Current Status of the 55m Luas trams

Phil.x

prinzeugen wrote: »

What's the problem? Just explaining 35% longer does not mean 35% more power is needed.

It's too much like shop talk.

Stephen15

Isin't the long term ambition to have all Luas 5000 class trams upgraded to 54m

prinzeugen

Phil.x wrote: »

It's too much like shop talk.

Just an informed reply. I don't know why the new trams are having issues but I can bet it is software related.

zom

If current 40m Citadis takes 1020 amps from overhead 750v DC, 55m Citadis takes 1360 amps (extra 33%). As far as I know each bogies (2 motors) uses its own converter/cooling units so this was also added, but there may be part of the traction control system that wasn't upgrade with 40-55m conversion and can't cope now with extra 340amps ?

Any idea if Citadis 5000 series can even work with doubled pantograph / traction control systems ?

prinzeugen

zom wrote: »

If current 40m Citadis takes 1020 amps from overhead 750v DC, 55m Citadis takes 1360 amps (extra 33%). As far as I know each bogies (2 motors) uses its own converter/cooling units so this was also added, but there may be part of the traction control system that wasn't upgrade with 40-55m conversion and can't cope now with extra 340amps ?

Any idea if Citadis 5000 series can even work with doubled pantograph / traction control systems ?

No it does not work like that. The amount of power a Luas can draw is limited. It will still run, but slower. Put the oven and a few rings on the cooker, the lights will dim.

The Luas supply is the same.

Bit like an electric toothbrush going flat. It will still go but slower.

A double pantograph is not needed unless, they are running as 2 trams in multiple but without cabs between, much like the 4 car Darts.

Two pantographs are asking for trouble with the damage to the carbon strips from wire bounce!

An AC motor would be self cooling but the noise may be from the brake units. The Luas uses regeneration and/or Dynamic brakes which produce vast amounts of heat.

If it does not go back into the lines as volts, it is converted to heat on the roof. That is why you hear the fans on a 5xxx tram going nuts at every stop.

devnull

Phil.x wrote: »

It's too much like shop talk.

It's not your place to tell others what they can and cannot post.

- Moderator

BowSideChamp

Has the 55m tram have an increased number of motorised bogies? The smaller versions had 3?

zom

BowSideChamp wrote: »

Has the 55m tram have an increased number of motorised bogies? The smaller versions had 3?

I thought they have but according to @prinzeugen overall power draw for 55m trams is the same as for 40m so no point to have additional motorised car (save money and weigh?). Actually it would be good to have trailer car instead, with extra flange lubrication unit because of length of 55m Luas.

Lumen

I don't have anything useful to contribute but I'd just like to show some appreciation for the tramnerds. This thread is enlightening.

I feel like standing up on the Luas and shouting "I don't know what a pantograph is!".

zom

Not sure if it was mentioned here but there is pretty interesting lecture on youtube about Luas conversion - https://www.youtube.com/watch?v=aS-joOgLpqo

Tow

prinzeugen wrote: »

Being 35% longer does not mean 35% more amps are required. The power to weight ratio might suffer a bit though. A 55m tram is the same as a 40m tram filled with very heavy people.

I fully agree the power requirements between an empty tram and one loaded will passengers packed like sardines is different. It is an accumulate effect, one 55m tram does not make much difference, but all trams at 55m and 3 minute frequency is another story. Pack a 55m tram with passengers and if you want to maintain the same performance more power is required than for a 40m tram. ie. accelerating as they climb up the hill to Charlemont.

When the over head line voltage drops, more amps are drawn to compensate. Something has to give somewhere. Just like a basic Hornby train set, the more engines you put on a track the slower they will become, until the motors start to stall. With VFD driven motors this gets more interesting and their programming and interaction with other systems comes into play.

This should not be a problem with just one or two 55m trams at the current reduced frequency. And of course they are also limited to 10Kph in the city.

zom

Tow wrote: »

When the over head line voltage drops, more amps are drawn to compensate.
.

Isn't it like compensation happens only for alternating current (AC) ? Overheads for Luas are DC.

goingnowhere

Laws of physics, if the voltage goes down the amps have to go up if the energy draw is the same

The VVVF AC drive the trams has is fairly hungry and has a fairly constant amps draw, it does not fall off with speed like DC drives did

zom

goingnowhere wrote: »

Laws of physics, if the voltage goes down the amps have to go up if the energy draw is the same

For DC you have basic Ohm's law - if the voltage goes down, the amps goes down too. But it works differently on AC. And also not that simple in case of regulated power control like one used in trams.

