What implications does the latest battery train results have on future UK electrification ?.

[Technologist]

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.

Have a look at what modern batteries are able to charge at; the most advanced automotive LFP can charge at 10C peak and about 6C average over a full charge. If we are talking about charging at a terminus then it's likely that we will spec a train with about twice the battery capacity needed to go end to end so we can still do a reduced service if we lose or curtail a charge. In which case we are likely looking at a 5 minute charge maximum.

Ironically the best trainline for battery usage might actually be the London underground, the lines are really short so you can easily install enough batteries to do double the line length with substantial margins. The over large batteries means that a partial charge can be done in the 2-3 minute turn around that the highest utilisation lines have.

In exchange you get to remove all the electrification equipment from the system which should save a considerable amount of money in maintenance over time, removing the electrification also gets you to the point where you could run the system un-manned as isolating the track during evacuation was one of the tasks of the driver.

 

[CMS1]

Hence discontinuous electrification projects like the borders railway are a complete waste of money. The services have circa 20 minutes to charge at Edinburgh plus 3 miles OHLE before/after

== Doublepost prevention - post automatically merged: 16 Sep 2025 ==

Ironically the best trainline for battery usage might actually be the London underground, the lines are really short so you can easily install enough batteries to do double the line length with substantial margins. The over large batteries means that a partial charge can be done in the 2-3 minute turn around that the highest utilisation lines have.

In exchange you get to remove all the electrification equipment from the system which should save a considerable amount of money in maintenance over time, removing the electrification also gets you to the point where you could run the system un-manned as isolating the track during evacuation was one of the tasks of the driver.

Interesting, if it enabled that it could be a very good investment, saving circa £300M per year?

 

[SynthD]

Interesting, if it enabled that it could be a very good investment, saving circa £300M per year?

Where is that number from? How long would it take the yearly saving to pay off the investment in the remaining long list of obstacles to driverless trains?

 

[WAO]

I'm not sure that a LUL low floor train would have much room for batteries. In my experience, only a trailer had any space for ballast.

Also when ORR recovers from its 3rd rail panic attacks what will it require for battery safety and crash worthiness?

WAO

 

[hwl]

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.

Exactly NMC (cheapest) has far higher fire risks than LFP (safer) or LTO (safer still) but the public perception fire risk is mostly based on the most common NMC issues in cars (or often poor assembly and control electronics in consumer goods) not the more expensive technologies used in rail and rail also takes extensive mitigation actions.

 

[HSTEd]

Exactly NMC (cheapest) has far higher fire risks than LFP (safer) or LTO (safer still) but the public perception fire risk is mostly based on the most common NMC issues in cars (or often poor assembly and control electronics in consumer goods) not the more expensive technologies used in rail and rail also takes extensive mitigation actions.

Aren't LFP batteries normally considered to be cheaper and lower performance than NMC batteries?

 

[BayPaul]

Aren't LFP batteries normally considered to be cheaper and lower performance than NMC batteries?

They are very much safer, but have lower energy density. Generally a good choice for applications like rail where flamability is critical (they won't explode in a collision for example, and thermal runaway is extremely unlikely), but size is less vital.

 

[hwl]

Aren't LFP batteries normally considered to be cheaper and lower performance than NMC batteries?

LFP cells are 3.2V vs 3.6V for NMC hence you tend to end up needing more LFP cells to achieve the same pack voltage which pushes the cost up when you get to real systems rather than measuring in £/kWh.

(LTO are lower still at 2.8V).

The useful side effect is for low cell voltage is when all the other design criteria are factored in they end up being subjects to lower charge/discharge rates than NMC which hammers the battery pack less...

 

[Brubulus]

LFP cells are 3.2V vs 3.6V for NMC hence you tend to end up needing more LFP cells to achieve the same pack voltage which pushes the cost up when you get to real systems rather than measuring in £/kWh.

(LTO are lower still at 2.8V).

The useful side effect is for low cell voltage is when all the other design criteria are factored in they end up being subjects to lower charge/discharge rates than NMC which hammers the battery pack less...

LFP batteries have much better longevity than NMC batteries, and when properly managed, as they would be in a rail application, this will be further strengthened. Automotive grade LFP batteries are what the railway needs, with charge/discharge rates of at least 4C average 10-80% and long lifespans.

