Dublin Metrolink - future routes for next Metrolink

marno21

CatInABox wrote: »

Totally agree Marno, but this is the "alternate route" thread, if we can't break out the crayons here, where can we?

I don't agree with Strassenwolf at all, I think the only show in town is the corridor as proposed, but I'd prefer all this fantasy stuff to be here rather than in the main thread.

Sorry if I wasn't clear; any Metro serving Harolds Cross/Terenure area will be totally seperate from Metrolink. Crayons are great, but any Metro along that corridor will be a totally independent project. I was just making clear that they have no connection.

strassenwo!f wrote: »

Marno, we have to see if it's appropriate to devote money to improving a line which is already good, and which can be improved as illustrated above, over spending money on working on a new strategy.

As I say on an almost weekly basis, yes the line is currently good, but the upgrade is to facilitate further capacity at a stage where the line would no longer be considered "good".

I would have no issue with a SW Metro but trying to add in another €1bn worth of tunnelling to what is already by far the largest infrastructure project in the history of the state is not wise or prudent.

strassenwo!f

marno21 wrote: »

Sorry if I wasn't clear; any Metro serving Harolds Cross/Terenure area will be totally seperate from Metrolink. Crayons are great, but any Metro along that corridor will be a totally independent project. I was just making clear that they have no connection.

Yes, marno, thank you very much for your clarification, but I think all of us on the board know what the current plan is.

marno21 wrote: »

As I say on an almost weekly basis, yes the line is currently good, but the upgrade is to facilitate further capacity at a stage where the line would no longer be considered "good".

Other cities in Europe have developed a range of options to ensure that all their citizens can get into town fairly quickly. Tram, underground, Heavy rail. I'm not seeing this in Dublin.

I read today in one of the Irish newspapers that the eventual plan in Cherrywood is to have an area with a population of around 30,000 people. This would put it into the top ten areas, by population, in the state. Presumably, they'll be delighted to get to Sandyford by a rump LUAS and to then try to push their way on to a metro going to the city.

Dublin obviously needs to diversify, and build tram or underground lines to many areas, and particularly to build underground lines to areas which can't be served by overground lines, like the areas in the southwest .

With Cherrywood, an overground LUAS or Metro line along the N11 seems to be the only solution. If that area is actually going to have such a population, a rump LUAS to Sandyford is just not going to cut it.

marno21

strassenwo!f wrote: »

Yes, marno, thank you very much for your clarification, but I think all of us on the board know what the current plan is.



Other cities in Europe have developed a range of options to ensure that all their citizens can get into town fairly quickly. Tram, underground, Heavy rail. I'm not seeing this in Dublin.

I read today in one of the Irish newspapers that the eventual plan in Cherrywood is to have an area with a population of around 30,000 people. This would put it into the top ten areas, by population, in the state. Presumably, they'll be delighted to get to Sandyford by a rump LUAS and to then try to push their way on to a metro going to the city.

Dublin obviously needs to diversify, and build tram or underground lines to many areas, and particularly to build underground lines to areas which can't be served by overground lines, like the areas in the southwest .

With Cherrywood, an overground LUAS or Metro line along the N11 seems to be the only solution. If that area is actually going to have such a population, a rump LUAS to Sandyford is just not going to cut it.

There will be no pushing onto a Metro at Sandyford as it's the beginning of the line. Sandyford boardings alone won't fill the Metro. With upto 90 second frequency there will be no issues there.

The N11 corridor is perfectly served with a BRT solution for at least the medium term. It has Metro to the west and DART to the east.

Places like Tallaght and Blanchardstown seem to get on ok with a rump Luas and bus services.

strassenwo!f

marno21 wrote: »

There will be no pushing onto a Metro at Sandyford as it's the beginning of the line. Sandyford boardings alone won't fill the Metro. With upto 90 second frequency there will be no issues there.

The N11 corridor is perfectly served with a BRT solution for at least the medium term. It has Metro to the west and DART to the east.

