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DART+ (DART Expansion)

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  • Given that the energy density of diesel is 3-4 times higher than current Li-ion storage, can we assume that BEMUs will be more like DMUs than EMUs in terms of acceleration/deceleration performance?

    I had always assumed that EMUs had much better acceleration than DMUs but maybe that was just a perception?




  • What will be the benefit of the Maynooth DART line really? Won't it just be slower overall to the city center as they may add stops... obviously it will be more frequent. Is the overall benefit that you could go Maynooth to Drogheda on one train (taking about 2 hours)...




  • FrankN1 wrote: »
    What will be the benefit of the Maynooth DART line really? Won't it just be slower overall to the city center as they may add stops... obviously it will be more frequent. Is the overall benefit that you could go Maynooth to Drogheda on one train (taking about 2 hours)...

    The benefit is the abilty to deliver a much greater frequency and therefore greater capacity on the route through it being resignalled.

    Journey times will more or less remain the same as the time spent stopping at the extra station at Pelletstown will be offset by faster acceleration/deceleration.

    No train will be going from Maynooth to Drogheda - you would still have to change at Connolly.




  • LXFlyer wrote: »
    The benefit is the abilty to deliver a much greater frequency and therefore greater capacity on the route through it being resignalled.

    Journey times will more or less remain the same as the time spent stopping at the extra station at Pelletstown will be offset by faster acceleration/deceleration.

    No train will be going from Maynooth to Drogheda - you would still have to change at Connolly.

    Would it not make sense just to order more trains on the existing line and then just have some express and some not? It's not the frequency that's the issue, it's the journey time.




  • gjim wrote: »
    Given that the energy density of diesel is 3-4 times higher than current Li-ion storage, can we assume that BEMUs will be more like DMUs than EMUs in terms of acceleration/deceleration performance?

    I had always assumed that EMUs had much better acceleration than DMUs but maybe that was just a perception?

    Yes, EMUs have much better acceleration than DMUs due to instant electric torque motors (same reason Tesla’s have insane acceleration).

    Battery EMUs are the same as conventional EMUs except that they store their energy on board (which adds weight). This extra weight will slow down acceleration (probably not massively). If you wanted to save battery, reducing the rate of acceleration would be a good idea.

    I’m fairly sure the plan is to have the batteries removed after electrification is done.
    Ideally, no BEMUs would be ordered and the Dart+ fleet would be purely EMU. There is a lack of trust between Govt, IÉ, NTA on electrification delivery. Batteries are the insurance policy. They add cost and weight.


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  • FrankN1 wrote: »
    Would it not make sense just to order more trains on the existing line and then just have some express and some not? It's not the frequency that's the issue, it's the journey time.

    Electric trains have lower operating costs, better performance and a better public image.

    There are extra intercity carriages ordered for delivery from next year onwards which could allow more intercity trains to Sligo.

    However, capacity for express service is very limited as there is only one track in each direction. It’s currently impossible for an express train to overtake a slow one. There is some potential for passing loops between the M50 and the city, but IÉ don’t seem to have any interest.

    The frequency on the Maynooth line off peak is not great (2 tph). It should be at least 3-4tph off peak mon-Sun imo.

    Capacity is stretches at peak (pre COVID) so an increase in frequency is necessary for that.




  • FrankN1 wrote: »
    Would it not make sense just to order more trains on the existing line and then just have some express and some not? It's not the frequency that's the issue, it's the journey time.

    There are only two tracks. There is nowhere to overtake. So no is there answer re express trains.

    Frequency *is* important - the trains were jammed to capacity per-Covid.

    More capacity through operating more trains is essential, particularly as more development takes place along that route.




  • Trains will be quieter, cleaner and smoother in operation which makes for a nicer trip. There is a thing known as the "sparks effect" where usage increases after lines are electrified as its seen as a higher class service.




  • L1011 wrote: »
    Presumably some of the BEMU are intended to be used initially on Maynooth or Docklands also, as Drogheda does not need 13 halfs, and Maynooth/Docklands needs rather more than 6.

    The 13 BEMUs half sets are all for the Northern Line. I think the PVR now is 40 cars/10 halfs. An additional morning departure from Drogheda is planned once the 41 ICR carriages arrive. That would use two more halfs and the other half would be spare.

    And the 6 EMU halfs are to "provide additional capacity on the existing electrified area". It looks like carriages for Maynooth and Hazelhatch will follow this order.
    I’m fairly sure the plan is to have the batteries removed after electrification is done.
    Ideally, no BEMUs would be ordered and the Dart+ fleet would be purely EMU. There is a lack of trust between Govt, IÉ, NTA on electrification delivery. Batteries are the insurance policy. They add cost and weight.