GM228

GM228 wrote: »

5028 (not 5027) failed and 5007 was assisting.

The following day 5027 also failed in Dundrum and was assisted by 5013 in the same way with 5027 leading the consist back to the depot.

Another LUAS failure yesterday, obviously not involving a 55m set as they are out of service, but it shows as I explained recently (above) the failed set leading the way back to the depot. 5024 failed this time assisted by 5005.

What is apparent from any LUAS failure is that the assisting set always pushed the failed set (makes sence on a tram system) home so I assume they must have some sort of multiple system allowing the failed set control power controls from the assisting set.

https://www.youtube.com/watch?v=TGbpHVMDhcc

Stephen15

GM228 wrote: »

Another LUAS failure yesterday, obviously not involving a 55m set as they are out of service, but it shows as I explained recently (above) the failed set leading the way back to the depot. 5024 failed this time assisted by 5005.

What is apparent from any LUAS failure is that the assisting set always pushed the failed set (makes sence on a tram system) home so I assume they must have some sort of multiple system allowing the failed set control power controls from the assisting set.

https://www.youtube.com/watch?v=TGbpHVMDhcc

Would it not make sense to invest in a shunter for Luas breakdowns.

end of the road

Stephen15 wrote: »

Would it not make sense to invest in a shunter for Luas breakdowns.

i think they still have a unilock loco that was used for construction of the original part of the system. i wonder could that be adapted? i'd agree it would be better to have some sort of loco rather then taking a tram possibly out of service to bring the failed one back to the depot.

Jamie2k9

There would be no time savings, its just easier to use the tram behind. This failure has clearly been down to reduced maintenance because of the construction in Sandyford. They admired this week there was a backlog and there was 4 less trams operating last week because of it.

end of the road

Jamie2k9 wrote: »

There would be no time savings, its just easier to use the tram behind. This failure has clearly been down to reduced maintenance because of the construction in Sandyford. They admired this week there was a backlog and there was 4 less trams operating last week because of it.

fair point.

Tow

GM228 wrote: »

I assume they must have some sort of multiple system allowing the failed set control power controls from the assisting set

Yes, there is a short shot towards the end where you can see multiple interconnecting control lines. I remember one breakdown years ago, when they connected two trams the 'fault' transferred to the good tram. They were ages at that, 'rebooting' the trams (they run Windows XP, or did back then).

bg07

Are all the 55m trams in service yet?

Any progress on the plans to lengthen all green line trams to 55m?

Jamie2k9

bg07 wrote: »

Are all the 55m trams in service yet?

Any progress on the plans to lengthen all green line trams to 55m?

There should be all in service or the final one should be about to enter service and yes existing will be lightened over time.

Lord Glentoran

Jamie2k9 wrote: »

There should be all in service or the final one should be about to enter service and yes existing will be lightened over time.

Can the system cope with all 55 metre trams?

GM228

Everyone wondered what the problems which saw the new fleet temporarily withdrawn a while back was, well now we know, and no it wasn't a case of them simply being too long or traffic issues etc, we recently found out the issue at a sitting of the Joint Committee on Transport, Tourism and Sport:-

https://www.oireachtas.ie/ga/debates/debate/joint_committee_on_transport_tourism_and_sport/2018-05-16/4/

....an electrical fault with the new trams.

These two new longer trams were in regular service during morning peak periods. On 12 March, the first of the new trams failed in service and the following day, the second new tram also failed in service with the same fault indicated. Alstom, the tram manufacturer, assembled and brought in a troubleshooting team from France on 14 March. Alstom traced the root cause of the electrical fault to the control board for the static converter.

zom

GM228 wrote: »

Everyone wondered what the problems which saw the new fleet temporarily withdrawn a while back was, well now we know, and no it wasn't a case of them simply being too long or traffic issues etc

In general new infrastructure seems to be more error prone- new leap card validators for example, every second not working from where I travel (green line). The old validators have at least little LED light indicating green while working and red when broken / disconnected. New validators you have to come closely and look at the display, although sometimes they can display correctly and still refuse to work.

I got new tickets machines not reading my leap card few times and so I tend to use old ones if I need to top it up. New ticket machines also have a problem to recognise some Euro notes - after you feed them with €20 bill for example they show like nothing happen - this may be very stressful especially for tourists.

And as I said - error ratio for new infrastructure is much higher then for the old one. But it seems to be global tendency to produce worse and worse crap every year...

KD345

Have all the new 7 trams entered service yet?

Are they in regular service?