But I read today in the Irish Times, or the Independent, or (less likely) the Examiner, that there's a plan for a population of around 30,000 in the town around Cherrywood.

I must find it for you.

My guess is that it was in the Indo and thus, probably, a story to be cautious of.

marno21 wrote: »

Places like Tallaght and Blanchardstown seem to get on ok with a rump Luas and bus services.

But those locations don't have a rump Luas.

Tallaght has a LUAS which gets people into to town in around 44 minutes. It's not ideal, for a city which is the third largest in the state. I think lots should be done to explore the possibiliites of connecting it to the proposed Western DART Line, via Clondalkin.

But in no way is it a rump LUAS.

And Blanchardstown doesn't even have a LUAS.

The only rump LUAS in Dublin is the [roposed section between Cherrywood and Sandyford.

The proposed town of 30,000 people in Cherrywood is not going to be served directly by the LUAS/metro into town. So, if it's true that that is the projected population, how is it going to be accomodated within the city's transport network?

They'll pile on to the rump LUAS to Sandyford, and join the other rump Luasers trying to get onto a LUAS or metro into town, or maybe they'll find a way down to somewhere on the N11 where they can get on to the bus into town.

If the area around Cherrywood is to happen, with it's projected 30,000 population, it seems to me that a major rethink is required.

marno21

strassenwo!f wrote: »

But I read today in the Irish Times, or the Independent, or (less likely) the Examiner, that there's a plan for a population of around 30,000 in the town around Cherrywood.

I must find it for you.

My guess is that it was in the Indo and thus, probably, a story to be cautious of.

It was the Independent: https://www.independent.ie/business/commercial-property/green-light-given-for-313-new-homes-in-cherrywood-37241858.html

If you leave the Green Line as is, it'll be transitting through the areas north of Milltown and not stopping as it'll be full, so it'll become a Luas just for Cherrywood and surrounding areas. There is no panacea here, but what we are getting is the best compromise.

But those locations don't have a rump Luas.

Tallaght has a LUAS which gets people into to town in around 44 minutes. It's not ideal, for a city which is the third largest in the state. I think lots should be done to explore the possibiliites of connecting it to the proposed Western DART Line, via Clondalkin.

But in no way is it a rump LUAS.

And Blanchardstown doesn't even have a LUAS.

The only rump LUAS in Dublin is the [roposed section between Cherrywood and Sandyford.

The proposed town of 30,000 people in Cherrywood is not going to be served directly by the LUAS/metro into town. So, if it's true that that is the projected population, how is it going to be accomodated within the city's transport network?

They'll pile on to the rump LUAS to Sandyford, and join the other rump Luasers trying to get onto a LUAS or metro into town, or maybe they'll find a way down to somewhere on the N11 where they can get on to the bus into town.

If the area around Cherrywood is to happen, with it's projected 30,000 population, it seems to me that a major rethink is required.

Rump was the wrong word. What I meant re: Tallaght is that the Red Line will one day be overloaded too as it's underpowered for all it's trying to do, and there is no easy solution with the Red Line. 44 minutes is poor also for that journey length.

They will have to walk off a Luas at Sandyford and onto a Metro. It's not the end of the world. Most parts of Dublin would kill for that level of service.

Plenty of people will have to hop onto feeder buses to connect with the Metro, and I don't see them being accommodated in such a manner.

strassenwo!f

So there's a town planned for around 30,000 people at the end of the current LUAS Green line.

But the metro is only going to go as far as Sandyford, and not on to the planned town with 30,000 people.

Can you just remind us why this proposed metro is not continuing on to the planned town with 30,000 people?

It would seem to be easier for everybody concerned if it did.

antoinolachtnai

It would certainly be easier, but is there any real requirement?

30,000 people just isn't that many. Is it worth building a tunnel or a new elevated line to send a metro train down 3 or 4 times an hour?

