Why no longer Third Rail Electrification?

[The Lad]

Surely the capacity issue is that upgrading feeder stations has not kept pace with the potential ability of the stock to draw current. ( as well as the difficulty of discriminating between a long train accelerating hard and a short circuit)

 

[A0]

I agree with all that you've said above except that the decision about more third rail electrification can only be considered against the case for that vs. 25kV OLE. For heavy rail, there is no case for anything other than 25kV ac on OLE since the removal of 6.25kV in the late '70s and the last installation of 1500VDC in the early '50s. The majority of all new electrification schemes (certainly in the 50Hz world) are at 25kV 50Hz ac even in countries with extensive legacy 1500/3000VDC systems so consequently, suppliers have developed their products with that demand in mind.
Even when the EU influence on selection of systems no longer impacts directly on the UK, it is extremely unlikely that anything else would even be considered for anything other than closed loop light rail projects.

The 6.25kv was only ever envisaged as a 'filler' where clearances were insuffiicient for the safe deployment of 25kv. As technology improved and various other works took place the 6.25kv was converted - fairly easily - to 25kv.

What is interesting to speculate is had WW2 not intervened how things would have progressed, the LNER were already a long way down the road in terms of planning to electrify lines at 1,500kv DC - the likelihood is the GC mainline might have followed the Woodhead line which would have given a Manchester - London electrified mainline by the mid 1950s....

 

[mwmbwls]

http://orr.gov.uk/__data/assets/pdf_file/0017/17621/dc-electrification-policy-statement.pdf

The ORR have laid down a policy which does not preclude further third rail electrification but does lay down some rigorous requirements before such developments can occur. So far. I cannot recall any such projects being passed and with the development of new bi-mode DEMU or IPEMUs, I cannot foresee one happening. The ORR's chief concern is the exposed third rail - now some systems such as the DLR and IIRC the old Manchester to Bury service did not rely on top contact allowing the top surface to be sheathed.

 

[swt_passenger]

As a diversion route during times of disruption and/or engineering works east of Basingstoke

They already have their diversion routes via Havant for Basingstoke, and via Cobham for Woking. There is no need to run the through services you suggest, and I can't think precedent for a major electrification length of this nature just for diversions..

There are no plans for the passenger service you suggest, what public plans there are require extension of AC electrification for trains from Heathrow to Basingstoke as part of Western Access. If these are extended further, perhaps to Southampton, then they would need to be dual voltage EMUs in the absence of electric spine.

 

[edwin_m]

In terms of arcing, it's more the distance over which arcing can take place, rather than the frequency, which is presumably why there are strictures about what height you can safely get to on the edge of a platform (without going anywhere near the cable) with OLE, whereas there is no such risk with third rail.

In terms of platforms, there is a long standing convention that the third rail is always laid on the opposite side to the platform face, which negates the hazard of people falling on to it.

My point is that passengers behaving "normally" are extremely unlikely to come within arcing distance of OLE - OLE-related injuries are overwhelmingly due to illegal behaviour such as climbing on trains.

Climbing from a platform onto the track is also illegal, but more likely to happen given that some people would see it as safe to retrieve a dropped object. And even with the third rail on the far side of the track, a tall person toppling full length off the platform edge would be close to it.

The shoegear on the opposite side of a train from the third rail is also live and could be hazardous to, for example, someone trying to retrieve an umbrella that had fallen into the platform gap but remained vertical.

 

[yorksrob]

My point is that passengers behaving "normally" are extremely unlikely to come within arcing distance of OLE - OLE-related injuries are overwhelmingly due to illegal behaviour such as climbing on trains.

Climbing from a platform onto the track is also illegal, but more likely to happen given that some people would see it as safe to retrieve a dropped object. And even with the third rail on the far side of the track, a tall person toppling full length off the platform edge would be close to it.

The shoegear on the opposite side of a train from the third rail is also live and could be hazardous to, for example, someone trying to retrieve an umbrella that had fallen into the platform gap but remained vertical.

Such scenario's are still very unlikely and in third rail land, electric shocks are far more likely to happen due to people misbehaving than those going about their everyday business. Certainly no justification for not electrifying diesel islands.

