DART Underground - Why it won't be built.

D.L.R.

Sam Russell wrote: »

Why was it OK to build the Port Tunnel, which has benefited Dublin hugely by taking the HGVs out of the city centre, but it is not OK to build the DU or MN which would remove a large number of cars from the city centre?

Short answer, bad planning.

The Port Tunnel was a motorway tunnel at a time of massive motorway construction. DU is a completely different animal and a far bigger project with expertise required that we don't even have. I'm not convinced the state actually has the capacity to make it happen. We've never even managed a bog standard metro line, let alone a full sized rail tunnel with full size stations.

Which brings me to my next point.

DU's full role is still surprisingly vague... will it be Dart-only services or a mainline for all types of services including intercity trains? That hasn't been clarified sufficiently. Does it even need to be a full sized mainline railway tunnel?

The idea of a metro-sized DU tunnel hasn't been given enough consideration for me, as it would still deliver the primary objective of a cross city metro service. I'm not sure a full size railway tunnel is absolutely essential for a city region of less than 2 million people.

If its so impossible/prohibitively expensive to do a full size rail tunnel then what about a metro sized DU? Comments welcome.

Sleeper12

BonnieSituation wrote:

The fact that people (and the govt) need to be convinced of the benefits of DU show how utterly unlikely it is that this will be built.

BonnieSituation wrote:

The cost benefit of it to the WHOLE ISLAND must be off the charts.

Totally agree here. I don't use public transport but I spend 25 plus hours per week getting to my jobs all over Dublin. I'm in favour not because I can switch to public transport but because the better public transport we have in Ireland the more people will use it. This in turn will take a some of the cars off lets say the m50. So I will get the benefit even if I never use public transport

markpb

D.L.R. wrote:

The Port Tunnel was a motorway tunnel at a time of massive motorway construction. DU is a completely different animal and a far bigger project with expertise required that we don't even have.

I'm not sure that's true. The difficulty is building the tunnel. Putting tarmac or rail lines inside it is more or less irrelevant in terms of complexity.

D.L.R. wrote:

If its so impossible/prohibitively expensive to do a full size rail tunnel then what about a metro sized DU?.

What do you mean by a full sized tunnel?

Sam Russell

D.L.R. wrote: »

Short answer, bad planning.

The Port Tunnel was a motorway tunnel at a time of massive motorway construction. DU is a completely different animal and a far bigger project with expertise required that we don't even have. I'm not convinced the state actually has the capacity to make it happen. We've never even managed a bog standard metro line, let alone a full sized rail tunnel with full size stations.

Which brings me to my next point.

DU's full role is still surprisingly vague... will it be Dart-only services or a mainline for all types of services including intercity trains? That hasn't been clarified sufficiently. Does it even need to be a full sized mainline railway tunnel?

The idea of a metro-sized DU tunnel hasn't been given enough consideration for me, as it would still deliver the primary objective of a cross city metro service. I'm not sure a full size railway tunnel is absolutely essential for a city region of less than 2 million people.

If its so impossible/prohibitively expensive to do a full size rail tunnel then what about a metro sized DU? Comments welcome.

The DU tunnel could be a single bore the size of one Port tunnel - not sure why not as most of the London Underground and the Paris Metro is built like that.

The DU can allow Malahide to Hazelhatch, or even Kildare but I doubt diesels could work over the length of the tunnel without suffocating the passengers. I think Bray to Maynooth, and Malahide to Hazelhatch is the plan.

The key is to maintain the 1.6m gauge so the trains can operate over the Dart line. The Bakerloo line has small trains that operate in conjunction with Overground (full size) trains.

If MN is built with 1.6m gauge, then the possibility allows for connection to the Northern line at, say Donabate, and continue it onto the old Harcourt Line at Ranelagh, with the Luas turning left or right at the canal. Perhaps that is too much like crayoning.

murphaph

We're taking these big tech and finance companies for granted in Dublin. They will eventually get sick of their employees complaining about terrible commutes and start to look elsewhere. Might already be happening for all we know. This period was our golden opportunity to capitalise on their presence and further drive investment in Dublin.

