New Luas/Metro lines we might like.

MJohnston

strassenwo!f wrote: »

The situation on the DART is not particularly relevant to what is happening, or might happen, with Dublin's trams, because of the much shorter stopping distance required for even a 55m tram - all of us have seen a tram being able to stop pretty quickly when faced with a car or the inevitable Dublin jaywalker on O'Connell Street and elsewhere in the city.

Why are you talking about trams? This is a thread about METRO

Bray Head

Strassenwo!f makes the reasonable point that level crossing timing in Ireland seems much more conservative than what you see in most of Europe.

Maybe this represents a different level of risk tolerance or health and safety assessment. It would be interesting to learn why.

CatInABox

Bray Head wrote: »

Strassenwo!f makes the reasonable point that level crossing timing in Ireland seems much more conservative than what you see in most of Europe.

Maybe this represents a different level of risk tolerance or health and safety assessment. It would be interesting to learn why.

There's way too many variables to realistically figure it out without a definitive answer from NTA/IR, etc. Even around the world, there is different timing for difference crossings, some better and worse than what we see in Ireland.

Insurance costs, expected payout from a successful insurance claim, speed limits, number of trams, number of cars, number of pedestrians, length of trams, expected stopping distances in an emergency, the effect of weather on braking distance, the type of level crossing used, the proximity of stations, all of these things would need to be considered before setting a time for crossings.

salmocab

Ive just gone through Dunville ave a few minutes ago and timed the crossing, it took 14 seconds from the light changing to the back of the tram passing the crossing and presumably another 1/2 secs for the light to change again. That’s conservatively 15 secs per tram if anyone cares to work out the maths. It was a 55m tram I’m pretty sure.

MJohnston

salmocab wrote: »

Ive just gone through Dunville ave a few minutes ago and timed the crossing, it took 14 seconds from the light changing to the back of the tram passing the crossing and presumably another 1/2 secs for the light to change again. That’s conservatively 15 secs per tram if anyone cares to work out the maths. It was a 55m tram I’m pretty sure.

So the context for this particular conversation has been lost as it's still in another thread, but it was originally in reference to the Green Party idea of increasing Luas frequency on the Green Line instead of upgrading it to Metro, as well as increasing tram length (I'm going to assume they don't mean beyond 55m, but who knows what goes through their heads).

Their plan would have to involve nearly 40tph in each direction, about 70tph in both directions. So that's about once every 50 seconds. Using your 15 seconds per tram closure figure, that leaves 35 seconds in every minute for traffic to proceed.

Good luck to them with that!

salmocab

MJohnston wrote: »

So the context for this particular conversation has been lost as it's still in another thread, but it was originally in reference to the Green Party idea of increasing Luas frequency on the Green Line instead of upgrading it to Metro, as well as increasing tram length (I'm going to assume they don't mean beyond 55m, but who knows what goes through their heads).

Their plan would have to involve nearly 40tph in each direction, about 70tph in both directions. So that's about once every 50 seconds. Using your 15 seconds per tram closure figure, that leaves 35 seconds in every minute for traffic to proceed.

Good luck to them with that!

Yeah that’s pretty much it, even with the proposal that trams could wait to cross simultaneously it seems a ludicrous idea and we really can’t afford to have trams waiting on such a tight schedule anyway.

MJohnston

As someone pointed out on Twitter too - the current Luas capacity just barely works in the city centre, so 70tph would be disastrous north of Charlemont.

strassenwo!f

salmocab wrote: »

Ive just gone through Dunville ave a few minutes ago and timed the crossing, it took 14 seconds from the light changing to the back of the tram passing the crossing and presumably another 1/2 secs for the light to change again. That’s conservatively 15 secs per tram if anyone cares to work out the maths. It was a 55m tram I’m pretty sure.

That's very much in line with my calculation above that it should take just under 12 seconds for a 55m tram to get across the crossing. Add in 2 seconds or so that the driver needs to check that there are no messers near the crossing and you get to the 14 seconds you saw. Another second or two for the lights to change and you get to, let's say, for the sake of argument, 20 seconds for the whole operation.

I've checked the throughput at that location several times, both on the website and by being there, and it is clear that the current throughput is 20 tph at peak times, in the morning peak heading into town. A tram, on average every 3 minutes. As I also mentioned above, my local traffic lights (on a two-way road, a single lane in each direction) gets on average 10 cars across the junction, in each direction (20 in total).

