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

[DerekC]

But you can assume that traction batteries will be fitted to most if not all new EMUs ordered from now on. It is so cheap compared to the cost of the train, and offers many benefits, not least in disruption.

I totally agree that this is the right solution for North Downs (and Marshlink and Uckfield) and that traction batteries should be fitted to new EMUs - but the industry has a terrible history of not doing the thing that's obvious common sense, either because no individual operator can make a business case for it which pays back quickly enough to fit DfT's rules or because Network Rail sees it as risky for some reason and throws a spanner in the works by demanding lots of dosh even to investigate. Extra load to charge batteries on electrified sections is the obvious spanner. The technical solution is obvious and Network Rail should be brought on board to help, not hinder. Therefore it's an excellent test case for the brave new GBR world.

And please, please don't complicate the issue by talking about fitting the EMUs for AC as well just in case somebody works out a case and a timetable for getting to Oxford one day in the unforeseeable future. Oxford is a red herring in this context - and so is Tonbridge. There should be a very good case for a fleet of battery fitted DC-only EMUs to replace diesels on Southern non-electrified routes, even without considering west of Basingstoke. And in the same brave new GBR world, it shouldn't matter the cost of a platform ticket who is going to operate them.

PS - and don't let anyone mention technical risk. It's very nearly ten years since the IPEMU (Independently Powered EMU) trial proved (surprise, surprise) that what works in lots of other places in the world works in GB as well - and there have been battery powered EMUs in the world since 1911!

Sorry - rant over!

 

[WAO]

They are very busy in the peaks - hordes of people get off them at Guildford. It serves busy prosperous towns (and Reading should be a city by now) which are linked by poor and very congested roads.

Reaching for the crayons I think it really needs a new chord so that a Farnham/Aldershot to Reading stopper can run.

You're on my Christmas list!

WAO

 

[Bald Rick]

Extra load to charge batteries on electrified sections is the obvious spanner.

Not so much a spanner, but it does need considering. In the case of the North Downs, the extra power required to run the servcie with BEMUs would be (approximately) the same as the power required to run it with vanilla EMUs if it were electrified. The issue is that where the power is drawn is different in each scenario. However given we are talkign about 4 car units twice an hour, which will be charging largely on parts of the network with capacity for 10/12 car units at higher frequencies (much higher in the case of Redhill area), then I suspect there won’t be too much of an issue in this case.

 

[WAO]

PS - and don't let anyone mention technical risk. It's very nearly ten years since the IPEMU (Independently Powered EMU) trial proved (surprise, surprise) that what works in lots of other places in the world works in GB as well - and there have been battery powered EMUs in the world since 1911!

Sorry - rant over!

There is technical risk in any new class of stock, the greater, the more technical innovation. Usually, a production prototype is tested first for performance and failure modes. This allows modifications to production runs that minimise (but don't entirely eliminate, think IET) problems. Even then, mileage accumulation trials would take place. This does take time and money but think 769, 701, 442 and Vivarail. That's why we end up buying foreign.

There was an electric locomotive in 1842, IIRC - but no charger!

WAO

 

[Railwaysceptic]

. . . . I wonder if this would also be a viable for Reading-Basingstoke (might need 3rd rail at Reading 'Newbury' bays, or can it take from AC too?)

That's an interesting idea. I've sometimes pondered if a stopping service between Portsmouth and Reading would generate new custom.

 

[JonathanH]

I've sometimes pondered if a stopping service between Portsmouth and Reading would generate new custom.

Considered recently here https://www.railforums.co.uk/threads/reading-to-portsmouth.275116/#post-6972753

 

[DerekC]

Not so much a spanner, but it does need considering. In the case of the North Downs, the extra power required to run the servcie with BEMUs would be (approximately) the same as the power required to run it with vanilla EMUs if it were electrified. The issue is that where the power is drawn is different in each scenario. However given we are talkign about 4 car units twice an hour, which will be charging largely on parts of the network with capacity for 10/12 car units at higher frequencies (much higher in the case of Redhill area), then I suspect there won’t be too much of an issue in this case.

