Thanks for that, RichardB! 

 
Good video about the battery train here

https://www.youtube.com/watch?v=sARTvQj5jIg

 
I presume Sunday's exercise was a success, since 230001 ran up and down on time all day.

 

I have never been convinced that repurposing these ex LUL multiple units is such a good idea, I am not certain it actually saves that much money over building new

 

If you go down in the Park today,
You're sure of a big surprise.
If you go down in the Park today,
You'd better go in disguise.
For every battery D76 that ever there was
Will gather there together because
Today's the day the systems have their testing.

 
If you go down to Castlebar Park Halt today you might be mildly surprised to find a train running on a Sunday. 230001 is doing a full-day trail, or as near as Sunday opening hours permits - 28 runs each way. All on time so far (bit I've now jinxed it, of course). All part of the testing of the batteries, on-board and in this case particularly the lineside ones.

 
A very interesting video from he Great Western Fast Charge train team. Lots of very interesting information (historical, future and technical).

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

 
Roger French not so impressed with the 230's
https://busandtrainuser.com/2024/05/09/are-class-230s-worth-all-the-hassle/
Rail companies which bought into the Vivarail idea of refurbished London Underground D78 stock becoming diesel/battery Class 230 and electric Class 484 trains in their new guise haven’t had a lot of luck with their purchases.
........continues......

 

I did see it at West Ealing stabling sidings on Wednesday, I would think the normal move will be into Plat 4 and reverse.   Platform 5 the old Milk Sidings 

The real test for the 230's will be on the Maidenhead - Bourne End line with the gradient in the wet out of Furze Platt towards Maidenhead.

One, slightly off topic, observation is the GWR green livery seems to suit any of the rolling stock its applied to

 
230001 has made it to Greenford! RTT can't confirm that, as Greenford East is not only a mechanical box but still has semaphores (though not on the GFD-WEA route). However, there are not many valid ways of getting from P1 to P2 at South Greenford.

This morning's run was just a final "make sure it fits" run, and the fast charging kit isn't in operation yet. This afternoon's run was cancelled, as it's been graffitied and needs more cleaning (its duties involve having its picture took for PR - assuming it all works!).

The move from Reading took place on Tuesday, and it's being kept at the end of one of the sidings that 387s stable in. Getting from there onto the branch is a bit convoluted, involving going out to Hanwell Bridge Loop to reverse. Getting back from WEA P5 is even worse, unless it uses P4 to reverse. So near and yet so far ...

 
Sounds logical as Exeter depot can only really handle 2/3 car units. They would be used to the single leaf doors which are not ideal on the metro trains.

 

Class 175s are supposed to be coming.ing to GWR.

Plan was 2 carriage 175s on Okehampton, 3 carriage 175s on Barnstaple with 2 and 3 carriages working together on  penzance to Plymouth  and Exeter services allowing last castle hsts to go as well as freeing up class 150/2's for Devon.and Cornwall metro and 158s to boost the Cardiff to Portsmouth hbr service

 
I'd imagine that GWR have a plan to use the battery electrics for Henley/Marlow/Windsor and perhaps Basingstoke branches where they can be maintained in Reading, but will play it safe before they go public.

As for further west, seems more likely that GWR will muddle through until Project Churchward replaces the DMU rolling-stock en-masse.

 

The crosscity line in Birmingham is a good example to look at. Could even copy what us Welsh are doing on the valley lines. With electric/battery powered trains. GWR having a fleet of flirts with level boarding now that be great for the city

 

I thought about that too, but the type of kit in use is not something designed to draw power from a 25 kV supply. Modifications to Vivarail's idea would probably bump up the cost to more than that of wiring up Henbury, if the cost can be brought down to £1.5 million per track kilometre as Mayor Dan said. Portishead would be another electric kettle of fish though. My guess is that there will be a lot of diesel miles under wires for a long time to come. If, however, electricity does finally come to Avonmouth and Severn Beach, and if there's a bit more dualling of track, would there be a case for having more than 3 tph/2 tph on the branches? That would be cart first in the usual way of doing, but having pure electrics all around Bristol would make it look like a real Metro in a way that diesels can't match.

 

As you suggest, electrifying Filton Bank would cover half the route from Temple Meads to Henbury. That suggests the use of battery-electric trains could be the way to go on this line. But if WECA's 'Branch Line Study' has a positive outcome, we'll be looking at 3tph to Avonmouth and 2tph to Henbury. Would that justify full OHLE?

