Should third rail be considered again for future electrification projects?

[Gareth]

I can very well imagine it would but that doesn't necessarily provide a rebuttal to anything I just said.

 

[SouthEastBuses]

Yes, I think third rail should be used on infill schemes in the South East and as extensions of the Merseyrail. Makes no sense to use 25 kv AC (looking at you, North Downs Line) where you have parts of the line already electrified using third rail

 

[Sm5]

If you introduce a live exposed conductor rail to a place that didn't already have one you've introduced a new risk, which will have a different potential danger compared to track that's had the same risk profile for decades.

Happened on every third rail at sometime. If it went 25kv whats the difference ?

I grew up round Bury, I cant count how many times I bunked BQ on a sunday as a kid. I even had a wooden earth pole from a unit at home at some point.
i’m still alive.

The difference today is safety is much more conscious, no fencing, no cctv, no sensors, even the third rails wooden boards were always rotten in those days.

What happened to those Yellow plastic third rail protectors that replaced wooden boards a few decades back, they seemed a good idea but not around as much today.

 

[Snow1964]

If you introduce a live exposed conductor rail to a place that didn't already have one you've introduced a new risk, which will have a different potential danger compared to track that's had the same risk profile for decades.

Actually the risk profile depends on other things such as frequency of trains, not been a constant for decades.

You cannot really take adding a third rail as an unacceptable risk when there is plenty of it around already that there is no policy of getting it all removed. There is something known as managing risk which is done when can’t eliminate it.

 

[XAM2175]

Maybe but that would've been the case when the existing third rail was put in.

Yes. The 'problem' now is that the industry has changed its opinion on the acceptability of that risk.

If it went 25kv whats the difference ?

Roughly 4.7 metres vertically.

I grew up round Bury, I cant count how many times I bunked BQ on a sunday as a kid. I even had a wooden earth pole from a unit at home at some point.
i’m still alive.

Congratulations.

Actually the risk profile depends on other things such as frequency of trains, not been a constant for decades.

You cannot really take adding a third rail as an unacceptable risk when there is plenty of it around already that there is no policy of getting it all removed.

Yes, the risk profile does also depend on other things such as the frequency of trains. Or are you trying to argue that the presence or absence of conductor rail is irrelevant to the risk?

 

[supervc-10]

Personally I'd think that infill is a bit of a no brainer- especially smaller projects like Marshlink, or ones like Uckfield which also removes diesel from a polluted city centre.

But new major extensions away from 3rd rail land? Nope. Salisbury is a possibility, but as so many services continue to Exeter it might be better as 25kV (although it would definitely benefit from bi-modes in its current state).

Anything isolated away from existing electrification would probably be better off with 750v overhead as used on tram networks rather than 750v 3rd rail as a way to minimise risks and costs, although I do wonder if just building to 25kV would be better from the beginning.

I do wonder though if it would be possible to have a train shoe which can work with both top and bottom contact 3rd rails. I don't think existing units could, due to the shoe beams and the outside frames, but an inside frame bogie with a 2 sided shoe might be possible. But I dropped out of my engineering degree... so maybe there's a very good reason why it can't be done!

 

[JohnElliott]

Studies dont always reach the sensible conclusion.. I recall a study on a proposed mainline steam locomotive new build proposing the only safe option for wheels was solid not spoked..

Was the author's name Bulleid?

 

[Sm5]

Was the author's name Bulleid?

he was a visionary, afterall he proposed burning turf, instead of coal.

 

[Gareth]

Personally I'd think that infill is a bit of a no brainer- especially smaller projects like Marshlink, or ones like Uckfield which also removes diesel from a polluted city centre.

But new major extensions away from 3rd rail land? Nope. Salisbury is a possibility, but as so many services continue to Exeter it might be better as 25kV (although it would definitely benefit from bi-modes in its current state).

Anything isolated away from existing electrification would probably be better off with 750v overhead as used on tram networks rather than 750v 3rd rail as a way to minimise risks and costs, although I do wonder if just building to 25kV would be better from the beginning.

