DART+ (DART Expansion)

PlatformNine

https://www.boards.ie/discussion/comment/123766884#Comment_123766884

https://www.irishrail.ie/en-ie/news/stay-safe-at-level-crossings-international-level-c

To add some numbers to this, when IE published some data for international LC awareness day, there had been 30 incidents reported across the country. At least 16 of these had happened with the Dublin commuter network, with the most incidents being at:

• Serpentine Avenue (5 incidents)
• Sutton (3 incidents)
• Bray, Claremont, Coolmine, and Sandymount (2 incidents each)

It doesn't list where the other 14 incidents happened as they would have been LCs with one incident each, but I would think that at least a few of them were also within the Dublin network.

While 5 isn't exactly the majority of reported incidents, let alone the actual number of incidents, the fact that any individual LC accounts for a sixth of all reported LC incidents across the country is in my mind (and likely also IE's) completely unacceptable and a sign that it needs to be closed. Additionally Sandymount also having 2 incidents and being less than 500m away from Serpentine Ave I think makes it look even worse.

cgcsb

https://www.boards.ie/discussion/comment/123766850#Comment_123766850

"Every move to restrict traffic just leads to it being moved elsewhere"

Except that is completely untrue, and has been proven to be untrue all over the world again and again in hundreds of cities.

spacetweek

Transport demand is mostly on the supply side. Whatever you prioritise in terms of supply, that’s what will be very popular. If the eastern bypass had been built there would have been a huge increase in the supply of car capacity which would result in a huge increase in driving. Greatly improving the Dart - which requires level crossing closure - will increase public transport usage and reduce or at least hold steady car demand.

Consonata

https://www.boards.ie/discussion/comment/123757040#Comment_123757040

I just don't see how you expand Dart services to Wicklow in any meaningful way without tunnelling/Bypassing Bray head. Doing this on single track is going to be incredibly challenging and most of the pathings on the line are already used up. There's not much slack there.

https://www.boards.ie/discussion/comment/123766850#Comment_123766850

In order of the people I have sympathy for, an area which has the best transport access in the country, with an average house price of 1mill, my tiny violin will have to come out I'm afraid.

citizen6

Given the cost of another line through or around Bray Head, is there any benefit to running longer trains on the existing line?

Maybe a shuttle between Bray and Greystones (or Wicklow or Gorey), with the platforms lengthened. Those trains wouldn't stop at any stations where it wasn't worth extending the platforms.

thosewhoknow

Surely it would be cheaper upgrading Bray Head for double-decker trains than tunnelling through it.

scrabtom

https://www.boards.ie/discussion/comment/123770645#Comment_123770645

We'd have to buy bespoke narrow gauge double decker trains just for that short stretch of track then as they couldn't be used anywhere on the network because of bridge height.

Maybe worth doing if we fixed all of the bridges on one of the main lines to take them but that would be very expensive, otherwise it sounds like a tough sell.

riddlinrussell

It would be a relatively straightforward job for a TBM to do a tunnel, I don't believe the ground composition there is awful generally. The issue is it not having a CBA that justifies the expense of a TBM?

A thought occurs, given the TBM would 'come out the other end' and its a relatively short section of tunnel, could you do it as a preliminary step in DART underground? Cut the Dart tunnel through Bray Head, local teams get practice with the equipment and techniques in a 'lower risk' environment. TBM comes out on the far end and is transported directly to the main project tunnel portal?

scrabtom

https://www.boards.ie/discussion/comment/123770793#Comment_123770793

I might be wrong but I don't think the actual tunnel boring machine is the big cost when building tunnels, it's actually getting them in the ground and operating them, doing surveys etc.

orb123

https://www.boards.ie/discussion/comment/123769243#Comment_123769243

It can be done. According to the Wicklow Capacity Study:

"The timetabling assessment indicates 1 train per hour per direction Wicklow to City Centre and existing DMU Gorey/Rosslare services can operate without the need for corridor track capacity enhancements."

"1tphpd BEMU enables the integration of Wicklow to City Centre services into the existing timetable and future DART+ Train Service Specification with allowance for service perturbation."

Post Dart+, a shuttle service is planned for south of Wicklow.

loyatemu

https://www.boards.ie/discussion/comment/123770793#Comment_123770793

It would be a very straightforward project from an engineering perspective, straight tunnel through rock, no stations.

