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What implications does the latest battery train results have on future UK electrification ?.
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BerkshireRails
On Moderation
On low use lines it will either be 25kv AC OLE recharging bar or a 750v DC fast charger, or recharging off the already electric network.
except that the trouble is that to get maximum use out of trains and crew many branch lines have a very tight turnround. Look at Windermere for an example. Another, Colne, even has the luxury of some 17-minute turnrounds!
I reckon that the "least-used lines" are probably the tightest, having already been screwed up as tight as they can possibly go - and sometimes beyond what common sense says would be sensible.
43096
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If you charge stationery from from the OHLE, it will probably catch fire...
Nottingham59
Established Member
When running as a shuttle, there seems to be a 20 minute turnround at Oxenholme. A Stadler FLIRT Akku can fully recharge from the wires in 15.
except that the actual terminus is Windermere! Maybe I took "terminus" too literally. Diagrams which come from Manchester then do a trip or two on the branch before going back down the main line are not uncommon.
Sounds ideal. The train charges on the way from Manchester, then runs on batteries for a few trips, before recharging on the way home. No new infrastructure needed at all.
stevieinselby
Established Member
"Terminus" can be either end of the route (or both), whatever is more suitable in terms of power supply and layover time. The Greenford shuttle has its charging point at West Ealing, not at Greenford.
JohnRegular
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I wonder if this might be a more cost effective (and presumably safer) solution for use in depots?
Presumably less need for rapid charging, fewer issues caused by having to physically plug on, and minimal benefit from being under the wires during acceleration. Could you even just use a car charing standard?
If batteries are to cause OLE to be binned, then they must be able to offer substantial equivalence. Running the 230 gently overnight over a generally level route is bound to give a maximum range. What this could be in practice is another matter.
The latest Hitachi order for 9 sets (for £300M including servicing) includes c£10M for batteries, i.e c£1M per set. They also wisely include Diesels! Now one estimate gives the cost of LiP cells at £100/kWhr and a mass of c5 - 10kg/kWhr occupying 5 - 10l/kWhr. Diesel fuel by contrast offers about 4kWhr/kg! Thus if each set is 5 cars then we have 2000kWhr per car, 10 - 20t, 10 - 20 000l. Now an oddity of rail use is that a carriage consumes about 3kWhr/km, almost independent of speed, i.e c5kWhr/mile. Now these batteries are a little delicate and only perhaps 60% should be used to keep the cells in emf tolerance, so we have 1200kWhr usable per car, or 240 miles off grid. When one recalls that an HST set could approach 1000miles/day, we can see that continuous use of batteries needs excessive charging time, reducing availability. Also, what would the axle load be? We can use the last mile argument successfully, in that after a long run the batteries are fully charged (80%!) and so could access the main line branches, without terminal recharging. However, if only a few workings required battery use, then either all units in a fleet must be fitted or a sub class created, like the 777/1's which could be an expensive nuisance. Clearly short wiring avoiding whole fleet fitting of extensive battery capacity would still have attraction.
We can imagine the Guard announcing over the PA, " We apologise for the slow running, the lack of air conditioning and the low lighting today; this is because of low battery state."
The above tentative figures could vary either way. My present conclusion is that batteries are not a get-out-of-jail-free card for OLE investment - more is needed before even partial electrification can work.
Good luck to the industry, anyway. EOE!
WAO
The latest Hitachi order for 9 sets (for £300M including servicing) includes c£10M for batteries, i.e c£1M per set. They also wisely include Diesels! Now one estimate gives the cost of LiP cells at £100/kWhr and a mass of c5 - 10kg/kWhr occupying 5 - 10l/kWhr. Diesel fuel by contrast offers about 4kWhr/kg! Thus if each set is 5 cars then we have 2000kWhr per car, 10 - 20t, 10 - 20 000l. Now an oddity of rail use is that a carriage consumes about 3kWhr/km, almost independent of speed, i.e c5kWhr/mile. Now these batteries are a little delicate and only perhaps 60% should be used to keep the cells in emf tolerance, so we have 1200kWhr usable per car, or 240 miles off grid. When one recalls that an HST set could approach 1000miles/day, we can see that continuous use of batteries needs excessive charging time, reducing availability. Also, what would the axle load be? We can use the last mile argument successfully, in that after a long run the batteries are fully charged (80%!) and so could access the main line branches, without terminal recharging. However, if only a few workings required battery use, then either all units in a fleet must be fitted or a sub class created, like the 777/1's which could be an expensive nuisance. Clearly short wiring avoiding whole fleet fitting of extensive battery capacity would still have attraction.