I do wonder though if it would be possible to have a train shoe which can work with both top and bottom contact 3rd rails. I don't think existing units could, due to the shoe beams and the outside frames, but an inside frame bogie with a 2 sided shoe might be possible. But I dropped out of my engineering degree... so maybe there's a very good reason why it can't be done!

I don't agree with Salisbury. That line should be 25kv AC OHLE, with trains that can run on both systems. Long term, other parts of the South West network could probably do with conversion too. It has quite long distances that South Central & South East don't really have.

750/1500v DC, regardless of whether it's a conductor rail or wire, has some performance advantages on local systems but not outside of that. Unless some new metro systems are built in our large cities, I don't see any new third rail bar some modest extensions of existing systems.

As for a third rail shoe that can do both top and bottom contact, I'm sure I read of its existence somewhere. Not sure how it works exactly. I may even have imagined it.

EDIT: didn't imagine it. Apparently, some Metro-North units over in New York have them...

Third rail - Wikipedia

en.m.wikipedia.org

 

[O L Leigh]

The 'problem' now is that the industry has changed its opinion on the acceptability of that risk.

Well it's more that industry has had to catch up with the increasingly litigious nature of society. Gone are the days when you could say "serves you right" if someone came to harm due to their own misadventure.

As for safety, studies reaching conclusion that says its dangerous, despite being surrounded by thousands of miles of track safely operating for nearly 100 years, and likely to continue so for another hundred sounds more academic than substance.

Er, not really. The ORR's current presumption against further CRE schemes is based not on academic studies but on figures from the RSSB concerning fatalities and weighted injuries due to the different electrification systems. At the risk of going over ground already well-trod around 18 months ago, the ORR's DC Electrification Policy Statement contains the following statement.

ORR’s most significant concern in regard to legacy third rail systems (the “legacy network”) is the running of bare, live conductors through publicly accessible areas. These conductors are not insulated or shrouded. The legacy network does not allow quick, secure isolations, and exposes individuals to a range of risks whilst carrying out isolations. Due to the difficulty in obtaining isolations on the legacy network, a lot of work tends to be carried out on or near the live conductor, further undermining safety and weakening compliance with the applicable legislation. This is not an abstract or theoretical risk: the harm done to both workers and members of the public by the legacy network occurs significantly more frequently than on the overhead AC network.

They then give reference to a footnote which says...

This is borne out by data from RSSB’s safety risk model – despite the legacy network being only half the size of the AC network (4400km compared to 8200km), it contributes almost eight times more (in terms of fatalities and weighted injuries per year) to overall risks on the railway. See FWI comparative data for OLE / conductor rail / non-electrified: Network Rail Electrical Power Asset Policy December 2012 (Table 2.1, page 52).

When we finally got to see the information contained within Table 2.1 it showed that the average annual risk to an adult trespasser was 10 times greater from CRE than from OLE. You can see the table for yourself attached to this post.

 

[tomuk]

Well it's more that industry has had to catch up with the increasingly litigious nature of society. Gone are the days when you could say "serves you right" if someone came to harm due to their own misadventure.



Er, not really. The ORR's current presumption against further CRE schemes is based not on academic studies but on figures from the RSSB concerning fatalities and weighted injuries due to the different electrification systems. At the risk of going over ground already well-trod around 18 months ago, the ORR's DC Electrification Policy Statement contains the following statement.



They then give reference to a footnote which says...



When we finally got to see the information contained within Table 2.1 it showed that the average annual risk to an adult trespasser was 10 times greater from CRE than from OLE. You can see the table for yourself attached to this post.

What you have posted my well be true and 3rd rail is 10 times more dangerous than OLE but OLE is very safe and the number of incidents is very small so even at 10x worse the number of 3rd rail incidents is still small.

I see no problem with small extensions/infills to 3rd rail. Marshlink, Uckfield, North Downs, Preston, Wigan, Wrexham. Salisbury-Basingstoke/Southampton is probably to large.

Suitable measures to reduce risk further such as better fencing, removal of foot crossings, 3rd rail boards/shrouds could be taken. Auto switching on/off power on train approach or monitoring for trespass through CCTV or other means are too complicated.

 

[O L Leigh]

I posted that to reassure @Sm5 that the reluctance of the ORR was based on real figures rather than some piece of academic work that he would appear to be mistrustful of.

