Would electrifying the WEML, Marshlink, North Downs and Uckfield lines with third rail be possible under the ORR's current policy?

[Nicholas Lewis]

An 8 car battery train is very doable….

Less doable is 8 car platfroms all along the North Downs.

Not sure east of Guildford needs more than 4 and they were extended where necessary for the 769's

 

[Stephen42]

Selective door opening is a thing

Several of the stations with shorter platforms have a level crossing right next to them so selective door opening wouldn't be an option. 4 cars would be fine and is probably sufficient for the level of traffic.

 

[Meerkat]

Hasn't the modelling been done for the Uckfield line and found that battery trains aren't currently viable?
From memory it was due to the country end power supply being too weak for the chargers, and the London end not having the spare power to charge the trains as well as power them.
I haven't any idea how difficult it is to bump the London end power supply (again) but presumably country end will need new HV routes to be justified by more than just a railway, and I don't know how many more houses they can stuff in round there with the environmental restrictions.

 

[Nicholas Lewis]

Hasn't the modelling been done for the Uckfield line and found that battery trains aren't currently viable?
From memory it was due to the country end power supply being too weak for the chargers, and the London end not having the spare power to charge the trains as well as power them.
I haven't any idea how difficult it is to bump the London end power supply (again) but presumably country end will need new HV routes to be justified by more than just a railway, and I don't know how many more houses they can stuff in round there with the environmental restrictions.

Find it hard to believe the London end is short of power now they have the new grid connection from New Cross Gate as well as the reduced train service that is now running post covid. At Uckfield they would probably struggle to get more than a couple of MVA off the distribution network without the DNO having to reinforce the network but this is where the VivaRail approach (Siemens also have something similar) to trickle charge a trackside battery which then contains enough energy to to quick charge the BEMU whilst its at Uckfield. The deeper problem is range from Oxted to Uckfield especially when you make an allowance for disruptive working and the fact you wouldn't want to deplete the battery to less than 20%. You can't underestimate that at extreme temps the batteries performance fall off as well as teh train having a much higher hotel load from air con or heating.

 

[Meerkat]

Find it hard to believe the London end is short of power now they have the new grid connection from New Cross Gate as well as the reduced train service that is now running post covid. At Uckfield they would probably struggle to get more than a couple of MVA off the distribution network without the DNO having to reinforce the network but this is where the VivaRail approach (Siemens also have something similar) to trickle charge a trackside battery which then contains enough energy to to quick charge the BEMU whilst its at Uckfield. The deeper problem is range from Oxted to Uckfield especially when you make an allowance for disruptive working and the fact you wouldn't want to deplete the battery to less than 20%. You can't underestimate that at extreme temps the batteries performance fall off as well as teh train having a much higher hotel load from air con or heating.

At the London end there must be a lot of long trains needing that power, and they bank on them not all needing power all the time (as a train that was recharging would).
The trickle charge thing looks great for applications with at least one of short branches/short trains/infrequent service, but would it stand up to the frequency and train length power requirements of the Uckfield line in the peak?

 

[WAO]

I know that it's heresy but what's wrong with a Diesel/electric hybrid for a long branch siding like Uckfield, i.e a 769 equivalent that actually works.

The Azumas, IIRC, although electric only nevertheless have a single Diesel engine "for emergency use", i.e it can give several hours ETS or get to the next station/home for detraining, albeit at 08 speeds. (What is the level balancing speed?). It has this because the weight/size/capacity of batteries doesn't meet the requirement.

We can have low carbon but not no carbon. Even breathing out adds c300ml/min of CO2 to the atmosphere.

WAO

 

[miklcct]

Moderator note: Split from

Headbolt Lane to Kirkby not electrified due to "safety concerns" ?

Probably also worth adding that since that section has long had a reputation for antisocial behaviour, the likelihood of a potentially fatal trespass incident would be above average.

www.railforums.co.uk

Is there any chance that electrifying the WEML, Marshlink, North Downs and Uckfield lines with third rail are possible under this policy, especially since they link exclusively with third rail sections except for AFK and RDG (unless they plan on relegating the latter to Thameslink)?

I don't think so.

West of England line should be electrified to 25kV AC, with bi-power trains replacing the current old trains.
Marshlink and Uckfield lines have so little usage that bi-mode trains should be used.
North Downs should become 25kV AC such that it can remain with GWR using Class 387 stock.