The rest of the country needs to get behind the idea of pushing Dublin as our world city.

plodder

The fact there is talk of expanding the reach of existing lines rather than building new ones, shows that people (politicians and the public) don't really get the benefit of a network. Made this point loads of times before. DART underground is seen as a tunnel between two mainline stations (that already have a tunnel between them), and not as the core/foundation of a new network.

The loss of the web summit is partly down to infrastructure like public transport. That's a hundred million a year lost to the city. What other opportunities are being lost for same reason? Brexit will probably identify potential (lost) opportunities worth billions.

D.L.R.

markpb wrote: »

I'm not sure that's true. The difficulty is building the tunnel. Putting tarmac or rail lines inside it is more or less irrelevant in terms of complexity.

Not really. Building the rail systems and integrating it into the existing network and streets above at multiple sites is much more difficult than having a road tunnel thats only accessible from the two ends.

Not condoning it by the way, spending a decade building motorways and virtually nothing else was moronic.

markpb wrote: »

What do you mean by a full sized tunnel?

One large enough for mainline trains, ie Irish Rail trains. Metro trains and tunnels are generally smaller. Metro North is planned as a smaller metro tunnel, not a mainline railway tunnel. Huge difference in size.

D.L.R.

Sam Russell wrote: »

The DU tunnel could be a single bore the size of one Port tunnel - not sure why not as most of the London Underground and the Paris Metro is built like that.

London doesn't have single bore tube lines. The earliest lines are cut-and-cover, and the later ones are small profile twin tube. Not sure about Paris. I think Spain has single bore tunnels, could be a solution I guess. Seems less safe though.

Sam Russell wrote: »

The DU can allow Malahide to Hazelhatch, or even Kildare but I doubt diesels could work over the length of the tunnel without suffocating the passengers. I think Bray to Maynooth, and Malahide to Hazelhatch is the plan.

The key is to maintain the 1.6m gauge so the trains can operate over the Dart line. The Bakerloo line has small trains that operate in conjunction with Overground (full size) trains.

If MN is built with 1.6m gauge, then the possibility allows for connection to the Northern line at, say Donabate, and continue it onto the old Harcourt Line at Ranelagh, with the Luas turning left or right at the canal. Perhaps that is too much like crayoning.

So long as DU uses Irish gauge it doesn't really matter how large or small the tunnel is. Having two gauges hinders us though, for sure.

LeinsterDub

D.L.R. wrote: »

So long as DU uses Irish gauge it doesn't really matter how large or small the tunnel is. Having two gauges hinders us though, for sure.

He's referring to the size of the bore of the tunnel not the gauge of the rails. Like how the red and green lines have the same rail gauge but different clearance gauge.

D.L.R.

LeinsterDub wrote: »

He's referring to the size of the bore of the tunnel not the gauge of the rails. Like how the red and green lines have the same rail gauge but different clearance gauge.

The Dart could operate from Hazelhatch to Malahide just fine through a smaller bore. Just need smaller Darts!

Sam Russell

LeinsterDub wrote: »

He's referring to the size of the bore of the tunnel not the gauge of the rails. Like how the red and green lines have the same rail gauge but different clearance gauge.

No I'm not.

I am referring to the use of 1.6m gauge that Irish Rail uses. Why we went for 4ft 8.5 inch for the Luas (I presume) was to buy off the shelf standard gauge trams at a small saving compared to the overall cost.

The difference in gauge is 6.5 inches or 16.5 cm, which is too small to run three rails so four rails would be needed if dual gauge operation was to be considered which would be madness.

The distance between the tracks is also important, but that only applies if the trains are significantly wider.

DU and electrifying the Maynooth line and the line out to Hazelhatch would need to be part of the plan but not necessarily of the DU project. The overall idea is to build a network independent of the roads that support the bus and Luas systems.

Extending the Dart to Balbriggan or even Belfast would achieve nothing for Dublin traffic. What is needed is the ability to get from any place in Dublin City to any other with no more than one change within a reasonable time. Buses would only achieve this if there were few cars, bus lanes and no parking on bus routes.

Maybe BRT might achieve this in the short term, but trams would only be slightly more expensive and use the same type of road design.