 

[InTheEastMids]

Oh, and it is sometimes possible to put out battery fires.

what will it require for battery safety and crash worthiness?

Both these posts are making good points, so I'll build on them with a few of my own.

• Several battery incidents occurred with early systems that lacked more sophisticated management / protection systems.
• The issue with things like scooters is often poor quality batteries being electrically abused by poor quality chargers
• Some incidents were worse than they could have been because fire fighters were unprepared and/or unequipped to deal with a battery fire; in some cases they didn't know it was a battery fire and believed it was another type of equipment.

These will not be issues in GB rail applications (either trackside or on-train).
Issues that I'm sure have been looked at during the trial but perhaps are not fully solved might include

• Thermal runaway resulting from mechanical abuse - as @WAO points out, nobody wants a collision to become more catastrophic because a battery has been pierced and is now in thermal runaway - a lot of that can be designed out but makes me think that energy density will be significantly lower than in other applications
• Fire fighting approach is usually to let the battery burn out and concentrate on avoiding the spread of fire; this reduces the chance of reignition later on, but if/how that works in various scenarios needs to be thought about - in tunnels, very isolated/rural areas, crush-loading

Ironically the best trainline for battery usage might actually be the London underground

I disagree. LU means crush-loading and a risk of trains stranded in very tight clearances in tunnels - it must be difficult to evacuate or have emergency services attend an incident. Agree there is benefit of self-recovery to the next station, but this has to be balanced against the increase in fire risk/impact score from carrying around a lot of batteries. And once you increase the battery beyond what is needed to get to the next station, growing the battery increases risk score without delivering any safety benefit. Has this has been a discussion topic around the new Siemens tube trains? I don't know as I haven't been following it.

 

[Brubulus]

Both these posts are making good points, so I'll build on them with a few of my own.

• Several battery incidents occurred with early systems that lacked more sophisticated management / protection systems.
• The issue with things like scooters is often poor quality batteries being electrically abused by poor quality chargers
• Some incidents were worse than they could have been because fire fighters were unprepared and/or unequipped to deal with a battery fire; in some cases they didn't know it was a battery fire and believed it was another type of equipment.

These will not be issues in GB rail applications (either trackside or on-train).
Issues that I'm sure have been looked at during the trial but perhaps are not fully solved might include

• Thermal runaway resulting from mechanical abuse - as @WAO points out, nobody wants a collision to become more catastrophic because a battery has been pierced and is now in thermal runaway - a lot of that can be designed out but makes me think that energy density will be significantly lower than in other applications
• Fire fighting approach is usually to let the battery burn out and concentrate on avoiding the spread of fire; this reduces the chance of reignition later on, but if/how that works in various scenarios needs to be thought about - in tunnels, very isolated/rural areas, crush-loading

I disagree. LU means crush-loading and a risk of trains stranded in very tight clearances in tunnels - it must be difficult to evacuate or have emergency services attend an incident. Agree there is benefit of self-recovery to the next station, but this has to be balanced against the increase in fire risk/impact score from carrying around a lot of batteries. And once you increase the battery beyond what is needed to get to the next station, growing the battery increases risk score without delivering any safety benefit. Has this has been a discussion topic around the new Siemens tube trains? I don't know as I haven't been following it.

Rail applications will have relatively high quality batteries operating within normal limits in environments with a low level of abuse. It is highly unlikely that batteries will suffer any form of physical deformation, in which case that is likely the least if the railways concerns. From a fire safety perspective, it is likely safer than carrying hundreds of litres of diesel.

 

[Bald Rick]

Also when ORR recovers from its 3rd rail panic attacks what will it require for battery safety and crash worthiness?

Given that we already have 2 fleets of BEMUs in daily passenger use on the network, and a fleet of traction battery equipped locomotives certified for main line use as well, you could ask them…

 

[WAO]

Safety does tend to work in arrears.

No one would be happier than me if batteries were to give 100% trouble free service in widespread use. Certainly collision risk is now much lower with TPWS.