We can imagine the Guard announcing over the PA, " We apologise for the slow running, the lack of air conditioning and the low lighting today; this is because of low battery state."
The above tentative figures could vary either way. My present conclusion is that batteries are not a get-out-of-jail-free card for OLE investment - more is needed before even partial electrification can work.
Good luck to the industry, anyway. EOE!
WAO
BerkshireRails
On Moderation
And non stop at most economical speed of 30-40mph with certain auxiliary's turned off.
Trainbike46
Established Member
OHLE is not likely to be removed anytime soon, though I could see the removal of small bits of third rail at high-risk locations. All exisiting applications of BEMUs in the UK either involved more electrification installed (756s in the Welsh Valleys), or involved extending services beyond the limits of electrification (Merseyrail 777s). The likely next deployment of BEMUs (Scotrail) also involves extra electrification installed for charging purposes, which is being installed as we speak (as discussed in the relevant Scotland threads).
This is a very weird set of assumptions, the batteries will charge while the train is operating in service on the sections of line that have electrification, whether that is third rail or OHLE.
That depends on where you are; there are places where all the infrastructure needed for BEMUs is in place today (e.g. Uckfield), and there are places where more will need to be installed (e.g. the lines towards Exeter and Penzance).
BerkshireRails
On Moderation
I think Network Rail would like to remove third rail at Pointwork to make it easier to repair and that can be done with adding more shoes to units and keeping them spread over the largest distance possible to prevent gapping.
zwk500
Veteran Member
Some junctions span longer than the maximum lengths of the trains. If you have multi-track sections with multiple ladders in parallel the safe distance of no third rail could easily exceed train lengths. Batteries makes that problem simply disappear.
Batteries have further advantages as well, such as enabling the third rail to be remove at areas vulnerable to trespass such as stations (highlighted by the SouthEastern interview on Green Signals mentioned above), in situations where the third rails need to be turned off due to trespass or planned work (again, highlighted by SE on Green Signals), and also contributing to a more efficient power management system.
Class15
Established Member
I wouldn’t personally remove any current third rail, but the batteries would come in very useful in power isolations, preventing Lewisham incidents etc.
HSTEd
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Battery enabled regeneration in third rail areas would remove the need for substations to provide voltage headroom for regen.
You could then trim the voltage on the substations to the top of the specification. That could meaningfully reduce currents and thus losses.
You could then trim the voltage on the substations to the top of the specification. That could meaningfully reduce currents and thus losses.
stevieinselby
Established Member
That's fine until you have a 3-car unit running solo, where Imelda Marcos could cover it in shoes and it still wouldn't span the gap.
I wonder how easily/quickly and frequently the battery/3rd rail or OLE changeover can be done?
Can it be as simple as flicking a switch on the driver's desk, then back again once past the junction?
zwk500
Veteran Member
I suspect the answer is 'depends on the design of the train'. In theory, it'd be perfectly possible to design a train's on-board software to operate from the external and on-board supply simultaneously. I suspect the driver would have some input, but with APCO beacons and a suitable power managment software setup, you could basically put the power mode in 'full auto' or whatever it ends up being called, and the train would draw from the battery whenever it detected the external supply dropping too low, recharging the battery when it wasn't using power and even returning power to the traction supply if able.
Some BEMUs may be designed to a slightly simpler option of having a switch that allows only one option at a time, but a battery shouldn't need to warm up and would be able to discharge almost instantly so the transition could conceivably be on the move.
Class73Electro
Member
Hmm, when I was on the Class 93, and we switched from Diesel to Battery, we had to wait a few minutes before we could set off again, can't remember what it was (Should have taken notes!), sure we was waiting for a indicator to reach a certain level
zwk500
Veteran Member
Quite possibly. I was very much talking about 'in theory', it may be that the Class 93s have batteries that are most efficient in a certain thermal range or something else.