BRT involves restricting cars, so why not restrict them anyway?

LeinsterDub

Sam Russell wrote: »

No I'm not.

I am referring to the use of 1.6m gauge that Irish Rail uses. Why we went for 4ft 8.5 inch for the Luas (I presume) was to buy off the shelf standard gauge trams at a small saving compared to the overall cost.

DU is always going to be Irish gauge. When would a Luas ever be running in it? I don't understand why this is even being discussed?

Idbatterim

I agree about the one change max point, anything more than that, and getting out of the car is a lot, lot less attractive...

murphaph

Idbatterim wrote: »

I agree about the one change max point, anything more than that, and getting out of the car is a lot, lot less attractive...

Ah it depends how good the connections are really. I have to take a regional train in to central station where I change onto a tram and head to the kindergarten with my son. Then I either take a bus direct to my office if I have timed it well or take 2 underground trains if not. Generally it all works. Obviously I'd prefer no changes if it were an option but I wouldn't buy a house in a certain location to make it happen as the job can move anyway.

Bray Head

plodder wrote: »

The fact there is talk of expanding the reach of existing lines rather than building new ones, shows that people (politicians and the public) don't really get the benefit of a network. Made this point loads of times before. DART underground is seen as a tunnel between two mainline stations (that already have a tunnel between them), and not as the core/foundation of a new network.

Very true. Ironically enough DB and IE always refer to their services as a 'network' when they aren't really. Modal and intra-modal switches aren't really that common in Dublin.


Dart Underground actually has the potential to make planning a journey with changes involved useful and feasible. The benefit is not only of getting from Connolly to Heuston but of the fact that it makes more of existing infrastructure.
This is not something that Irish politicians really get.

Sam Russell

Bray Head wrote: »

Very true. Ironically enough DB and IE always refer to their services as a 'network' when they aren't really. Modal and intra-modal switches aren't really that common in Dublin.


Dart Underground actually has the potential to make planning a journey with changes involved useful and feasible. The benefit is not only of getting from Connolly to Heuston but of the fact that it makes more of existing infrastructure.
This is not something that Irish politicians really get.

Connolly to Heuston is not possible by DU, unless you change at Pearse.

However it does make the Dart from Malahide to Heuston possible and Bray to Maynooth possible (assuming the electrify the line to Maynooth) And Airport to SSG (assuming they build the Clongriffin spur).

The joining of the two Luas lines is also a misnomer - they just cross each other. They are still two separate lines with no connection at all. The connection is just for stock transfer.

marno21

Sam Russell wrote: »

Connolly to Heuston is not possible by DU, unless you change at Pearse.

However it does make the Dart from Malahide to Heuston possible and Bray to Maynooth possible (assuming the electrify the line to Maynooth) And Airport to SSG (assuming they build the Clongriffin spur).

The joining of the two Luas lines is also a misnomer - they just cross each other. They are still two separate lines with no connection at all. The connection is just for stock transfer.

Airport to SSG would surely be handled by Metro North when built, which at present will be before the expansion of the DART Network.

Sam Russell

marno21 wrote: »

Airport to SSG would surely be handled by Metro North when built, which at present will be before the expansion of the DART Network.

True - maybe that is why DU will not be built. Still think the Airport - Clongriffin - DU would be quicker.

Bray Head

Sam Russell wrote: »

marno21 wrote: »

Airport to SSG would surely be handled by Metro North when built, which at present will be before the expansion of the DART Network.

True - maybe that is why DU will not be built. Still think the Airport - Clongriffin - DU would be quicker.

Quicker to build or a quicker journey time???

Sam Russell

Bray Head wrote: »

Quicker to build or a quicker journey time???

BonnieSituation

Councillors getting on the DU bandwagon.

Not a fan of Lavelle but I'm heartened by this.

http://www.irishtimes.com/news/social-affairs/dart-underground-needed-to-enable-17-000-new-homes-1.2725448

---

If MN is built before DU then this city and country can go fupp itself. Jokeshop.

Sam Russell

BonnieSituation wrote: »

Councillors getting on the DU bandwagon.