2018 costs:

bk

https://www.boards.ie/discussion/comment/123771952#Comment_123771952

Construction costs have at least doubled since 2018 and in Ireland we tend towards the expensive end of projects, so realistically you'd be looking at €350 million (3.5 x 50 x 2). Also we would probably go with the dual tunnel option given the issues the existing tunnel has, so that is closer to €490 million

Even if you feel that is on the expensive end, it is still going to cost at least €200 million.

But the real issue is where is the justification for this?

Are trains leaving Greystones in the morning peak full at the moment? The passenger numbers from the rail survey don't indicate they are.

Going from 2 trains an hour to 3 trains is a 50% increase in capacity and frequency. If that can be done for 1/10th of the above cost, then why would you spend that money?

Would it be nice for Greystones to have a 10 minute service, sure, but something being nice isn't going to justify the above cost.

I'm not saying it will never happen, 50 years from now perhaps Greystones and Wicklow have grown so much that a 10 minute service is necessary. But in the meantime we have the low hanging fruit of increasing frequency without tunnelling, that should be the priority and focus.

The Mathematician

https://www.boards.ie/discussion/comment/123772748#Comment_123772748

My worry would be the robustness of the timetable. Greystones will have a train every 20 minutes on paper, but will this be sustainable day to day. If something goes wrong, will we be able to recover, or will things remain wrong for the rest of the day? Also, will this impact on the line north of Bray, and will the whole line be regularly messed up for the day.

It is quite unusual for a line with metro frequency to end up in a single track line like this. It would be much more usual to run the single track line separately and require a change to trains on the double track line. I doubt it would be politically acceptable to require a change of trains at Bray, so it might be worth considering an investment like this to avoid the timetable on the whole line being regularly messed up.

bk

https://www.boards.ie/discussion/comment/123773272#Comment_123773272

Surely that is down to the experts at Irish Rail?!

If they think it can be done, who are we to doubt them? Do you have any evidence otherwise?

Keep in mind that the line is getting upgraded with a new modern signalling system, ECTS, which allows trains to run much closer together and more frequently.

if the experts think it can be done, then surely we try it first, before going spending hundreds of millions on a tunnel. Grand if it doesn’t work, back to the drawing board, but not like anything would be lost as the work needed for 20 minute service, double tracking up to the tunnel, ECTS, etc. would all be needed if you were to dig another tunnel anyway.

Let’s see what the experts have to say when they publish detailed plans for this upgrade and we can all pour over the engineering docs.

loyatemu

the current 30 minute service is unreliable, I'm sceptical they can run a 20 minute frequency that requires trains to pass each other at a short passing loop. But as you say, they're not building a new tunnel anytime. I'd be happy if they just improved the weekend frequency, which would require no engineering.

The Mathematician

https://www.boards.ie/discussion/comment/123773494#Comment_123773494

My evidence is as a regular traveller on the Sligo line, and also what happened in the timetable change last autumn. A train every 10 minutes on a single line isn't radical in itself, but when it is feeding in to a much higher frequency line which in turn interacts with other lines, the margin for error is very slim.

Of course it all might work (talking about the whole DART+ now), but I have my doubts, especially with all the flat junctions. I have spent enough time waiting at Praed Street Junction earlier in my life to know how these destroy capacity.

I also don't think it will be grand if it doesn't work, can you imagine the press coverage and public opinion if all the money spent on DART+ ends up in a total mess. It will be the Childrens' Hospital all over again. The government will then be very reticent to spend money on railways again. At the very least it should be brought in gradually and not in one big bang.

Consonata

https://www.boards.ie/discussion/comment/123773494#Comment_123773494

I mean, I assume Irish Rail have more knowledge of this stuff than I do, but the recent havoc caused by the timetable changes, which were in part designed to sweat more capacity, I think would go against this line of thinking

KrisW1001

https://www.boards.ie/discussion/comment/123773666#Comment_123773666

But there, they were trying to push more services despite having no extra capacity; instead they reduced the amount of slack in the existing plans to create new slots, and that’s why the system became more unstable. DART+ actually adds capacity, a lot of it. The signalling improvements alone will allow the system to function more reliably without needing such long intervals between services.

loco_scolo

https://www.boards.ie/discussion/comment/123774190#Comment_123774190

Will the new signalling system also speed up level crossing closures? I know there are reasons why the gates close for so long, but it seems like complete overkill.

I'd say a decent portion (perhaps a majority) of level crossing incidents are caused by people's impatient to wait.