 
There's a bit more about what the test run involved and what the results were here:

https://www.oxfordmail.co.uk/news/24125628.gwr-battery-powered-train-travels-uk-record-distance/

 

It was, and possibly still is. The various diagram options quoted in the past are updated with each new idea or problem, and Severn Beach to Bath was once part of the mix. That seems to have been superseded by the extension of MetroWest to Westbury (presumably to be renamed MetroWestbury) and other extensions such as to Gloucester instead of Yate. The whole issue will probably only be decided when both phases are up and running, something not helped by Phase 2 overtaking Phase 1 in terms of probable opening date.

As for the use of battery power on either SVB or the Portishead branch - I don't know the answer. I would think it unlikely, at least at first, because of the passenger numbers on SVB and likely heavy use of the Portishead line. The single track on both routes may be a limiting factor, but the biggest hurdle may be infrastructure. AIUI, the charging mechanism is a little more complex than what I have in the garage, involving huge currents to effect recharging without long dwell times, and lots of batteries to store the power so as to avoid the need for a grid connection rated in the megawatt range. Electrification of a short part of the SVB route and longer portion of the Henbury line could be the impetus for wiring up those branches soon afterwards to allow pure EMUs to be deployed. That possibility may mean that other areas have a better case for battery power.

And we are talking about something that has just had its first public outing. A lot more will be known once regular passenger services start somewhere, and I think I would prefer that somewhere to be somewhere else to start with. Better the diesel you know, as they say.

 

Wasn't a Severn Beach - Portishead route once on the cards for Metrowest?  A charging point a each end would work nicely.

 
It was looked at a few years ago in a route study, (I forget which one), with a view to LO or even Chiltern taking it over. Neither option made much sense, especially since with the GOB line being recently wired LO were not interested in reintroducing a couple of DMUs to their fleet. In Chiltern’s case it was apparently a possibility, but would still have meant awkward empty stock running with no real advantage over GWR operationally.

Paul

 

It was of course a trip with few passengers and no station stops, taking two hours to travel 70 miles. My own EV experience shows that more speed equals less range, and trundling along an empty M5 at 35 mph for 2 hours would probably give me half my car's claimed range again. It is hardly a real-life test in service conditions, but I am still impressed. The technology works, the train moved when asked, and if it only manages 70 miles between charges in real life, that isn't bad. Subject to the fast recharging kit doing what it says on the tin. I think we are still in the early days of battery development. You can't beat those pesky laws of physics, but I am sure big improvements will arrive before too long. This certainly looks a bright idea.

 

I think it could go on Severn beach services if it just shuttled between Bristol TM and Severn Beach etc.

Certainly the figures from today have surprised everyone unit did the trip just using 45% of the  charge on the batteries the engineers saying it could have done 120 miles between charges. Well have to see how it performs on tje Greenford branch now. No doubt all going to plan well see more 230s on the other branches in the Thames Valley  possibly other areas too.

Wont be surprised to see other TOCs consider it

 
Remind my why the West Ealing to Greenford service is not overground?



Or perhaps The Siemens Line - https://www.siemens.com/global/en/company/about/history/stories/on-track.html

 

He's extremely fortunate to have found a workable 5G (or even 1G) signal in this neck of the woods, with which to post his video

 

I'm wondering if any of those are with Metrowest in mind.

 
Tim Dunn is aboard and reporting live on X (link to thread):

https://twitter.com/MrTimDunn/status/1758447007469895732

 
This is the one you want https://www.realtimetrains.co.uk/service/gb-nr:K00487/2024-02-16/detailed

 

Link not working for me!

 
Paths on realtime trains for 230001 to make its way to Reading depot tomorrow.

https://www.realtimetrains.co.uk/servic ... 6/detailed

Theres a lot of eyes watching this trial.all going to plan batterybtrains could appear on a few of GWR's branch lines Chiltern are watching this trial too

 
Railadvent have a bit about the battery train's testing in west London this spring.  Link below:


https://www-railadvent-co-uk.cdn.ampproject.org/v/s/www.railadvent.co.uk/2024/02/battery-trains-to-be-tested-in-west-london-this-spring.html/amp?amp_gsa=1&amp_js_v=a9&usqp=mq331AQGsAEggAID#amp_tf=From%20%251%24s&aoh=17073910041782&csi=0&referrer=https%3A%2F%2Fwww.google.com&ampshare=https%3A%2F%2Fwww.railadvent.co.uk%2F2024%2F02%2Fbattery-trains-to-be-tested-in-west-london-this-spring.html

 

You can hear it does. As the train slows for the stop, the inverters are running until the last few seconds, then cut out abruptly. From what I recall about it, running the inverters and supplying a field to the motors uses power, even if the field is in step with the motor and not driving nor braking it. At very low speeds the power available from regeneration is too low to make this worthwhile; also the braking force reduces with speed so friction braking has to be used right at the end anyway.