Given that there are fewer trams going against the peak direction, it should assuredly be very easy to set the traffic signals to favour trams travelling in the peak diection of travel, and trams going in the other direction may have to wait a short time. Thus in the morning peak they would prioritise northbound traffic at this junction and southbound traffic might have to wait a short time before crossing. This should not be a problem - it happens at many junctions in the city that a tram has to wait a short time.

At Dunville Avenue, at present, the above figures should give, on average, 2 minutes and 40 seconds to cross before the next tram cycle. Allowing 1 minute and 15 seconds for each direction, with a 10 second gap for the change, that equates to around 60 cars going across the crossing during each tram cycle, assuming the figures for my local crossing are pretty much replicated (and I can't see why they wouldn't be). 20 such cycles per hour (given a tram throughput of 20 tph) should theoretically allow 1,200 cars across that crossing per peak hour.

There are probably going to be people who 'just need to pop in for a second' to Morton's, at peak times, to pick up the week's supply of arugula and coconut milk, and park awkwardly outside the shop, screwing the whole thing up.

But even at just half the above figure (600 cars per hour), is there really such a level of demand to cross at Dunville Avenue at peak times?

If the LUAS Green line were to go to the maximum throughput which is currently allowable for tram systems in Ireland, 24 tph (a tram every 2.5 minutes), the corresponding figures would be a tram cycle of 150 seconds, a traffic cycle of 130 seconds, and a theoretical throughput of 960 cars per hour across that crossing at peak times. (If we factor in an occasional necessity to take the 4x4 to get some Manuka honey in Morton's, at peak times, and 'just park outside for a second', we can probably reduce that to a practical capacity of around 500 cars per hour).

Interestingly, in relation to this junction at Dunville Avenue, an increase of tram throughput to around a tram every 2 minutes - as seen in several European cities - would not appear to have a disastrously negative effect on the local road traffic at peak times. It would, of course, require a change to the current transport rules in Ireland - but that's easily done (much easier than the recent abortion change, or the civil partnership change, in the country's big rule book).

The next step for Dublin, from the current 20 tph to the maximum currently allowed (24 tph), would then be to a tram cycle of 120 seconds, which would probably be too short for travel in both directions at the Dunville Avenue junction. Thus you could dispense with the two-way traffic mentioned above, saving 10 seconds on the proposed changeover across that crossing.

Thus, a tram cycle of 2 minutes (120 seconds) would equate to 100 seconds of car traffic throughput of around 40 cars in just one direction on each cycle. The first cycle would be from one direction, the next would be from the other, and with 30 cycles per hour that equates to 600 cars across that crossing.

That would involve people waiting to cross the crossing, in some cases for about 4 minutes, but that is really quite small compared to what other Dubliners have to do to get across a junction. People travelling in cars across the DART line, for example, would often face much longer waits.

And it would probably be necessary at that stage to tighten up on the peak-time demand for quinoa-infused avocado.

strassenwo!f

MJohnston wrote: »

So the context for this particular conversation has been lost as it's still in another thread, but it was originally in reference to the Green Party idea of increasing Luas frequency on the Green Line instead of upgrading it to Metro, as well as increasing tram length (I'm going to assume they don't mean beyond 55m, but who knows what goes through their heads).

Their plan would have to involve nearly 40tph in each direction, about 70tph in both directions. So that's about once every 50 seconds. Using your 15 seconds per tram closure figure, that leaves 35 seconds in every minute for traffic to proceed.

Good luck to them with that!

My feeling is that a Green line upgrade should happen when the time is right. At the moment there is much that needs to be done elsewhere in Dublin.

Going by the figures provided by metrolink.ie, it doesn't seem that it will be necessary to upgrade the Green line to metro standard until the mid-2040's, if proper measures, common in other cities in Europe, are used to increase capacity for it as a tram line.

If those figures of 40 tph are correct, and I have no reason to doubt you, then it is clear that the Greens are trying to use a LUAS to replicate the kind of capacity that a metro can bring, and that is madness.

But an undeniable problem is that a metro to Sandyford delivers the kind of capacity that it appears will not be needed until well into the next century.