Yes I agree that it still represents a small total number of incidents, but it still represents a greater risk. It is for this reason that the RSSB started a consultation last year to try and work out whether or not CRE can still be used for electrification schemes (I linked to the discussion about it back in post #3). What comes out of this process still remains to be seen. However, as I mentioned, these measures of risk are clearly a large part of what informs the ORR's presumption against CRE.

 

[tomuk]

I posted that to reassure @Sm5 that the reluctance of the ORR was based on real figures rather than some piece of academic work that he would appear to be mistrustful of.

Yes I agree that it still represents a small total number of incidents, but it still represents a greater risk. It is for this reason that the RSSB started a consultation last year to try and work out whether or not CRE can still be used for electrification schemes (I linked to the discussion about it back in post #3). What comes out of this process still remains to be seen. However, as I mentioned, these measures of risk are clearly a large part of what informs the ORR's presumption against CRE.

I'm aware of the consultation and hopefully the ORR will be told to remove it's presumption. Maybe a statistical analysis could be carried out to see the risk of fatalities and injuries is higher due to the current service, eg diesel pollution, increased car journeys due to poor service, injuries during more frequent maintenance.

 

[O L Leigh]

Maybe a statistical analysis could be carried out to see the risk of fatalities and injuries is higher due to the current service, eg diesel pollution, increased car journeys due to poor service, injuries during more frequent maintenance.

I don't think that would be helpful, as it would assume that the risks due to road travel are a direct consequence of failure to electrify when that clearly isn't the case. Without some meaningful uplift in the service I don't think that you should expect any correspondingly measurable modal shift, and such an uplift could come even without electrification.

It may be that some of the mitigation ideas you had in your previous post will come to pass, although this will mean an increase in the cost of a DC electrification scheme. We shall have to wait and see. I don't think that RSSB has the authority to tell ORR anything about it's stance. It will depend on ORR being convinced based on whatever mitigations the consultation comes up with.

 

[Snow1964]

Well it's more that industry has had to catch up with the increasingly litigious nature of society. Gone are the days when you could say "serves you right" if someone came to harm due to their own misadventure

When we finally got to see the information contained within Table 2.1 it showed that the average annual risk to an adult trespasser was 10 times greater from CRE than from OLE. You can see the table for yourself attached to this post.

This is where lack of joined up thinking often fails

Use of trespass figures (which are from another area, or include other areas), then use them to appraise a rule for a line where there may never have been any incidents of trespass.

So get a theoretical risk number which is based on similar (but not the correct) facts.

It would be more useful if someone said how many incidents on similar bits of track, much more useful if you base data on say Wareham-Weymouth than use data including busy urban Clapham Junction area.

I choose Wareham-Weymouth simply because the line (mainly rural with couple of big towns) and train frequency is similar, and have got 24 years of data since it was electrified. And if want to have a look there is also about 20 years of diesel operation before that for a comparison.

Perfect data for current diesel operation vs proposed electric operation for a relevant risk analysis.

 

[O L Leigh]

This is where lack of joined up thinking often fails

Use of trespass figures (which are from another area, or include other areas), then use them to appraise a rule for a line where there may never have been any incidents of trespass.

So get a theoretical risk number which is based on similar (but not the correct) facts.

It would be more useful if someone said how many incidents on similar bits of track, much more useful if you base data on say Wareham-Weymouth than use data including busy urban Clapham Junction area.

I choose Wareham-Weymouth simply because the line (mainly rural with couple of big towns) and train frequency is similar, and have got 24 years of data since it was electrified. And if want to have a look there is also about 20 years of diesel operation before that for a comparison.

Perfect data for current diesel operation vs proposed electric operation for a relevant risk analysis.

That is a slight misrepresentation of what the report shows. It is a presentation of the risks associated directly with different electrification systems based on actual figures of injury or death to workforce, passengers and trespassers across the entire network rather than simply a collation of the number of trespass incidents. In the case of both systems this will include urban as well as rural areas, some of which may be a very good parallel to certain routes, such as Marshlink or the North Downs.