WAO

 

[Technologist]

I disagree. LU means crush-loading and a risk of trains stranded in very tight clearances in tunnels - it must be difficult to evacuate or have emergency services attend an incident. Agree there is benefit of self-recovery to the next station, but this has to be balanced against the increase in fire risk/impact score from carrying around a lot of batteries. And once you increase the battery beyond what is needed to get to the next station, growing the battery increases risk score without delivering any safety benefit. Has this has been a discussion topic around the new Siemens tube trains? I don't know as I haven't been following it.

To address you first point first, no the idea stems from my own independent curiosity and having a Tesla as part of the package in my old job.

I think cars are pretty illustrative of what things are likely to be an issue with a BEMU and what won't be. Space for battery packs is not really an issue, from my modelling I don't think we need to put more than 300KWh of batteries per carriage, which is basically three large EV batteries which fit beneath the floor of a medium sized saloon car. A pack is in the region of 2.2m long, 1.4m wide and 0.1m thick. Within reason we can squash or stretch that pack into any shape we want. With cell to pack or even cell to body arrangements we might even smear that whole volume over the carriage floor and make it ~30mm thick, or we hide it under a few seats.

With regard to fires, EVs are less likely to burst into flames following a car crash than an ICE vehicle and obviously car crashes generate much higher g loadings than train crashes (40mph-0 in ~20cm), it will be entirely credible to package the battery where it will survive a crash which is entirely un-survivable to the passengers.

Where is that number from? How long would it take the yearly saving to pay off the investment in the remaining long list of obstacles to driverless trains?

I think the £300m figure is the approximate value of the salaries of the drivers, actual employment cost once you factor in NI, pensions and support costs are likely to be much higher. Amusingly the cost of the batteries to run the entire London Underground is in the region of £100m and that's assuming the battery packs have a decent premium over automotive units. Ergo this would have a very good pay back ratio especially as the chargers at the terminals are ultimately going to be much cheaper than the costs of the electrification equipment in the tunnels both to purchase and to operate and maintain. The costs of keeping workers safe on an electrified line while maintenance takes place must be pretty significant. I also assume that the electrification equipment underground is taking up a fair bit of space that could ultimately be used for stuff like HVAC or something else useful.

I think the majority of estimates of the cost and difficulty of running the LU unmanned are far from objective normally being written by somebody with skin in the game.

1: These estimates normally assume that platform screen doors are a requirement and then proceed to quote a ridiculous cost for said doors. Firstly I'm pretty sure that they could be implemented more cheaply without as much need to integrate them with signalling systems and rolling stock. Secondly I'm not sure they are actually needed, the same checks the drives do around the doors could be done either by people on the platform or remotely by a control room based operator, the DLR doesn't need a driver for this. Thirdly I suspect we could do this with machine vision systems/ AI it's not like we lack training data.
2: Other underground systems manage to deal with passenger issues and evacuations without needing a driver.
3: The biggest issue would probably be the drivers getting wind of it and striking, obviously two solutions to that, 1: if they are doing a nationally significant job it could be made illegal for them to strike, see police and army 2: build a volunteer driver corps 3: tube drivers are not popular being perceived to be paid a fortune to do an easy job due to being able to hold the capital to ransom

 

[Brubulus]

To address you first point first, no the idea stems from my own independent curiosity and having a Tesla as part of the package in my old job.

I think cars are pretty illustrative of what things are likely to be an issue with a BEMU and what won't be. Space for battery packs is not really an issue, from my modelling I don't think we need to put more than 300KWh of batteries per carriage, which is basically three large EV batteries which fit beneath the floor of a medium sized saloon car. A pack is in the region of 2.2m long, 1.4m wide and 0.1m thick. Within reason we can squash or stretch that pack into any shape we want. With cell to pack or even cell to body arrangements we might even smear that whole volume over the carriage floor and make it ~30mm thick, or we hide it under a few seats.

With regard to fires, EVs are less likely to burst into flames following a car crash than an ICE vehicle and obviously car crashes generate much higher g loadings than train crashes (40mph-0 in ~20cm), it will be entirely credible to package the battery where it will survive a crash which is entirely un-survivable to the passengers.