I think I am going to agree with you, but I have to work up to it! The energy that's required for a BEMU for a particular service on a specific route would be a bit more compared with a vanilla EMU because the energy recovery from the battery is less than 100% - but I agree, approximately the same. The power demanded by the BEMU on the electrified section will depend on how fast it's trying to charge its batteries, which depends on what proportion of its diagrammed time is on electrified compared with non-electrified track. For North Downs, about half (I made it 47%) of the total cycle time (Reading to Gatwick and back plus turnaround time at both ends) is on non-electrified route, so the total energy transferred via the third rail to the train on the electrified sections will need to be about double that needed for the normal motion of the train (of course there will be variability depending on stops). The traction control will presumably limit the current demanded to the normal maximum for a 4-car unit, but that's OK because of course the train only draws maximum current during acceleration, so there will be lots of time for the batteries to charge whilst the train is running at constant speed under power or coasting - and of course regenerated energy can be fed into the batteries when braking, as well. So peak current won't increase but will last longer. And I am sure you are right - all the electrified bits (in the case of North Downs) carry 10/12 car trains and a 4-car train drawing more energy than normal should be fine.

There is technical risk in any new class of stock, the greater, the more technical innovation. Usually, a production prototype is tested first for performance and failure modes. This allows modifications to production runs that minimise (but don't entirely eliminate, think IET) problems. Even then, mileage accumulation trials would take place. This does take time and money but think 769, 701, 442 and Vivarail. That's why we end up buying foreign.

Yes, of course, but what we are talking about with a BEMU is integration risk - there isn't a lot of technical innovation risk - batteries and how to charge them are very well established technologies. However integration risk (as you imply) is exactly what the UK industry is bad at - not just with rolling stock but signalling and power and all the interfaces between them as well. Projects just don't allow enough money and time to carry out the testing - "if the supplier has done the job properly it should work first time". How many times have I heard that!!

 

[Bald Rick]

And I am sure you are right - all the electrified bits (in the case of North Downs) carry 10/12 car trains and a 4-car train drawing more energy than normal should be fine.

Strictly speaking, Guidlford - Ash doesn‘t carry 12 car trains, although I suspect it could if it needed to. I‘m fairly confident it can cope with an extra couple of 4 car units per hour, even if they are drawing full current the whole time.

 

[JonathanH]

Strictly speaking, Guidlford - Ash doesn‘t carry 12 car trains, although I suspect it could if it needed to.

12 car 450s via Ash at various times today, with diversion of Alton trains via Guildford - eg https://www.realtimetrains.co.uk/service/gb-nr:Y17691/2024-12-15/detailed#allox_id=0

 

[Bald Rick]

12 car 450s via Ash at various times today, with diversion of Alton trains via Guildford - eg https://www.realtimetrains.co.uk/service/gb-nr:Y17691/2024-12-15/detailed#allox_id=0

Thanks - and assuming the substations and Traction Parallelling Huts don’t trip out, we can therefore safely assume there is enough juice in that part of the system to accommodate 4 car BEMUs twice an hour.

 

[Starmill]

12 car 450s via Ash at various times today, with diversion of Alton trains via Guildford - eg https://www.realtimetrains.co.uk/service/gb-nr:Y17691/2024-12-15/detailed#allox_id=0

Are they subject to extra restrictions when going that way? It doesn't seem all that uncommon regardless, similarly to running via Woolston.