At the risk of inducing topic drift, I would say on the basis of 16 years of staring out of the front of a train (I really must take a break) that it is a myth that there is more trespass in big cities than in rural areas. Naturally the type of trespasser varies depending on where you are (the rural variety is more likely to be carrying a gun), but I would say that the split between urban and rural is about equal. The issue is that it is often much easier to access the network in rural areas than it is in urban ones, because there are far more crossings out in the countryside and the fencing tends to be easier to penetrate.

Comparing the risks posed by diesel compared to proposed electric operation is meaningless, as the fact that people are getting harmed by electrification shows that it is inherently riskier than not having electrification. The point is that if the decision is going to be taken to electrify the next decision will have to be between CRE and OLE, and that's going to be where the measure of risk is going to enter the discussion. It may well be that CRE is still selected on the proviso that certain mitigation measures are taken that may not be required if OLE is chosen (e.g. better fencing, closing crossings and erecting footbridges), and if that's the decision then I'm fine with it. However, the cost of these mitigations will have to be included in the total cost of the scheme.

 

[Tio Terry]

The Railways and Other Guided Transport Systems (Safety) Regulations 2006 as amended (October 2021) mandates the use of The Common Safety Method for Risk Evaluation and Assessment for changes to railway infrastructure. This would need to be applied for each project on a project specific basis, not on a general national basis. So rural risk assessments are likely to differ from suburban ones. Risks would need to be identified on a project basis along with mitigations for the type of electrification specified, or, if none is specified, then for both CRE and OLE if any electrification at all is to be used.

Risk identification workshops need to have the right people in attendance, with the right competencies and skills.

It would be very interesting to read the Risk Identification Reports and, of course, the proposed mitigations!

 

[gordonthemoron]

Should new tram lines be built using the same principle as Newcastle NSW, where OHLE is not used, but instead the battery powered trams charge up at each stop via the pantograph?

 

[O L Leigh]

The Railways and Other Guided Transport Systems (Safety) Regulations 2006 as amended (October 2021) mandates the use of The Common Safety Method for Risk Evaluation and Assessment for changes to railway infrastructure. This would need to be applied for each project on a project specific basis, not on a general national basis. So rural risk assessments are likely to differ from suburban ones. Risks would need to be identified on a project basis along with mitigations for the type of electrification specified, or, if none is specified, then for both CRE and OLE if any electrification at all is to be used.

Risk identification workshops need to have the right people in attendance, with the right competencies and skills.

It would be very interesting to read the Risk Identification Reports and, of course, the proposed mitigations!

Yes of course. And the RSSB report I linked to is clearly not that. However, it does still have a role to play in the discussions given that it informs the ORR's position on electrification.

I would be interested to know how you assess the risk of a specific electrification project when the absence of electrification across that route represents an equivalent absence of specific local data. Presumably a measure of risk has to be applied which comes from somewhere.

 

[Bletchleyite]

Should new tram lines be built using the same principle as Newcastle NSW, where OHLE is not used, but instead the battery powered trams charge up at each stop via the pantograph?

There are upsides and downsides of doing that. The more likely way is that you'd do what they are doing in Birmingham, with trams able to charge up out of the city centre, removing the need for wires there.

If you did want to OHLE Merseyrail, this would probably be the only practical way to do it, certainly for the Northern Line where the Link tunnels have quite tight clearance.

 

[mr_jrt]

Thinking about Merseyrail - given the only real problem is the tunneled core, would a simple solution not be to have AC units with secondary batteries, and have the tunneled section operated on said batteries that are recharged on the long sections over the rest of the system? That gets rid of one of those legacy 3rd rail islands.

 

[Bletchleyite]

Thinking about Merseyrail - given the only real problem is the tunneled core, would a simple solution not be to have AC units with secondary batteries, and have the tunneled section operated on said batteries that are recharged on the long sections over the rest of the system? That gets rid of one of those legacy 3rd rail islands.

You could do that, but I'm not sure why Merseyrail is a problem as a third rail island as it is self contained and intended to be that way. With regard to safety it could fairly easily be swapped to 750VDC bottom contact.

Merseyrail is no more of an issue being third rail than London Underground is. And indeed it's less of an issue than Metrolink being DC overhead which can't mix with AC overhead.