I think the £300m figure is the approximate value of the salaries of the drivers, actual employment cost once you factor in NI, pensions and support costs are likely to be much higher. Amusingly the cost of the batteries to run the entire London Underground is in the region of £100m and that's assuming the battery packs have a decent premium over automotive units. Ergo this would have a very good pay back ratio especially as the chargers at the terminals are ultimately going to be much cheaper than the costs of the electrification equipment in the tunnels both to purchase and to operate and maintain. The costs of keeping workers safe on an electrified line while maintenance takes place must be pretty significant. I also assume that the electrification equipment underground is taking up a fair bit of space that could ultimately be used for stuff like HVAC or something else useful.

I think the majority of estimates of the cost and difficulty of running the LU unmanned are far from objective normally being written by somebody with skin in the game.

1: These estimates normally assume that platform screen doors are a requirement and then proceed to quote a ridiculous cost for said doors. Firstly I'm pretty sure that they could be implemented more cheaply without as much need to integrate them with signalling systems and rolling stock. Secondly I'm not sure they are actually needed, the same checks the drives do around the doors could be done either by people on the platform or remotely by a control room based operator, the DLR doesn't need a driver for this. Thirdly I suspect we could do this with machine vision systems/ AI it's not like we lack training data.
2: Other underground systems manage to deal with passenger issues and evacuations without needing a driver.
3: The biggest issue would probably be the drivers getting wind of it and striking, obviously two solutions to that, 1: if they are doing a nationally significant job it could be made illegal for them to strike, see police and army 2: build a volunteer driver corps 3: tube drivers are not popular being perceived to be paid a fortune to do an easy job due to being able to hold the capital to ransom

The primary difficulty for automation of the Underground is the lack of evacuation walkways. I believe that door control should be done in a remote control centre with the assistance of automated technologies. Even if the tracks are no longer directly electrified, it would still be difficult to convince the ORR of the safety of passengers on an unaccompanied train in a tunnel with no walkway, though a direct control centre video link alongside a quick response team could alleviate these fears. Striking will always be an issue for the railway/underground, even automated systems will require safety critical staff at some point, though I can see how batteries could enable automation of the underground.

Battery fire safety is pretty close to a non issue, especially when compared to live exposed electrical currents or hundreds of liters of flammable diesel. EVs will have to put up with what is likely to be more overall abuse compared to the predictable and stable, but intense and constant usage of rail applications, while the physical damage and G loadings faced by automobile batteries are likely to be far higher than rail batteries, even in worst case scenarios.

 

[HSTEd]

Where is that number from? How long would it take the yearly saving to pay off the investment in the remaining long list of obstacles to driverless trains?

London Underground has approximately 3250 Train operators on strength, as shown in various Freedom of information requests.

Typical salary is apparently in the range of £60,000-£75,000.

Direct salary requirement will be of the order of £200-250m, actual cost of employment is probably double that, including management, training and pensions.

Obviously, calculating a payback period requires us to make all sorts of assumptions that I am not entirely comfortable making off the hoof..... but the payback period is likely getting shorter over time.

 

[InTheEastMids]

With regard to fires, EVs are less likely to burst into flames following a car crash than an ICE vehicle

To be clear my contribution was about LU, where ICE engines are irrelevant, so the comparison is with todays 3rd/4th rail operation and whether changing to batteries keeps safety risk as low as reasonably practicable. At the current state of battery maturity, I think it will be very challenging to persuade people that this carried the same or lower safety risk than traditional conductor rails. After all, EV fires are about 1/20 as common as ICE fires (according to one report), so there is still a non-zero risk of a battery fire in a tube train.

A fire in a crush-loaded tube, deep underground is probably (one of) the most difficult scenarios I could imagine emergency services trying to deal with. Loading a tube train with stored energy can only increase this risk, no matter how many controls are put in place.

Having said that, the entire future of mass transit is hopefully a very long time, and things do change, so I am not saying "it'll never happen". What I am saying is that there are good reasons for underground trains to play it very safe with technology and be late adopters.

 

[Annetts key]

All this discussion of using battery trains on the LU is all very well, but...

For a Tube train to become driverless needs the signalling system to be suitable. How many lines have an existing suitable signalling system? And how much would it cost to install suitable replacement signalling systems? And where is this money coming from?