 

[Nicholas Lewis]

I think I am going to agree with you, but I have to work up to it! The energy that's required for a BEMU for a particular service on a specific route would be a bit more compared with a vanilla EMU because the energy recovery from the battery is less than 100% - but I agree, approximately the same. The power demanded by the BEMU on the electrified section will depend on how fast it's trying to charge its batteries, which depends on what proportion of its diagrammed time is on electrified compared with non-electrified track. For North Downs, about half (I made it 47%) of the total cycle time (Reading to Gatwick and back plus turnaround time at both ends) is on non-electrified route, so the total energy transferred via the third rail to the train on the electrified sections will need to be about double that needed for the normal motion of the train (of course there will be variability depending on stops). The traction control will presumably limit the current demanded to the normal maximum for a 4-car unit, but that's OK because of course the train only draws maximum current during acceleration, so there will be lots of time for the batteries to charge whilst the train is running at constant speed under power or coasting - and of course regenerated energy can be fed into the batteries when braking, as well. So peak current won't increase but will last longer. And I am sure you are right - all the electrified bits (in the case of North Downs) carry 10/12 car trains and a 4-car train drawing more energy than normal should be fine.

The DC traction limit is set by the train at 4500A or 6000A not train length (it was 6800A on the routes to the channel tunnel) depending on whether the route is running its pre 94 infrastructure configuration or is it a route that has had traction reinforcement work. So a 4 car could draw well over its rated traction power rating for battery charging purposes. Also there is no formal limit on current through an individual shoe unlike OLE where its set at 300A.

The other issue that has to be considered is the overall load on the HV distribution system and BEMUs will increase that by more than just traction load but the addition of charging load as well. Very few parts of the HV distribution system run anywhere near maximum capacity where its based on 33kV or 22kV but the 11kV fed systems (Tonbridge-Hastings, Bournemouth-Weymouth, Cosham-St.Denys/Eastleigh) have limitations when they have extended feeding due to outages and were nominally 8 car railways although have procedures for emergency use of 12 cars. The anomaly is Sth. Croydon to E.Grinstead which is still fed from the 11kV system but it was reinforced to allow 12 car 377/700's to run down there. It added additional substations, it was originally an 8 car railway when electrified, and it added an additional HV infeed at Eden fed off the Tonbridge-Redhill HV system which was designed for class 92 operation (never used) so had spare capacity. I don't know this for fact but I suspect the HV distribution system from Purley up to Oxted might be stretched on voltage regulation if the original 1987 33/11kV distribution transformers at Purley are still in use. These transformer both power the Caterham/Tattenham Cnr branches as well as part of the E.Grinstead line at Upper Warlingham through a cable in the public highway between Whyteleafe Sth and Upper Warlingham. So whether it could support Uckfield BEMUS motoring and charging simultaneously is certainly an area that would need to be assessed. Changing a transformer is relatively inexpensive digging up the highway if the cable needs uprating a lot more.

 

[weeklycommuter]

I stand by my statement in post #43 "Whatever the legal issues there is no logic to this effective ban on third rail electrification infill. It is impossible to close down the very extensive third rail network South of London and it is financially impossible to convert it all to 25 kV AC overhead so risks need to be managed and if necessary the law should be changed to make third rail infill possible in places where it is needed." I just have to agree to disagree with those who take a different view. I agree with the article on pages 96 and 97 of Modern Railways April 2025 "Has ORR reached its Waterloo? Time for some common sense on third rail electrification"

 

[AM9]

I stand by my statement in post #43 "Whatever the legal issues there is no logic to this effective ban on third rail electrification infill. It is impossible to close down the very extensive third rail network South of London and it is financially impossible to convert it all to 25 kV AC overhead so risks need to be managed and if necessary the law should be changed to make third rail infill possible in places where it is needed." I just have to agree to disagree with those who take a different view. I agree with the article on pages 96 and 97 of Modern Railways April 2025 "Has ORR reached its Waterloo? Time for some common sense on third rail electrification"

Ah, the 'common sense' argument, (as opposed to established safety precautions).

 

[Dr Hoo]

Amazing that the article in Modern Railways somehow managed to avoid any reference to the Electricity at Work Act 1989 or that BR/Network SouthEast didn’t initiate any further schemes after it came into effect. (The extensions to Weymouth, Channel Tunnel links and Merseyrail extensions to Chester and Ellesmere Port had already been initiated.)