 

[Tio Terry]

Yes of course. And the RSSB report I linked to is clearly not that. However, it does still have a role to play in the discussions given that it informs the ORR's position on electrification.

I would be interested to know how you assess the risk of a specific electrification project when the absence of electrification across that route represents an equivalent absence of specific local data. Presumably a measure of risk has to be applied which comes from somewhere.

If you are applying CSM correctly you would not consider the ORR's position as that would influence any risk assessment.

As an example. Network Rails Standards state that for a linespeed above 100MPH the safe lineside clearance for staff is 2M. But if you are correctly applying CSM you would disregard this and risk access what the safe standing distance actually is for that particular project. So just because the ORR have stated their views you would not automatically accept them.

 

[Grumpy]

Before we fall too far down the rabbit hole yet again, this piece of work needs to be completed first.

The work was due to be completed this month.

 

[O L Leigh]

If you are applying CSM correctly you would not consider the ORR's position as that would influence any risk assessment.

As an example. Network Rails Standards state that for a linespeed above 100MPH the safe lineside clearance for staff is 2M. But if you are correctly applying CSM you would disregard this and risk access what the safe standing distance actually is for that particular project. So just because the ORR have stated their views you would not automatically accept them.

Right. But my question was more to do with where the measurement of risk comes from when assessing a new project. If you disregard the ORR position and the Rule Book requirements, how do you assess the risk? Presumably there has to be a metric against which you make your assessment.

 

[javelin]

I'm not seeing the need, since the problem areas that seem to be talked about are short extensions and infill. The Merseyrail is planned to be extended with battery-capable units. The remaining unelectrified parts of the southeast network are relatively short infill. It seems battery, with perhaps some third rail charging at stations, should eventually be able to cope with these. So is there really a huge need for large stretches of new DC?

 

[Gareth]

You could do that, but I'm not sure why Merseyrail is a problem as a third rail island as it is self contained and intended to be that way. With regard to safety it could fairly easily be swapped to 750VDC bottom contact.

How would you go about converting Merseyrail to bottom contact? Presumably, shoes that can do both? Essentially, any new extensions such as Skem, I suppose, could then be bottom contact and the legacy system replaced as and when renewal comes up.

Btw, what about DC overhead? Would the clearance issues be less stringent than with 25kv AC? It could be installed whilst the existing third rail was still operational. I've often wondered if 1500kv DC would be more efficient for a suburban metro like Merseyrail, akin to what the Tyne & Wear Metro has.

I also think it doesn't do the Merseyrail network justice to refer to it as a third rail "island". It makes it sound like a small, idiosyncratic nonstandard line surrounded by a sea of OHLE, rather than a significant operation in its own right. Merseyrail is no more a third rail island than London Underground is a fourth rail island.

 

[mr_jrt]

Merseyrail has apparently ~75 miles of 3rd rail, only 6.5 miles of which are underground. London Underground has about 250 of 4th rail, heaven knows how much of which is underground, but it's a lot more than 6.5 miles. Merseyrail also uses standard-sized NR trains, London Underground does not, for the most part. If we can do away with any ground-level electrified rails, we probably should. It's a lot more feasible to do that in Liverpool than London. Merseyrail is also getting battery trains, which make things more feasible - London Underground does not have these.

 

[Tio Terry]

Right. But my question was more to do with where the measurement of risk comes from when assessing a new project. If you disregard the ORR position and the Rule Book requirements, how do you assess the risk? Presumably there has to be a metric against which you make your assessment.

Rather than me trying to explain the process it's probably better if you read the guidance notes contained within the following:-

Common Safety Methods (CSMs)

The Common Safety Methods (CSMs) describe how the safety levels, the achievement of safety targets and compliance with other safety requirements should be fulfilled.

www.era.europa.eu

 

[Wolfie]

You could do that, but I'm not sure why Merseyrail is a problem as a third rail island as it is self contained and intended to be that way. With regard to safety it could fairly easily be swapped to 750VDC bottom contact.

Merseyrail is no more of an issue being third rail than London Underground is. And indeed it's less of an issue than Metrolink being DC overhead which can't mix with AC overhead.

Pedantically, London Underground is not and never has been third rail.