Suggestion: Conversion of former Southern Region DC to AC

[Bletchleyite]

Absolutely unless a bit becomes life expired before then.

A whole chunk of it won't in practice become life-expired in one go. Bits of it will, so replace them as needed.

 

[LexyBoy]

To briefly touch on the actual topic, is there really a need to convert the inner suburban lines? Although DC is inefficient and expensive, wouldn't it take many decades to recoup the presumably hundreds of billions that it would cost (both directly and through disruption)?

It's a long time since I did any physical chemistry and I don't know what that one means, but if you're saying a litre of hydrogen at atmospheric pressure has more energy than a litre of petrol then I don't believe you. As soon as you have to compress it then the extra weight of the pressure vessel needs to be accounted for.

A litre of diesel contains more hydrogen than a litre of liquid hydrogen. And vastly more than a litre of compressed hydrogen.

Hydrogen at 700 bar contains 5.6 MJ/L or 142 MJ/kg
Diesel contains 36 MJ/L or 48 MJ/kg

I've no idea what the relative constraints on mass versus volume are in a rail vehicle so I don't know how much of a deal an increased fuel volume would be (presumably more for a MU than a loco). However, to match diesel's energy density weight for weight you would need storage comprising no more than 2 kg container per kg hydrogen. This is way higher than any current or in-development technology I'm aware of (compare typical gas cylinders which weigh about 70 kg to contain 1 kg hydrogen at only 230 bar).

Generating hydrogen from electrolysis is very inefficient compared to using the electricity directly - which a rail vehicle, tied to the permanent way, is ideally suited to. Yes, there is research into generating hydrogen directly from sunlight, but algae can already use sunlight to generate hydrocarbons and are rather good at it.

As hazards go, hydrogen does get a bad rep. Petrol is more dangerous from a fire perspective, and although compressed gases have their hazards, the energy released in an exploding hydrogen cylinder is much less than a natural gas or nitrogen (for example) cylinder at the same pressure (disregarding the subsequent fireball).

 

[Deepgreen]

Why? Third rail technology still works.

Third rail is in a small minority and will almost certainly succumb to the majority. I happen to favour third rail because of its visual unintrusiveness compared with OHLE, but that's only one element of the issue, of course.

BTW, I mentioned fuel cells, etc., purely as examples of current alternative energy developments, not to suggest that those specific regimes would be 'the future'.
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I strongly disagree. 25kV AC is the optimum voltage for railway applications and a direct supply of electricity from source to train will always beat any alternative. The amount of energy used by the railway is so enormous that the upfront energy cost of installing OHLE and the assorted other components of the traction supply is dwarfed.

Noting your bold typed word; so you envisage trains (if they still exist) in, say, 3010, still using 25kV because it can never be bettered by any other energy supply regime (that we not even be dimly aware of today)?

 

[The Ham]

To briefly touch on the actual topic, is there really a need to convert the inner suburban lines? Although DC is inefficient and expensive, wouldn't it take many decades to recoup the presumably hundreds of billions that it would cost (both directly and through disruption)?

It would depend on when it is done, in the case of the lines that SWT run their suburban lines, if (or you can use "once" depending on how likely you feel Crossrail 2 is) the inner section goes across to running through the Crossrail 2 tunnels then the level of disruption to converting those lines (one at a time) to OHLE will be less onerous than whilst they still only run into Waterloo.

Most of the other lines can be switched over in sections between junctions so as to minimise the disruption.

The more difficult bit will be the lines from Clapham Junction inwards, however if the works are all done and they then do a big switchover on one weekend (probably overnight Saturday to Sunday so they could iron out any problems during the day on Sunday if needed) then it would be little different to any other engineering works over that section overnight.

 

[swt_passenger]

It would depend on when it is done, in the case of the lines that SWT run their suburban lines, if (or you can use "once" depending on how likely you feel Crossrail 2 is) the inner section goes across to running through the Crossrail 2 tunnels then the level of disruption to converting those lines (one at a time) to OHLE will be less onerous than whilst they still only run into Waterloo.