 

[zwk500]

so risks need to be managed

The most effective management of a risk is to not let it happen at all, of course.

and if necessary the law should be changed to make third rail infill possible in places where it is needed

By all means go to your MP and campaign for the relevant legislation to be repealed.

Time for some common sense on third rail electrification"

"Common sense" on top-contact third rail would be to recognise that there are also lines where battery trains would permit de-electrification as well as infill lines where electrification might be justifiable. But I very rarely see anybody suggesting de-electrification as part of a comprehensive review of safety risk, indeed the only suggestions I can remember for it are on a transactional basis (if we de-electrify xkm of line we should then be allowed to electrify an alternate section the same distance). The most obvious case for de-electrification is the Seaford Branch.

I've made my position clear at other posts on this thread, I think - the existing gaps in the third rail network could be covered with no more than 1-2km extensions of the third rail 'round the corner' and then batteries for the remainder of the distance. Marshlink, North Downs, Romsey, Uckfield all fall into this category. ALL EMUs should be BEMUs, with the majority of the fleet fitted with emergency batteries to get to the next station if the power shuts off unexpectedly, while the remainder would be fitted with service batteries for a c.50-60mile range between charges, which is easily enough to cover all the gaps mentioned above.

 

[biggerisbetter]

I agree with this. With discontinuous third rail electrification combined with battery EMUs you could fill in the obvious gaps - Uckfield, Marshlink, North Downs and Merseyrail extensions in a way where risk can be mitigated by avoiding the most sensitive areas (say no third rail within 100m of a station or level crossing or foot crossing as an example). The benefits would in my view outweigh this risk and help contribute towards decarbonisation and air quality improvements. Given that more passengers are carried on third and fourth rail vehicles than overhead electrified and diesel services combined, the safety risks can’t be ‘that’ great.

 

[zwk500]

Given that more passengers are carried on third and fourth rail vehicles than overhead electrified and diesel services combined, the safety risks can’t be ‘that’ great.

I would be very interested to see a Killed-or-Seriously-Injured per passenger-km (and per vehicle-km) statistic breakdown for the various electrification systems in GB (third rail, four-rail, AC overhead and the two types of DC overhead). AFAIK nobody's ever published one, but I'd be very interested to see one if it has been done, even if quite old!

 

[Dr Hoo]

‘Passengers’ aren’t necessarily those most at risk. The two third rail electrocutions that I had to deal with (sadly in fairly quick succession) were a nine-year-old trespasser and a very experienced electrified track engineer who was working right next to me.

 

[WAO]

The greatest risk on the railway is moving trains, not electricity.

About 250 trespassers and suicides die on the track each year. Apart from their families' grief there is the PTSD suffered by so many drivers and the staff having to recover the scenes. Some mitigation of risk is being implemented but not the cessation of operation.

WAO

 

[stevieinselby]

Given that more passengers are carried on third and fourth rail vehicles than overhead electrified and diesel services combined, the safety risks can’t be ‘that’ great.

The number of passengers carried is irrelevant – the risk to anyone on the line is the same whether it's a 2-car Sprinter or a full-and-standing 12-car Thameslink.
And much of the fourth rail network is in tunnels where access to the track is virtually impossible, almost all of the rest of it is in a setting where public access is explicitly prohibited ... how many level crossings and foot crossings are there on the London Underground?

Is there much risk of wild animals being electrocuted by coming into contact with a live rail? For a start, we have a duty of care to minimise harm to animals – but also, I can imagine that if a deer got zapped and was dead on the tracks, you're not going to want to hit that with a train.