 

[Trainbike46]

I know that it's heresy but what's wrong with a Diesel/electric hybrid for a long branch siding like Uckfield, i.e a 769 equivalent that actually works.

The Azumas, IIRC, although electric only nevertheless have a single Diesel engine "for emergency use", i.e it can give several hours ETS or get to the next station/home for detraining, albeit at 08 speeds. (What is the level balancing speed?). It has this because the weight/size/capacity of batteries doesn't meet the requirement.

We can have low carbon but not no carbon. Even breathing out adds c300ml/min of CO2 to the atmosphere.

WAO

There's a few reason a battery would be preferable:
- you can eliminate the need for diesel engines and their maintenance specialisms in the southern region
- batteries need less maintenance
- we should be going to zero carbon long-term, especially where it is easy (including the railway)
- diesel engines are noisy and smelly. the railway is nicer without them / with fewer of them
- With batteries, you will have the accelleration advantages of EMUs even on the non-electrified sections

If supply upgrades are necessary, those can be done. we do power supply upgrades all the time.

 

[Railwaysceptic]

I know that it's heresy but what's wrong with a Diesel/electric hybrid for a long branch siding like Uckfield, i.e a 769 equivalent that actually works.

As a short term fix until a better solution is implemented, nothing wrong at all.

North Downs should become 25kV AC such that it can remain with GWR using Class 387 stock.

There is no chance at all that the North Downs Line will have all its third rail ripped out and replaced with overhead wiring.

 

[Minstral25]

I don't think so.

West of England line should be electrified to 25kV AC, with bi-power trains replacing the current old trains.
Marshlink and Uckfield lines have so little usage that bi-mode trains should be used.
North Downs should become 25kV AC such that it can remain with GWR using Class 387 stock.

Don't think that works either

West of England - not busy enough to electrify in short term, so probably discontinuous electrification and utilise Battery Electric Units
Marshlink - Battery Electric Units not diesel bi-mode - Power upgrades so that units can recharge on Third Rail sufficiently fast
Uckfield - Trains are actually very busy in peaks, so Battery operation with Charge points
North Downs - A/C will be far too expensive (especially costly is the protection at swap over points from existing third rail, which is not going anywhere quickly), so new Battery Electric Units solution (needs some power upgrades though) and brought into Southern instead of GWR so that new BEMU's can be shared with Uckfield and Marshlink

 

[Bald Rick]

Hasn't the modelling been done for the Uckfield line and found that battery trains aren't currently viable?

No. I saw modelling well over a decade ago showing it was viable.

I haven't any idea how difficult it is to bump the London end power supply (again)

Not difficult, and in any event if its needed at all (which I doubt), then it’s needed for a straight EMU solution too.

but presumably country end will need new HV routes to be justified by more than just a railway

No. Trickle charge to lineside batteries.

 

[Minstral25]

No. Trickle charge to lineside batteries.

Presumably that's how GWR's fast charge works so no peaks required from the power network.

 

[Meerkat]

No. I saw modelling well over a decade ago showing it was viable.

That’s more credible than my memory. I’m sure I read a credible source rather than just pro 3rd rail stuff, but can not remember where I read it!

Not difficult, and in any event if its needed at all (which I doubt), then it’s needed for a straight EMU solution too.

Is it? The straight EMU would be taking less power as it would only want traction and not charging too.

No. Trickle charge to lineside batteries.

If you need enough power for regular 8 car trains is it still a trickle that local networks can cope with?

 

[AM9]

That’s more credible than my memory. I’m sure I read a credible source rather than just pro 3rd rail stuff, but can not remember where I read it!

Is it? The straight EMU would be taking less power as it would only want traction and not charging too.

If you need enough power for regular 8 car trains is it still a trickle that local networks can cope with?

There is considerable reserved inbuilt energy based on the diversity of demand patterns. From time to time minor uprating of feeds can cover incremental growth, e.g. train lengthening, new services etc. The Uckfield service is currently 1tph which is lost in the noise of the 8 and 12-car 700s, up to 12-car Electrostars, and closer in, the demand of TfL 378s, and even closer in the SE trains. Even if new BEMUs are treated as 2x normal full running current on the section to Hurst Green, it would herdly be noticed in the overall demand, especiall;y as new BEMUs would likely be more energy efficient than 30 year old Electrostars.