Stations that are currently unstaffed, or minimally staffed my need to become staffed or have more staff.

In terms of fire risk, with third or fourth rail electrification systems, electrical fires (assuming they have not caused other items to catch fire) can be extinguished by turning the power off. Although any battery powered tube train should have suitable protection against the battery causing fires, should a fire start, how are you going to deal with it if there are no crew on the train?

Besides, the priority is to invest in the "main line" railway using battery technology, not the LU.

 

[AndrewE]

All this discussion of using battery trains on the LU is all very well, but...

For a Tube train to become driverless needs the signalling system to be suitable. How many lines have an existing suitable signalling system? And how much would it cost to install suitable replacement signalling systems? And where is this money coming from?

Stations that are currently unstaffed, or minimally staffed my need to become staffed or have more staff.

In terms of fire risk, with third or fourth rail electrification systems, electrical fires (assuming they have not caused other items to catch fire) can be extinguished by turning the power off. Although any battery powered tube train should have suitable protection against the battery causing fires, should a fire start, how are you going to deal with it if there are no crew on the train?

Besides, the priority is to invest in the "main line" railway using battery technology, not the LU.

I don't see why "driverless" has anything to do with it. I could understand a case being made for a) removing all 3rd and 4th rails as you get rid of lots of complications at junctions and trip and electrocution hazards everywhere, plus the maintainance in tunnels. Balanced to some extent by paying for and maintaining battery EMUs and the chargers at termini - but that is all in well-lit sheds or other places with safe access/none needed.

Unfortunately Tesla car batteries (and their Powerwalls) were Li-ion batteries and were guaranteed to run away thermally (i.e. explode in flames) if there was any damage, but the LiFePO4 batteries apparently are almost intrinsically safe, apart from the external consequences of short circuits.

Plus there must be hundreds of thousands of Tonnnes of scrap steel to be recovered and sold, quite a pure iron alloy, I believe.

 

[Annetts key]

I don't see why "driverless" has anything to do with it. I could understand a case being made for a) removing all 3rd and 4th rails as you get rid of lots of complications at junctions and trip and electrocution hazards everywhere, plus the maintainance in tunnels. Balanced to some extent by paying for and maintaining battery EMUs and the chargers at termini - but that is all in well-lit sheds or other places with safe access/none needed.

The driverless point is referring to the discussion started by Technologist:

Ironically the best trainline for battery usage might actually be the London underground, the lines are really short so you can easily install enough batteries to do double the line length with substantial margins. The over large batteries means that a partial charge can be done in the 2-3 minute turn around that the highest utilisation lines have.

In exchange you get to remove all the electrification equipment from the system which should save a considerable amount of money in maintenance over time, removing the electrification also gets you to the point where you could run the system un-manned as isolating the track during evacuation was one of the tasks of the driver.

Unfortunately Tesla car batteries (and their Powerwalls) were Li-ion batteries and were guaranteed to run away thermally (i.e. explode in flames) if there was any damage, but the LiFePO4 batteries apparently are almost intrinsically safe, apart from the external consequences of short circuits.

Plus there must be hundreds of thousands of Tonnnes of scrap steel to be recovered and sold, quite a pure iron alloy, I believe.

Li-ion cells and batteries are not "guaranteed to run away thermally (i.e. explode in flames) if there was any damage".
There are a number of factors and variables that have an effect. Even the cheapest rubbish quality cells won't react if they are damaged if they discharged below a certain level for example. And high quality cells or batteries that are housed in good quality enclosures are fairly well protected in normal use.

And no high energy, high capacity cell or battery is completely risk free. As with many things, good engineering can reduce the risk to an acceptable level in many cases. But what is an acceptable level in one application may not be in another.

Steel rails can be melted down and reused, but there is the fairly high cost of recovering them from the railway. This quickly reduces the amount of money that can be made from selling the used rail.

 

[Technologist]

To be clear my contribution was about LU, where ICE engines are irrelevant, so the comparison is with todays 3rd/4th rail operation and whether changing to batteries keeps safety risk as low as reasonably practicable. At the current state of battery maturity, I think it will be very challenging to persuade people that this carried the same or lower safety risk than traditional conductor rails. After all, EV fires are about 1/20 as common as ICE fires (according to one report), so there is still a non-zero risk of a battery fire in a tube train.