The people there will be able to get to the city faster with frequent Luas + Metro than they would with an infrequent metro.

strassenwo!f

Well, what are the numbers in Sandyford?

With the logic from your post above, is it worth upgrading to a metro?

antoinolachtnai

We know what the cost to sandy ford will be - a few hundred million euros.

Can you give us your guess at what a link to Cherrywood would cost? I reckon it would be about a billion euros in addition to the 300m to upgrade the Luas. So now you are talking about adding a billion euros to the cost of the project to serve a town of 30,000 which already has adequate light rail.

Can you also supply us with your figures for how the Luas can be run at 36 trains per hour? How will this work when the luas has to cross another luas line which will block the line about half the time? How will it work when the traffic lights only come around 30 times per hour? Where will the luas trams queue when they are waiting to cross the junctions?

strassenwo!f

antoinolachtnai wrote: »

We know what the cost to sandy ford will be - a few hundred million euros.

Can you give us your guess at what a link to Cherrywood would cost? I reckon it would be about a billion euros in addition to the 300m to upgrade the Luas. So now you are talking about adding a billion euros to the cost of the project to serve a town of 30,000 which already has adequate light rail.

Can you also supply us with your figures for how the Luas can be run at 36 trains per hour? How will this work when the luas has to cross another luas line which will block the line about half the time? How will it work when the traffic lights only come around 30 times per hour? Where will the luas trams queue when they are waiting to cross the junctions?

Antoin, could you first answer the questions I posed to you?

antoinolachtnai

What numbers do you want now?

You are the contrarian here. It is really up to you to come up with the numbers.

salmocab

Has this gone from arguing that there is no need for the metro as luas could be more frequent to the metro doesn’t go far enough?

strassenwo!f

salmocab wrote: »

Has this gone from arguing that there is no need for the metro as luas could be more frequent to the metro doesn’t go far enough?

:P

I have several posts where I have advocated that the current Green Line should eventually be a metro line. One of 4-5 branches emanating from perhaps 2 cross-city metro tunnels.

But I don't think it's the most high priority corridor for development, as there is already a line there which may well be being underutilised.

My current question is that, if it is to be the first corridor which is to have a metro, why does the metro part of this corridor not stretch to a proposed town of 30,000 people (possibly the most populous single area along the southside portion of what is now the LUAS Green line).

salmocab

strassenwo!f wrote: »

:P

I have several posts where I have advocated that the current Green Line should eventually be a metro line. One of 4-5 branches emanating from perhaps 2 cross-city metro tunnels.

But I don't think it's the most high priority corridor for development, as there is already a line there which may well be being underutilised.

My current question is that, if it is to be the first corridor which is to have a metro, why does the metro part of this corridor not stretch to a proposed town of 30,000 people (possibly the most populous single area along the southside portion of what is now the LUAS Green line).

There isn’t money to have a metro from swords to somewhere in SW Dublin.
The green line will need upgrading at some stage so it makes sense to run the metro along that line as it’s financially the best use of limited resources.
To bring the metro past sandyford would mean lots more upgrading works as there quite a few at grade crossings both roads and pedestrian. This would cost a huge amount. A luas into sandyford and crossing a platform to get on a metro within 90 seconds is not really any hassle.
Im aware you don’t agree and will continue to argue against the plans and that’s fine, this is a good plan it’s not perfect but for the money that it will cost it’s as good as we can expect. Any political interference for rerouting will only serve to put this back again.

strassenwo!f

salmocab wrote: »

There isn’t money to have a metro from swords to somewhere in SW Dublin.
The green line will need upgrading at some stage so it makes sense to run the metro along that line as it’s financially the best use of limited resources.

