[article] RPA defends capacity of proposed metro trams

[undo]

This article from the Irish Times was posted at here a couple of days ago:

Specifications for Dublin's Metro North to be released later this month are to concentrate on 90-metre trams as opposed to the higher capacity heavy rail carriages, the Railway Procurement Agency has confirmed. Tim O'Brien reports.

The confirmation comes amid mounting concern over capacity problems on the existing Luas lines as well as fears that Metro North could suffer similar peak-hour capacity problems within a decade of opening.

The Irish Times has learned the RPA was advised by some of the bidders for the Metro North contract that even if it opts for the narrower 2.4 metre tram system, it should build the tunnel wide enough to later convert to 2.8 metre carriages.

The RPA has also been told that comparable capital cities to Dublin, including Prague, Hamburg, Vienna, Berlin, Lisbon, Munich and Madrid all utilise the higher capacity, wider-bodied carriages in their undergrounds.

Munich, which was the subject of a Department of Transport visit in 2005, uses a "low capacity metro" at 2.8 metres wide, and is capable of carrying in excess of 30,000 people per hour in each direction , some 50 per cent more than the 20,000 capacity of the proposed Dublin underground. Dublin's Dart which can be up to 170 metres long has capacity for 36,000 people per hour per direction. The capacity issue comes as RPA planners face criticism over passengers being left on the platform during the morning rush because trams are full. A Dublin City Business Association spokesman, Tom Coffey, said "to be credible the underground has to have a capacity of about 35,000 people per hour in each direction.

"We can't have a metro which is going to reach capacity six years after it opens. There is no going back to widen a tunnel after it is built and this infrastructure should be designed to last 100 years, as it did in London and elsewhere," he maintained.

The issue also comes as a two-day conference on infrastructure heard details of a Dublin Institute of Technology Futures Academy report which predicted population on the island would rise to seven million people by 2020, with about 1.5 million extra people moving into the Dublin Belfast corridor.

A number of commentators including the head of the National Roads Authority Fred Barry said the population increase - similar in size to the existing population of Dublin - would require another large-scale increase in public transport. Mr Barry said the increase would result in demand for much more rail transport as part of "a successor to Transport 21, a Transport 22, if you like".

However, speaking at the conference the chief executive of the RPA, Frank Allen, said he was "absolutely confident" that the capacity of 20,000 people per hour in each direction was sufficient for Metro North.

He remarked that just "isolated parts" of the London and Paris metros were operating above that capacity and it would be very hard to find other examples in cities in Europe. He said he was "very, very confident" of the capacity of the 90-metre carriages operating at a two minute frequency during peak times.

Mr Allen said the population forecast in the Fingal County Development plan was more pertinent than the all-island forecast. Metro North was, he said, "fully integrated with population projections" and "Fingal is absolutely confident that the capacity is more than is required".

The Irish Times

The Independent also isn't too sure about metro light's capacity (link):

Metro 'too small' to cope with demand, says expert

Wednesday February 06 2008

A boss of world metro maker Siemens says the planned Metro from Dublin city centre to the capital's airport will be far too small to cope with projected demand.

Dr Werner Kruckow, chief executive of Siemens Ireland, said yesterday that the proposed Dublin Metro will only be able to handle 20,000 passengers an hour in each direction which is far "too small".

The transport chief said the development of a sustainable city like Dublin requires the fast implementation of a high capacity transportation network, similar to that in other European cities.

Munich in Germany had a metro with a capacity for 36,000 passengers per hour in each direction, yet the maximum it has ever carried was 30,000.

"Dublin is planning for a peak of 20,000 per hour in each direction. This is much too low," the Siemens chief said in Dublin yesterday.

The Metro plan also failed to take account of projected population increases, which is due to reach two million.

[Mark]

The issue here is not length of trams and stations or frequency but rather the actual width of the units which in order to keep costs down and to provide interoperability with the Luas is set at 2.4m. Most metro units are 2.65 or 3m wide.

Something will have to give.

[Mark Gleeson]

Figures which I've seen suggest a 22.5-25k capacity

Originally it was 18k

Question: Will it be busier inbound or outbound in the Morning Rush?

[Brian Condron]

What is the actually story regarding tunnel widths, forgetting about the station platforms at the moment, can the tunnels cater for wider trams?

Surely in this day and age it is possible to have platform edges which automatically extend to meet the tram? In New York when the two subway systems were combined, automatic ramps were installed so that trains from the narrower system could use stations from the wider system. Some stations still have them.

[undo]

Originally Posted by Brian Condron

Surely in this day and age it is possible to have platform edges which automatically extend to meet the tram?

But that would require the RPA admitting that underground Luas won't cut it. And that they are currently not prepared to do.

[Mark]

Originally Posted by Brian Condron

What is the actually story regarding tunnel widths, forgetting about the station platforms at the moment, can the tunnels cater for wider trams?

Surely in this day and age it is possible to have platform edges which automatically extend to meet the tram? In New York when the two subway systems were combined, automatic ramps were installed so that trains from the narrower system could use stations from the wider system. Some stations still have them.

Given the height of the trams plus OH is 3.8 m plus and the tunnels are singel bore then the width of the trams wont be an issue. Its platforms and at grade and elevated structures which are the issue.

[undo]

It's interesting you should mention the overhead wire. That reminds me how proper metro systems normally use third rail, not overhead - for the very reason that it allows smaller diameter tunnels to be bored, reducing costs. Of course, with a third rail, at-grade intersections are impossible. I wonder if the RPA ever weighed the higher cost of proper segregation against the reduced costs of tunelling at a lower diameter. It might just turn out that a real metro is even cheaper to build.

