[article] Dublin trams set to get longer

Navan Junction

Tim O'Brien, Irish Times

Tue, Nov 13, 2007

The Railway Procurement Agency is considering extending Luas trams to up to 52m in length.

However, the agency is less sure about using other new developments in tram manufacture to avoid overhead wires in architecturally sensitive areas of Dublin's inner-city such as near Trinity College and College Green.

The agency, which is currently converting its 30m Red Line trams to 40m, said peak-time capacity problems on the Green line and increasing demand meant new trams would need to be longer and run more frequently.

With 58 trams in use or on order for the existing lines and a further seven new lines proposed under Transport 21, the Luas order for new trams, taken together will be one of the largest tram orders in the world.

An agency spokesman said it had not as yet determined how many new trams would be required. But French company Alstom - manufacturers of the current Citadis tram in use in Dublin - confirmed the order could be one of its largest.

Recent developments in the building of Citadis trams have eliminated the raised floor areas, giving a complete low floor tram which is slightly longer than the original trams.

This means the new trams would be 52m long while extending existing trams would result in 50m sections.

However, while the agency is interested in longer trams a spokesman appeared to pour cold water on other new developments, such as the use of "flywheels", batteries or underground power supplies.

An underground power supply has been used by Alstom in Bordeaux and Nice in France where the city authorities did not want to put up overhead wires. Other options developed by Alstom include a "flywheel" which can power a tram over a short distance.

The agency spokesman said the difficulty with buying new trams with batteries or flywheels was that all existing trams would need to be converted and using an underground power supply was significantly more expensive.

© 2007 The Irish Times

John_C

Could they extend the tram but not have any doors on the bit at the end to eliminate the need for longer platforms?

BrianD

The article gives the impression that they are extending existing trams but on closer examination they are saying that future trams will be 52m long.

GerardKeating

John_C wrote: »

Could they extend the tram but not have any doors on the bit at the end to eliminate the need for longer platforms?

Are the platforms not 50m already ?

Victor

GerardKeating wrote: »

Are the platforms not 50m already ?

That includes 2 ramps, each 5m long.

The agency spokesman said the difficulty with buying new trams with batteries or flywheels was that all existing trams would need to be converted and using an underground power supply was significantly more expensive.

Then use the existing trams on a section without gaps in the OHLE and use the new trams on the sensative sections. Not difficult folks. :rolleyes:

Bogger77

Victor wrote: »

That includes 2 ramps, each 5m long.
Then use the existing trams on a section without gaps in the OHLE and use the new trams on the sensative sections. Not difficult folks. :rolleyes:

So do you expect passengers on an regular tram to switch trams at some point on the journey, to the new non ohle version?

The setup of the network at moment, allows a tram from green to be transfered to red line to cover for damaged trams etc. So there's a pool of spare trams. You're suggesting we have 2 or more differing tram types, that are not interchangeable.

The Overhead Lines and Trinity is a red herring, they use Overhead lines in places like Rome, done correctly it can blend in. Noise rounding curves would be more of an issue.

Underground supply, which sounds like a covered third rail arrangement is more dangerous than overhead. It would be too easy to access.

Victor

Bogger77 wrote: »

The setup of the network at moment, allows a tram from green to be transfered to red line to cover for damaged trams etc. So there's a pool of spare trams. You're suggesting we have 2 or more differing tram types, that are not interchangeable.

We already have different types of tram, as the fleet grows to several hundred, there will be even more types.

Underground supply, which sounds like a covered third rail arrangement is more dangerous than overhead. It would be too easy to access.

Exposed third rail, that is only turned on by a radio signal from a tram directly overhead.

BrianD

Do we not have the one model in two lengths - 30m and 40m and now the 30m are becoming 40m.

Captain Chaos

GerardKeating wrote: »

Are the platforms not 50m already ?

Have you seen most of the Red line platforms, the 40m extended trams just about fit them with inches each end to spare. The Red line cannot take 50m trams without extending post of the platforms, and signal changes at some junctions would have to be looked at as a 50m tram would block traffic if it has to stop at them.

aliveandkicking

Victor wrote: »

We already have different types of tram

The trams on both lines are identical (with the exception of the 30m trams on the red line yet to be lengthened to 40m.) Design wise they are exactly the same. We do not have two types of tram at present.

Captain Chaos wrote:

Have you seen most of the Red line platforms, the 40m extended trams just about fit them with inches each end to spare. The Red line cannot take 50m trams without extending post of the platforms, and signal changes at some junctions would have to be looked at as a 50m tram would block traffic if it has to stop at them

The platforms on both red and green lines are exactly the same length (40m with 5m ramps at either end). Extending the green line to 50m+ would be easier than the red line but at the same time extending the red line to 50m is not impossible. Jervis and Heuston are the only stops I can think of being problematic.