 

[AM9]

Such scenario's are still very unlikely and in third rail land, electric shocks are far more likely to happen due to people misbehaving than those going about their everyday business. Certainly no justification for not electrifying diesel islands.

We live in an increasingly litiginous society. It's important that somebody trespassing doesn't accidentally suffer injury/death so generally the measures taken to protect those who work on the infrastructure is usually a sufficient safeguard. In the case of the OLE hazard, there is no circumstance where a rail worker would come within the critical hazard area under any maintenance task, even an emergency without comprehensive protection measures.
In the case of 3rd rail electrification, its fundamental mode of operation is such that specific training, personal protection and (timely) detailed knowledge is central to the safety of infrastructure operatives. Protection of casual or habitual trespassers once beyond the perimeter fence, or off the formal passenger/road user area is virtually impossible. Any such attempt to justify access by untrained/unauthorised trespassers would fail both technically and legally. For those reasons, it is unlikely that the areal envelope of current 3rd rail infrastructure which exists through grandfather rights, is extended at all, and there will be increasing pressure to remove that which exists today at every opportunity.

 

[AM9]

The 6.25kv was only ever envisaged as a 'filler' where clearances were insuffiicient for the safe deployment of 25kv. As technology improved and various other works took place the 6.25kv was converted - fairly easily - to 25kv.

Actually, the conversion of the 6.25kV lines was justified by performing 'tests' to determine just how far clearances could be reduced before flashover occurred (from the conductor wire to a steam loco chimney I believe). The original minimum safe distance of about 13 inches was then reduced to something less than 8 inches and under some circumstances, even less. So very few structures then required modification in order to comply. It was more risk taking (or 'optimising of safety standards' from a management viewpoint) than much technology improvement.

What is interesting to speculate is had WW2 not intervened how things would have progressed, the LNER were already a long way down the road in terms of planning to electrify lines at 1,500kv DC - the likelihood is the GC mainline might have followed the Woodhead line which would have given a Manchester - London electrified mainline by the mid 1950s....

I agree that would probably been the case, but in more recent times, the push for higher speeds, higher density and better power efficiency that modern traction systems bring would probably have resulted in a steady trend towards 25kV which is the case on the continent, except where 16.7Hz ac is used.

 

[Camden]

We live in an increasingly litiginous society. It's important that somebody trespassing doesn't accidentally suffer injury/death so generally the measures taken to protect those who work on the infrastructure is usually a sufficient safeguard. In the case of the OLE hazard, there is no circumstance where a rail worker would come within the critical hazard area under any maintenance task, even an emergency without comprehensive protection measures.
In the case of 3rd rail electrification, its fundamental mode of operation is such that specific training, personal protection and (timely) detailed knowledge is central to the safety of infrastructure operatives. Protection of casual or habitual trespassers once beyond the perimeter fence, or off the formal passenger/road user area is virtually impossible. Any such attempt to justify access by untrained/unauthorised trespassers would fail both technically and legally. For those reasons, it is unlikely that the areal envelope of current 3rd rail infrastructure which exists through grandfather rights, is extended at all, and there will be increasing pressure to remove that which exists today at every opportunity.

And yet the number of people who are electrocuted by third rail in any area where expansion is needed stands at...

There have been more people electrocuted by overhead in and around Liverpool over the years than have come a cropper from the third rail.

I wouldn't call the "pressure" to remove third rail wherever it exists to be increasing. It just seems to be strange, and incessant. And coming mainly from just a few on here.

If there is a reasonable business case and positive reason for converting from 750v DC third rail to 25kv AC overhead then I'm sure it will have its day (such as in the south). If however it makes absolutely no sense to mess up a contained metro network, costs more and offers no benefit, possibly even a detraction (Merseyrail), then it would be ridiculous to indulge the debate whether for renewal or expansion.

 

[AM9]

And yet the number of people who are electrocuted by third rail in any area where expansion is needed stands at...

What has "any area where expansion is needed" got to do with the risk of electocution? Would the Merseyrail area conveniently just happen to be one them?

There have been more people electrocuted by overhead in and around Liverpool over the years than have come a cropper from the third rail.

So if you care for your fellow human beings, you should be campaigning for the WCML and the recently electrified Chat Moss route to be converted to 'safer' 3rd rail.