KrisW1001

https://www.boards.ie/discussion/comment/123774276#Comment_123774276

I doubt it, as the gates close early to make sure that other traffic will be out of the way by the time the train crosses. The gates already lift pretty much as soon as the train has passed. Perhaps more accurate train positioning would allow the gates to close a little closer to the time when the train crosses, maybe?

But, by increasing the number of trains allowed per hour, new signalling will probably increase the overall length of time when the gates are down.

goingnowhere

Signalling won't help, the current DART line uses a computer driven scheduler to optimise closures, different service types get a different timing sequence to reflect stopping pattern.

Elsewhere on the network gate closure is purely a strike in point basis so has no consideration of train stopping pattern. Maynooth line operates on this basis.

spillit67

https://www.boards.ie/discussion/comment/123768026#Comment_123768026

Yes it is the case here. You simply are not going to change people’s driving decisions from the East Link to Blackrock / N11.

People already account for massive delays, they don’t care because the alternative (the M50) is far worse. This is basically a case of our old school pre Motorway infrastructure still persisting.

The Sandymount strand cycle lane won’t impact on people’s decisions whether to drive or not, it’s a scenic bike path. But it absolutely impacts on the traffic on other roads around there.

spillit67

https://www.boards.ie/discussion/comment/123768868#Comment_123768868

Not in this location. It’s a route of national importance but is being served by a series of half built infrastructure (why do you think the East Link was built?) leading to narrow roads.

spillit67

https://www.boards.ie/discussion/comment/123772748#Comment_123772748

Again I really don’t think you fully get demand. Demand is also impact by levels of service AND location. Now location of a station likely would never change (but I don’t know, would there be value in a Greystones North station?) but increasing the quality of service there to “turn up and go” (which Bray arguably has) would clearly have an impact on demand. Already it is an in demand station. In particular if you cut out the meandering elements of the existing service you could cut journey times to Greystones to the City Centre to more towards 50 mins, making it more attractive. I don’t know if this passes a CBA but it seems to me that people fit in their notions to fit the situation. When we have other rail plans we emphasise the potential of providing improved services but here we talk that down.

riddlinrussell

I'd argue that the TBM itself is still a fairly big chunk of the cost of any tunneling project! Especially if the rest of the project is a straightforward, fairly short, bored tunnel through solid rock with no stations etc.

I think the CBA for it is a hard sell standalone, but if there were no technical reason for the TBM not to immediately be removed and transported to a DU tunnel portal compound via M11/M50 then suddenly a big chunk of the costs of it become "free" and the CBA for it looks far rosier. The TBM for both would need to be the same size and the tunnel fitouts would be identical to suit DART, so I can't think of a better opportunity to do a Bray head tunnel, if one were ever going to get done.

KrisW1001

https://www.boards.ie/discussion/comment/123775528#Comment_123775528

It’s not exactly “free”, as the cutting head is specified for a volume of tunnelling. Also, if the rocks that form Bray Head are different to the ground under Dublin, then it’s a completely new head, or even a new machine, and that’s a big cost. Dublin Port Tunnel needed two TBMs not because there were two bores, but because there were two very different types of ground that had to be tunnelled through, and one machine couldn’t do both.

jwm121

https://www.boards.ie/discussion/comment/123775185#Comment_123775185

Would there be any prospect of moving the Greystones station further south, closer to the park and ride, which would also be closer to whatever (hopefully zoned residential) is built on the 60 acre former Charlesland golf course sight?

loyatemu

https://www.boards.ie/discussion/comment/123776042#Comment_123776042

if something is built on Charlesland GC (personally I'd like to see at least a big chunk of it become a public park) they could open an extra station. The existing station is bang in the middle of the town - it would be a retrograde step to move it IMO.

riddlinrussell

Thanks, that would be what I was after regarding an actual "technical" reason it couldn't be done. I would still argue its the most likely chance of a Bray head tunnel going ahead, but likely wouldn't even be considered due to risk of scuppering the DU

A1ACo

It may not just be the benefit of potentially TBMs going between tunnelling projects, but also cross-fertilization as it were of various other equipment, parts and also specialized construction, design and surveying staff - between up to three tunnelling projects one-after-the-other, or partly in-tandem.. I.E any DU iteration, Metrolink and a Bray Head tunnel(s).

There might also be some benefits in training, supply chains and other build-ups for following projects, and added attractiveness for bidders if there were a selection of projects on the go?