It would be much better, in my opinion, to use the years to the 2040's to develop new areas (in rail terms) of Dublin, on a gradual basis, and then come back to the Green line when it really needs it, and upgrade it to a metro at that stage. Probably in the mid 2040's.

marno21

strassenwo!f wrote: »

My feeling is that a Green line upgrade should happen when the time is right. At the moment there is much that needs to be done elsewhere in Dublin.

Going by the figures provided by metrolink.ie, it doesn't seem that it will be necessary to upgrade the Green line to metro standard until the mid-2040's, if proper measures, common in other cities in Europe, are used to increase capacity for it as a tram line.

If those figures of 40 tph are correct, and I have no reason to doubt you, then it is clear that the Greens are trying to use a LUAS to replicate the kind of capacity that a metro can bring, and that is madness.

But an undeniable problem is that a metro to Sandyford delivers the kind of capacity that it appears will not be needed until well into the next century.

It would be much better, in my opinion, to use the years to the 2040's to develop new areas (in rail terms) of Dublin, on a gradual basis, and then come back to the Green line when it really needs it, and upgrade it to a metro at that stage. Probably in the mid 2040's.

Nobody is doubting that there are lots of needs in Dublin.

However, the cost of the Green Line upgrade to Metro is a small fraction of what another Metro Line would cost. And the small cost of the Green Line is small compared to the benefits it leads to.

CatInABox

strassenwo!f wrote: »

But an undeniable problem is that a metro to Sandyford delivers the kind of capacity that it appears will not be needed until well into the next century.

You might not be aware that the Green Line is due to be extended upon completion of the Metrolink upgrade. It's through mostly greenfield sites, allowing a massive concentration of new developments, quite like the current Cherrywood development.

Is there any such potential along any other possible Metro route? Bear in mind that Dublin is currently going through a ridiculously tough housing crisis? How many billions more have to be spent to get another Metro & Luas combination that unlocks that much development potential?

Also, bear in mind that developers have already been told that no large scale projects will be accepted in those areas until public transport provision has been upgraded i.e. the arrival of the Luas.

Dats me

Also Strassenwolf, even given your very diligent calculations around Dunville Avenue, I'm afraid the city-centre section of the Green Line wasn't tunneled (I wasn't around boards at the time, can anyone remember what the feeling was about LCC when it was being planned?), so while Dunville Avenue could possibly deal with more trams , from what I've seen College Green, Dawson Street and the quays probably can't take any more than is there at the moment. Northbound 55m trams really screw with things around Trinity.

You would also have to say that a tram line from Bray to Finglas would be massively long, and a luas extensions to these areas would be great. So severing the Green Line will actually allow more light rail coverage in Dublin.

strassenwo!f

marno21 wrote: »

Nobody is doubting that there are lots of needs in Dublin.

However, the cost of the Green Line upgrade to Metro is a small fraction of what another Metro Line would cost. And the small cost of the Green Line is small compared to the benefits it leads to.

Marno, I am very disappointed to see that the Greens are talking about building metro lines to Rathfarnham, and lines from Booterstown to Tallaght, without apparently any thought as to the cost. It seems to me to be nonsense.

But it seems to me, that a metro to Sandyford would provide that part of the southside of the city with a level of service (about 18,000 passengers per hour) which is way beyond what is needed at this stage. We see the metrolink.ie figures, and they're saying that they envisage a level on the Green line of 13,000 in 2057. You, I am sure, can see the difference here between the demand, and the capacity.

Much better, to my mind, to use the TBM - which will soon hopefully be going between Swords and the City - to do as much as it can to develop other parts of Dublin, probably quite gradually, in the period between now and the 2040's.

Gradually is the key word here.

But I'm aware that it's obviously relatively cheap to do what you say, now.

antoinolachtnai

This is if the Green Line stayed as it is. But the proposal is for the Green Line to be linked to the city tunnel. This will draw thousands more passengers to the Green Line section.

Metrolink will mean it is viable to commute from, say, Maynooth to Sandyford or vice versa on public transport. This will mean that there will be many more journeys on the green line section than there are today. Equally, a public transport commute to/from Swords or Malahide to Sandyford will be viable. This will certainly amount to thousands of new journeys at the peak hour.