But the energy recovered isn't going to extend the battery life by much in any case.

 
I would be surprised if it didn't have regenerative braking: if it doesn't then I wonder why not.

Dave

 
230001 to make its way to Reading on Friday 16th February.  Testing showing its managing 70 miles before needing charging although batteries Re still said to have plenty of energy lefy

 

It's the inverters or motor drives, now a part of all train designs. Some of them sing, some warble, these do rather scream in chorus.

 

Oh the nostalgic sound of those motors.  I'm used to hearing it in subterranean London and now my brain feels pleasantly disoriented when I hear it pictured in rural Gloucestershire.

I guess the higher-pitched sound is something to do with the new control equipment needed for the battery power source.

 
230001 is now out testing on the mainline. Hopefully won't be too long before it moves to Reading.

https://youtu.be/dQ7EtCkGffc?si=gwgmE0teT1PLKNy6

 
The Daily Mail seems to think this is "Exclusive" ...

 

From The BBC

 

Bit odd though. RTT shows most services between Bidston and Wrexham as being bustituted. On 6 April, 230010 arrived at Wrexham 0658 from Birkenhead EMU depot, before forming 2F50, the 0731 to Bidston. The return 0833 to Bidston leaves 7L, and isn't shown as being 230010 like the earlier service is. Whatever ran the service arrived at Wrexham at 0941, 9L, and the return service is cancelled out of Central, starting from Wrexham General at 0942, presumably not the same train. It looks like the train that arrived at Wrexham at 0941 returned empty to Bidston, leaving at 1209. The coming week's actual trains on the route are marked as DMUs, then no service at all in w/c 17 April. Only from 25 April do the D-trains start to form the day's services. I can't tell whether it was issues with 230010 or other problems unrelated, but it doesn't seem to have been an entirely smooth entry into service, more like a tentative trip or two for the papers to start with.

 
The ongoing Vivarail saga doesn't seem to have had an adverse impact on the introduction of hybrid Class 230s for Transport for Wales as the link below would seem to confirm.


https://news.tfw.wales/news/uks-first-hybrid-train-enters-service-on-borderlands-line

 

I am obliged.


I am between spectacles, and read that as "might get D76 stuck on the Severn Beach Line". A prophecy if I ever saw one coming.

 

DfT have huge powers over a TOC, so GWR will certainly need to agree this with them. The contract gives DfT explicit rights of approval when GWR (1) buy a train or (2) take on employees or workers. And despite this not being a franchise agreement, there is still a load of stuff about assets, franchise assets, primary franchise assets, etc. One clause gives the SoS the right to designate any asset as a franchise asset. Nanomanagement!

 
As I read it, it could be a pretty complete purchase. I wonder if this means we might get D76 stock on the Severn Beach line.  Just imagine the political gains - "We have brought the underground to Bristol"

 
The VivaRail staff won't have been TUPE-D, because VivaRail was already in administration & therefore those staff already made redundant.

Also, I don't see why GWR would have needed DfT approval to buy those assets. Surely a risk taken completely by GWR needs no approval. From *their* ultimate owners (FirstGroup) very likely though.

 
Battery power might be useful as an addition to OHLE in two circumstances:

• Providing limp-home traction and running heating, air conditioning and lighting on passenger trains in case of OHLE failure
• For low-speed, short-distance freight manoeuvres in places where it's impractical to install OHLE for other reasons, such as ports and quarries, where waggons need to be loaded from above

Obviously only the first applies directly to GWR, and it might turn out that for the second, a small fleet of diesel shunters is more practical (but dirtier).

 

I was thinking that too. There was a press release from First group, which I think is exactly the text from Twitter quoted above - so it's explicitly GWR that will be the owner. DfT is mentioned, but then they always were a "partner" in the trails programme. As a TOC, GWR must have had DfT approval, but not necessarily any money, do do this. I guess there will be agreements between DfT, GWR, and First covering who ends up with what. Of course the "what" may not have any value by next year anyway.

 

I wonder has First Group Bought it or is it a franchise asset - essentially DfT buying it?

