you, if you are looking for lost opportunities the the state has forgone, it would be a very long list. Add to that list all the mistakes and mis-steps and that would also be a long list.

    White-water rafting anyone?

  • Registered Users Posts: 1,107 ✭✭✭gjim

    Not to piss on your idea but it's a dreadful idea. The principles which guide the route design of motorways are completely different to those for mass urban transport.

    When designing mass transport, you chose routes which link and pass through places where people live, work, shop or study. The environment right next to motorways is unpleasant in terms of noise and air pollution - so generally we don't build such centres right beside motorways. The M50 may carry a huge amount of traffic but it isn't traffic carrying people from one point on the M50 to another.

    And for this specific proposal, linking the airport to the city centre via the M50 and the Phoenix Park would mean at least a 20km route - nearly the full length of the Green Luas, which takes about an hour and 10 minutes end-to-end. More than 3 times as long as the direct 8km route ML will offer or twice as long as it currently takes by coach via the port tunnel. It's not a runner at all.

  • Registered Users Posts: 106 ✭✭47akak

    Tbh some extremely poor arguments, was mainly looking for informed opinion - cost, connectivity, access to users & demand, problems building & maintaining the infrastructure, planning issues, ownership issues, how it would fit with future planning strategy etc.

    Luas journey time is mainly down to stops/traffic not track distance and it's not comparable as there wouldn't be 35 stops between the PP and the airport, the Luas can travel at 70kmph which a track along the M50 would be ideal for. And the fact is there isn't a metro line, and won't be, so comparing it to something that won't exist isn't relevant, might as well compare it to helicopter. As for "build centres right beside motorways" (?), it's a particularly peculiar comment as nowhere is it suggested it is a good idea and should be done, ignores the salient fact is M50 is already there as is Dublin, built all around it. Blanch, Clondalkin, Finglas, Ballymun, Swords are all big populations centres in very close proximity to the M50.

    We're building several new Luas lines and with the enormous growth in Dublin to come outside the M50 seems one way or another orbital routes will be an important part of that. Many large institutions and employers (or even adding up all the small employers) are based close to the M50 and outside it too. That is only going to increase as a % of the total employment in Dublin. Having a pre-made route around/into/through the city for pretty much all of the city north to south seems like it would take an enormous amount of the pain and cost away, especially given what's planned for Finglas, new bridges, and so on.

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  • Moderators, Science, Health & Environment Moderators Posts: 19,357 Mod ✭✭✭✭Sam Russell

    If you want an orbital route for Luas then use the South Circular Road. Build a Luas line from Grand Canal Dock along/beside the Canal and onto SCR to Charlemont and onto Dolphins Barn with a full integration at both Dolphins Barn and Charlemont to allow routes to go both direction along the Red and Green lines. That would give connection with Metrolink, Dart, and Heuston. The route could continue along the NCR to Croker and onto the docks if the demand was there.

    The M50 is too far out to be much use for most commuters - the line would be too long and too slow.

    Edit: 10 km of track would do GCD to Connolly along the SCR and NCR orbital route.

  • Registered Users Posts: 1,107 ✭✭✭gjim

    I'm sorry - your idea is dreadful - it's as simple as that. I suggest you do a bit of reading before accusing others of being uninformed.

    The cost of construction of light rail tracks and supporting infrastructure for a route which will pick up or drop off almost no passengers for most of its length means the cost/benefit will be horrendous - construction cost is likely to be about 50m per km. And if passengers are not going to get on or off along the M50 section, then why go around the M50 at all instead of going directly into town. It makes no sense on any level.

    Tram lines generally have stops at least every 500m to 1km or so, that means either your route has huge gaps with no stops (completely inappropriate for tram, maybe for heavy rail - but still bearing the cost of the rails and electrical infrastructure) or else, yes it's going to take at least an hour end to end assuming typical tram dwell times.

    The median distance for walking to a tram stop is about 380m - now count how many people live within 380m of the median of the M50 or live in the Phoenix park. Or just look at a density map of dublin - you'll see that your route mostly passes through some of the lowest residential density areas of the city. Again not what trams are used for.

    It will not provide an alternative to people currently driving on the M50 because, nobody driving on the M50 starts their journey on a point along the M50. The M50 is a traffic artery and an orbital by-pass, not a route that connects destinations like centres of employment, retail, residential, etc.

    The reason nobody is taking your idea seriously because it's not a serious idea. I suggest you read the design documents for DART+ or ML or the like, or look at how cities with world-class tram networks actually design such systems to see what kind of factors are considered - you could start here

  • Registered Users Posts: 9,268 ✭✭✭cgcsb

    You're definitely right about one thing. There is no realistic way to cross the liffey without a car west of Chapelizod. And that is a thundering disgrace. You have huge towns like blanch and Clondalkin/Tallaght which have hundreds of thousands of people, are only a few short kms apart as the crow flies and the car is the only way to reach each other.