    It was an insurance policy but they will definitely be used for Drogheda initially before electrification. This is basically just swapping out the existing diesels and replacing them with BEMUs with the existing timetable in 2024 instead of waiting until 2027. Even if electrification is completed on time in 2027, it gives them a 3 year head start.

    The batteries are staying in place for the foreseeable future. Their maintenance and replacement is included in the contract. IÉ believes, and I agree, that they could just be used for other areas awaiting electrification once the Northern line is electrified.




  • LXFlyer wrote: »
    The benefit is the abilty to deliver a much greater frequency and therefore greater capacity on the route through it being resignalled.

    Put another way, there are no benefits to Dart Plus outside of this resignalling element


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  • AngryLips wrote: »
    Put another way, there are no benefits to Dart Plus outside of this resignalling element

    The whole premise of DART+ is to deliver a more reliable and frequent rail service along the four commuter rail lines.

    Resignalling the line delivers:
    * The ability to operate far more trains through shorter signalling sections
    * A more reliable service through elimination of the level crossings and replacement of the old signalling equipment

    Electrification delivers
    * More sustainable rolling stock capable of faster acceleration and deceleration through being electric powered rather than diesel
    * A more pleasant travel experience - quieter and smoother

    The two combined mean the ability to eliminate the severe overcrowding that was present on the Maynooth line pre-Covid and offers the ability to transport more than double the existing numbers of passengers.

    The electrification will also free up rolling stock to be redeployed elsewhere to increase capacity where it is needed.

    You make all of that sound rather negative?




  • Peregrine wrote: »
    The 13 BEMUs half sets are all for the Northern Line. I think the PVR now is 40 cars/10 halfs. An additional morning departure from Drogheda is planned once the 41 ICR carriages arrive. That would use two more halfs and the other half would be spare.

    And the 6 EMU halfs are to "provide additional capacity on the existing electrified area". It looks like carriages for Maynooth and Hazelhatch will follow this order.

    The pre-Covid Northern Line timetable into Connolly from Newry, Dundalk and Drogheda required in the morning peak:

    1 x 7 car ICR
    1 x 6 car ICR
    5 x 8 car 29000
    1 x 4 car 29000

    The 7-car ICR would then be deployed on Intercity services, while some of the other sets interwork with the Maynooth line as well.




  • LXFlyer wrote: »
    You make all of that sound rather negative?


    What I'm negative towards is the elaborate marketing spin associated with what is essentially a minor infrastructure upgrade with no discernible benefits to the end user. The existing infrastructure,coupled with the re-signalling element of this project, would be enough to increase capacity to meet the needs of the network. Everything else that is being touted under Dart+ is the equivalent of handing in unfinished homework and expecting your teacher to be impressed. The elements that would really bring the project to life, like additional stations and extra connectivity, are missing. It's lipstick on a pig.




  • AngryLips wrote: »
    What I'm negative towards is the elaborate marketing spin associated with what is essentially a minor infrastructure upgrade with no discernible benefits to the end user. The existing infrastructure,coupled with the re-signalling element of this project, would be enough to increase capacity to meet the needs of the network. Everything else that is being touted under Dart+ is the equivalent of handing in unfinished homework and expecting your teacher to be impressed. The elements that would really bring the project to life, like additional stations and extra connectivity, are missing. It's lipstick on a pig.

    I was specifically talking about the Maynooth line in my response as that was what the previous poster asked about.

    With all due respect, renewing the signalling, electrifying the route, eliminating the level crossings on that line and replacing all of the rolling stock is a major project in railway terms.

    More than doubling the passenger capacity through the ability to run far more trains frankly will deliver visible improvements to the passengers.

    Pelletstown station is already under construction to be completed next year.




  • FrankN1 wrote: »
    Would it not make sense just to order more trains on the existing line and then just have some express and some not? It's not the frequency that's the issue, it's the journey time.

    Actually, the frequency is the issue. Study after study, both internationally and in Ireland, has shown commuters rarely have any issue with journey time, and instead their main concerns centre around frequency and reliability.

    The bigger the gap between services, the less satisfaction commuters have, meaning that less people use it.

    The better the reliability, both in terms of being on schedule, and in terms of journey time, the more satisfaction people have.

    Journey time, if it matters to commuters at all, is very much down the list of things that they worry about.