 

I agree completely. Whatever battery technology is decided upon, they will still hopefully make a living from licensing the charger idea. They have, to paraphrase a music publisher, bought the real estate. That presupposes that there is something discrete about the design that couldn't be assembled by any Tom, Dick or Isambard from parts available already.

 

I think its a bit wider than just the 'D' Stock. GWR has bought the intellectual property rights to the high-performance battery and fast charging technology, this is the part that is deployable to other rolling stock types, the 'D' Stock could be seen as the test bed. 

I can seen GWR partnering with a train builder for new rolling stock and or train builders buying a licence to use the technology 

 

Jam tomorrow then, although that was probably said of the now ubiquitous Lithium ion battery for the first 30 years or so of development.


Early days indeed, although sodium ion batteries were being looked into some years ago, until it became clear that Lithium was going to be the winner in the rechargeable battery race. Sodium is back in contention because of cost and availability rather than any chance of replacing the usurper. From what little I have read, it looks like weight would preclude use for transport applications, although as a static power source it seems potentially useful. Not just iron and sodium  - I get emails announcing, with a fanfare of trumpets or roll of drums, some new idea involving aluminium or sulphur, both of which benefit on the electron count compared to lithium or sodium. All need a lot of playing with before any real result happens or the idea fades. Regime change in batteries can be as sudden and total as in the totalitarian wing of politics, or in matters like light bulbs. The new idea becomes affordable and safe with big advantages over the old, and old one is toast in the twinkling of an eye. The development is slow, though. The period between the start of serious research into a workable lithium ion battery and its near total domination over other small rechargeable types almost exactly mirrored the period from the introduction of VHS and Betamax to the almost complete demise of tape-based recording of video in the home.

That's a fascinating topic for deeper discussion on another thread, but does lead me nicely back to GWR's bargain purchase. Imagine that the research into how to optimise current battery technology continued under the aegis of GWR, with a select few of Vivarail's TUPE'd boffins working both in the laboratory and field, emerging with singed eyebrows and ticked boxes on worn clipboards occasionally. It is entirely possible than in a few years time they would come up with a workable solution that would become obsolete during the ceremony to roll out the 100th train produced to their design. For this reason, I can't see GWR pulling out every stop to bring the battery train into service. It may be worth carrying on slowly, maybe evaluating new developments to sort wheat from chaff rather than doing their own research. Intellectual property can sit quietly in a safe in case someone suddenly wants to buy or lease it. I hope I'm wrong, but there probably won't be much news here in the foreseeable.

 
There also seems to be some encouraging developments in developing sodium-ion batteries instead of lithium-ion. However it seems still to be early days, and (if I understand what I have read so far correctly) advantages of not being reliant on China for lithium, fewer safety issues, faster charging and longer life are offset to a degree by lower energy storage.

There is however an issue that no-one seems to have addressed - a small fleet of battery units operating on a small number of branches surely reduces flexibility, and means that if a unit fails it is going to be difficult to procure a replacement from a limited pool of units. More cost-effective means of electrification of branch lines may well be more cost effective in the long run.     

 
Battery technology is improving, and apparently there is hope for types based on iron, avoiding the problem of needing rare minerals. But that's still in the future...

 

Battery beats diesel. I have a nasty feeling that the laws of physics will beat battery in the real  world unless there is a diesel engine just in case. That will make it a hybrid, like the ones sold by the Indulgence Specialists, unbeloved by broadgage with good reason.

 
Battery beats diesel though, right?

So a very reasonable way of removing diesel where costs of electrifying plus the time needed are deemed excessive?

 

Your view isn't shared by the authors of the Regional Traction Decarbonisation Strategy. They give amber to battery power for passenger transport to 75 mph, read for 100 mph, but green for hydrogen in both cases. That doesn't make sense to me unless they are happy with the steam reforming of hydrogen. Even then, battery would win because we already have an infrastructure for that. Like johnneyw, I am surprised, given Mark Hopwood's antipathy towards the idea in the past. Possibilities for his volte-face (should it be Volt here?) include an improvement in the technology since Vivarail dropped the viva, a Damascene conversion on the road to West Ealing, an opportunity to greenwash something else, or a jolly good price for something that might come in handy in the future.

I don't see either battery or hydrogen as having a big future on railways. It will be OHLE, diesel, or closure.

 
The biggest problem with the Bedford - Bletchley 230 units, and presumably the TfW version, was the diesel power pack reliability.  The DC only SWR class 484 version is already maintained in house, hopefully spares provision was included.

