Cross-border review of rail network officially launched

KrisW1001

https://www.boards.ie/discussion/comment/123419614#Comment_123419614

It's been explained several times now why this isn't going to happen. But to add another barrier : planning. The railway order for DART+ North includes substations for 1500 V DC power. If you wanted to change your mind and go for AC, the locations and type of those substations have to change, which means you need to go back to get new planning.. why would you do that?

In any case, there's no point in using 25 kV here as the long term future of the Dublin-Belfast inter city service isn't even on this corridor: the AIRR recommended a new, more direct, track routing from Clongriffin to Drogheda, which would make Malahide-Drogheda a DART-only line. If you want your 25 kV line to Drogheda, then that future direct link north of Clongriffin is the only likely option…

A1ACo

Relocation may not be the problem, but increasing the land take of 1-2 of the planned DC substations for AC use (and the use the other DC plots for storage…?), then maybe a relocation if they cant be expanded? But also the possible difficulties in the connections to the ESB. Also, possible planning issues of variation of/ ‘cherry-picking’ implementation etc. of the railway order, or need for a new order?

Anyway, before retreating again with baited breath for an ‘Enterprise’ train replacement order to reveal itself…

Here is a techy article from around 2013, from Poland about considerations of optimizing its 3Kv DC system for higher speeds from 2014, after the Polish government postponed a 25Kv AC high speed railway:

A 3 kV DC Electric Traction System Modernisation for Increased Speed and Trains Power Demand – Problems of Analysis and Synthesis – Power Quality Blog

Here is a more very techy presentation from SNCF from 2019 looking at pros/cons of all available AC DC electrification options (stated 1.5Kv or 3Kv – DC vs 15Kv – MVAC vs 25Kv - MVAC) regards its 1.5Kv DC system of 6,000km that needed to be renovated or replaced with 25kV AC – and where a new 9Kv – MVDC might instead come into it for SNCF:

Présentation PowerPoint

Lastly and from 2024, the last word (for now) from the Netherlands ProRail research manager and seemingly author of the much earlier ‘…really promising business case and study at the time’ for 3Kv DC potential upgrade project – that the migration is not foreseen for now, and that focus is on other projects and optimisation of existing and other new systems to cater for rail needs for the years to come.

OFF THE RAILS: Senior Program Manager for Research at ProRail, Arjen Zoeteman

KrisW1001

https://www.boards.ie/discussion/comment/123422325#Comment_123422325

Thanks for the very interesting links.

While the SNCF slides suggest the 9000 V DC system as being “suitable for use by nations not yet electrified”, in Europe, that description really just means us (2,200 km in the Republic + 500 km in NI) and Albania (450 km)… hardly a huge area of opportunity, and we’re not even planning to electrify all of our network.

9000 V is a great way to increase the capacity and performance of a widespread 1500 V network without disruption to existing services, but I don’t see why any operator would start with that system if they had a free choice, as we mostly do. All of the infrastructural advantages 9000 V has over 1500 V also apply even more to 25 kV, because they are functions of using a higher transmission voltage. AC versus DC makes things a little more complex, but that complexity falls more onto the trains than the OHLE system itself. In a system like ours, with less than 100 mainline trains on the island, a higher cost per train isn’t actually that much of an issue.

9000 V may be “just as good”, but 25 kV AC is standardised, widely used across the world and is compatible with a wider variety of rolling stock. A railway the size of France’s can afford to go it alone with a different standard (and for them 9000 V is the sensible choice), but in a small railway like ours, where we’re already “special” thanks to our track gauge, we need to use as much off-the-shelf systems as we can to save money.

Pete_Cavan

https://www.boards.ie/discussion/comment/123419718#Comment_123419718

DART+ North doesn't have a RO yet and obtaining one doesn't guarantee that it will be built. Again, as I have said several times already, with BEMUs meeting the objective of sending electric trains to Drogheda. With that in place, and D+ W and SW under way, there is a reasonable chance electrification gets pushed out. If a new review is carried out 10 years after the publication of the DART+ plan, it could make different recommendations.

I doubt any other country would be sending DARTs to Drogheda but it was recommended here because of many constraints which currently exist. If some of those are eased by BEMUs in the short term, new dual voltage trains operating on the line in the medium term and potentially increased capacity into Connolly under FourNorth in the longer term, a different plan could be adopted in the future.

The AISRR is just a high level look at what potentially could be done. It certainly isn't policy and doesn't try to make an actionable business case for any of what's in it. Nothing from it will be delivered this decade and very little will even go to design this decade. Most of it isn't even in the NDP which is an official policy document.

Anyway, fine if you want to insist that everything that has been printed on government reports in the past few years is exactly what is going to happen eventually. I don't think the government of the day or the delivery teams in the NTA or IÉ are going to be slavishly trying to implement plans published by governments multiple elections previous.

bk

https://www.boards.ie/discussion/comment/123423217#Comment_123423217

Ah, now, DART+ North RO has been submitted and is currently being reviewed by ABP and is due to be decided in a few months. Given it is relatively straight forward I see no particularly reason why it won't get approval, just like the electrification parts of West and SW did.

You are suggesting to rip up all that and go back to square one for no benefit!

I doubt any other country would be sending DARTs to Drogheda but it was recommended here because of many constraints which currently exist.

That isn't true! Plenty of S-Bahn's run that distance, it would be on the outer limit, but certainly not considered unusual! In particular the new DART+ fleet seems more optimised for commuter then urban services.

You really haven't articulated why this idea makes any sense versus the current DART+ North plan.