John_C

aliveandkicking wrote: »

Extending the green line to 50m+ would be easier than the red line but at the same time extending the red line to 50m is not impossible. Jervis and Heuston are the only stops I can think of being problematic.

Back to an earlier question, would extending the platforms be a sticking point? Could the trams not just have 5m either end without a door?

Occidental

aliveandkicking wrote: »

The platforms on both red and green lines are exactly the same length (40m with 5m ramps at either end). Extending the green line to 50m+ would be easier than the red line but at the same time extending the red line to 50m is not impossible. Jervis and Heuston are the only stops I can think of being problematic.

Would Connolly not also be a problem due to the crossover points just short of the platforms?

L1011

Occidental wrote: »

Would Connolly not also be a problem due to the crossover points just short of the platforms?

Is Connollys platform not longer than 40m to begin with, though?

Our trams *are* two different models, Citadis 301's that have been stretched and Citadis 401s.

BrianD

Apparently these new 52m trams are being bought for the Green Line extension and it will necessitate the rebuilding platforms and big changes in the maintinance depot at Sandyford.

aliveandkicking

MYOB wrote: »

Our trams *are* two different models, Citadis 301's that have been stretched and Citadis 401s.

No the model is Citadis. Both red and green line trams are Citadis models. The red line trams were shorter than the green lines trams but were still Citadis model trams identical in every way except length.

Cionnfhaolaidh

BrianD wrote: »

Apparently these new 52m trams are being bought for the Green Line extension and it will necessitate the rebuilding platforms and big changes in the maintinance depot at Sandyford.

So I assume that the new platforms they're building on the Cherrywood extension are longer than the current ones?

BrianD

Probably not!! I don't know to be honest.

dogmatix

And why not a battery operated tram? The batteries would power the tram over the whole journey with recharging stations at the terminus or at every stop. With batteries you could then eliminate the overhead lines - and with the over head lines gone, bring in double decker units? Double decker commuter trains are not unusual in the US and Canada.

Drumm battery trains operated on the harcourt street line (now the green line) from the early 30's until the late 40's and could go the whole route to bray on a single charge - surely after 60+ years the technology is now even more advanced.

The downside is that you would probably have to get a completley new set of rolling stock but if as some sources are suggesting, the green line will have to be upgraded to a light rail system in the future, then this might be an idea.

Red Alert

It's an amazing story about those Drumm battery trains. I think there were a few early steps to develop a locomotive like them, and the plans involved some stretches of conductor rail or wires to assist acceleration and provide a boost charge en-route. In the UK there are still some so-called Electro Diesels operating on mainline routes. Basically they are an electric locomotive with a small backup generator so they can run low-speed off-wires.

Even more interesting is that this battery-backup route might not be too difficult a one to go down in the trinity college area. The LUAS's design with roof mounted equipment packs could be very easy to modify, although I would imagine electrically it is a major undertaking - the LUAS's motors are rated for a phenomenal output if you go look at Alstom's website.

Fratton Fred

Bogger77 wrote: »

The setup of the network at moment, allows a tram from green to be transfered to red line to cover for damaged trams etc. So there's a pool of spare trams.

All you need to do for a quick and easy transfer is to build a few miles of track so the trams can actually go from one line to another:D

Fratton Fred

Do they need longer trams or can they not just reduce the time between each one?

Victor

Fratton Fred wrote: »

Do they need longer trams or can they not just reduce the time between each one?

There are problems then with signalling and the availibility of junctions shared with general traffic. The Red Line has spare trams - the problem is there are no time slots available in the city centre.

Also, you eventually run up against a power limitation - too many trams drawing too much power and you'll short the system. I'm not sure how the balance works between two small trams and one tram exactly twice the size.

Capt'n Midnight

dogmatix wrote: »

With batteries you could then eliminate the overhead lines - and with the over head lines gone, bring in double decker units? Double decker commuter trains are not unusual in the US and Canada.

double decker trams weren't unusual here a while back either.

the luas lines are all high enough to clear a double decker bus so you could have double decker trams here without messing with the cables at all.

dogmatix

Sounds like double deckers would be a good idea so - maybe greatly increase carrying capacity of the luas and avoid the "nose stuck in someones sweaty armpit" situation. It would be interesting going over the milltown viaduct on the top deck of double decker in a severe crosswind.

Victor

Occidental wrote: »

Would Connolly not also be a problem due to the crossover points just short of the platforms?

From the stops to the points is about 46 metres, as to whether that can be lengthened by the overhand at the front of a tram, I don't know, but certainly not by much.