I wouldn't call the "pressure" to remove third rail wherever it exists to be increasing. It just seems to be strange, and incessant. And coming mainly from just a few on here.

If the cash was available, the business case would not be purely on potential hazards and doing nothing would be indefensible. I don't think that this forum represents a statistical cross section of public opinion, - more a group of rail enthusiasts, some of whom want to see a disappearing technology retained for nostalgic reasons despite the hazards that it presents to railway staff and some members of the public.

If there is a reasonable business case and positive reason for converting from 750v DC third rail to 25kv AC overhead then I'm sure it will have its day (such as in the south). If however it makes absolutely no sense to mess up a contained metro network, costs more and offers no benefit, possibly even a detraction (Merseyrail), then it would be ridiculous to indulge the debate whether for renewal or expansion.

The only real difference between 'the south' and the other UK metropolitan rail networks is that of traffic/passenger volume, which is why capital expenditure is greater for serving the capital. This in turn means that despite having the largest concentration of surface 3rd rail track in the world, it is dealing with the issues that arise from that method of providing traction power. Where L & SE leads, other areas that share the same legal system and have idiots from the same gene pool, will eventually follow.

 

[AndyW33]

And yet the number of people who are electrocuted by third rail in any area where expansion is needed stands at...

I don't think that has come out the way you meant it to. If there is no third rail on a line obviously nobody can be electrocuted by it. I assume you meant that adjoining areas of existing third rail had low to nil casualties.

I wouldn't call the "pressure" to remove third rail wherever it exists to be increasing. It just seems to be strange, and incessant. And coming mainly from just a few on here.

Surely the people who are opposed to third rail expansion and want to see conversions to 25kv overhead, and post here aren't also in positions of power in the DfT, NR, ORR, RSSB etc? The "pressure" you describe is coming from these official organisations, not an internet forum. Frankly it matters not at all whether posters here claim that all 3rd rail lines should be converted to overhead immediately, or that the MML electrification should be done as 3rd rail. Nobody in a position of authority will even see the posts.

We are fortunate to have posters who are involved in implementing electrification schemes and can describe the background to some of the decisions that have already been made - but unless I'm seriously mistaken they aren't the people who took the decisions.

 

[GRALISTAIR]

Surely the people who are opposed to third rail expansion and want to see conversions to 25kv overhead, and post here aren't also in positions of power in the DfT, NR, ORR, RSSB etc? The "pressure" you describe is coming from these official organisations, not an internet forum. Frankly it matters not at all whether posters here claim that all 3rd rail lines should be converted to overhead immediately, or that the MML electrification should be done as 3rd rail. Nobody in a position of authority will even see the posts.

We are fortunate to have posters who are involved in implementing electrification schemes and can describe the background to some of the decisions that have already been made - but unless I'm seriously mistaken they aren't the people who took the decisions.

One of the best posts on the thread- thank you

 

[yorksrob]

s.
In the case of 3rd rail electrification, its fundamental mode of operation is such that specific training, personal protection and (timely) detailed knowledge is central to the safety of infrastructure operatives. Protection of casual or habitual trespassers once beyond the perimeter fence, or off the formal passenger/road user area is virtually impossible.

As a schoolboy in 1980's Kent, I and my cohort had "specific training" which taught us not to go on the railway and not to touch the third rail. Surely this is the sum of the knowledge that people need in relation to the third rail, and should be taught in schools and through public information campaigns anyway.

The diesel islands exist in areas where the third rail is already a fact of life, so the danger is no greater to the public than from neighbouring lines.

 

[lancastrian]

I have been really enjoying the debate so for from my post. I have found many of the arguments very interesting, as well as very informative.

However I have been looking at the currant (no pun intended) situation concerning 3rd Rail. There are only two basically self contained systems. Merseyrail and Southern.

First of all Merseyrail.
There are only five possible, realistic extensions to that system, which are:

• Kirkby to Wigan Wallgate 12 miles.
• Ormskirk to Burscoungh Bridge 3 miles
• Ellesmere Port to Helsby 4 miles
• Bidston to Wrexham 28 miles
• And the projected Skelmersdale Branch 2 miles

All this is less than 50 route miles. All these extensions would now terminate at their logical conclusions.

