DART+ (DART Expansion)

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".

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).

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.

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".

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.

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?

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

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.

LXFlyer

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 would further assist in the ability to overtake.

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

MJohnston wrote: »

Right but that's just one specific spot, and I'm sure there are a few more of them in various places along the line. It wouldn't have to be "every house along the tracks on whichever side you want to add tracks" as someone else said before.

I've been messing around on AutoCAD, the problem is you need a pretty straight corridor so the pinchpoints will inform the alignment. If you move the track to the north to avoid houses on the south at one point, you might not be able curve the track back in time to avoid houses on the south.

This is pretty crude, and I don't have access to the OS map tiles in .dwg format (if anybody has and wants to send them my way...), had to use an aerial photo but I make it six houses definitely clipped by the track, and another 20 or so that would lose most of their gardens. The White line is the current centreline of the track (as best I could make out), and each coloured line is offset 2.5m from the next. So the full corridor is 25m.

AngryLips

Pete_Cavan wrote: »

I think the best way to increase commuter capacity on the Northern Line is to use big trains. Double decker trains are common on the continent and are not much higher than standard trains.

This does nothing to solve the problem on the northern line, which is the need to separate out the direct intercity services from the suburban services.

Brian CivilEng wrote: »

No I mean physical walls of houses. Extensions yes, but part of the building. Again, my disclaimer is that I live on one of these streets so I may be biased. Look at Belmont Park to Foxfield Grove.

Right but that's just one specific spot, and I'm sure there are a few more of them in various places along the line. It wouldn't have to be "every house along the tracks on whichever side you want to add tracks" as someone else said before.

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.

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.

lucernarian wrote: »

Irish rail said ~300 million for 3 and something like 850 million for 4... Where's your sources?

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?

MJohnston wrote: »

But why? I'm sure gardens would have to be CPO'd, but what you've said there doesn't seem especially borne out by the physical reality.

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.

MJohnston wrote: »

I don't mean this in a confrontational way but can someone point me to where the aforementioned houses are that prevent the Northern Line being widened?

I see a lot of back gardens for sure, but even in places where that's true I see a buffer either side of the existing tracks that seems enough to make a widening possible.

To me it seems like the bigger problem is there's no way to widen the line without closing the Northern Line for a significant amount of time.

Yeah, the options to develop this while using minimal land take, even for 3 tracks, is almost horrifying. That's the real issue with the work, not the land take.

MJohnston wrote: »

By "back walls of houses" do you mean their boundary walls? Because I genuinely don't see where you mean!

No I mean physical walls of houses. Extensions yes, but part of the building. Again, my disclaimer is that I live on one of these streets so I may be biased. Look at Belmont Park to Foxfield Grove.

Pete_Cavan wrote: »

That is not true. 3 tracks would require much the same work and expense as 4.

Irish rail said ~300 million for 3 and something like 850 million for 4... Where's your sources?

Brian CivilEng wrote: »

Between Raheny and Killester there are points where the gap between back walls of houses each side of the line is 20m. Combined with the track being in a cutting. On the Kildare route project, the cross section was about 22m fence to fence on the flat.

By "back walls of houses" do you mean their boundary walls? Because I genuinely don't see where you mean!

MJohnston wrote: »

I don't mean this in a confrontational way but can someone point me to where the aforementioned houses are that prevent the Northern Line being widened?

I see a lot of back gardens for sure, but even in places where that's true I see a buffer either side of the existing tracks that seems enough to make a widening possible.

To me it seems like the bigger problem is there's no way to widen the line without closing the Northern Line for a significant amount of time.

Between Raheny and Kilbarrack there are points where the gap between back walls of houses each side of the line is 20m. Combined with the track being in a cutting. On the Kildare route project, the cross section was about 22m fence to fence on the flat.

Equium

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.

Pete_Cavan wrote: »

The "buffer either side of the existing tracks" is a several metre high embankment from south of Killester to north of Raheny. To add more tracks, you need to dig out the embankment and to do that you need space for large plant to operate. Think large excavators digging out the ground and multiple large dumper trucks removing it and driving routes, turning circles, etc. for them. You also need to build a new embankment or retaining wall which will require more space. All this heavy construction work will have to take place with a sufficient buffer from the existing operational tracks. At the stations, the new track(s) would have to go behind the station which remains live so further back from the existing tracks. If doubt all this can be practically done with only taking gardens, and even if it could, the new embankment/retaining wall would be starting at the back wall of the houses. Every house along the tracks on whichever side you want to add tracks would realistically have to be CPOed.

But why? I'm sure gardens would have to be CPO'd, but what you've said there doesn't seem especially borne out by the physical reality.

lucernarian wrote: »

It doesn't need quad tracking to achieve almost the same outcomes as 3 tracks... Are you reading what I posted at all... This vastly reduces the need for demolitions except on the approach to Howth Junction.