  • CatInABox wrote: »
    Actually, the frequency is the issue. Study after study, both internationally and in Ireland, has shown commuters rarely have any issue with journey time, and instead their main concerns centre around frequency and reliability.

    The bigger the gap between services, the less satisfaction commuters have, meaning that less people use it.

    The better the reliability, both in terms of being on schedule, and in terms of journey time, the more satisfaction people have.

    Journey time, if it matters to commuters at all, is very much down the list of things that they worry about.

    I agree with this. The rare time that I get a train from Kilcock to Dublin, the length of the journey is of very little concern to me. Main concern is how late will the train be as it has never been on time. Over 5 minutes late is the best I've encountered.

    Missing the train would be the next concern as it could be a couple of hours or more until the next train despite the station being in a commuter fare zone.

    So due to the above two points, I usually arrive at least 5 minutes before the scheduled time and then could be waiting 15/20 minutes for the train to actually arrive. One time it just did not arrive and everyone went to get the 115 bus.

    So yeah, frequency and reliability are big things for me. Once on the train and moving along, whether the journey takes 50 or 60 minutes doesn't bother me much at all




  • AngryLips wrote: »
    What I'm negative towards is the elaborate marketing spin associated with what is essentially a minor infrastructure upgrade with no discernible benefits to the end user. The existing infrastructure,coupled with the re-signalling element of this project, would be enough to increase capacity to meet the needs of the network. Everything else that is being touted under Dart+ is the equivalent of handing in unfinished homework and expecting your teacher to be impressed. The elements that would really bring the project to life, like additional stations and extra connectivity, are missing. It's lipstick on a pig.

    Agreed it's fundamentally underwhelming. The most impressive part of the whole DART+ project is the widening to 4 tracks between ParkWest and Heuston (but then that capacity will be wasted because they're not going to built any stations on the line)

    Really it is standard maintenance + the electrification that should have been completed in the late 1950s / early 1960s along with the rest of Europe. In an Irish context and a Dublin context, it's a game changer though because it's an actual service you'd expect in the late 20th century in a city of 1 million+ and we've starved Dublin of transport money for so long so this looks like a feast.




  • Are Battery EMUs quieter than the existing Diesel commuter trains? Specifically for people who live in close proximity to train lines - would the reduction in sound be noticeable?




  • SMdPP87 wrote: »
    Are Battery EMUs quieter than the existing Diesel commuter trains? Specifically for people who live in close proximity to train lines - would the reduction in sound be noticeable?

    Significantly. Some motor whine and the actual track noise is all you'll hear.

    Basically, think of the difference between a DART and a diesel train. A newer EMU/BEMU should be a little bit quieter than the DART too.

    There will still be diesel trains on all lines, albeit less of them.
    AngryLips wrote: »
    The elements that would really bring the project to life, like additional stations and extra connectivity, are missing. It's lipstick on a pig.

    Glasnevin alone is going to be the biggest improvement in connectivity the rail network has seen since 1891.




  • L1011 wrote: »
    Significantly. Some motor whine and the actual track noise is all you'll hear.

    Basically, think of the difference between a DART and a diesel train. A newer EMU/BEMU should be a little bit quieter than the DART too.

    Interesting I hadn’t realised. If you don’t mind me piggy backing on your knowledge and save me reading through hours of this board, can I ask - when are we likely to see these Batt EMUs operational?


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  • SMdPP87 wrote: »
    Interesting I hadn’t realised. If you don’t mind me piggy backing on your knowledge and save me reading through hours of this board, can I ask - when are we likely to see these Batt EMUs operational?

    On the Maynooth line that is




  • Based on the current plans I would not expect BEMU to Maynooth, just normal EMU when electrification is done. That's expected for 2025. These will also be the same amount quieter.

    The Sligo (definitely) and Longford/Mullingar (probably) trains will still be diesel, that's about one each way an hour at most.




  • Another benefit would be the reduction * of PM and NOX emissions for people who live near the line.

    * Reduction, as L1011 points out, there will still be some less frequent Diesel trains, but the BEMU's should be zero emission themselves.

    There would also be a reduction in green house gas emissions.




  • Peregrine wrote: »

    It was an insurance policy but they will definitely be used for Drogheda initially before electrification. This is basically just swapping out the existing diesels and replacing them with BEMUs with the existing timetable in 2024 instead of waiting until 2027. Even if electrification is completed on time in 2027, it gives them a 3 year head start.

    The batteries are staying in place for the foreseeable future. Their maintenance and replacement is included in the contract. IÉ believes, and I agree, that they could just be used for other areas awaiting electrification once the Northern line is electrified.