I can't really agree. In the presumed post Crossrail 2 timetable, most of the SW branches still have both Crossrail and Waterloo trains. Then the main suburban lines will be used by both the remaining inner suburban services into Waterloo, and the middle distance outer suburban trains that currently run on the main fast lines, from places such as Alton or Basingstoke. It stil won't neatly divide into main and inner suburban anymore after Crossrail 2, and that's before you start taking account routine engineering works and regular Sunday morning maintenance which runs on a two track railway.

You might theoretically get away with separate timescales for the Windsor side and the main side, which are notionally completely separate as far as it looks to passengers, but then there's the problem of ECS to from Clapham Yard.

 

[adrock1976]

Quite a few interesting replies so far - including some unexpected responses.

I bet the OP didn't expect that after a few hours the majority of replies would be about the pros and cons of hydrogen...

I was not expecting to have a physical chemistry lesson here

However, I am skeptical about hydrogen fuel cells at this moment in time being used for public transport, as I do not fancy having a huge lump of metal exploding into bits around me in the event of an accident.

To briefly touch on the actual topic, is there really a need to convert the inner suburban lines? Although DC is inefficient and expensive, wouldn't it take many decades to recoup the presumably hundreds of billions that it would cost (both directly and through disruption)?

Snip

That is why I suggested leaving the inners/local all stations services to be converted last, and to concentrate on the outers/long distance limited stop services first.

It would realistically have to be done from the outside of the network inwards towards major junctions. Hence all stock used on wider electrifications such as to Weymouth or to Exeter via Salisbury would have to be dual voltage to run into Waterloo.

I suggest the likely timescales required mean it would be pointless worrying about allocation of current stock such as 450s, it would be approaching retirement before there was nowhere left to run it on DC, given it could be re-allocated anywhere on the DC network as other older stock (e.g. ex BR) is phased out Alternatively it's far more likely they'd progressively convert significant numbers of 450s and 444s into dual voltage for electric spine purposes anyway.

It is not at all straightforward to suggest that TfL operated routes could be separated for the purposes of electrification policy, transfers to TfL cannot be done on a line by line basis, everyone will still be sharing the same track layouts, there are far too many flat junctions and crossings to separate into AC and DC.

BTW, and as an aside, I fail to see the logic of suggesting Class 542 for an AC EMU. 5XX series is still allocated to DC only, new AC or dual voltage will more likely be in the 300 or 700 ranges.

Although I may not have been clear at first, working from outwards in towards London was the kind of gist I was attempting to portray in the opening post, so as to avoid making it more lengthier from a lengthy post.

Regarding the reference to Class 542, I thought that would be a good progression from the often discussed about Class 442s, which were specifically designed for the limited stop Bournemouth and Weymouth services when the third rail was extended in 1988. Perhaps 342 or 742 instead?

Why? Third rail technology still works.

It does indeed, but I believe it is best restricted to short distance local all stations services, and not for limited stop long distance runs such as London - Weymouth/Dover/Portsmouth/etc.

It would depend on when it is done, in the case of the lines that SWT run their suburban lines, if (or you can use "once" depending on how likely you feel Crossrail 2 is) the inner section goes across to running through the Crossrail 2 tunnels then the level of disruption to converting those lines (one at a time) to OHLE will be less onerous than whilst they still only run into Waterloo.

Most of the other lines can be switched over in sections between junctions so as to minimise the disruption.

The more difficult bit will be the lines from Clapham Junction inwards, however if the works are all done and they then do a big switchover on one weekend (probably overnight Saturday to Sunday so they could iron out any problems during the day on Sunday if needed) then it would be little different to any other engineering works over that section overnight.

Clapham Junction will be looming and challenging as conversion progresses. As CLJ is 2 different railway companies, which part would be best to convert first - the L&SWR side (possibly the most trickiest, but there are several tracks there), or the LB&SCR side (possibly the easiest as there are fewer tracks, but probably less options to temporarily revise services to switch to another set of tracks)?

 

[po8crg]

I think that the general idea of doing the outside, fast, main lines like Southampton and Brighton first makes sense.

 

[NotATrainspott]

Noting your bold typed word; so you envisage trains (if they still exist) in, say, 3010, still using 25kV because it can never be bettered by any other energy supply regime (that we not even be dimly aware of today)?