Not a fan of Lavelle but I'm heartened by this.

http://www.irishtimes.com/news/social-affairs/dart-underground-needed-to-enable-17-000-new-homes-1.2725448

---

If MN is built before DU then this city and country can go fupp itself. Jokeshop.

I like this from the IT quoted:

http://www.irishtimes.com/news/social-affairs/dart-underground-needed-to-enable-17-000-new-homes-1.2725448

A Strategic Development Zone (SDZ) was established for Adamstown in 2003 to allow the fast-track development of a new suburb for the rapidly growing population of west Dublin.

Not sure if it was intended - but yes - we need a fast track DU to be built.

Carawaystick

If you're boring a tunnel, won't the height of the catenary determine the bore diameter?

You'll need clearance space from the top of tunnel to the power line,
pantograph space, train space, sub floor height to the rail and the difference between 1600mm and 1435mm space between the rails is small beans after this.

Idbatterim

shows you the level of morons we are dealing with. I wrote to Lavelle a few months back, simply dont saction the new suburb, until ground is broken on DU...

Rail based transport is a large part of the solutions to dublins gridlock and housing crisis...

“We cannot deal with the housing crisis unless we deal with this looming transport crisis. Clonburris will be a non-runner without Dart Underground. The surrounding road network cannot take any more traffic, and I would expect councillors will vote against the SDZ if Dart Underground is not reinstated.”

I said they had central government balls in a bit of a vice on this and shouldnt let them off the hook. All they care about is how they are perceived and pressure, they back down at the hint of conflict. Simply vote against the SDZ until DU ground is broken...

BonnieSituation

Idbatterim wrote: »

shows you the level of morons we are dealing with. I wrote to Lavelle a few months back, simply dont saction the new suburb, until ground is broken on DU...

Rail based transport is a large part of the solutions to dublins gridlock and housing crisis...

I said they had central government balls in a bit of a vice on this and shouldnt let them off the hook. All they care about is how they are perceived and pressure, they back down at the hint of conflict. Simply vote against the SDZ until DU ground is broken...

I completely agree but maybe vote for it under the condition that DU goes ahead. Build in conjunction?

I mean even opening Kishogue is a start?

That station is a prime example of a sh!tshow of a State that we all live in.

murphaph

Carawaystick wrote: »

If you're boring a tunnel, won't the height of the catenary determine the bore diameter?

A solid rail is mounted to tunnel roof, inches below it. The pantograph is pushed right down inside the tunnel, lower than it normally would be.

Idbatterim

seeing as DU and MN if they ever get built are years away, could we not have a connection out to the airport done for little money?

just use diesel locomotives to serve it? get these from the imminent shutting down of one or two lines?

people say there is an issue with capacity, but the airport rush hour, starts earlier than normal rush hour...

as you would normally be there at least an hour before flight departure, a good bit before that if it is long haul...

Chivito550

Idbatterim wrote: »

seeing as DU and MN if they ever get built are years away, could we not have a connection out to the airport done for little money?

just use diesel locomotives to serve it? get these from the imminent shutting down of one or two lines?

people say there is an issue with capacity, but the airport rush hour, starts earlier than normal rush hour...

as you would normally be there at least an hour before flight departure, a good bit before that if it is long haul...

Half arsed approaches like the above only serve as an excuse to not do things properly (MN and DU).

Bray Head

Chivito550 wrote: »

Half arsed approaches like the above only serve as an excuse to not do things properly (MN and DU).

Agreed. While the construction period would quicker due to the lack of tunneling you would face very similar issues with planning, planning appeals, EIS, tendering, CPO, etc.

The Clongriffin spur also falls down on its own merits, but this is a separate issue.

Chivito550

Bray Head wrote: »

Agreed. While the construction period would quicker due to the lack of tunneling you would face very similar issues with planning, planning appeals, EIS, tendering, CPO, etc.

The Clongriffin spur also falls down on its own merits, but this is a separate issue.

Clongriffin Spur wouldn't allow for that much frequency as DART services would still need to serve Malahide and Howth, and Connolly would struggle to handle even more services.

It's such a classic short term solution.