 

[MarkyT]

There is considerable reserved inbuilt energy based on the diversity of demand patterns. From time to time minor uprating of feeds can cover incremental growth, e.g. train lengthening, new services etc. The Uckfield service is currently 1tph which is lost in the noise of the 8 and 12-car 700s, up to 12-car Electrostars, and closer in, the demand of TfL 378s, and even closer in the SE trains. Even if new BEMUs are treated as 2x normal full running current on the section to Hurst Green, it would herdly be noticed in the overall demand, especiall;y as new BEMUs would likely be more energy efficient than 30 year old Electrostars.

Adding batteries to the trains could allow a traction system to throttle back a little on the conductor rail draw and mix in some onboard battery current so as not to lose performance in a short peak demand voltage drop scenario. That could help general performance compared to the same event today. Charge management tuned to specific duties will be an interesting area. For example, taking a full charge en route from the line may not be the best tactic on a particular run if leaving a margin to take braking energy on a long downhill section is important.

 

[Bald Rick]

Is it? The straight EMU would be taking less power as it would only want traction and not charging too.

There‘s two factors to consider, max power draw, and total electrical energy. For the former, a unit charging need not draw more than it needs to under full acceleration, so thats not an issue. The latter is potentially an issue, as the BEMU would be drawing full power on the con rail for longer than a straight EMU would. This might cause one of more substations to go over capacity under certain conditions, although I think that is unlikely. There is another small benefit of the BEMUs, and that is that on the DC railway units often cannot use regen braking as there is insufficient demand on the DC network to accept it. A BEMU will always regen into the battery, so long as there is battery capacity left. This means that net peak demand is lowered, slightly.

If you need enough power for regular 8 car trains is it still a trickle that local networks can cope with?

Yes easily. I forget the precise numbers, but IIRC a 4 car BEMU would need something in the region of 300kwh of juice to get from Hurst Green to Uckfield. Even allowing for 2 x 8 cars an hour, that needs 1,200kwh of juice in the lineside battery each hour, which implies a trickle charge of 1,200kw. of 20kw - say 25kw to allow for system losses. Or put another way, about a dozen kettles. Im sure the Uckfield power network can cope with that.

 

[A0]

There‘s two factors to consider, max power draw, and total electrical energy. For the former, a unit charging need not draw more than it needs to under full acceleration, so thats not an issue. The latter is potentially an issue, as the BEMU would be drawing full power on the con rail for longer than a straight EMU would. This might cause one of more substations to go over capacity under certain conditions, although I think that is unlikely. There is another small benefit of the BEMUs, and that is that on the DC railway units often cannot use regen braking as there is insufficient demand on the DC network to accept it. A BEMU will always regen into the battery, so long as there is battery capacity left. This means that net peak demand is lowered, slightly.




Yes easily. I forget the precise numbers, but IIRC a 4 car BEMU would need something in the region of 300kwh of juice to get from Hurst Green to Uckfield. Even allowing for 2 x 8 cars an hour, that needs 1,200kwh of juice in the lineside battery each hour, which implies a trickle charge of 20kw - say 25kw to allow for system losses. Or put another way, about a dozen kettles. Im sure the Uckfield power network can cope with that.

Genuine question - would there be a difference if the battery was used as the sole power provider and the con rail to continually charge the batteries ? I'm thinking in the way some cars now the petrol engine is solely to charge the battery and the battery provides the power for the motors as in an EV.

 

[SynthD]

Genuine question - would there be a difference if the battery was used as the sole power provider and the con rail to continually charge the batteries ? I'm thinking in the way some cars now the petrol engine is solely to charge the battery and the battery provides the power for the motors as in an EV.

Yes, but less than hybrids. While both have the brake regen, hybrids have the efficiency of running the engine at a fixed rpm for peak performance. That 25kw requirement might rise a little.

 

[Bald Rick]

Genuine question - would there be a difference if the battery was used as the sole power provider and the con rail to continually charge the batteries ? I'm thinking in the way some cars now the petrol engine is solely to charge the battery and the battery provides the power for the motors as in an EV.

Perhaps a little, but marginal in the whole scheme of things.

 

[Stephen42]

Yes easily. I forget the precise numbers, but IIRC a 4 car BEMU would need something in the region of 300kwh of juice to get from Hurst Green to Uckfield. Even allowing for 2 x 8 cars an hour, that needs 1,200kwh of juice in the lineside battery each hour, which implies a trickle charge of 20kw - say 25kw to allow for system losses. Or put another way, about a dozen kettles. Im sure the Uckfield power network can cope with that.