Yes. Of course, there will be technological improvements but the fundamental idea will remain.

In the next decade it is likely that all smartphones will be able to be powered wirelessly over a distance of several metres and further in future. This will be less energy efficient than a wire but this is more than outweighed by the extra convenience it would bring. Due to the fact that trains can only move forward and backwards along a prebuilt track, there's almost no gain to be had in developing wireless power as it's possible to build OHLE over every possible place where a train can run.

 

[rebmcr]

Storing hydrogen at any pressure and at any energy density is a non-starter because its molecules are so small that they literally leak through solid containers' walls.

 

[najaB]

Storing hydrogen at any pressure and at any energy density is a non-starter because its molecules are so small that they literally leak through solid containers' walls.

That's not entirely true. It is possible to design low-loss hydrogen tanks, but they'll be a lot heavier than an equivalent tank for a hydrocarbon.

 

[GRALISTAIR]

To get back OT

London & South Western Railway


1)
Continue the conversion westwards from Southampton Central to Weymouth.

2)
Continue the conversion eastbound from both Southampton and Eastleigh to Portsmouth Harbour, also eastbound from Basingstoke to Woking, plus the fast lines to London Waterloo.

As the conversion from DC to AC is a complex project, I believe it is better to build on from the proposed Electric Spine project (if it ever gets off the ground). Regarding engineering staff to do the work, I would suggest the simple method of how British Rail proposed in their 1980 AC electrification report for routes north of the Thames by having 4 teams on the ground. 2 routes split into 2 teams, with one starting at each end and meeting in the middle.

I agree on these as the start point- and although OT because it would not be conversion but new, I would do Basingstoke -Salisbury at the same time (later on to Exeter).

I think these could happen in my lifetime and IMHO the Electric Spine will go ahead but just be heavily delayed.

 

[DerekC]

Yes. Of course, there will be technological improvements but the fundamental idea will remain.

In the next decade it is likely that all smartphones will be able to be powered wirelessly over a distance of several metres and further in future. This will be less energy efficient than a wire but this is more than outweighed by the extra convenience it would bring. Due to the fact that trains can only move forward and backwards along a prebuilt track, there's almost no gain to be had in developing wireless power as it's possible to build OHLE over every possible place where a train can run.

Hmm. If there was a way of transmitting power to the train contactlessly, it wouldn't half improve reliability. I agree that there isn't, but who knows? It boils down to the fact that you can't plan for transformational change - but it is unwise to assume that what is best now will be best for ever.
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That's not entirely true. It is possible to design low-loss hydrogen tanks, but they'll be a lot heavier than an equivalent tank for a hydrocarbon.

Fuel cells have been designed which run on ammonia, which is nasty stuff chemically but eases the storage problem.

 

[222ben]

Unsure if there are any similar old threads regarding this topic.

As it has been publicly known the proposals for the will it, won't it go ahead Electric Spine project, I have thought about converting the whole of the former Southern Region from DC to AC. This assumes that Southampton - Basingstoke (both routes via Eastleigh and Laverstock Junction) - Reading - Oxford - Bletchley - Bedford Midland and Midland Railway metals northwards have already been committed and teams mobilised for that project. I have outlined the details for each of the 3 Southern Region companies below.

London & South Western Railway


1)
Continue the conversion westwards from Southampton Central to Weymouth. I believe that most of this section was third rail electrified in 1988, which tied in with the introduction of the most discussed class of traction on this forum. The third rail equipment could then be used as spares for the Isle of Wight.

2)
Continue the conversion eastbound from both Southampton and Eastleigh to Portsmouth Harbour, also eastbound from Basingstoke to Woking, plus the fast lines to London Waterloo. Furthermore, convert the Portsmouth Direct route via Haslemere, and the Guildford New Line via Cobham & Stoke d'Abernon to AC. Perhaps a new AC only class of trains could be built for these routes, and be given the designation of Class 542?

3)
Convert the line from Pirbright Junction to Alton, plus the spur from Aldershot to Guildford, and Ash Vale to Ascot. These routes to be operated by something similar to the Class 542s (perhaps Class 543s?) that are suited to this medium distance/local routes.