So although without any firm evidence, I’d expect that the diesel power packs are completely irrelevant to GWR’s aims for the trial and won’t have been included in the deal.

PS

Roger Ford has also summarised it in his e-mail preview that just arrived:

“The good news, breaking just as I was about to send out e-Preview, is that GWR has agreed contracts to buy the intellectual property (IP), rolling stock and equipment for the high-performance battery and Fast-Charge technology which was due to be tested on the Greenford Branch.

GWR has also employed nine former Vivarail staff to support the trials and project development.

The IP acquired is essentially the patents protecting the Fast-Charge system.”

Paul

 
Commercial opportunities with other TOCs for the supply of maintenance etc.?

 
Encouraging, interesting and perhaps a little surprising given that I seem to recall Mark Hopwood being somewhat dismissive of the prospects of GWR using Vivarail D-Train a few years ago.  I suppose that it might have been because the battery power version was a less proven option then.

 
Glad to hear that this project is still going ahead. Battery power is IMHO the future for lines that cant be electrified affordably.

I hope that the new trains enjoy greater success than some other new types.

 
Bringing this thread back to life owing to new developments....

From Today's Railways, on twitter

 
Don’t know if it’s connected but the Greenford Branch is closed over the August Bank Holiday weekend and the first two Saturdays in September.  (There are no Sunday services anyway).

 

One thing that's implied, but not mentioned at all in that publicity, is that presumably this involves charging from on-board traction power. That would be a new bit of Vivarail's kit of parts, but one you could have guessed they'd be working on. It leaves open the question of whether shore power or a charger would be needed at the far end of the line.

 
Eversholt have announced that they are getting Vivarail to add some batteries to their "Renatus" modernised Class 321 EMUs. From their news page:

Since this is the same traction package as on the 455s, it must use 750V as its intermediate DC voltage. So the batteries and linking electronics can be the same as on the 230s, or a bit beefed up.

What applications do they have their eye on? Much the same as for the ones based on the D78s, I guess, but offering a real train?

 

"Later this year", according to Vivarail. Were you expecting anything more specific?

 
Any news on when the trial start?  Trains in public service?

 

The use of carbon ceramic make sense especially as it is static current collection also the shoe look larger than normal travelling shoes.  The key as always with electrical connections the greater the current the larger the surface area required the surface area can be reduced by contact pressure, there is a limit of when you start to lift the train 


This has been in discussion with RSSB, ORR and NR for at least 5 years

 

That's a relief.  I wouldn't want to be the driver who had his train cancelled because he forgot to plug it in the the charger...a headline makers dream!

 
There's now a youtube video of a presentation by Vivarail on Fast Charge, recorded at a PWI* on-line. It concentrates on the safety case, perhaps because of the audience, which leads to the impression it will have a lot of failures due to false alarms. But I can see that for their programme to do the Greenford trial, getting ORR and NR approvals was probably the biggest activity and highest identified risk.

The numbers are not quite the ones I got from their previous presentations: now 300 kWh of batteries per DM (and 1 MWh per Trackside Charge Unit). The transfer is of 1 kA at 800 V, and is expected to replace 30-50 kWh per train used in a 5-mile round trip in three minutes. So the control system design has dictated by the need to charge automatically for as long as possible during the turn-round, and without the driver stopping to do anything special.

One those numbers there is easily enough capacity to cope, but then there's no mention of "losses" or "efficiency". You just can't shovel all those kWh around at that rate without a lot of them escaping!

*Permanent Way Institution

 

Of course it is - as announced by Vivarail! The relevant story on their Fast Charge system is hard to find, for want of links, and some the other details are elsewhere. But it does include:

So they are trying to prove this Fast Charge approach and the hardware. They reckon the buffer battery at trackside is worthwhile to avoid a high-power mains feed. The fast transfer of energy from it to the onboard batteries is well above what a small train like this would normally need, by AC or DC. But clearly adding AC would cost a lot at any power level, while at DC the current goes straight into the batteries. The electronics to control it and match voltages can be offboard, apart from the cells' charge controllers that are built into the batteries.

They talk about current levels of 1 kA or a low multiple of that, and that agrees with what ET said above. They also mention ceramic shoes to cope with the heat, and I don't suppose they will use standard conductor rails either for the same reason.

So it's all been planned out and, apparently, ready to go ... soon. Of course getting it all up and running on schedule is the hard bit, and the suppliers of both new and rebuilt trains have now got a truly lousy reputation for that.