A fire in a crush-loaded tube, deep underground is probably (one of) the most difficult scenarios I could imagine emergency services trying to deal with. Loading a tube train with stored energy can only increase this risk, no matter how many controls are put in place.

Having said that, the entire future of mass transit is hopefully a very long time, and things do change, so I am not saying "it'll never happen". What I am saying is that there are good reasons for underground trains to play it very safe with technology and be late adopters.

Regulatory thinking along these lines is on it's way out, regulators are going to be forced to consider broader implications of their policies (make something more expensive and you displace demand onto more dangerous alternatives, is £100m for a Bat Tunnel the most efficient way to save Bats?) rather than just a straight up argument of what is theoretically safer. In the case of the underground the worst theoretical accident is something akin to the Moorgate crash and that is something which you could design a battery to withstand. Lets do some basic maths:

Occurrence	Probability/Consequence
Moorgate Style Full Speed Crash into Terminus or Stationary Train	1 in 1000yr for whole system (likely a conservative estimate as it would indicate only an order magnitude improvement of LU performance pre- Moorgate)
Train Battery Catches Fire Following Major Accident	1 in 100 (conservative estimate, a BEV has never caught fire following automotive crash testing, hundreds of tests have been conducted, thousands of serious EV crashes have happened globally, fires after them are pretty rare)
Train fire causes injured people trapped in crashed train to die	Again if we baseline off Moorgate we had ~40 deaths and 80 injured, if we conservatively assume that a post crash fire kills half the injured people

If the benefits case runs to £200m per year then the cost per life saved is nominally £500bn per life, if we assume that we are an order of magnitude out on each of those those estimates then the total cost saved per life is £0.5bn (crash happens every 100 years, 1 in 10 chance of uncontrolled fire, 400 people die)

I don't think there is a reasonable safety case against using battery powered trains underground, we've been flying aircraft with large lithium ion batteries in them for well over a decade.

== Doublepost prevention - post automatically merged: 17 Sep 2025 ==

I don't see why "driverless" has anything to do with it. I could understand a case being made for a) removing all 3rd and 4th rails as you get rid of lots of complications at junctions and trip and electrocution hazards everywhere, plus the maintainance in tunnels. Balanced to some extent by paying for and maintaining battery EMUs and the chargers at termini - but that is all in well-lit sheds or other places with safe access/none needed.

Unfortunately Tesla car batteries (and their Powerwalls) were Li-ion batteries and were guaranteed to run away thermally (i.e. explode in flames) if there was any damage, but the LiFePO4 batteries apparently are almost intrinsically safe, apart from the external consequences of short circuits.

I had the potential to go driverless as a benefit in addition to the ones you have listed, I think it would fly on that basis of operational improvements and then you could work to being unmanned once you had got rid of the electrification.

Tesla battery packs have a fair amount of fire proofing in them so that a thermal runaway in a number of cells at the same time is contained, you normally need to grossly damage the pack or drive a large penetrator through it. Also a lot of EVs that burn post crash do so because of an electrical fire rather than the battery pack being the initiator of the fire. LFP packs trade some of the fire protection for less weight and volume in the pack to offset their lower power density.

 

[Trainbike46]

I don't think there is a reasonable safety case against using battery powered trains underground, we've been flying aircraft with large lithium ion batteries in them for well over a decade.

BEMUs are being used underground right now, on the Merseyrail network - anyone suggesting it is not possible has clearly missed something!

== Doublepost prevention - post automatically merged: 17 Sep 2025 ==



I had the potential to go driverless as a benefit in addition to the ones you have listed, I think it would fly on that basis of operational improvements and then you could work to being unmanned once you had got rid of the electrification.

Going unstaffed on any tubeline would be a major project, and I'm not convinced it is worth the cost.

One major thing that seemingly hasn't been brought up is the question of where on a tube train you could fit these batteries - LU trains are some of the most space restrained stock around, and anything that reduces passenger capacity (or more realistically, does not expand passenger capacity by the maximum possible), is going to be unacceptable given peak loading levels.