4)
Have a separate team to continue the wires west of Laverstock Junction to Barnstaple, Exmouth, the Yeovil curve, and maybe to Okehampton/Plymouth via Tavistock. The routes beyond Exeter could be done in partnership with the GWR team if wires ever reach that far along GWR metals. The present Waterloo - Exeter to be operated by Class 542s.

The present day Class 450s (I believe there are 127 of them) can be transferred to the local all stations stopping services that operate within and just beyond the London Zones, meaning that the Class 455s (I believe that they were built in 1982) can be retired. This may or may not determine what stock will be used if TfL ever takes over responsibility for the local London services, and what form the Chelsea - Hackney project will look like when it is constructed. The Inner London local services to be converted to AC when the Class 450s are due for retirement.

London, Brighton, and South Coast Railway

1)
I'll start here with what I perceive to be the blindingly obvious: Continue the wires from City Thameslink all the way to Brighton via both the Quarry route and via Redhill. Also the fast lines from London Victoria to East Croydon as well, and the branches to Tattenham Corner and Caterham too. This would be one less thing to go wrong in the core as the train would no longer have to switch between different voltage systems.

2)
Convert Three Bridges - Littlehampton and Bognor Regis via Horsham to AC, and Keymer Junction - Seaford to AC as well. Then Brighton - Eastbourne and Hastings (also reinstating the top side of the triangle north of Hampden Park Sussex), and Brighton - Havant. The Class 313s can be retired, as they are used on the local all stations services east and west of Brighton. New class of trains for the limited stop services to/from Victoria and London Bridge, perhaps Class 552s?

The Class 377s could then be transferred to the local all stations services within and just outside London, so as to retire the Class 455s. Inner London local services to be converted to AC when the Class 377s are due to be retired.


South Eastern Railway/London, Chatham, & Dover Railway


1)
Convert Ashford – Ramsgate via Canterbury West, Dover Priory – Margate – Faversham – Swanley, and Swanley – Ashford via Maidstone to AC. Also the line to Sheerness-on-Sea to be converted as well. This would allow the Class 395s to run solely on AC.


2)
Convert the fast lines out of Charing Cross and Cannon Street to AC via the SER mainline to Hastings and Tonbridge – Dover Priory. Electrify Hastings – Ashford (Kent), and convert Ashford – Chislehurst Junction too. A new class of trains to be introduced for the limited stop services, perhaps designated Class 562s?


3)
Convert Chislehurst Junction – London Victoria fast lines to AC, Tonbridge – Strood, Sevenoaks – Otford, Shortlands – Blackfriars, and East Croydon – East Grinstead and Uckfield/Lewes.


4)
Fill in the missing gaps of the Reading, Guildford, & Reigate Railway using AC. Dual voltage Class 377s could be used initially before the DC sections are converted to AC. Perhaps the conversion could be done in conjunction with the Waterloo – Reading/Windsor & Eton Riverside project when that is due to be converted?


5)
The final route outside of London to be converted to AC would be the Redhill – Tonbridge section, as I believe that was upgraded in the early 1990s for Eurostar. The dismantled DC equipment could then be reused on the Isle of Wight as spares.


On a final point, I have deliberately not made many references to converting local all stations services that operate within or just outside the London fare zones, as it has been mentioned in earlier threads that TfL would like to be responsible for those services. Also, forgive me if my suggestions may not be entirely clear, as it is not often I venture south of the mighty Thames. As the conversion from DC to AC is a complex project, I believe it is better to build on from the proposed Electric Spine project (if it ever gets off the ground). Regarding engineering staff to do the work, I would suggest the simple method of how British Rail proposed in their 1980 AC electrification report for routes north of the Thames by having 4 teams on the ground. 2 routes slit into 2 teams, with one starting at each end and meeting in the middle.

Just convert 450s into 350s

 

[Bald Rick]

Hmm. If there was a way of transmitting power to the train contactlessly, it wouldn't half improve reliability. I agree that there isn't, but who knows?

There is. Various tram and electric bus systems around the world use it. Induction.

 

[jopsuk]

Transformers work because of induction- they have to have an insulating gap!

 

[edwin_m]

There is. Various tram and electric bus systems around the world use it. Induction.