Clearly, there is the money to get somewhere in the SW of the city, if there's enough money to build a tunnel to at least Charlemont and then upgrade the entire line between the canal and Sandyford. (I don't have the capabilities to quantify the economic loss to the city, and the country, of the Green line being closed for an indeterminate period)

I have never suggested that the same funds could get the metro terribly deeply into the SW of the city, It would be reasonable to expect that those same funds could get the line from, say, St. Stephen's Green, to at least, say, Harold's Cross - in an initial phase via a 3-station platform around Camden Street - and to buy another few vehicles to increase the capacity on the LUAS Green line

This would introduce a new corridor for rapid rail in the city, and a station (at Camden Street or thereabouts) which would be designed - with its 3 platforms - to facilitate further eventual development to other areas.

Once the most difficult part, tunnelling from Swords to Harold's Cross, has been completed, it should then be relatively easy to find around 100 million a year or so in the next funding period to gradually extend to Kimmage, the KCR and Walkinstown, and to Rathmines, Terenure and maybe Rathfarnham, over certainly less than a decade.

The key things are:

Firstly, at each stage new suburbs are being incorporated into a system of rapid connection with the busiest parts of the city, which would not happen with the current proposal.

Secondly, large swathes of the city would experience greatly reduced journey times, while the current journey time reduction between Sandyford and the river will, it appears, be marginal.

Thirdly, each increment along SW corridors introduces a very large number of transport paths which can be carried out rapidly, because you would have a combination of the SW line(s) and the LUAS line. Piling further investment into the Green line adds no rapid transport paths on the southside, at all.

I reckon, for example, that a Walkinstown Cross - Sandyford journey could be undertaken in less than 35 minutes under an arrangement such as I described above, with an interchange at St. Stephen's Green, with of course major knock-on effects on the journeys of the many bus passengers who travel through Walkinstown Cross from many other areas of the city.

All of the cities I've lived in have done it like this. They held off putting further investment into an obvious winner, primarily because if the first line is a winner, lines to other areas with about the same density will be winners too.

strassenwo!f

I'm sorry, that was a mistake.

I reckon that the journey between Walkinstown Cross and the river could be done in around 15 minutes. The journey time between Walkinstown Cross and Sandyford should be doable in around 40 minutes.

antoinolachtnai

strassenwo!f wrote: »

I'm sorry, that was a mistake.

I reckon that the journey between Walkinstown Cross and the river could be done in around 15 minutes. The journey time between Walkinstown Cross and Sandyford should be doable in around 40 minutes.

How would you gradually extend a TBM tunnelled metro system without vast waste?

Would you apply for a new railway order every two or three years?

What are the economics of bringing in all the specislised skills to build tunnels and stations to build one short stretch and one tunnel?

Would you take out and reinsert the TBM each time?

If not, where would the spoil go as you gradually extended? The obvious route, through the tunnel, would now be blocked.

After three years would you not find yourself under pressure to link the green line to the underground line? Your new line will most likely result in demand increasing on the green line. It certainly won’t reduce demand.

We are still waiting for the detail on your plan to run 36 luas trams an hour on the Green Line.

strassenwo!f

Antoin, if you look at the many cities which have extended their metro lines gradually, it is clear that there are ready answers to all of the above questions.

To take just one city, Munich, most (perhaps all, I'm actually not sure), were extended by cut and cover, once the difficult bit of tunnelling through the city centre was out of the way. In the case of the U-Bahn first line in that city, the city centre tunnel was built first and it has been extended a further five times.

I would remind you that I did not suggest that there would be 36 trams per hour on the Green Line. I suggested that increasing the throughput may well be possible, from the current 15 per hour.

Dats me

Cut and Cover?! You talk of the "indeterminate loss.of closing the green line", but completely closing this whole stretch of road that is already the most congested in the city is a great idea? You would have the SW probably unable to commute while it was being built, where would they go?

The SW metro is a lovely idea, and one that everyone in this thread supports as far as I can see, when speaking of it's benefits you're preaching to the converted. But Metrolink has the green line upgrade because in the GDA Transport Plan 2016-2035 the need for upgrade of the green line to metro standard was established, and it makes sense to do it at the same time as Metro North. I know you speak of rapid transport, but the yoke crawls after Charlemont, it's ridiculous. This will greatly reduce journey time for that section.