 
I understand thst is so

 
Won’t they be using their modified D78 stock?  In other words no pantograph fitted, but fitted with DC shoe gear?

 
For fast charging, perhaps a short length of 25 KV overhead might be simpler.
Out of reach, so can be left live all the time.
Much lower current due to the higher voltage.
Can be of a cheap and simple design as not intended to be used at significant speed.
Multiple pantographs are possible, in order to pick up enough current.

Another advantage is that if needs change, the trains can re deployed to other routes that are partly electrified.

 

Based on tests I have been involved in at IPH Berlin ( https://www.cesi.it/about-us/overview/iph-gmbh/ ) testing third rail shoe contact current capacity when static.   Once you get over about 4kA (4000A) at 750V DC arcing and burning starts which is not a problem for a train if it starts to move as the contact surfaces scrub.  To get over the 4kA DC limit the downward pressure of the shoe gear needs to be increased but you get to the point of the mechanical limit of the force required.

Of course the transfer may be AC not sure the ORR would be keen on an RMS Voltage above 750V AC.  Another option could be high frequency AC but then there are RFI issues and the risk of shock from exposed conductors.

It will be interesting to see what the charging system will be.

 
I doubt that charging from empty in three minutes would be possible.
I presume that they mean replacing the amount of charge used in the previous journey, which is still impressive.

 
no, that wasn't mentioned/asked

 

Did they how empty that was from? My guesstimate upthread was that it would have used a sixth of a batteryfull, and replacing that would take a couple of minutes.

 
That's what I thought & asked for confirmation that I'd heard correctly.

 

That's a lot of Joules (one kilowatt-hour is equivalent to 3.6 megajoule)

 
Update from a meeting with GWR this afternoon.

The unit will charge to full in just three minutes at West Ealing on each return there.

 
I believe the unit is to be stabled and serviced in West Ealing sidings with light maintenance being carried out in the Plasser works next door, so no lengthy runs required.  Probably one of the reasons why the Greenford route was chosen for the trial.

 

Does the first run of the day still start from Paddington and the final run end there?

 
I see that the distance from West Ealing to Reading depot is approx 29 miles as the crow flies. If the train will be stored at Reading overnight, presumably it will need a top up before it departs for West Ealing in the morning otherwise it will be close to or over it's 62 mile range.

 
I would assume that is taken into account in coming up with the 62 mile range quoted, based on an assumed typical cycle of acceleration, braking and coasting.

 

I think a diesel hybrid might need to do that, but it seems a bit too much to allow for a pure electric train.

Going back to those numbers, 80 kWh 33 times per 24 hours averages out at 110 kW. That (plus a bit for losses - say 120-150 kW) is quite a chunky "trickle". It could be supplied at 400 V three phase from a large enough commercial installation. Whether a small station like West Ealing would have anything like that available is another matter. NR may be able to do things differently, especially at the carriage sidings. If the power used is the lower of those two figures, say 70 kW, it's obviously easier to source.

That does not make use of the full battery range, of course. If it can do five trips (or ten if that's right) without replacing that charge from the buffer store, that  much might instead be done overnight and from another supply.

Vivvarail's marketing emphasises not needing a lot of heavy infrastructure, and even the "pop-up" electric train service needing a big box of batteries dumped in each station car park and little else.

 

I imagine the 80% is too allow for regenerative braking, if for example the unit has been charged at the top of a hill.

 

In reality a traction unit dose not draw full power 100% of its journey, it will coast or "throttle" back for a large portion of its journey.   It will sit on its charging point and the unit software will decide what charge rate to adopt.



The project team will almost certainly have talked to the local DNO for a supply.

Another method to derive the power would be a 25kV transformer in theory 6 MW is posible in reality an aux supply transformer of 1 or 2MW have been used on the National system the output voltage what every you chose, it could feed a SFC to produce 3 phase from the single phase input

 
For all those desperate for another fix of facts and numbers, there's some in a long railengineer article dated October 2020 and a US presentation from April 2019. So these data can be added to the knowns list:

The DC bus voltage is 750 V, as it was before conversion. It's a very hard thing to alter, even if they have changed pretty much everything that connects to it, and of course it's essential to allow the option of third rail power.