    Of course this is deliberate. It's a revenue protection measure to make sure people use the west link toll bridge in their cars. What's needed is a bus/bike/pedestrian Bridge somewhere between liffey Valley and blanch. But that's not in any of the strategies, it would mean lots of people not paying the toll.

  • Moderators, Science, Health & Environment Moderators Posts: 19,357 Mod ✭✭✭✭Sam Russell

    It always smelt a bit that the West Link toll bridge was the only crossing point there, and only for cars. The bridge was built for IR£10 million and bought out by the Gov for nye on a billion euro. I wonder who benefited from that - clearly not the people who use it.

  • Registered Users Posts: 27,169 ✭✭✭✭blanch152

    What is needed is tolling all along the M50. Build a bridge for local traffic from N3 to N4 and toll on the basis of the shorter the journey, the higher the toll.

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  • Registered Users Posts: 7,190 ✭✭✭MrMusician18

    To be honest with the OP I'm actually surprised that this wasn't done, as something like this has been done in the only western country with worse public transport than ours, the USA.

    The reason why this is a bad idea is because light rail, correctly done is meant to link population centres together. Using the M50 alignment, that is impossible: there is no place to locate stations that are easily accessible to the pedestrian, that are close to population centres. Its one of the main reasons why there are no orbital buses on the M50.

    You could use it as an airport express route then go in the navan road, but then that also represents a missed opportunity. For the expenditure, you could have a direct route to the airport, one that intercepts existing populations that are underserved by PT. It allows you free hand to design the most suitable route, rather than shoehorning it into a constrained pre existing one.

  • Registered Users Posts: 1,107 ✭✭✭gjim

    I hate PPPs as much as the next person and think that they are never the appropriate way to finance public infrastructure projects.

    But the picture you paint is a bit one sided I think.

    First there was a bit more than IR£10m spent on it. It cost IR£30 million to build (about €100 in todays money) and the subsequent expansion must have cost €150m at least. And money would have been spent on it over the years in maintenance.

    Also when it was initially built, the country didn't have a pot to piss in and the idea that the country was about to enter a period of celtic tiger like growth would have seemed like a complete fantasy at the time - as well as the fact that only a part of the M50 actually existed at the time to feed traffic onto the bridge. So it only seems like a slam dunk for NTR with hindsight.

    Also the state did o.k from the buy-out - paying €600 million once-off but taking in on average €100m in tolls every year since. They've already earned back the €600m years ago I'd guess.

    Nonetheless I agree that PPPs suck.

  • Moderators, Science, Health & Environment Moderators Posts: 19,357 Mod ✭✭✭✭Sam Russell

    Now I am not privy to the details but I believe there was a clause in the original deal that precluded any other crossing of the Liffey at that point - or at least that was one of the reason why an alternative link from the N4 to the M50 before Blanch.

    Now PPP is a construct that passes Public money into Private Pockets, as the Public takes all the risks, and the Private takes the Profits. It is unlikely that in the current circumstances a private fund could raise finance cheaper than is available to the Irish Government, particularly if EU development or Brexit money was available. This is particularly apposite for Metrolink funding.

    PPP stinks as a funding model.

  • Registered Users Posts: 3,586 ✭✭✭roadmaster

    Apart from a lack of ambation why cant this still be built? The land take from porterstown up to blanch is even still there

  • Moderators, Science, Health & Environment Moderators Posts: 19,357 Mod ✭✭✭✭Sam Russell

  • Registered Users Posts: 3,586 ✭✭✭roadmaster

    Why not both, They would be both used and will be operational in one form another for over 100 years.

  • Registered Users Posts: 5,446 ✭✭✭Charles Babbage

    What they should have done was plan for express buses on the M50 which interchange with radial routes at the junctions. This would have involved specific provision at the junctions for this interchange and perhaps bus only lanes or ramps there. For instance they could have stop at m50 level, maybe under the roundabouts above and stops for radial routes on the roundabout level where passenger could go down a level to change over. Perhaps at Sandyford the M50 buses might have made their way to LUAS as a terminus.

  • Registered Users Posts: 1,107 ✭✭✭gjim

    It would be very expensive? Perhaps not meeting the bar in terms of cost/benefit.

    A more practical idea would be to first build the 2nd/western west-link bridge as a bus/cycle/pedestrian link allowing a bus service along the proposed route to gauge demand.

    Orbital routes are far less common world-wide and are usually the last pieces added to rail based PT networks. On average they will be passing through areas of lower density than cross-city/radial routes and with fixed per-km rail infrastructure costs, it will be more expensive to provide per passenger journey. And if you've a decent selection of radial connections, an orbital service will only be attractive for shortish journeys as trips covering a bigger arc are often quicker by going through the centre.