That is not true. 3 tracks would require much the same work and expense as 4.

MJohnston wrote: »

I don't mean this in a confrontational way but can someone point me to where the aforementioned houses are that prevent the Northern Line being widened?

I see a lot of back gardens for sure, but even in places where that's true I see a buffer either side of the existing tracks that seems enough to make a widening possible.

To me it seems like the bigger problem is there's no way to widen the line without closing the Northern Line for a significant amount of time.

The "buffer either side of the existing tracks" is a several metre high embankment from south of Killester to north of Raheny. To add more tracks, you need to dig out the embankment and to do that you need space for large plant to operate. Think large excavators digging out the ground and multiple large dumper trucks removing it and driving routes, turning circles, etc. for them. You also need to build a new embankment or retaining wall which will require more space. All this heavy construction work will have to take place with a sufficient buffer from the existing operational tracks. At the stations, the new track(s) would have to go behind the station which remains live so further back from the existing tracks. If doubt all this can be practically done with only taking gardens, and even if it could, the new embankment/retaining wall would be starting at the back wall of the houses. Every house along the tracks on whichever side you want to add tracks would realistically have to be CPOed.

Brian CivilEng wrote: »

My own view of four tracking the northern line is possibly biased as I live on a street in Raheny which would require properties to be purchased and demolished (my own home is safe). But with that disclaimer, I don't think it is the best solution. There is a separate rail needs study being carried out, and I believe that it will recommend a new high speed line from Belfast to Dublin. Taking the inter-city traffic from the northern line and leaving it for just DART and commuter services should reduce the capacity issues.

It doesn't need quad tracking to achieve almost the same outcomes as 3 tracks... Are you reading what I posted at all... This vastly reduces the need for demolitions except on the approach to Howth Junction.

I don't mean this in a confrontational way but can someone point me to where the aforementioned houses are that prevent the Northern Line being widened?

I see a lot of back gardens for sure, but even in places where that's true I see a buffer either side of the existing tracks that seems enough to make a widening possible.

To me it seems like the bigger problem is there's no way to widen the line without closing the Northern Line for a significant amount of time.

There is a separate team looking at DART+ coastal (existing) route so I'm sure they will explore options on the Northern Line in more detail. I can't see it being feasible to add tracks aloneside the existing tracks. Between Killester and Raheny is in a cutting which can't be easily widened and houses right up to the top of the cutting on either side. To fit in the tracks and everything else they need (drainage, cabling, signalling, etc.) and allowing working space for construction with sufficient spacing for the existing tracks to remain operational, they would have to CPO every property along one side. That is too contentious and would likely face insurmountable opposition, nevermind the enormous cost. I don't see how adding one track would be easier than two. You still have much the same space requirement allowing for construction, two metres less for tracks in still going to require CPOing the whole property.

I think the best way to increase commuter capacity on the Northern Line is to use big trains. Double decker trains are common on the continent and are not much higher than standard trains. Raising a few bridges might be needed but that is a small enough job, particularly when you consider that the bridge would have to be widened anyway if adding more tracks.

riddlinrussell

Brian CivilEng wrote: »

My own view of four tracking the northern line is possibly biased as I live on a street in Raheny which would require properties to be purchased and demolished (my own home is safe). But with that disclaimer, I don't think it is the best solution. There is a separate rail needs study being carried out, and I believe that it will recommend a new high speed line from Belfast to Dublin. Taking the inter-city traffic from the northern line and leaving it for just DART and commuter services should reduce the capacity issues.

Agreed on the need for a high speed line, I'd expect possibly a recommended route that passes under the city to Heuston (possible stop at Cross Guns?) But the expense of that project would be fairly steep. I can see at a minimum 3 tracking sections of the northern line no matter the grief it will cause, because a separate HS line is a very long term prospect unless Ireland unifies and the EU/UK are providing some sweet unification bonuses

My own view of four tracking the northern line is possibly biased as I live on a street in Raheny which would require properties to be purchased and demolished (my own home is safe). But with that disclaimer, I don't think it is the best solution. There is a separate rail needs study being carried out, and I believe that it will recommend a new high speed line from Belfast to Dublin. Taking the inter-city traffic from the northern line and leaving it for just DART and commuter services should reduce the capacity issues.

I find this plan exciting, because there is a good chance of it actually going ahead. As bk said above, it allows the entire project to be broken down into a series of smaller projects, each with their own lower costs and benefits. Plus a minor issue holding up construction in one suburb isn't going to delay the roll out of the entire project.

I am also positive about the fact that nothing in the plan precludes DART Underground from being built later. In fact it enhances the chances of it being built, as you would imagine with a tripling of DART usage Irish Rail would find themselves in a better position financially.

Don't let the great be the enemy of the good. If we get all of Metrolink, DART+, Finglas Luas and Bus Connects all built we will be left with a public transport network for Dublin to be proud of.