You are going to need a lot more kettles, 1,200kwh over an hour is a constant charge of 1,200kw. Realistically not all trains need to be fully recharged during peak and can then halve the trickle charging speed. The 4 car BEMU on those numbers would need to draw on average 450kw while on the third rail to fully recharge if no charging occurred at Uckfield. Would still agree that on those numbers it shouldn't be that much of a challenge for the existing power arrangements to cope.

 

[AM9]

You are going to need a lot more kettles, 1,200kwh over an hour is a constant charge of 1,200kw. Realistically not all trains need to be fully recharged during peak and can then halve the trickle charging speed. The 4 car BEMU on those numbers would need to draw on average 450kw while on the third rail to fully recharge if no charging occurred at Uckfield. Would still agree that on those numbers it shouldn't be that much of a challenge for the existing power arrangements to cope.

450kW is about 1/3 of the maximum draw of a four-car Electrostar. Given that most of the EMUs passing through East Croydon are 8 cars or more and in the peak there are more than 12 trains per hour, the single 4, 8 or even 12-car Uckfield BEMU is going to be less than 10% extra energy draw including the suggested 450kW for battery charging.

 

[Bald Rick]

You are going to need a lot more kettles, 1,200kwh over an hour is a constant charge of 1,200kw. Realistically not all trains need to be fully recharged during peak and can then halve the trickle charging speed. The 4 car BEMU on those numbers would need to draw on average 450kw while on the third rail to fully recharge if no charging occurred at Uckfield. Would still agree that on those numbers it shouldn't be that much of a challenge for the existing power arrangements to cope.

You are quite right, my arithmetic & physics failed me dismally. Apologies to everyone reading, will correct the post. Nevertheless, still doable, as you say.

 

[Energy]

You are going to need a lot more kettles, 1,200kwh over an hour is a constant charge of 1,200kw.

We don't know how big and powerful @Bald Rick's kettle is .

No. Trickle charge to lineside batteries.

Presumably that's how GWR's fast charge works so no peaks required from the power network.

I believe this is what Vivarail/GWR are using.

Trickle charge & fast charge would be used where modeling has shown charging while coasting & stationary to be insufficient. Charging while stationary or coasting would just require the train to know its max power draw and to adjust its charging speed to never exceed the max, hardly difficult.

Similarly, most EV home chargers allow a CT clamp to be connected and adjust the charging speed to never exceed the rating of the DNO cutout fuse to the house.

 

[DjU]

There’s no interest in electrifying with third rail, either.

This has been said a few times in this thread. And I don't think its strictly true...

Network Rail have on a number of occasions in presentations in the past 24 months said they are actively investigating making a safer 3rd rail electrification proposal for extensions. And electrification of Uckfield as 3rd rail is one of the most 'likely' of these if it was ever allowed.

Will it ever come to frution - maybe not - but they ARE looking at it...

Here is the very latest time they have given a variation of this presentation from July this year. This is less technical than the previous 4 or so of the ones out there on the web but same jist

 

[brad465]

There's an article in the latest RAIL edition reporting SWR and NR are looking at new third rail "islands" along the WoE line between Basingstoke and Exeter as part of plans to replace the 159 fleet with stock capable of third rail and battery operation. It didn't say where the islands might be, only they were looking at around 50 miles in total, centred on where power demand is likely to be highest.

 

[WAO]

Surely an island or two of 25kV would be preferable all round....but with better stock than 769's!

WAO

 

[Energy]

Surely an island or two of 25kV would be preferable all round....but with better stock than 769's!

WAO

25kv needs a fat transformer on the train, and a substantial grid supply or static frequency converters. If 25kv is used elsewhere it isn't as much a problem but using 750V third rail makes more sense here.

 

[AM9]

25kv needs a fat transformer on the train, and a substantial grid supply or static frequency converters. If 25kv is used elsewhere it isn't as much a problem but using 750V third rail makes more sense here.

... apart from the fact that further 3rd rail is unlikely to get approval under the ORR's current safety policy. Unless that changes, new 3rd rail is a dead duck.

 

[brad465]

Surely an island or two of 25kV would be preferable all round....but with better stock than 769's!

WAO

The same article said SWR looked at that but deemed it unfeasible, citing the area for a transformer would have to be taken up by a battery.

 

[WAO]

The same article said SWR looked at that but deemed it unfeasible, citing the area for a transformer would have to be taken up by a battery.

Are they seriously maintaining that a 5-car tri (or quad!) mode train isn't feasible?

WAO