Involves putting coils under the track, minimising the air gap to coils on the vehicle, and presumably making sure they are switched on only when the vehicle is above them. For continuous feed these would need to be repeated all along the track, and nobody's mentioned the efficiency factor.

I think for reliability I'd prefer a piece of copper wire up in the air, even if it does fall down occasionally.

 

[Bald Rick]

Involves putting coils under the track, minimising the air gap to coils on the vehicle, and presumably making sure they are switched on only when the vehicle is above them. For continuous feed these would need to be repeated all along the track, and nobody's mentioned the efficiency factor.

I think for reliability I'd prefer a piece of copper wire up in the air, even if it does fall down occasionally.

I agree - I wasn't advocating the contactless system, just stating that it existed!

 

[apk55]

Involves putting coils under the track, minimising the air gap to coils on the vehicle, and presumably making sure they are switched on only when the vehicle is above them. For continuous feed these would need to be repeated all along the track, and nobody's mentioned the efficiency factor.

I think for reliability I'd prefer a piece of copper wire up in the air, even if it does fall down occasionally.

Air gap transformers are not very efficient particularly to a moving vehicle above where the alignment between the two coils is constantly shifting. Also you would probably need to at higher than mains frequency so you would require inverters. Eddy current losses in any nearby metalwork would increase the losses. I would be surprised if they could even achieve 80% efficiency. Costs would be horrific as you would require substantial sized inverter units every 100m or so plus switches to select the coil where the tram is located.

 

[AM9]

Air gap transformers are not very efficient particularly to a moving vehicle above where the alignment between the two coils is constantly shifting. Also you would probably need to at higher than mains frequency so you would require inverters. Eddy current losses in any nearby metalwork would increase the losses. I would be surprised if they could even achieve 80% efficiency. Costs would be horrific as you would require substantial sized inverter units every 100m or so plus switches to select the coil where the tram is located.

Having gone to the extent needed for current transfer, you might just as well provide an aluminium eddy plate on the train and operate it as a linear motor.

 

[najaB]

Having gone to the extent needed for current transfer, you might just as well provide an aluminium eddy plate on the train and operate it as a linear motor.

If you're going to do all that, then having wheels on rails seems like a waste...

 

[The Ham]

To get back OT



I agree on these as the start point- and although OT because it would not be conversion but new, I would do Basingstoke -Salisbury at the same time (later on to Exeter).

I think these could happen in my lifetime and IMHO the Electric Spine will go ahead but just be heavily delayed.

Personally I think that Yeovil Junction makes a better end point for the wires, as it removes some more services from being DMU and it allows cross platform changes from DMU to EMU (although I would still think that there would be some, say one every 2 hours, through services).

One three of the four lines at Basingstoke are done (or at least planned) then I think that Basingstoke to Woking would happen fairly soon after. As that would likely allow some speed enchantment and has a number of bridges which are already high enough to allow OHLE (not least the M3 and the two station footbridges at Fleet and Farnborough, although there appear to be others).

 

[SpacePhoenix]

Apart from the obvious of the Southampton tunnel, what would be the hardest places to adjust to allow for the installation of OLE west of Basingstoke?

 

[AM9]

Apart from the obvious of the Southampton tunnel, what would be the hardest places to adjust to allow for the installation of OLE west of Basingstoke?

Didn't Soton tunnel recently get the floor dropped to bring the route up to W10 gauge? I believe that W10 in a twin track tunnel generally provides clearance for catenary support hardware in the crown and given the low speed limit there, restricted clearances could be permitted to avoid much of the heavy architectural modifications.

 

[Philip Phlopp]

Didn't Soton tunnel recently get the floor dropped to bring the route up to W10 gauge? I believe that W10 in a twin track tunnel generally provides clearance for catenary support hardware in the crown and given the low speed limit there, restricted clearances could be permitted to avoid much of the heavy architectural modifications.

W10 isn't a cast-iron guarantee of providing clearance - as we all know, most tunnels and many bridges were built with curved/circular/semi circular profiles, with carriages and locomotives having suitably curved roofs in most cases to make efficient use of the available space.