If left as is (trams every 3 minutes, long trams so at capacity according to the NTA although it's clear you, Strassenwolf know better than the NTA), green line teams will be full coming into Sandyford due to Cherrywood development etc. So this investment will make a line that will be unusable in 2027 usable again. That is worth a huge amount even if in 2018 they don't deserve any more investment. Bear in mind that there have been howls from Ranelagh about the segregation, this isn't been done because it's easy, but because it has to be. And if it has to be done, we should do it while we're building the rest of the beginning of our Metro.

If you truly want to see Metro SW, you would be better off emailing your TDs and the NTA about it's benefits as a project, rather than using it to argue with people who also want to see it while dismissing any piece of evidence that shows you how it doesn't fit into MetroLink.

antoinolachtnai

What route would your 30-foot wide cut-and cover trench run along?

You don't give much consideration to the mess that would be made at the point where the SW metro and the Luas intersected in the city centre. There would be literally hundreds of people per minute trying to get between the luas above ground to the metro below ground. It would be a much bigger mess than anything that could possibly happen at Sandyford, where the volumes would be lower and both Luas and Metro would be above ground.

As I understand it, the NTA has forecast its capacity for the Luas based on 20 trains per hour and 400 punters per train to give 8000 passengers per direction per hour. How high do you think the frequency can go?

strassenwo!f

Antoin, I've seen cut and cover done a few times, along city streets, and I've never seen a 30-foot wide trench.

No, in the places I've seen it, it involved a trench about 3-4 metres wide.

So, and I'm presuming here that the poster Dats me is referring to the Rathmines Road - though he doesn't specify that, so I may be wrong - you might build your trench along one side of the road (and probably the pavement), do the necessary work along that stretch, then cover it over. Then repeat on the other side of the road for the other underground track. That would be one approach.

This doesn't need to cause huge disruption to traffic. No outbound traffic in the morning, and no inbound traffic in the evening would be one possibility, with buses going against the flow of this traffic taking alternative routes at the appropriate hours. It shouldn't be terribly complicated.

In any case, it is way to early to deal with the specifics of how this might be done. The important this is to focus on the specific advantages, outlined above, which could be delivered by building a line or lines to the SW of the city over upgrading a line which is already operating but probably needs higher throughput.

In relation to the throughput, Dats me, they're not running trams every 3 minutes at the moment. It's an average of every 4 minutes.

Dats me

strassenwo!f wrote: »

In relation to the throughput, Dats me, they're not running trams every 3 minutes at the moment. It's an average of every 4 minutes.

"The existing 26 Green Line trams will be lengthened and eight more trams will be added to the fleet.


The project will begin next year, following on from the Luas Cross City expansion, which is set to open on December 9th. When it is finished, the capacity on the Green Line will be 8,160 passengers per direction, per hour, based on 24 trams an hour."



https://www.irishtimes.com/news/environment/luas-green-line-to-carry-extra-1-700-people-per-hour-1.3291849


NTA forecast demand of 11,000 ppdph, as can be seen in the public consultation document on metrolink.ie


Strassenwolf, if you're being deliberately antagonistic please just tell us. Otherwise, please outline how upgrading a line that needs to be upgraded anyway is a waste of money?


Yes as SW Metro would be nice and should happen, but why shouldn't the green line be upgraded when it needs to be upgraded? Especially since you suggest using disruptive cut-and-cover, one tunnel at a time that would half the capacity of the road for years and years.

Idbatterim

“NTA forecast demand of 11,000 ppdph, as can be seen in the public consultation document on metrolink.ie” L O L. What did the nta reckon the figure would be with original metro north?

antoinolachtnai

strassenwo!f wrote: »

Antoin, I've seen cut and cover done a few times, along city streets, and I've never seen a 30-foot wide trench.