Admittedly it would make sense to redouble the routes from Fazackerley to Rainford, and Ormskirk to Burscough Bridge. The later would be single track as it enters the Burscough South curve and would terminate in a separate platform just before the bridge, and junction with the Southport line. The north curve would be reopened to link Preston with Southport and the route from Buscough Bridge would be re-doubled and 25AC electric to Southport. No need for dual voltage.

The Wiagn line could terminate in the bay platform at Wallgate, keeping the electric somewhat separate. The extension the Helsby is simple and basic. And the Wrexham line is also basically a separate route. I would envisage no 3rd rail extension from Hunts Cross, because the Warrington Central line should be 25AC. All this would save Merseyrail the extra costs of providing dual voltage trains.

On to Southern now.
Again there are very few routes that need doing to infill. These are:

• Aldershot South Junction to Wokingham Junc 12 miles
• Reigate to Shalford Junc 17 miles
• Ashford to Ore 25 miles
• Hurst Green to Uckfield 25 miles

A total of 79 miles. All are again simply infills, honestly I have never understood why they have not been done so far, especially as they are in the South East, which seems to get the lions share of rail investment.

Looking at all this it seems to me very strange that for some reason the simple, logical option of electrifying these routes with 3rd Rail has not been done, when it makes total sense to me.

Looking forward to your interesting comments on these thoughts.

 

[Domh245]

I have been really enjoying the debate so for from my post. I have found many of the arguments very interesting, as well as very informative.

However I have been looking at the currant (no pun intended) situation concerning 3rd Rail. There are only two basically self contained systems. Merseyrail and Southern.

First of all Merseyrail.
There are only five possible, realistic extensions to that system, which are:

• Kirkby to Wigan Wallgate 12 miles.
• Ormskirk to Burscoungh Bridge 3 miles
• Ellesmere Port to Helsby 4 miles
• Bidston to Wrexham 28 miles
• And the projected Skelmersdale Branch 2 miles

All this is less than 50 route miles. All these extensions would now terminate at their logical conclusions.

Admittedly it would make sense to redouble the routes from Fazackerley to Rainford, and Ormskirk to Burscough Bridge. The later would be single track as it enters the Burscough South curve and would terminate in a separate platform just before the bridge, and junction with the Southport line. The north curve would be reopened to link Preston with Southport and the route from Buscough Bridge would be re-doubled and 25AC electric to Southport. No need for dual voltage.

The Wiagn line could terminate in the bay platform at Wallgate, keeping the electric somewhat separate. The extension the Helsby is simple and basic. And the Wrexham line is also basically a separate route. I would envisage no 3rd rail extension from Hunts Cross, because the Warrington Central line should be 25AC. All this would save Merseyrail the extra costs of providing dual voltage trains.

On to Southern now.
Again there are very few routes that need doing to infill. These are:

• Aldershot South Junction to Wokingham Junc 12 miles
• Reigate to Shalford Junc 17 miles
• Ashford to Ore 25 miles
• Hurst Green to Uckfield 25 miles

A total of 79 miles. All are again simply infills, honestly I have never understood why they have not been done so far, especially as they are in the South East, which seems to get the lions share of rail investment.

Looking at all this it seems to me very strange that for some reason the simple, logical option of electrifying these routes with 3rd Rail has not been done, when it makes total sense to me.

Looking forward to your interesting comments on these thoughts.

Probably because the infills aren't as easy as might have been thought. Whenever Marshlink comes up, it is usually pointed out that the feeding arrangements would be pretty difficult.

 

[Elecman]

I have been really enjoying the debate so for from my post. I have found many of the arguments very interesting, as well as very informative.

However I have been looking at the currant (no pun intended) situation concerning 3rd Rail. There are only two basically self contained systems. Merseyrail and Southern.

First of all Merseyrail.
There are only five possible, realistic extensions to that system, which are:

• Kirkby to Wigan Wallgate 12 miles.
• Ormskirk to Burscoungh Bridge 3 miles
• Ellesmere Port to Helsby 4 miles
• Bidston to Wrexham 28 miles
• And the projected Skelmersdale Branch 2 miles

All this is less than 50 route miles. All these extensions would now terminate at their logical conclusions.