Freight gauges are mainly concerned with the outer extremities of containers, which of course are flat roofed, ensuring that the corners of containers don't connect with the curving off centre sections of circular structures. Track lowering in such cases drops the track, wagon and container below the point where it will come into contact with the structure in question, at the same time, increasing the space available dead centre of the structure, whether it's single or double track. That additional space can be sufficient for OLE installation.

If, however, the structure has a flat roof/underside - iron/steel/box girder type bridge, for example, dropping the track will only ever provide clearance for the container, and not for any OLE above it. In most cases, W10 clearance will simultaneously provide space for OLE, but not in all cases.

 

[SpacePhoenix]

Would the "overhead rail" system be looked into first and the lowering of the track considered only if the "overhead rail" system won't fit?

 

[jon0844]

I am not sure why we're even considering such work, as no switch should be made until the 442s are no longer usable. According to posts on here, they're good for use everywhere for the next 1000 years at least.

 

[Bald Rick]

I am not sure why we're even considering such work, as no switch should be made until the 442s are no longer usable. According to posts on here, they're good for use everywhere for the next 1000 years at least.

AC conversion for them Jon.
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Would the "overhead rail" system be looked into first and the lowering of the track considered only if the "overhead rail" system won't fit?

I may stand corrected by my colleague, but the conductor bar doesn't require any less clearance in tunnels. It's better for low maintenance, which is more difficult in tunnels.

 

[AM9]

W10 isn't a cast-iron guarantee of providing clearance - as we all know, most tunnels and many bridges were built with curved/circular/semi circular profiles, with carriages and locomotives having suitably curved roofs in most cases to make efficient use of the available space.

Freight gauges are mainly concerned with the outer extremities of containers, which of course are flat roofed, ensuring that the corners of containers don't connect with the curving off centre sections of circular structures. Track lowering in such cases drops the track, wagon and container below the point where it will come into contact with the structure in question, at the same time, increasing the space available dead centre of the structure, whether it's single or double track. That additional space can be sufficient for OLE installation.

If, however, the structure has a flat roof/underside - iron/steel/box girder type bridge, for example, dropping the track will only ever provide clearance for the container, and not for any OLE above it. In most cases, W10 clearance will simultaneously provide space for OLE, but not in all cases.

Southampton tunnel is almost circular I believe, (as opposed to elliptical) so with the lowered floor it looks OK for low profile catenary and supports, or if the conversion becomes important enough, rigid rail for its length. The Kingsway, St Mary's & Northam Road bridges might need some adjustment though but in the grand scheme of things, they would be small meat considering the lifetime benefits of converting such a busy mixed traffic line.

This picture gives some idea of the clearance above a 444:

https://www.google.co.uk/search?q=southampton+tunnel&client=tablet-android-samsung&prmd=mniv&source=lnms&tbm=isch&sa=X&ved=0ahUKEwi_3b39gI7NAhUELMAKHTfRC8YQ_AUICSgD&biw=1280&bih=800#imgrc=4wZuHI_wAGUDjM%3A

https://www.google.co.uk/search?q=s...UICSgD&biw=1280&bih=800#imgrc=4wZuHI_wAGUDjM:


--- old post above --- --- new post below ---

AC conversion for them Jon.

For those who can't bear the thought of 442s ending up as razor blades, how about a cascade to rid the countryside of these eyesores:
https://www.google.co.uk/search?q=living+in+old+railway+coaches&client=tablet-android-samsung&prmd=inv&source=lnms&tbm=isch&sa=X&ved=0ahUKEwi__9HJg47NAhXmJ8AKHRT0AAIQ_AUIBygB&biw=1280&bih=800#imgrc=OiZybkcOH2QRIM%3A

 

[najaB]

I may stand corrected by my colleague, but the conductor bar doesn't require any less clearance in tunnels. It's better for low maintenance, which is more difficult in tunnels.

I would have thought that the insulators can be connected directly to the tunnel roof, rather than having catenary+dropper then the overall vertical height required would be less. Looking forward to Phil Phlopp's reply.

 

[Philip Phlopp]

Would the "overhead rail" system be looked into first and the lowering of the track considered only if the "overhead rail" system won't fit?

Dropping the deck is usually the last option, particularly if there are platforms which need lowered at the same time.