Alkers

antoinolachtnai wrote:

Metrolink will mean it is viable to commute from, say, Maynooth to Sandyford or vice versa on public transport. This will mean that there will be many more journeys on the green line section than there are today. Equally, a public transport commute to/from Swords or Malahide to Sandyford will be viable. This will certainly amount to thousands of new journeys at the peak hour.

And take some pressure of the m50

strassenwo!f

antoinolachtnai wrote: »

This is if the Green Line stayed as it is. But the proposal is for the Green Line to be linked to the city tunnel. This will draw thousands more passengers to the Green Line section.

But that would also be the case if the tunnel was going to the southwest of the city, wouldn't it?

antoinolachtnai wrote: »

Metrolink will mean it is viable to commute from, say, Maynooth to Sandyford or vice versa on public transport. This will mean that there will be many more journeys on the green line section than there are today. Equally, a public transport commute to/from Swords or Malahide to Sandyford will be viable. This will certainly amount to thousands of new journeys at the peak hour.

But it would still be viable to travel between Sandyford and Maynooth, just with one change.

A metro line directly between the Airport and Terenure would mean that you'd have to make a change to get a Teddy's ice cream in Dun Laoghaire. How many changes does it require now to get a Teddy's ice cream from Templeogue?

Dats me

That's his point. We all support a SW metro, but Green Line has to be upgraded beyond a tram anyway. Why not do it now for the €150m that it will cost?

Campaign for a SW metro all you want, we'll be right there with you, but to leave the Green Line unupgraded would be irresponsible really given the situation and try development that's going to take place.

antoinolachtnai

strassenwo!f wrote: »

But that would also be the case if the tunnel was going to the southwest of the city, wouldn't it?



But it would still be viable to travel between Sandyford and Maynooth, just with one change.

It wouldn't be viable to commute at peak time from Sandyford to Maynooth.

There would be a route, sure enough.

But it would be very difficult to get on the Luas Green Line tram. The reason is that there wouldn't be enough capacity on the Green Line segment.

MetroLink solves this problem.

MJohnston

strassenwo!f wrote: »

But that would also be the case if the tunnel was going to the southwest of the city, wouldn't it?

Not quite:



The Green Line area is clearly much more 'active' in terms of residential density, available jobs, and student areas than the southwest (not including Tallaght because that's already served by Red Line and wouldn't be served by a Rathfarnham Metro anyway).

strassenwo!f

Dats me wrote: »

That's his point. We all support a SW metro, but Green Line has to be upgraded beyond a tram anyway. Why not do it now for the €150m that it will cost?

Well, what will it cost?

We originally understood that the tunnel was going to emerge at Charlemont. Now it appears that the preferred option is for the tunnel to emerge south of Beechwood. Extra cost, and reduced access. No noticeable effect on the Dunville Avenue crossing.

I think it's unnecessary to make these changes. Just keep it as a LUAS line, make some small changes in the city centre to help improve throughput, and off you go.

MJohnston

Also, the map I just posted is based on 2011 census data, which is before the expansion of Cherrywood SDZ really took hold. The balance would be even greater towards upgrading the Green Line if that map was regenerated with 2016 data, I believe.

MJohnston

strassenwo!f wrote: »

Well, what will it cost?

We originally understood that the tunnel was going to emerge at Charlemont. Now it appears that the preferred option is for the tunnel to emerge south of Beechwood. Extra cost, and reduced access. No noticeable effect on the Dunville Avenue crossing.

I think it's unnecessary to make these changes. Just keep it as a LUAS line, make some small changes in the city centre to help improve throughput, and off you go.

The figures are freely available in the reports on Metrolink.ie and you know this because they've been posted in reply to you several dozen times on the other thread.

MJohnston

Here are the figures:


4B was the previous option. So we're talking about an extra €77m, nearly all in extra tunnelling costs.

BTW, tunnelling costs works out to about €70m per km of tunnel. This means a tunnel to the south-west, presumably towards Ballyboden, would cost somewhere in the ballpark of €455m in tunnelling alone compared to stopping at SSG.