Annetts key
Established Member
All cells and batteries have preferred operation (discharge into a load) temperature ranges. Similarly, they also have preferred temperature ranges for recharging (which may be different to the operation range but normally overlap). Hence in some designs there are heating and/or cooling systems.
The power from the cell or battery may be available instantaneously, but the control system may have to wait for the heating or cooling system to "start up" or for other parts of the power management system to confirm that they are ready. As the power management system will almost certainly also have a cooling system.
The specifics depend on the cell / battery type and the design of the control and power systems.
Accurate gripe. It was said on this forum that these new Bimodes would likely come in two single voltage variants.
This may be one of those cases where it's an early adopter or last to fill in. Platform 4 at Leamington has other users beside this one, but 1 with additional signalling could be dedicated to charging this service. It depends on whether it's expensive to make that change.
Yes, we know that the 200km run was five times as efficient as regular use, from all the regular use runs it's had.
Are we THAT certain about high capacity traction batteries?
www.bbc.co.uk
'We are playing with fire': Fears persist over battery storage
More battery energy storage facilities are needed around the world, but fire risks remain.
www.bbc.co.uk
Trainbike46
Established Member
Because diesel trains famously don't have a tank full of flammable liquid onboard.
Evidence from cars shows that Internal Combustion Engine Vehicles catch fire 5 to 6 times more often than Battery Electric Vehicles. I would expect a similar situation for trains.
So yes, BEMUs are a good idea, and they will increase safety on the railways.
But you can extinguish a Diesel fire because you can break the combustion triangle that releases the chemical energy.
A battery fire can have the energy released by shorting - the fire is then incidental and not controllable.
Imagine a cable short without a CB or fuse.
WAO
InTheEastMids
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But it's not really quite that simple. The risk is lower, but the impact (might) be higher because battery thermal runaway is more difficult to extinguish than a conventional fire.
You can engineer around that (e.g. use fire-rated enclosures that provide time to evacuate and direct pressure away)
In practical terms for the railway, the biggest issue might be disruption, because of the time taken to make what's left of a battery train safe enough to be removed from site and reopen the railway.
Trainbike46
Established Member
As InTheEastMids says, it is possible to engineer for fire safety, and I'm sure the people designing the BEMUs are considering fire safety throughout the design.
Fire risks is also one of the factors impacting battery chemistry choice.
Overall though, it is quite clear that BEMUs are safer than DMUs.
Fire risks is also one of the factors impacting battery chemistry choice.
Overall though, it is quite clear that BEMUs are safer than DMUs.
Annetts key
Established Member
With a battery, it's not the chemicals that are the biggest issue. It's the amount of energy stored that can be released quickly that is the issue. This is not a new issue. Large lead acid cells and batteries also are a risk due to the amount of current that can flow into a short circuit. Ask any mechanic that has dropped a spanner across the terminals of a battery...
Take a humble D size NiMH cell. Ever had one short out due to putting in your pocket, the very same pocket that you have your metal keys in? It gets very hot very quickly...
So, with a correctly designed and manufactured battery system, there must be built-in protection systems that can cut-off the output from the battery system in the event of an overload or short circuit. Or if the temperature is outside the normal working range.
Plus, there must be suitable physical protection against impact.
Finally, the charging system must be correctly designed so that the battery can never be overcharged.
For any large industrial system, you would also want multiple redundant protection and control systems so that protection is not lost if one system fails.
Oh, and it is sometimes possible to put out battery fires. The thing is though, water, foam, carbon dioxide etc. are not the correct tools. Removing the cause (short circuit) or physically separating elements after dumping dry sand over them may help.
Take a humble D size NiMH cell. Ever had one short out due to putting in your pocket, the very same pocket that you have your metal keys in? It gets very hot very quickly...
So, with a correctly designed and manufactured battery system, there must be built-in protection systems that can cut-off the output from the battery system in the event of an overload or short circuit. Or if the temperature is outside the normal working range.
Plus, there must be suitable physical protection against impact.
Finally, the charging system must be correctly designed so that the battery can never be overcharged.
For any large industrial system, you would also want multiple redundant protection and control systems so that protection is not lost if one system fails.
Oh, and it is sometimes possible to put out battery fires. The thing is though, water, foam, carbon dioxide etc. are not the correct tools. Removing the cause (short circuit) or physically separating elements after dumping dry sand over them may help.
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