DART+ (DART Expansion)

90101 is on the other end

Two separate classes

90x01 through 90x31 (Battery)

80x01 through 80x06 will appear also in due course, 80x07-80x26 look likely to be ordered soon (No Battery)

It seems its going to be the same numbering scheme as the 29Ks with the 3rd number corresponding to the carriage number in the set? There is an interior picture on the previous page of the thread that shows an interior car with 90201, so I assume that is what they are planning.

Also, I don't think it relates to the unit number, but I can't seem to find what it means. What is the number on the far left for? the 01? I never noticed until I saw the new units, but looking at pictures the 22Ks, 29Ks, 2600s, and 2800s all seem to have some 0X number.

My concern with the battery hybrid is that there are no (or was no - when the decision was made) examples elsewhere of such a configuration being used in an actual highish frequency/capacity metro heavy rail system in a city of Dublin's size ballpark. So IE are effectively the first movers with this technology.

While I'm a big fan of battery tech generally and don't see obvious reliability or operational issues arising from it's use for metro-heavy rail - but as a matter of principle, I think that relatively small players like IE should hang back a bit when it comes to novel rail technologies - the concentration of risk is much higher for them.

Having said that I think timing has forced IE's hand a bit here - older stock reaching end-of-life and the DART+ expansion has forced taking on the risk of a novel train power system.

There's a good chance that at end of life of the battery packs, or even earlier, many of the BEMUs will simply be converted to EMU units instead of going forward for a battery replacement. These would stay in Dublin.

The big thing was that we, as a country, had no interest in investing in rail for such a long time. That looks to be changing with DART+ but my fear now is that the NIMBYs could derail the project (pun not intended).

80 km range isn’t “awful”: it’s exactly what IÉ specified when ordering these BEMUs from Alstom. If greater range was required, they’d have ordered larger batteries (or the same batteries with a more aggressive replacement schedule).

It's 37.5 km from Malahide to Drogheda. That is the longest possible distance the train has to travel to reach an electrified stretch or a charging station. Travelling that distance is never going to deplete the battery (if the battery doesn’t charge at Drogheda, the train will stay there and be replaced).

Adding more battery makes the train heavier, which increases operating cost. This isn’t an electric car where buyers are fooled into buying 500 km+ of range despite never, ever haven driven more than 200 km a day; these trains operate in a controlled, managed system, where the operator knows exactly what distances they travel, and how often; and they are serviced and re-charged to a strict schedule. The battery has been sized at 2x the typical distance between charging opportunities. Braking regeneration allows the train to add about 40 km of range to its battery while operating in the electrified stretch: traction power is drawn from overhead, and the energy recovered from braking tops up the battery (on a pure EMU, this recovered energy is fed back into the overhead lines for other trains to use).

“Range” isn’t a problem. The concerns are more long-term. One likely risk is that real-world use may result in faster degradation of battery capacity than was predicted, but this is completely fixable, most likely at Alstom’s cost, and all it means in practice is that the batteries have to be replaced after, say, 8 years instead of 12. It’s also as likely that battery degradation will be lower than predicted - our climate is actually quite gentle on Lithium batteries.

The BEMUs are not a permanent solution - they are a medium term (~10 years) risk reduction measure, so that all commuter services from Drogheda can be switched to electric trains, even if the planned line electrification to Drogheda is delayed. Switching commuter services to electric trains is essential to make the best use of limited line capacity: electric trains can run with shorter headways than diesels, and that means more slots per hour.

The alternative situation would be that no capacity improvements at all could be made until Malahide-Drogheda was electrified, despite continuing growth in demand.

And we have done this before

1936-1949 we had battery powered trains trundling up and down between Dublin and Bray, no recorded incidents of running out of juice, though did do Gorey Connolly return on a single charge once and limped home

No, not for these new trains. But from a historical point of view, it’s nice to know we had a battery train running, almost a hundred years ago.

We should have done lots of things, but can't go back and change things. So from where we actually are, rather than where we would be in some ideal world, the BEMUs are a very good move.

Once the whole DART+ network is electrified, the batteries will likely, as @goingnowhere suggested, become stationary lineside battery farms for the charging infra and presumably some will be sent to Galway, Cork or Limerick for commuter services there, but you’d wonder if they’ll keep a few sets with batteries in the GDA to operate a skeleton service in the event of a temporary power shortage/cut or storm (or vandalism for that matter) damage to the OHLE…? Would it be worth their while to do this? How does the DART currently work during a power outage?

I'm hearing ABP has granted a railway order to the DART+ South West scheme. I'll post more as I find out

quicker than Dart West. I think they also just approved another Busconnects corridor so maybe the logjam is clearing.

It's notable that 2 of the Dart+ ROs have gone to ABP and been approved and they still haven't even started the consultation on Dart+ South…

That's why I am not impressed at the 80 km range. Battery technology has improved by orders of magnitude since the 1930s, and the improvement in range of the BEMUs seems to be modest by comparison. What are the specific factors which account for this?

Also just heard south West has a railway order as well which is great.

South will be split between the Enhancements around Bray + Greystones and the Level Crossings. It makes sense from a delivery perspective. The LCs will be bogged down in challenges for years.