No, in the places I've seen it, it involved a trench about 3-4 metres wide.

So, and I'm presuming here that the poster Dats me is referring to the Rathmines Road - though he doesn't specify that, so I may be wrong - you might build your trench along one side of the road (and probably the pavement), do the necessary work along that stretch, then cover it over. Then repeat on the other side of the road for the other underground track. That would be one approach.

This doesn't need to cause huge disruption to traffic. No outbound traffic in the morning, and no inbound traffic in the evening would be one possibility, with buses going against the flow of this traffic taking alternative routes at the appropriate hours. It shouldn't be terribly complicated.

In any case, it is way to early to deal with the specifics of how this might be done. The important this is to focus on the specific advantages, outlined above, which could be delivered by building a line or lines to the SW of the city over upgrading a line which is already operating but probably needs higher throughput.

The people at the end of this cut-and-cover line who depend on this main road would face having their route to the city centre closed down for a generation. Where is this alternative route for buses to return against the prevailing direction in the Southwest? Jarrett Walker has been scouring Google Maps to try and find it.

salmocab

strassenwo!f wrote: »

In any case, it is way to early to deal with the specifics of how this might be done. .

Way too early for specifics? You do realize this is just a discussion for alternative routes, pretty much fantasy stuff! The upgrade of the green line is the only show in town. The metro link will either be built from the estuary to sandyford or it won’t be built at all and will go back through planning, political interference and objections.

antoinolachtnai

salmocab wrote: »

Way too early for specifics? You do realize this is just a discussion for alternative routes, pretty much fantasy stuff! The upgrade of the green line is the only show in town. The metro link will either be built from the estuary to sandyford or it won’t be built at all and will go back through planning, political interference and objections.

I do think the TBM could continue underground to the southwest from Charlemont so that the city centre and northern tunnel could serve both a new southwest line and the Green line. This is something that is very possible if the political will and finances are there in the early 2020s.

salmocab

antoinolachtnai wrote: »

I do think the TBM could continue underground to the southwest from Charlemont so that the city centre and northern tunnel could serve both a new southwest line and the Green line. This is something that is very possible if the political will and finances are there in the early 2020s.

That means having every second train not going to sandyford halving the capacity that direction

strassenwo!f

Dats me wrote: »

Strassenwolf, if you're being deliberately antagonistic please just tell us. Otherwise, please outline how upgrading a line that needs to be upgraded anyway is a waste of money?

I consider this a slur.

What on earth would be the point of spending time writing posts just to be 'deliberately antagonistic'?

I have repeatedly said that I think it would be a good thing to upgrade the Green line, but I am not convinced that it needs to be part of the first metro project in Dublin. As I have said, repeatedly, there is plenty of demand along other corridors which are not currently served by rail, but where rail could make a major difference to journey times.

A major problem for some posters here is that the LUAS green line is a bit slow in the relatively short section between Charlemont and O'Connell Bridge, which is as far as the vast majority of northbound passengers travel. It is, however, a lot better than what most passengers in Dublin enjoy on their daily journey.

Dats me wrote: »

"The existing 26 Green Line trams will be lengthened and eight more trams will be added to the fleet.

The project will begin next year, following on from the Luas Cross City expansion, which is set to open on December 9th. When it is finished, the capacity on the Green Line will be 8,160 passengers per direction, per hour, based on 24 trams an hour."



https://www.irishtimes.com/news/environment/luas-green-line-to-carry-extra-1-700-people-per-hour-1.3291849


NTA forecast demand of 11,000 ppdph, as can be seen in the public consultation document on metrolink.ie

One issue here is the capacity of a 55 metre tram.

Wikipedia has nothing to say about this, but it does say that the 30m trams on the Red line have a capacity of 256 passengers (broadly in line with similar size trams on other systems), and the capacity of the 40m Green line trams is 356 passengers (the reference is railway-technology.com).