 

[zwk500]

For a Tube train to become driverless needs the signalling system to be suitable. How many lines have an existing suitable signalling system? And how much would it cost to install suitable replacement signalling systems? And where is this money coming from?

Any line that operates ATO has a signalling system compatible with driverless operation, in theory, so any of the TBTC Deep Tube lines (Vic, Jubilee, Central, Northern(?), W&C(?)), and the subsurface lines will be once fully converted (H&C and Circle are now, District and Met underway)

The bigger issue with GoA4/UTO/'fully driverless' is detection of unexpected hazards (e.g. people on the track) or managing evacuations safely.

 

[Brubulus]

Any line that operates ATO has a signalling system compatible with driverless operation, in theory, so any of the TBTC Deep Tube lines (Vic, Jubilee, Central, Northern(?), W&C(?)), and the subsurface lines will be once fully converted (H&C and Circle are now, District and Met underway)

The bigger issue with GoA4/UTO/'fully driverless' is detection of unexpected hazards (e.g. people on the track) or managing evacuations safely.

Evacuations can be safely controlled from a control centre. A radar system would likely work well for obstructions on the track.

 

[ThirteenArches]

Ah well, it's only 90 or so years since the Irish introduced battery trains (between Harcourt Street, Dublin, and Bray, Wicklow). They worked pretty well for over 10 years - withdrawn because the firm that made the batteries went bust due to the war, or "Emergency" as it was called there). They had a range of about 100 miles in a much heavier train than would be used today.
They used nickel- zinc batteries, which are lower voltage (1.85V) and, for the same power, rather heavier than lithium types, but robust and, apart from the potassium hydroxide in them, safe as any source of huge current. Also, they don't flare in an accident. Also, no one's going to go to war over the ingredients, which are fairly common, cheap and easily recyclable. I see they are beginning to make something of a comeback, though not yet as traction batteries. I wonder what 80 years more continuous development would have done for them?

 

[waverley47]

Hence discontinuous electrification projects like the borders railway are a complete waste of money. The services have circa 20 minutes to charge at Edinburgh plus 3 miles OHLE before/after

Unfortunately for your assertion, there are between two and four diagrams that outstation at Tweedbank every night. There's no hotel power at Tweedbank to plug them in.

Let's say it's a particularly cold winters night, and the diagram has run a full days service the day before. Can you reasonably guarantee, with 100% confidence, that each and every single unit will still hold enough oomph to get a unit up and over the hills, and back under the wires. As soon as you start to bring in any uncertainty, you have to start having wires up to avoid stranding a unit at Tweedbank until something comes to drag it back over the hills.

That's why discontinuous electrification is necessary.

 

[Nottingham59]

Unfortunately for your assertion, there are between two and four diagrams that outstation at Tweedbank every night. There's no hotel power at Tweedbank to plug them in.

Let's say it's a particularly cold winters night, and the diagram has run a full days service the day before. Can you reasonably guarantee, with 100% confidence, that each and every single unit will still hold enough oomph to get a unit up and over the hills, and back under the wires. As soon as you start to bring in any uncertainty, you have to start having wires up to avoid stranding a unit at Tweedbank until something comes to drag it back over the hills.

That's why discontinuous electrification is necessary.

The answer for that scenario is trimodes. Size the battery for all normal daily operations, with a small diesel engine that is only occasionally needed, perhaps once a year, in emergencies.

 

[Trainbike46]

Introducing diesel engines adds a lot of extra complexity and cost, so that would be a bad idea - just have a larger battery, and in this case, charging facilities.

 

[Nottingham59]

Introducing diesel engines adds a lot of extra complexity and cost, so that would be a bad idea - just have a larger battery, and in this case, charging facilities.

Not really. An extra 2MWh battery, which you only used once a year, would weigh tons. 10MWh of diesel fuel would weigh only kilograms. And a diesel engine that is hardly used needs very little maintenance. That's why lifeboats on ships have them. And the SUV that will get the MOM out to a bimode BEMU stranded off the wires.

 

[Narrowgauge725]

No put a charging station at Tweedbank it does not need to be a rapid charger just like I charge my car on ‘fast’ charger overnight and that is all it ever needs. Why add a diesel engine when we are trying to decarbonise our railway?