Admittedly it would make sense to redouble the routes from Fazackerley to Rainford, and Ormskirk to Burscough Bridge. The later would be single track as it enters the Burscough South curve and would terminate in a separate platform just before the bridge, and junction with the Southport line. The north curve would be reopened to link Preston with Southport and the route from Buscough Bridge would be re-doubled and 25AC electric to Southport. No need for dual voltage.

The Wiagn line could terminate in the bay platform at Wallgate, keeping the electric somewhat separate. The extension the Helsby is simple and basic. And the Wrexham line is also basically a separate route. I would envisage no 3rd rail extension from Hunts Cross, because the Warrington Central line should be 25AC. All this would save Merseyrail the extra costs of providing dual voltage trains.

I would suggest you electrify Ormskirk to Southport via Burscough to connect both ends of the existing 3rd rail system especially given there is about to be a new feeder station at Hillside on the Southport line.

 

[najaB]

And yet the number of people who are electrocuted by third rail in any area where expansion is needed stands at...

I always wonder if the stats actually reflect reality. If someone is electrocuted and hit by a train as a result, does it get recorded as an electrocution?

 

[Dr Hoo]

There seem to be two aspects to this and other discussions about third rail extension.

Firstly, whether the ORR has 'moved the goalposts'. Given that the Electricity at Work regulations date from 1989, long before privatisation, the founding of ORR and the later transfer of railway safety responsibility to ORR it is not a question of ORR 'making up new law'.

Any government department or other statutory public body obviously has to obey the law and uphold the law as it stands when it exercises it's powers. It can't just 'ignore' it. There has been plenty of controversy over the years of public authorities 'turning a blind eye' to contraventions and 'neglecting' to protect the public.

In very simple terms the Electricity legislation says that you can't have live conductors where staff (and the public) might come into contact with them. Third rail fails this test for many rail staff and also the public, e.g. in falls from platforms or train evacuations, quite apart from trespass.

So ORR has very little choice but to decide that any more of this 'illegal' kit should be banned. (Yes, I know that the language is more nuanced than that.)

Secondly is my own experience. As it happens the first decade of my railway career saw me working in North London, Merseyside and the Southern Region as it was. So third rails seemed very normal and 'acceptable' to me.

Then I further happened to be working at a location where a 9-year old boy got onto the track and was fatally electrocuted. (What made it worse was that the hole in the fence had been made by rail staff taking short cuts to a depot.)

Not long afterwards I was standing next to a member of permanent way staff working on the third rail when the section was accidentally 'bridged up' by a shunt move. Obviously it should have been earthed but it wasn't (as was not untypical in those casual days). They too were 'electrocuted' but survived.

These experiences entirely changed my view about third rails.

Quite apart from the electrical efficiency and other economic arguments it is simply no longer acceptable IMHO.

 

[GRALISTAIR]

-----

These experiences entirely changed my view about third rails.

Quite apart from the electrical efficiency and other economic arguments it is simply no longer acceptable IMHO.

Quite. If you make all the hoo hah about raised bridges and parapets etc . for OHLE then 3rd rail safety has to come under the same scrutiny. IMHO

 

[Elecman]

In today's rules if you are working on. Supposedly dead 3rd rail you would be protected by application of shorting straps either side of your worksite to prevent accidental energisation by the likes of shunt manoeuvres train overruns. If working near Live conductor rail then sufficient shrouds over the 3rd rail should be applied over the 3rd rail to provide protection from accidental contact, and off course all tools are fully insulated.

 

[Hophead]

As many have pointed out, electrocutions from 3rd rail are extremely rare. However, this does not mean that people are not trespassing. Unfortunately, this is an all too common occurrence. In such circumstances, the power must be switched off and all trains must come to a halt while the situation is dealt with. The switch-off will usually cover more than the immediate area, with inevitable delays over a wide area for an extended period.

 

[edwin_m]

But what about while you are applying or removing the shorting straps and the shrouding?

 

[edwin_m]

I would envisage no 3rd rail extension from Hunts Cross, because the Warrington Central line should be 25AC. All this would save Merseyrail the extra costs of providing dual voltage trains.

I think you're contradicting yourself a bit here. You're saying the third rail shouldn't extend from Hunts Cross but also that the trains should not be dual voltage, so you must be saying that Merseyrail should terminate at Hunts Cross for the foreseeable future simply because of the third rail situation.

In fact the trains have been ordered including provision for adding 25kV equipment, and I think extension of Merseyrail from Hunts Cross to one of the Warrington stations is a very real possibility within the 30-year lifetime of these trains. It would solve the problem of skip-stopping by the current stoppers, which leads to very poor service at some stations, without compromising Warrington's fast train to Manchester and Liverpool every 30min.

So with the trains having 25kV capability the question of which system to use for future extensions becomes more open. Small isolated sections of 25kV are difficult because of the cost of the necessary feeder equipment, but if they can be connected (electrically even if not track-wise) to a larger 25kV network they become much more viable. This suggests 25kV might be the best choice for extensions such as Kirkby/Skem/Wigan and if it was decided to continue from Ormskirk towards Preston instead of Southport. If North Wales main line electrification ever happened it could also feed Bidston-Wrexham.

 

[JamesRowden]

The decisions to limit future 3rd rail expansion to virtually nothing has been influenced by several negative issues that it is responsible for:

it is much less safe than OLE for staff, passengers as well as trespassers and wildlife
it is much more wasteful on energy than HV OLE for most mainline applications
it requires complex and expensive feeder equipment in greater quantities per track kilometre
it requires that performance of modern rolling stock is limited artificially to keep the electrical load within the system's capabilities
it has climatic vulnerabilities that are more difficult/impossible to mitigate than for OLE
as time goes on, it is becoming more non-standard, resulting in equipment, materials and human resource shortages​

In summary, the above negative incentives to 3rd rail expansion can be attributed to environmental, safety, maintainability and economic reasons. The combined effect is driving a political will that likely prevents any more 3rd rail from being authorised.

Perhaps this statement in the draft Kent Route Study with respect to the cost of electrifying the Marshlink with either OHLE or third-rail will surprise you:

The cost of electrification is significant at £250m-£500m for 25kV AC overhead or £100m-£250m for 750V DC third rail.

 

[AM9]

Perhaps this statement in the draft Kent Route Study with respect to the cost of electrifying the Marshlink with either OHLE or third-rail will surprise you:

Projected costs contained in RUS documents seem to have little relationship to the eventual actual cost and more to do with steering the recipients of the studies towards the writers' perferred project.
I doubt that the Marshlink line will be electrified before the Folkestone main line nears OLE conversion when its current equipment is life-expired.

 

[JamesRowden]

Projected costs contained in RUS documents seem to have little relationship to the eventual actual cost and more to do with steering the recipients of the studies towards the writers' perferred project.
I doubt that the Marshlink line will be electrified before the Folkestone main line nears OLE conversion when its current equipment is life-expired.

Can you provide multiple references to prove for your accusation? What happened with the CP4/CP5 estimated electrification costs could be explained as one mistake, underestimating the cost of OHLE. You seem to be coming with a conspiracy theory to `steer the recipients' of your post `towards' your `preferred projects'.

 

[yorksrob]

Projected costs contained in RUS documents seem to have little relationship to the eventual actual cost and more to do with steering the recipients of the studies towards the writers' perferred project.
I doubt that the Marshlink line will be electrified before the Folkestone main line nears OLE conversion when its current equipment is life-expired.

We haven't heard anything about the great conversion project for a while. Is this actually going ahead or has it been quietly forgotten about.

 

[hwl]

Perhaps this statement in the draft Kent Route Study with respect to the cost of electrifying the Marshlink with either OHLE or third-rail will surprise you:

If you read the technical appendix and do some maths you will see that the OHLE cost is mostly bridges etc. not the electrification

 

[SpacePhoenix]

What's the typical lifespan for bridges that pass over the railway? Are many bridges in 3rd rail territory (excluding MerseyRail) anywhere near to the end of their lifespan?

 

[yorksrob]

What's the typical lifespan for bridges that pass over the railway? Are many bridges in 3rd rail territory (excluding MerseyRail) anywhere near to the end of their lifespan?

There are plenty of arched bridges which have been there since the routes opened, so I would expect them to last for as long as they are maintained.