[Colm Moore]

Originally Posted by Mark Gleeson

Question: Will it be busier inbound or outbound in the Morning Rush?

Given that the city centre and the Nass Road areas are the two prime destinations, why would it be busier outbound?

Originally Posted by Brian Condron

What is the actually story regarding tunnel widths, forgetting about the station platforms at the moment, can the tunnels cater for wider trams?

I imagine the difference in cost beteen the two tunnel sizes is relatively modest in terms of overall cost. If larger vehicles are used later, the smaller vehicles can be cascaded onto other lines

Surely in this day and age it is possible to have platform edges which automatically extend to meet the tram? In New York when the two subway systems were combined, automatic ramps were installed so that trains from the narrower system could use stations from the wider system. Some stations still have them.

I imagine it is better to operate with a single fleet. Designing the platform edges such that they can be changed over say a weekend closure in a "Big Bang" changeover would be desireable, although the familiarisation training of drivers on the new vehicles for the characteristics of that section of track might be an issue. Basic training of the drivers on the vehicles could be done somehwere else.

Originally Posted by undo

It's interesting you should mention the overhead wire. That reminds me how proper metro systems normally use third rail, not overhead - for the very reason that it allows smaller diameter tunnels to be bored, reducing costs.

Aren't new third rail systems banned on safety grounds?

[undo]

Originally Posted by Victor

Aren't new third rail systems banned on safety grounds?

By whom? The Irish government? Or on an EU level?

[Mark Gleeson]

Conductor rail systems are not recommended by the RSC

[Colm Moore]

Low-capacity design favoured for Metro North
From ireland.comSaturday, 22nd March, 2008

THE RAILWAY Procurement Agency (RPA) is to go ahead with a low-capacity design for Metro North, according to briefing documents circulated to the four consortiums which are bidding for the project. Tim O'Brien reports.

The agency confirmed to bidders at a specially organised "workshop" in recent weeks that it wanted to develop an underground which uses vehicles that are longer but similar in width and height to the overground Luas trams.

The Luas has already faced criticism from commentators, including Dr Garret FitzGerald, who say its current capacity problems relate to the fact that it is a lower-capacity tram system rather than a heavy-rail metro line.

However, the Green Line Luas was constructed so that it could be converted to a heavy-rail metro line by the addition of faster, wider-bodied carriages - at least from the Beechwood stop outbound.

However concern has been expressed that such an approach would not be possible under ground, unless the tunnel was constructed to a wider specification than that which has been indicated in the pre-tender advice given to the bidding companies at the workshop.

The agency's specification envisages a maximum 18,000-20,000 passengers an hour in each direction, in what would essentially be a 90m (295ft) underground tram.

In contrast, the overground Dart has a capacity of at least 36,000 passengers per direction per hour.

In a further difficulty for Metro North, its catchment area is much wider than the coastal Dart line, encompassing much of the mid-city, and taking in major installations such as the Mater hospital and its future extensions, DCU, Dublin airport and the expanding Fingal area of north Dublin.

RPA chief executive Frank Allen has said Metro North is fully compliant with population projections in the Fingal Development Plan.

However, the Dublin Institute of Technology Futures Academy has calculated that more than one million people could migrate to the Dublin-Belfast axis by 2020.

This would create additional development pressure beyond the Fingal administrative area, which would critically affect the usage projections for Metro North.

Faced with the problem, Minister for Transport Noel Dempsey has decided against asking the Railway Procurement Agency to build additional capacity in the Metro North tunnel, a feature he acknowledged would affect the cost.

However, Mr Dempsey failed to give the agency's plans his outright blessing, remarking that he "could not guarantee" that the capacity of the proposed Metro North was sufficient to meet population forecasts.

Speaking at the recent launch of plans for the CIÉ's underground Dart interconnector, which will use the wider-bodied trains, Mr Dempsey said he had been assured by the RPA that Metro North had sufficient capacity and, while he acknowledged that there were industry concerns about the issue, "the time for consultation and talking is finished".

The agency expects to issue tender documents to the bidders by May.

http://home.eircom.net/content/irela...view=Eircomnet

[arkk]

The agency confirmed to bidders at a specially organised "workshop" in recent weeks that it wanted to develop an underground which uses vehicles that are longer but similar in width and height to the overground Luas trams.

So is this another rehashed article stating that metro will be a light-metro like porto and unlike the DART, or are they actually now going to use on street style trams instead of the, erm, fat ones?

[MrX]

This is *MY* tax they're spending. I would like to see a full justification of this decision published a.s.a.p.

It seems completely short sighted.

Are they just fixated on Luas trams or is there some logic to this?!

[Mark]

Its partly costs and partly the ability of the metro concept to be interoperable with the Luas.

In my opinion I believe the Red line and Lucan line and possible Rathfarnham - Liffey Junction lines (ie on street) should be 2.4 and tramlike while all other lines should be at least 2.65 if not 2.8m in width.

Length or frequency are not the issues here - its width.

[clonsilladart]

I actually think there are no Technical reason whatsoever for the RPA's blind push for Trams.
The RPA will never recommend Heavy Rail, as this skirts far too close the IE's "expertise".

Bottom line on what should be done:
- Sort out the union issues within IE (Probably an imposable task at this stage)
- Combine the RPA and IE into a single body.
- Start making proper engineering based decisions (ie Heavy Rail on Major Corridors and Luas Trams as short interconnectors)

Unfortunately it's far too late for all of this. The easy decision was made years ago when the RPA was formed.