    I just think the Northern Line should’ve been electrified before the new trains arrive.

    Why is the Northern Line the last line to be electrified? What is the point leaving it 33% electrified until 2027. It could’ve had wires before the first carriage arrived and then all the diesels could go to Maynooth and Hazelhatch.




  • I just think the Northern Line should’ve been electrified before the new trains arrive.

    Why is the Northern Line the last line to be electrified? What is the point leaving it 33% electrified until 2027. It could’ve had wires before the first carriage arrived and then all the diesels could go to Maynooth and Hazelhatch.

    Northern DART+ is probably anticipated as one of the more challenging routes, beyond Malahide up to Drogheda, no problem, but the line south of that I expect they anticipate major uproar from NIMBYs with the widening to 3 track in certain places etc.

    Same with the southern section, I expect there to be uproar over closing Merrion Gates etc




  • Northern DART+ is probably anticipated as one of the more challenging routes, beyond Malahide up to Drogheda, no problem, but the line south of that I expect they anticipate major uproar from NIMBYs with the widening to 3 track in certain places etc.

    Same with the southern section, I expect there to be uproar over closing Merrion Gates etc

    I am big advocate for adding extra tracks to the Northern Line but I haven’t seen anything to suggest it will be done. The only change will be a southbound passing loop at Clongriffin.

    I wish the NTA luck when they try to close Sandymounts 5 level crossings. It’s going to be worse than Dunville avenue.




  • I am big advocate for adding extra tracks to the Northern Line but I haven’t seen anything to suggest it will be done. The only change will be a southbound passing loop at Clongriffin.

    I wish the NTA luck when they try to close Sandymounts 5 level crossings. It’s going to be worse than Dunville avenue.

    The extra tracks on the Northern Line are expected to be delivered as part of the Dublin/Belfast line upgrade from what I’m hearing, rather than DART+.




  • I just think the Northern Line should’ve been electrified before the new trains arrive.

    Why is the Northern Line the last line to be electrified? What is the point leaving it 33% electrified until 2027. It could’ve had wires before the first carriage arrived and then all the diesels could go to Maynooth and Hazelhatch.
    I'm fairly sure that the Northern line electrification project is going to be cheaper than the maynooth line and that it will be last as there is more of a benefit electrifying the maynooth line as it is more urban and stations are closer, therefore benefiting more from the improved acceleration of EMUs
    Also is there going to be any information announced soon about the belfast-dublin upgrade as there seems have been radio silence since IE and translink released their plan about two years ago?




  • Yes, EMUs have much better acceleration than DMUs due to instant electric torque motors (same reason Tesla’s have insane acceleration).

    Battery EMUs are the same as conventional EMUs except that they store their energy on board (which adds weight). This extra weight will slow down acceleration (probably not massively). If you wanted to save battery, reducing the rate of acceleration would be a good idea.

    I’m fairly sure the plan is to have the batteries removed after electrification is done.
    Ideally, no BEMUs would be ordered and the Dart+ fleet would be purely EMU. There is a lack of trust between Govt, IÉ, NTA on electrification delivery. Batteries are the insurance policy. They add cost and weight.
    I was under the impression that DMUs generally use electric motors also? The diesel engine just drives a generator which produces the electricity for the motors which drive the wheels? In that case, the differences in acceleration would be down to weight.

    I get the emissions reduction as a benefit of BEMUs but it would seems to me that there are plenty of negatives also in adopting a relatively novel train type as a temporary measure. Adding a brand new train type presumably with its own operational idiosyncrasies, doesn't seem like a particularly clever way to mitigate project risk?

    Won't the batteries require new infrastructure for charging in the depots or at certain stations? And I guess new engineering facilities will be required. But all this infrastructure is intended to be temporary? It feels incredibly wasteful while at the same time introducing further risks in terms of project management.


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  • gjim wrote: »
    I was under the impression that DMUs generally use electric motors also? The diesel engine just drives a generator which produces the electricity for the motors which drive the wheels? In that case, the differences in acceleration would be down to weight.

    The ability to draw on traction power for acceleration is not the same when its a DEMUs onboard generator as when its grid. And there is zero use for regenerative braking.

    Also, as far as I know, the 22000 class are not DEMU, being geared drive to the wheels; and this makes up a significant amount of the fleet to be replaced/transferred. Actually, do we have any DEMU units other than 29000s?

    edit: also, you drive harder/closer to the limits without the same environmental and noise impacts as doing it in anything diesel powered; not that I expect a working schedule to require that.


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