The one thing I can't source explicitly is whether the new batteries are around 100 kWh capacity, like the initial ones. I think they are; I just can't work out where I saw that. But that's not all used; they are operated between 20% and 80% charge by agreement with Hoppecke. The bottom 20% is "get you home" reserve, but how can the top 20% be used as a reserve? My guess is that as they get older the upper limit of charge is allowed to go up to keep the same working range of 60 kWh.

The planned and/or guaranteed life of the batteries in service is seven years, after which they are either recycled by the makers at once, or used in a trackside buffer store for ten years first.

The fast charging is done per vehicle, and for this train that's two batteries each end. It has room for three, and for COP26 the third one was said to be "for resilience". Given the nature of that one-off deployment away from its home depot, this makes most sense if it was a spare that could be swapped in in any siding by moving a few cables or borrowing a forklift. 

Exactly how many batteries are attached could have been altered, and indeed it could still change. There is room for three under each motor vehicle, and five under the central trailer. It may well be that the arrangements for using all of those, and for fast charging them, don't exist yet.

These new batteries need built-in cooling to cope with the "in excess of 1000 A" charging current per battery. So each fast charger needs to supply nearly 2 MW. I think that's within the range of what third rails and shoes can manage, though they do say they are using ceramic carbon shoes. Being static on the rail for several minutes may make the heat build-up worse, perhaps.

The objective to "fully replenish" a battery in 10 minutes, taken literally, but for 120 kW working capacity, requires 720 kW (a little under 1000 A). That has to be doubled for the vehicle. Balancing does waste charging current, and liberate heat, but it would be surprising if it added 10% to the charge current. But the numbers do match, more or less. Note that charging a battery needs a higher voltage, but the extra power isn't recoverable, so without extra information the numbers may not mean exactly what you think.

The US presentation includes a figure of 2 kWh per vehicle mile, which is a lot less than 9 kWh per km for three vehicles (nearly 5 kWh per vehicle mile). I wonder which is right? Either way, an 8 km round trip to Greenford would not take 10 minutes to replace. That's just as well, since keeping the current 2 tph with one train (as suggested by GWR) only allow 6 minutes total for both ends.

If the highest figures apply, and it used 80 kWh per round trip, it needs to put back 20 kWh per battery. In two minutes that needs 600 kW - which can be done, according to the data above.

 
I agree, broadgage, although NIMBYs aside, I doubt that a large lithium battery in a built up area would get the nod from the planning people on safety grounds.

Thank you, Paul, for checking my homework.

 
400 kw is in theory just about doable at UK standard supply of 415/433 volt three phase. It would however be a very "disturbing" load to add to the ordinary LV distribution system.

A dedicated substation supplied at 11 kv would probably be required. In a built up area, providing an extra substation is routine and probably cheaper than a local battery. The substation transformer and other equipment should last at least 50 years.
Any local battery would almost certainly need replacing many times in 50 years.

Another advantage of a dedicated substation is that the transformer may be of a suitable voltage for the fast charger, rather than incurring the capital cost and the losses in transforming 415/433 volts up the charging voltage.

Ideally fast charging should be available at BOTH ends of the line, but the on board battery capacity should enable a normal service to be operated with charging only available at one end. In case of transformer failure or local power cut.



There is also the NIMBY factor, I and many other people would oppose a large lithium battery near my home in case of accident. A local substation would no problem.

 
Looks about right to me, but for an accurate calculation you’d also have to look at the time spent decelerating and hence regenerating. 

But if you think about it another way, if the short relatively lightweight unit draws about 100A on average from its supply when moving, you’d have to expect many times that during the much shorter charging phase.  If you round up the typical DC line voltage to 800V, then 500A would give you your 400kW.  Of course with their shoreside battery bank they can use a voltage of their own choosing, within reason.

So I think you’re in the right ballpark.

Paul

 

The publicity does indeed suggest that it can be charged from solar panels, as can any battery. It looks good, and impresses the green lobby more than saying that it will be charged by electricity produced by a mixture of solar, wind (not solar wind), nuclear, coal and predominantly gas. The Cancun 3-car model could be powered by a solar array spread over 3.4ha according to the leaflet, a space which would probably see about 250 homes built on it were it to become available. I assume therefore that not only is it sunny in Cancun, but that land is cheap. Given the weather here, you would probably need most of Greenford covered in panels if you were to rely on that.

A 3-car train uses 9 kWh per kilometre. Greenford to West Ealing and back is 8 km, so the charge at each turn at the charging station would be in the order of 72 kWh. To do that in 10 minutes is quite an accomplishment - would that need a >400 kW charge? That seems far too high, so I assume I misunderstand the maths and/or physics.