Qrt

Simona1986 wrote: »

And take some pressure of the m50

Especially if the colossal M1 P&R materialises

salmocab

Qrt wrote: »

Especially if the colossal M1 P&R materialises

I don’t think this will really alleviate anything on the M50, the people who come off it will be replaced by others doing shorter journeys, so if there is an improvement some people that are avoiding it will start using it. It will take a lot more than one metro to sort it out. It is a start though but until enough people have a viable alternative then the M50 will always be jammed.

strassenwo!f

CatInABox wrote: »

You might not be aware that the Green Line is due to be extended upon completion of the Metrolink upgrade. It's through mostly greenfield sites, allowing a massive concentration of new developments, quite like the current Cherrywood development.

Is there any such potential along any other possible Metro route? Bear in mind that Dublin is currently going through a ridiculously tough housing crisis? How many billions more have to be spent to get another Metro & Luas combination that unlocks that much development potential?

Also, bear in mind that developers have already been told that no large scale projects will be accepted in those areas until public transport provision has been upgraded i.e. the arrival of the Luas.

I will try to get back to the other points soon, but I am initially very curious about this one.

I certainly wasn't aware that there was such a development planned. I'm aware of the welcome development of Cherrywood, but you're saying this is something else entirely. The metrolink documentation makes no mention of it.

Where can I find details about this development, and what is it going to be called?

Is it really possible that I could have missed a proposal for another south-east Dublin development similar to Cherrywood, to which the currently proposed metrolink is going to go?

strassenwo!f

Dats me wrote: »

Also Strassenwolf, even given your very diligent calculations around Dunville Avenue, I'm afraid the city-centre section of the Green Line wasn't tunneled (I wasn't around boards at the time, can anyone remember what the feeling was about LCC when it was being planned?), so while Dunville Avenue could possibly deal with more trams , from what I've seen College Green, Dawson Street and the quays probably can't take any more than is there at the moment. Northbound 55m trams really screw with things around Trinity.

I think you're right that areas like College Green and the quays couldn't deal with a higher tram throughput (20 tph) than there currently is.

This is why I have suggested that there would be a split in the Green line, at around Peter Place/Adelaide Road, with development of a short LUAS section to/from Baggot Street Bridge (initially, but with obvious potential to extend it along the canal to around the Grand Canal Dock area).

You'd almost certainly have to demolish that derelict building on the corner of Peter Place and Adelaide Road, and make some radical changes to the road layout in that area. But it should, overall, be relatively easy to build, and would directly serve an area (or areas) which are busy at peak times.

Dats me wrote: »

You would also have to say that a tram line from Bray to Finglas would be massively long, and a luas extensions to these areas would be great. So severing the Green Line will actually allow more light rail coverage in Dublin.

I'd certainly like to see the Green line extended to Finglas, but I can't see why an extension to Bray should happen (it already has the DART - would buses between Bray and Cherrywood not be able to do the job?). In any case, Cherrywood - Finglas would be very long, but you've got to remember that almost nobody would be going the whole way. The city centre is the key destination, and on any rail system in the world the largest group of people (not necessarily the majority) are those who wish to go to/from the city centre.

Nobody, on a Cherrywood - Finglas LUAS line, would face a journey of more than around 40 minutes to get to/from the city centre. Upgrading part of that line to a metro would, it seems, shave perhaps 2-3 minutes off the journey. Is that going to make any difference?

strassenwo!f

Dats me wrote: »

That's his point. We all support a SW metro, but Green Line has to be upgraded beyond a tram anyway. Why not do it now for the €150m that it will cost?

Are you seriously suggesting that it will cost just 150m euro to tunnel from St. Stephen's Green to beyond the Beechwood stop - it now seems they're not planning to tunnel just to Charlemont - and upgrade all the stops/stations out to Sandyford to a metro standard? Seriously?

Qrt

strassenwo!f wrote: »

Are you seriously suggesting that it will cost just 150m euro to tunnel from St. Stephen's Green to beyond the Beechwood stop - it now seems they're not planning to tunnel just to Charlemont - and upgrade all the stops/stations out to Sandyford to a metro standard? Seriously?

90% sure the 150m figure is for the station upgrades and other upgrades needed on the green line excl tunnel.

antoinolachtnai

How much do you think it will cost?

How much would your Baggot Street Special cost?

Under your plan, would the Luas not need to be extended to Charlemont to meet with the BSS and high frequency luas section in any case? Would there also need to be a very large station there to cope with the thousands of people per hour switching between Luas and Metro? How much would this cost?