Extrapolating from those you'd expect that a 55m tram would have a capacity of 470-490 passengers. On the other hand, the Irish times figure (based on 24 tph (?)) would imply a capacity of 340 for a 55m tram, and the metrolink documentation implies a capacity of 400.

It's hard to see why trams with an extra length of 15m would have been purchased if they could only add an extra 44 people, given the extra hassle at junctions and the extra energy required to haul them.

So a key question here is: what is the capacity of these long trams?

If we were to take the Irish Times' proposed throughput (24 tph) - and it is still a mystery where they came up with that throughput figure from - and multiply it by the maximum extrapolated tram capacity, you would reach a capacity (11,760 passengers per hour, northbound) which is already beyond where the NTA expect to be in 2037.

Given that the Irish Times article may be poor journalism, and the Wikipedia figures may be down to somebody engaging in David Drummology, I prefer to take the NTA figures from their metrolink documentation - they are, after all, closest to the project - which envisages a 20 tph throughput of 400-person trams, giving a total capacity northbound of 8,000 people per hour.

They envisage a capacity growth of 3,000 people per peak hour over the next 20 years, to 11,000 per hour (from 8,000 currently, at 20 tph), in 2037, in other words a growth of 150 people per year.

What I would suggest is that they start running trams every 3 minutes across the city, from Cherrywood to Broombridge, in line with their projection of an 8,000 capacity at a tram every 3 minutes, so that they get up to the 8,000 pretty rapidly. And then, every two years, they introduce just one extra tram (carrying 400 people), each hour, at peak times, terminating at the St. Stephen's Green siding.

By 2037, having introduced just one extra tram heading to the siding every two years, the capacity of the Green Line between Cherrywood and St. Stephen's Green would have been increased to 12,000, well ahead of the NTA projections (of 11,000) for that time period.

St. Stephen's Green is obviously not ideal for everybody, because it's not particularly central, but it's not bad for many, and who knows if the interim period won't have thrown up possibilities for extension of that siding?

It is also relevant that development of a metro to the SW of the city should certainly reduce road traffic in the city, and thus reduce conflicts between car traffic as the LUAS Green line throughput, on street, is enhanced.

Based on the above figures, I'm still not getting why it is so important to spend a lot of money tunnelling to Charlemont and upgrading all of the stations to Sandyford on the Green LUAS line.

Dats me wrote: »

Yes as SW Metro would be nice and should happen, but why shouldn't the green line be upgraded when it needs to be upgraded? Especially since you suggest using disruptive cut-and-cover, one tunnel at a time that would half the capacity of the road for years and years.

It shouldn't take more than about six to nine months to build the tunnel structure for a metro along all of Rathmines Road, between the Bridge and, say, a station in or around the petrol station on the Rathgar Road.

The track bed, lighting, signalling and other stuff can come in later.

antoinolachtnai

You feel that if we boil the lobster slowly enough, then it will not die?

bk

salmocab wrote: »

That means having every second train not going to sandyford halving the capacity that direction

True, though it could be ok in the short term, with still having enough capacity.

After all I would hope that it doesn't open to full capacity on day one and that it will be designed with room to grow as the population increases over the next 50 to 100 years.

Say a frequency of 3 minutes on each branch, 90 seconds on the shared section, could be ok in the short term.

But then also continue the tunnel North West East so that eventually the SW tunnel is completely separate and the Metrolink tunnel goes back to full capacity.

Something like:
- Open the planned Metrolink is 2027.
- Keep the TBM in the ground and immediately start building a SW tunnel to open in 2030 - 2032. Sections shared
- Keep the TBM in the ground and continue the SW tunnel through the city to the NW NE for opening in 2035 to 2037. The two lines now are separated and full capacity.

Not a bad idea. I've always said that my hope for Metrolink is that it proves underground Metro's to the Irish people and that it will be only the first of many.

BTW I won't even bother to comment on the absolutely mad idea of cut and cover Metro through the SW :eek: