Third rail - becoming a better option for electrification?

[NSEWonderer]

Ah yes Pigeon I see I've missed the squaring part. Indeed a 4th rail could help make third rail reduce that transmission loss if it were feasible.

 

[stuu]

The current size and scope of railway operations is not fixed and unchanging with time.

There is a perfectly realistic alternative - railway routes that cannot be operated with existing electrification and battery equipment cease operating.

Just because the railway has had three decades of massive political support and largely unchallenged budgets does not mean that this will be true forever.

Very true. And that may well come to pass in places. But I would be extremely surprised if we get to situation where an option for e.g. Birmingham-Derby is closure. So extension of electrification is almost inevitable

 

[JamesT]

Wouldn’t reducing the length of third rail sections stuff the regenerative braking? As I understood the way it was set up requires another train to be in the same section to make use of the energy?

 

[LBMPSB]

Interesting, why would derailment trip the system out ?
A crash or derailment ‘might’ but does not guarantee it.
Network rail state there are around 13,500 trespass incidents every year. Of course some don’t get reported, so almost certainly more.

‘Your son’, the son of someone who takes enough of an interest in the railway to come to this forum is not a very representative example of the UK population.

The railway is all about safety. There are inherit dangers with exposed ground level conductors energised to a high voltage. Whether or not people should know better is irrelevant, there is risk to life and the ORR will not want to increases the chances of someone being killed by it, by adding any significantly adding to the 3rd rail network.

There are other circumstances such as passengers taking it upon themselves to de-train themselves when trains are stuck. It has happened before, it has been fortunate not to end in a fatality but one wrong step is all it would take.

As soon as a Driver reports to the Signaller, or the Signaller gets reports of passengers detraining from a train other than at a station platform in Third Rail areas, they will immediately arrange an Emergency Awitch Off, current isolation of the third rail. If overheads have come down and passengers detrain, there is a far greater risk of electrocution as even though the OHL may no longer be connected to the electricity supply, because of the 25kV in them they will hold a charge for a considerable amount of time even lying on the ground, Third Rail doesn't.

Despite the dangers of third rail electrification it is not easy to get electrocuted. I spent many years in the 1980s working directly alongside it. My dad was an Electric Track Maintenance Ganger and worked directly with it for two decades maintaining it whilst the third rail was live, unlike they would today. As long as you did not complete a circuit, i.e. touch the third rail and the running rail and were dry, there was no danger. Most shoes, boots, trainers would also keep you insulated if you happened to stand on both third rail and running rail. I even knew pway men that sat on the third rail in the summer. I myself have brushed it several times with bare hands and had no shock. Unlike OHL, if you get closer than the safety 9 feet, there is a high chance you will fry, you do not even have to touch it, the electricity will bridge the gap. Only once did I get a "belt" from the "juice" as we called it. It was raining and I had on the old BR "Foreign Legion" wet-weather hat on. The rain was running down my back and came into contact with the third rail and if felt like I had been walloped on the back of my neck, but that was all. Falling across the Third Rail and running rail, as long as no bare skin came into contact and you were dry, there would be no electrocution. Wild life, from rats to Deer Cattle and sheep on the line, very rare you hear of sheep or cattle that are all over the lines in third rail areas getting electrocuted. I used to find foxes, domestics cats and dogs that had been electrocuted, but then they had attempted to cross, bare paws on running rail and third rail. Badgers had a habit of crawling under the third rail and up over the running rail, rarely making it. You see birds, mice even rats walking along a third rail with no effect. Third rail electocution is very rare.

A derailment would only trip out the system is the third rail shorted out by contact of third rail and running rail. A wheelset fails between running rail and third rail; a bogie with contact shoe drops off opposite side to third rail and the collector shoe comes into contact with the running rail thus completing a circuit with the third rail via other collector shoes that are on the third rail still; damage to infrastructure that affects the third rail and shorts it out.

When the Electrical Control Operators become aware of a short of the Thrd Rail, the circuit breakers comes out, they will make two recharge attempts,i.e. put back in the circuit breaker to see if it doesn't short again. If the second attempt does not hold, they will immediately contact the signaller of the area concerned.

There are risks in everything in life. Unfortnately the world we live in today is where no one takes responsibility for their own actions anymore. Anything happens, it is always someone else's fault because they haven't put into place things to mitigate against someone doing something they shouldn't. People lack common sense these day. Sign says Danger of Electrocution, do not pass this point; civil liberties, you can't tell me what to do and limit my freedom, so they pass it and get electrocuted. Because that person doesn't take ownership of looking after themselves, i.e. I must not pass that sign as there is a risk to my life; despite the promenant sign, it is not the fault of the person, but the fault of the company that put the sign there because they have not looked into the fact if a person should ignore the sign what else should have put in place to protect the person.

 

[HSTEd]

You still need a substation at the points where the grid feeds each group of third-rail substations, to take the grid voltage down to 33kV (I think it is, and it makes sense) that the railway uses to take the power on to the substations themselves. The spacing of these is similar to that of the 25kV ones, so really what you end up needing is the same-ish number of medium-voltage substations and a bunch of third-rail-feeding ones as we

Whilst this topology is the one that was used on Southern Railway and early BR electrification schemes, by the 1980s the trackside AC feeders had largely dissapeared on schemes like Weymouth.

The Weymouth line simply has traction substations take power supplies from the grid at whatever voltages are available. It even has 11kV fed substations.

I've got no inside information on why this happened, but I'd speculate it is merely a result of the major development of the normal electricity system. By the 1980s the railway doesn't really have a need to operate a major distribution system of its own to supply the substations as the rural electricity grid is far more reliable than it would have been in the 1960s, let alone the 1930s.

Wouldn’t reducing the length of third rail sections stuff the regenerative braking? As I understood the way it was set up requires another train to be in the same section to make use of the energy?

That limitation is mostly a limitation of the power electronics used in the substations, which are mostly quite old. With modern electronics in a new scheme, you could probably arrange for regeneration from the power rail to the grid and avoid this issue.

 

[DaleCooper]

even though the OHL may no longer be connected to the electricity supply, because of the 25kV in them they will hold a charge for a considerable amount of time even lying on the ground, Third Rail doesn't.

Could you explain this as I don't how a wire that has been disconnected from an AC supply can hold a charge.

 

[Lurcheroo]

As soon as a Driver reports to the Signaller, or the Signaller gets reports of passengers detraining from a train other than at a station platform in Third Rail areas, they will immediately arrange an Emergency Awitch Off, current isolation of the third rail

I assume by the way you wrote this, you’re not a driver. Yes GSMR is better and more reliable than ever, but there are still plenty of reason you wouldn’t be able to contact the signaller in an emergency and subsequently not be able to get a timely isolation from the ECO.

There are risks in everything in life. Unfortnately the world we live in today is where no one takes responsibility for their own actions anymore. Anything happens, it is always someone else's fault because they haven't put into place things to mitigate against someone doing something they shouldn't. People lack common sense these day. Sign says Danger of Electrocution, do not pass this point; civil liberties, you can't tell me what to do and limit my freedom, so they pass it and get electrocuted. Because that person doesn't take ownership of looking after themselves, i.e. I must not pass that sign as there is a risk to my life; despite the promenant sign, it is not the fault of the person, but the fault of the company that put the sign there because they have not looked into the fact if a person should ignore the sign what else should have put in place to protect the person.

I spent many years in the 1980s

I hear a lot of this type on nonsense from ‘old timers’ and I’m sorry but just because you weren’t killed by it, doesn’t mean others have, in fact there are hundreds of cases you can take a bit of time to read about.
Just because someone makes a what might just be a lapse in judgment (we all have when we’re younger, YOU included I have absolutely no doubt), does not mean they deserve to die.

I’m sure you would feel very differently if your child had been killed by it.

 

[yorksrob]

I’m sure you would feel very differently if your child had been killed by it.

The reality is that lots of aspects of life include elements of danger where a lapse in judgment can kill one. The alternative is not leaving your house.

 

[WAO]

LBMPSB's comments are real experience and would have been part of a competent ORR determination.

Armchair critics (even if from the climate controlled comfort of a driver's cab) should not dismiss them as "nonsense".

The blanket condemnation of third rail prevents the examination of improved protection and work practices for this necessary evil.

WAO

 

[Bald Rick]

I've got no inside information on why this happened, but I'd speculate it is merely a result of the major development of the normal electricity system.

It was done because the power demand was low, there were nearby supplies, and this was a cheap way of doing it. Hence all the operational restrictions on the line.

 

[snowball]

Could you explain this as I don't how a wire that has been disconnected from an AC supply can hold a charge.

Depends how much wire there is. It's all about capacitance and inductance. A live conductor can induce a current in a parallel disconnected conductor. That's why you need to not only disconnect something, but also earth it.

 

[LBMPSB]

Depends how much wire there is. It's all about capacitance and inductance. A live conductor can induce a current in a parallel disconnected conductor. That's why you need to not only disconnect something, but also earth it.

That is absolutely correct. Anyone going to work on disconnected OHL will first have had it earthed out by a competent person.

 

[swt_passenger]

Wouldn’t reducing the length of third rail sections stuff the regenerative braking? As I understood the way it was set up requires another train to be in the same section to make use of the energy?

I also pointed this out earlier, that you’d need an additional high current insulated circuit separate to but paralleling the hypothetically switched third rail, to maintain the normal traction current distribution which as we know is all interconnected over a very wide area, and of course you’d need the same to accept regeneration.

Replies suggested that it would be ok to run all the necessary parallel high current cable routes in addition to the existing system. That plus high current switchgear every few hundred metres, and a presumed necessity to have up and down and multiple lines in four track areas separately switched just leads to vastly more expensive hardware, hundreds of extra lineside equipment buildings etc etc. This is why I think it’s theoretical only and not affordable in the real world system.

 

[yorksrob]

As I said, the relevant law is the Health and Safety at Work Act 1974.

The specific regulations are the Electricity at Work Regulations, which explain how the law should be applied in relation to electrical works. These date from 1989 but came into force in 1990. I linked to them above, and I recommend you read them, they are actually quite interesting.

Well, it's no use people hiding behind a law from 1974, if the problem is caused by regulations that came into place in 1990.

The railway's electrification programme is being held back by regulations from 1990, not a law from 1974.

Regulations should be a lot easier to amend than a law.

These seem like excuses thrown about by people determined to hold back the electrification of the remainder of the Southern Region.

 

[Dr Hoo]

Well, it's no use people hiding behind a law from 1974, if the problem is caused by regulations that came into place in 1990.

The railway's electrification programme is being held back by regulations from 1990, not a law from 1974.

Regulations should be a lot easier to amend than a law.

These seem like excuses thrown about by people determined to hold back the electrification of the remainder of the Southern Region.

[Slight oversimplification, but seems to be needed.]

The Health & Safety at Work Act of 1974 (developed under the Heath administration) clearly established the principle that risks to safety should be "as low as reasonably practicable" (ALARP).

Obviously there are many types of risk in various spheres of work but the question of electrical safety across all industries was codified in the Electricity at Work Regulations of 1989.

The basic expectation was that all conductors carrying a lethal voltage should either be (a) properly insulated or, if not (b) out of reach.

Obviously most existing railway third (and fourth) rails were going to find it hard to comply with this. There was thus a 'carve out' for them to avoid such electrification effectively becoming 'illegal' overnight. (There were also other industry-specific provisions in relation to mining, which presented some of its own problems.) This carve-out might be thought of as 'grandfather rights', not that I like that colloquial term.

None of this detracted from the fact that any new work would clearly still have to be able to demonstrate that its risks were ALARP under the 1974 legislation. You may be aware that over a very long period of time, dating back to the Board of Trade, new railway works have to be 'approved' or 'permissioned' by safety authorities.

It is hardly to be expected that the 'grandchildren', 50 years later, can say, "Well, granddad got away with this in 1973 so I should be able to do exactly the same".

 

[yorksrob]

[Slight oversimplification, but seems to be needed.]

The Health & Safety at Work Act of 1974 (developed under the Heath administration) clearly established the principle that risks to safety should be "as low as reasonably practicable" (ALARP).

Obviously there are many types of risk in various spheres of work but the question of electrical safety across all industries was codified in the Electricity at Work Regulations of 1989.

The basic expectation was that all conductors carrying a lethal voltage should either be (a) properly insulated or, if not (b) out of reach.

Obviously most existing railway third (and fourth) rails were going to find it hard to comply with this. There was thus a 'carve out' for them to avoid such electrification effectively becoming 'illegal' overnight. (There were also other industry-specific provisions in relation to mining, which presented some of its own problems.) This carve-out might be thought of as 'grandfather rights', not that I like that colloquial term.

None of this detracted from the fact that any new work would clearly still have to be able to demonstrate that its risks were ALARP under the 1974 legislation. You may be aware that over a very long period of time, dating back to the Board of Trade, new railway works have to be 'approved' or 'permissioned' by safety authorities.

It is hardly to be expected that the 'grandchildren', 50 years later, can say, "Well, granddad got away with this in 1973 so I should be able to do exactly the same".

This is all very interesting, but it is absolutely no justification for not allowing the remaining infill electrifications on the Southern region.

 

[Nicholas Lewis]

Its pretty remarkable that with c1300 route miles of exposed conductor rail that the level of incidents are so low and by and large today are due to third party incursion rather than staff or passengers. This should provide a decent body of evidence to support the extensions which given they are far more rural in nature would represent a much lower risk. Stations remain the biggest risk exposure and more effort could be made to provide comprehensive protection boarding such that you see in many depots now. Yes it doesn't fully remove the exposed conductor risk but gives increased protection against trips/falls. Another alternative would be switchable sections but that comes with a load more assets costs and potential reliability issues. Another viable alternative would be BEMUs so that the con rail is removed in higher risk areas.

 

[may032]

Given the climate crisis, our climate commitments, and how antiquated/unacceptable diesel traction will be in a few years time (if not already), we need to electrify ASAP.

And given how we can’t deploy 25kV quickly or affordably, the only realistic option is 3rd rail / discontinuous 25kV / BEMU. It has to be made as safe as possible but to my mind it could be a useful option.

 

[Bantamzen]

Given the climate crisis, our climate commitments, and how antiquated/unacceptable diesel traction will be in a few years time (if not already), we need to electrify ASAP.

And given how we can’t deploy 25kV quickly or affordably, the only realistic option is 3rd rail / discontinuous 25kV / BEMU. It has to be made as safe as possible but to my mind it could be a useful option.

Firstly you can expect DMUs to be around for a fair while yet, new ones are still being delivered and brought into service so they will be around for at least another 20-30 years minimum. Secondly we could deliver OHLE a lot more cost effectively if we wished, its certainly possible elsewhere in the world so is not an insurmountable problem. What we don't need is panic bought solutions like throwing down third rail islands in the middle of OHLE networks, that would just be plain daft.

 

[stuu]

It is a bit surprising that this hasn't been suggested by the government as a cunning way to get cheaper electrification. I would be amazed if it has never been brought up by someone in a meeting at the DfT or wherever. The fact that it hasn't would suggest to me that there are some pretty solid arguments against it, as have been discussed in this and many many other threads ad nauseum

 

[Backroom_boy]

This thread has got me wondering what the most recent/last third rail electrification scheme was (excluding small scale projects like the new Feltham depot, sidings or Brading loop etc). Would it be the Redhill to Tonbridge electrification of the ‘90s?

If we're including 4th rail, then Northern Line extension to Battersea. How can LUL get their projects through? Is it because they are a combined 'total railway' organisation whereas on the mainline the safety case is split between NR and different TOCs?

 

[NSEWonderer]

If we're including 4th rail, then Northern Line extension to Battersea. How can LUL get their projects through? Is it because they are a combined 'total railway' organisation whereas on the mainline the safety case is split between NR and different TOCs?

Also most LU routes do not have allowances for alternative means of power like overheads which even if possible could end up becoming a danger at the heights trains like the Bakerloo, Nothern, VIctoria etc are at.

 

[zwk500]

It is a bit surprising that this hasn't been suggested by the government as a cunning way to get cheaper electrification. I would be amazed if it has never been brought up by someone in a meeting at the DfT or wherever.

It has. A lot. From extending existing to being a way of avoiding visual impact - it was mentioned as an option for the Maidenhead bridge when crossrail was examined at government committees, as well as Uckfield regularly cropping up from MPs. The RSSB also did a comprehensive review of the safety case for third rail and published clear guidance for what would be needed to make third rail safe enough to comply with legislation.

As has been mentioned by others - creating third rail islands in otherwise OLE territory really doesn't make sense as you've then got all the training, dual systems, transition zones, etc, other than self-contained metros like Merseyrail. But even the T&W Metro went on 1.5kv OLE.
I don't support a 'not one inch more' approach but I also don't see the justification for full infill with rapidly maturing battery technology. If anything, batteries may allow a judicious pruning of the third rail network (and even less disruptive conversion if you have OLE at one end).

 

[Bald Rick]

If we're including 4th rail, then Northern Line extension to Battersea. How can LUL get their projects through? Is it because they are a combined 'total railway' organisation whereas on the mainline the safety case is split between NR and different TOCs?

It comes down to what is ‘Reasonably Practical’, the safety risks concerned and the mitigations that go with it.

For recent LU extensions, they will have demonstrated that it is not reasonably practical to retrofit the existing line concerned with a different system. Also the risk of trespass is much reduced compared to the national network, the power is discharged when the system is not running, and staff are rarely on the track (outside depots) with the power on.

The simple fact of the matter in Southern DC territory is that even if a safety case could be made to infill the North Downs, Uckfield and Marshlink lines, there isn’t a business case to do so as the traffic is too light.

 

[WAO]

It comes down to what is ‘Reasonably Practical’, the safety risks concerned and the mitigations that go with it.

For recent LU extensions, they will have demonstrated that it is not reasonably practical to retrofit the existing line concerned with a different system. Also the risk of trespass is much reduced compared to the national network, the power is discharged when the system is not running, and staff are rarely on the track (outside depots) with the power on.

The simple fact of the matter in Southern DC territory is that even if a safety case could be made to infill the North Downs, Uckfield and Marshlink lines, there isn’t a business case to do so as the traffic is too light.

I think that you have answered your own objection in adducing the "reasonably practical" concept. LUL has in fact the majority of its route miles on the surface, not in tunnel.

Business cases can come and go depending on the value placed on the gains a project is said to yield, such as carbon saving etc. The original electrification RUS (2009) placed maximum emphasis on international links, which the North Downs feeder to LGW certainly is.

The Electricity at Work Regulations were improperly extended to cover the Railway (specifically exempted previously) without technical investigation. It is not legislation that makes for safety but scientific and engineering calculations and judgement, which had previously and properly assessed both 3rd rail and OLE systems as adequately safe. Of course improvements in technology since have enabled the margins of safety to be increased but they do not invalidate previous determinations.

A bureaucratic, lawyer based approach to safety codes, not based on engineering science makes for less safety not more.

WAO

 

[Bald Rick]

LUL has in fact the majority of its route miles on the surface, not in tunnel.

But recent extensions have almost exclusively been in tunnel, or in the case of Canning Town to Stratford, heavily segregated.

 

[Nicholas Lewis]

But recent extensions have almost exclusively been in tunnel, or in the case of Canning Town to Stratford, heavily segregated.

Still doesn't prevent incursion at stations which is where most NR trespass incidents happen that result in contact with the third rail although i see your point that the running sections have significantly more difficult barriers to access. Mind you NR isn't shy about installing palisade fencing in known areas of vandal and trespass although would considerable add to the cost for Uckfield and suspect lead to a load of whinging that its an eyesore. Be really interesting to see what LULs safety case was predicated on for the Stratford extension.

 

[eldomtom2]

The simple fact of the matter in Southern DC territory is that even if a safety case could be made to infill the North Downs, Uckfield and Marshlink lines, there isn’t a business case to do so as the traffic is too light.

I've never heard it claimed before that there isn't a business case for not electrifying the Uckfield line. Also, are you categorically stating that a battery service is suitable for all lines?

 

[zwk500]

I've never heard it claimed before that there isn't a business case for not electrifying the Uckfield line.

It gets studied about every 10 years or so. They haven't found one yet!

 

[TSG]

The Electricity at Work Regulations were improperly extended to cover the Railway (specifically exempted previously) without technical investigation.

The HSE can, and has, granted an exemption from certain parts if the regulations. When they granted it, and should they choose to change the scope of it, I would be confident that its done on the basis of evidence, including technical investigation.

It is not legislation that makes for safety but scientific and engineering calculations and judgement

Actually safety is underpinned by legislation. If it wasn't you would be left with only good intentions balanced against, for example, a director's legal duty to create value for the shareholders. Prescriptive laws generally allow you to derogate provided you demonstrate that what you are doing is at least as good.

which had previously and properly assessed both 3rd rail and OLE systems as adequately safe. Of course improvements in technology since have enabled the margins of safety to be increased but they do not invalidate previous determinations.

ORR policy appears to have been based on a Fatality Weighted Injuries score about 8 times worse than OLE on half the network size. Do you want them to base their policy on evidence or not?