 

[yorksrob]

I stand by my statement in post #43 "Whatever the legal issues there is no logic to this effective ban on third rail electrification infill. It is impossible to close down the very extensive third rail network South of London and it is financially impossible to convert it all to 25 kV AC overhead so risks need to be managed and if necessary the law should be changed to make third rail infill possible in places where it is needed." I just have to agree to disagree with those who take a different view. I agree with the article on pages 96 and 97 of Modern Railways April 2025 "Has ORR reached its Waterloo? Time for some common sense on third rail electrification"

You are quite correct. Fairly ridiculous to carry around full battery capabilities for the sake of a few stretches within the overwhelmingly third rail area.

 

[weeklycommuter]

Amazing that the article in Modern Railways somehow managed to avoid any reference to the Electricity at Work Act 1989 or that BR/Network SouthEast didn’t initiate any further schemes after it came into effect. (The extensions to Weymouth, Channel Tunnel links and Merseyrail extensions to Chester and Ellesmere Port had already been initiated.)

The Electricity at Work Act 1989 took effect on 1 April 1990. The Eastleigh and St Denys to Fareham and Cosham third rail opened on 14 May 1990 after the Electricity at Work Act took effect. The article does refer to proposals for further third rail electrification planned for completion in 1994 and 1995 which were postponed due to planned privatisation. I assume that at the time the Electricity at Work Act 1989 was not considered to have the effect of preventing extensions of third rail electrification.

 

[Harpo]

The bigger change was probably ORR’s policy on third rail where it sets out it’s interpretation of the law and how it believes it needs to apply it, in particular….

‘There is a presumption against the reasonable practicability of new build or extended third rail in view of the safety requirements duty holders must satisfy in order to justify the use of third rail.’

Under that policy there has been new 4 rail electrification to Battersea (Northern line) while battery power was needed to reach Headbolt Lane.

 

[Starmill]

The Electricity at Work Act 1989 took effect on 1 April 1990. The Eastleigh and St Denys to Fareham and Cosham third rail opened on 14 May 1990 after the Electricity at Work Act took effect. The article does refer to proposals for further third rail electrification planned for completion in 1994 and 1995 which were postponed due to planned privatisation. I assume that at the time the Electricity at Work Act 1989 was not considered to have the effect of preventing extensions of third rail electrification.

The works quoted entered service later than Eastleigh - St Denys. 1993 for Bournemouth - Weymouth and Tonbridge - Redhill, 1994 for Hooton - Ellesmere Port. As mentioned none of the work already authorised was considered to have been fatally reassessed. Shorter sections were also installed in the 00s e.g. Shoreditch - Dalston - Highbury & Islington.

 

[Tetragon213]

Theoretically speaking, would it be possible to convert from top contact third rail to either side or bottom contact? Seeing as the latter 2 options would allow for not only reduced issues with ice, but also allow for boards to cover the places where errant engineers are likely to accidentally make contact?

 

[zwk500]

Theoretically speaking, would it be possible to convert from top contact third rail to either side or bottom contact? Seeing as the latter 2 options would allow for not only reduced issues with ice, but also allow for boards to cover the places where errant engineers are likely to accidentally make contact?

Not within the lower sector loading gauge, I suspect. Certainly bottom contact would need a completely different design of shoe than for the existing top-contact positioning. Side Contact may be possibly workable although through bridges etc with raised beams there may be a higher risk of gapping.
In the US where there are networks that use a mix of top- and bottom-contact the third rail is placed outside the envelope of the train, taking advantage of the wider track centers there.

The bigger change was probably ORR’s policy on third rail where it sets out it’s interpretation of the law and how it believes it needs to apply it, in particular….

‘There is a presumption against the reasonable practicability of new build or extended third rail in view of the safety requirements duty holders must satisfy in order to justify the use of third rail.’

Under that policy there has been new 4 rail electrification to Battersea (Northern line) while battery power was needed to reach Headbolt Lane.

the new 4-rail electrification was entirely in a tunnel, of course. However I agree Headbolt lane was a clear case of a proportional extension where the safety case for third rail should have been able to be made.