 

How does that work? If it's a half hourly service on a 5 mile return trip then it would need recharging at least every 6 hours. And surely better to get used to topping up every time so that there are as many opportunities as possible to ensure that the process is robust and works every time, even if time constrained.

 
There is an over generation of renewable (solar mainly) in parts of the country, the problems are the DNO's do not always have the infrastructure to get this back to a TNO site. 

Its more complex than just feeding it backwards. The UK power network was designed and engineered bulk generating plants cascading power down to the end user, the DNO's and TNO are working to get the infrastructure in place but it takes time and money.

The lineside storage is a bit akin to the days of steam and the water tanks which had a trickle feed into them but had the ability to "charge" the tender of a locomotive quickly.

I believe the Vivarail will be a contact system in the four foot, the original concept was for a short length ( 3 or 4 metres) of standard type third or fourth rail, neither NR or the ORR were keen on that on safety grounds.   The collection contacts will only be energised when the train is stopped in the right place and the brakes applied. 

Charging at 300kW should not be an issue, if the previously stated 60 miles on a single charge is correct the unit will only need charging once it arrives at West Ealing from Reading TCD and then before it returns back to Reading TCD at the end of the day.

 

I suspect that should be seen as more of a supply-side storage battery. There are a lot pf places, especially (but not only) more rural ones, where there is no spare supply capacity further up the distribution chain. That's not just an issue with very short high-power peaks: you'd need to shift the load out of the main daytime high load periods into the night.

The supply industry (DNOs, mainly) are trying to work out how to interact with customers' own storage, but also looking at having their own. A few years ago there was a research project here (with SEPD as DNO) on storage distributed in the local network (i.e. street corners), to even out the load.

All of these general-purpose storage units interface to AC mains via an inverter/converter. This kind of local reinforcement is compatible with a "normal" charge rate, but with a high cost if required to supply a really high power peak for a very fast charge and/or a big battery.

 
https://www.bbc.co.uk/news/av/business-48764903

An interesting report from a couple of years ago in Guildford, where a storage facility is used to draw charge from the grid during the day to avoid putting too much pressure on the local supply overnight.  That's only for 9 buses as well.

 
For the Volvo 7900e (as in harrogate) the rooftop connector and the rather clunky "socket" it plugs into are of a proto-standard design called OppCharge. This appears to be led by ABB, but who makes the bits is less clear. The idea of promoting it as a standard is obviously that buyers don't want to be limited to a single supplier for new buses to use their chargers.

The draft standard says rather cheekily that there is no upper limit to the current (presumably referring to the standard's text, not to any real equipment). The voltage is in the nominal range 500-800, typically 700 or 750, and at the moment the maximum current is 600 A. ABB say their chargers can offer 150, 300, or 450 kW (i.e. 750V x 600A), citing ones in Brussels that can fully recharge Volvo electric hybrid buses in three to six minutes. But that's electric hybrids - with a diesel engine, so presumably a smaller battery.

The 7900e data sheet says its capacity can be 198, 264 or 330 kWh, and when using OppCharge is can accept 300 kW (or 150 kW DC or 11 kW AC via a plug-in lead). Obviously that's not going to do a complete charge from empty in six minutes! 300 kW at 400 V is roughly the total capacity of a typical substation circuit like mine. So it's reasonably easy to provide if a substation is nearby, otherwise you'll need an 11 kV feed, which could give a higher peak power.

Essentially, at the moment local buffering is a non-standard extra, and that's probably how VivaRail justify their otherwise rather implausible claim that their kit is first-of and patentable.

 

Thanks for that link - really interesting to read into the Harrogate project (which I have been doing while supping my coffee!).   I can't see a note there of how the power gets to the rapid chargers.   Do they have a battery storage reservoir at the charging points (which is what I am especially interest in with the Ealing experiment) so they can be filled up with a pathetic mains connection while there's no bus on stand, or is there a thumping great substation behind the bus station?

 

Indeed it already is in the UK too - see the electric buses in Harrogate. https://en.wikipedia.org/wiki/Harrogate_Bus_Company

 

You would not even need two wires ! One wire will work fine with the steel rails forming forming the other side of the circuit.
Various voltages have been used, recent trends have been towards relatively low DC voltages of from 550 volts up to 1,500 volts for shorter lines in urban areas, and with 25 kv AC finding favour for longer routes.

Both are lethal if touched but reasonably safe as well out of reach.

 
The irony - from Ian Visits