The only significant case of 'new' third rail developed wholly since the legislation mentioned above is, I believe, the East London Line conversion. And that's almost entirely elevated or in a cutting/tunnel, and was an extension of existing third rail services where dual-voltage didn't make sense and battery tech was not mature enough at the time.

 

[Meerkat]

I've made my position clear at other posts on this thread, I think - the existing gaps in the third rail network could be covered with no more than 1-2km extensions of the third rail 'round the corner' and then batteries for the remainder of the distance. Marshlink, North Downs, Romsey, Uckfield all fall into this category.

What’s your view on WoE mainline?
I thought Uckfield was blocked by a lack of power for charging on the 3rd rail into London, and Marshlink had been found not to work due to a lack of time on 3rd rail to charge it for the distance.
How much is the cost of an extra train in the circuit to cover one that is parked up charging (its not an extra crew as it’s just sitting there)? Though you still need two electrified sidings for charging, and time for the crew to switch the trains over.

Reeves wants a bonfire of the regulations to fuel growth - maybe someone should point her at the ORR 3rd rail policy? Though I assume NR/SWR have been given some hope or they wouldn’t be spending time and money looking at 3rd rail islands and battery conversions for the WoE?

 

[zwk500]

What’s your view on WoE mainline?

Long term, get on with AC OLE to Exeter and then have the Exeter end (to Cranbrook or Honiton), and Bristol-Westbury-Salisbury-Southampton on AC electrification, with DC/AC changeover near Overton, and AC as far down towards Tisbury as is practical. Tisbury to Honiton is just over 50 miles, which would be well within Battery range. Salisbury to Cranbrook is 83 miles, so right on the edge and would probably need a fast-charge at Yeovil Junction but that's also very viable.

I thought Uckfield was blocked by a lack of power for charging on the 3rd rail into London,

I can't see 1 extra 12-car charging being a big problem once on the London Bridge section. tbh. And it can charge from Hurst Green to South Croydon or in the turnround if needed.

and Marshlink had been found not to work due to a lack of time on 3rd rail to charge it for the distance.

With battery units running back to Brighton is an option. The connectivity was certainly appreciated by Sussex coast residents. but even if it stopped in Eastbourne I think Ore-Eastbourne and back with the turnround and a top up at ashford is viable (I'd extend the 3rd rail round the corner at Ashford as well).

How much is the cost of an extra train in the circuit to cover one that is parked up charging (its not an extra crew as it’s just sitting there)? Though you still need two electrified sidings for charging, and time for the crew to switch the trains over.

I wouldn't have trains parked up purely to charge, it'd all be done on the move or with a trickle-charged fast dump system a la Greenford trials. The power supply system (and National Grid generation) would need to be bulked up to meet the increased demand.

Reeves wants a bonfire of the regulations to fuel growth - maybe someone should point her at the ORR 3rd rail policy?

There are bigger fish to fry than the 3rd rail policy when alternative technologies exist. People are scared of BEMUs because they haven't been around long. Give it a few years in service and people will be demanding them.

Though I assume NR/SWR have been given some hope or they wouldn’t be spending time and money looking at 3rd rail islands and battery conversions for the WoE?

The options for these lines are, in essence, continuously under review. Uckfield gets a new study on a fairly regular basis without any indication that the political shifts necessary to achieve it are anywhere near happening.

 

[WAO]

Bottom contact electrification is of course already established; it's just that contact has to be made 4.7m above rail top.

The interesting case coming up will be TfL's plan for the Pudding Mill line from Kew to Cricklewood. This has a mix of systems but would clearly benefit from new third rail for the short gap from Old Kew Junction to South Acton 25kV. The wires should probably creep north to Willesden from Acton Wells, but batteries could work northwards to the Midland line for immediate passenger use.

We shall see whether there really is a bonfire of bureaucratic regulations (such as bat tunnels etc), including the wrong and sloppy application of the Electricity at Work Act 1990 to railways, which previously were covered separately.

More popcorn.

WAO