Third rail - becoming a better option for electrification?

[HSTEd]

Well no, because the problem of mass car use is not only about pollution and the carbon footprint, but congestion. Quite simply, our roads, particularly in cities, were not designed for the volume of traffic we have, let alone any increase.

Without the environmentalist angle, it will be very difficult to make the case for mass subsidies to the railway industry (as it exists now) on that basis.

If you engineer a railway with the mission to mitigate congestion in an efficient manner it would look very different to the railway we have now.

 

[dgl]

A big issue with 3rd rail electrification is the current and power loss issues due to the lower voltages required, 1MW @ 750V is 1,333A but only 40A @ 25kV and the higher the current the higher the heating losses in the transmission system (which is just wasted power). You'd need a decent anount more power available if you switched to 3rd rail at 750V and none of that extra power would be doing anything useful.

 

[Lurcheroo]

A crash or derailment will almost certainly trip out the power supply anyway. How many trespassers get electrocuted each year? Can't be many or the media would be jumping up and down about it. My son is seven. He understands that messing about on the track is a bad idea. And he's someone that absolutely loves to push boundaries.

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.

 

[yorksrob]

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.

There is absolutely no logical reason not to allow sensible extensions and infill to the existing third rail networks.

Those who say there is are merely holding the railway back and pushing people onto our far more dangerous roads.

 

[HSTEd]

Even without fancy segmentation of the system, a lot of lines would allow the third rail to be dead for a substantial fraction of the day.

Taking the example of Gillingham on the West of England line, there is a five hour gap in service overnight during the week. It's more like seven and a half hours on sundays.

When you add up all the gaps in service with earlier stops on weekends and public holidays, you probably have the rail dead a quarter of the time.
That would have a significant impact on risk to tresspassers and trackside staff.

 

[Bikeman78]

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.

If any part of the derailed train comes to rest in contact with the third rail, or it gets shunted into the running rails, it will trip out. 13,500 trespass incidents and how many fatalities? Doesn't that rather prove my point that is the risk is tiny.

 

[Bald Rick]

How many trespassers get electrocuted each year? Can't be many or the media would be jumping up and down about it. My son is seven. He understands that messing about on the track is a bad idea. And he's someone that absolutely loves to push boundaries.

Quite a few. I havent got precise numbers to hand but can think of 3 or 4 examples in the past year.

 

[Nicholas Lewis]

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

Its below 1000V so nominally low voltage under international standards despite the risk!! 25kV is nominally medium voltage high voltage kicks in at 36kV.

 

[Lurcheroo]

There is absolutely no logical reason not to allow sensible extensions and infill to the existing third rail networks.

Not saying that at all. I agree that small senesible extensions should be permitted.

If any part of the derailed train comes to rest in contact with the third rail, or it gets shunted into the running rails, it will trip out. 13,500 trespass incidents and how many fatalities? Doesn't that rather prove my point that is the risk is tiny.

So if it happens to derail on the correct side a 50/50 then that a short is provided to trip the system, even at a 50/50 that makes it a 25% chance. hardly reliable. Besides, as I have told you, 3rd rail is seriously dangerous kit.

However, this thread is entitled :

"Third rail - becoming a better option for electrification?"​

So, the danger that 3rd rail poses is a serious consideration and why on earth would anybody, let alone any regulatory body that would be held to account, want to install it for almost no serious benefit. its pretty easy to use that great search engine called google and find news articles where people have been killed accidentally due to 3rd rails. MArch 2023 in Weymouth just to start.

 

[trebor79]

A big issue with 3rd rail electrification is the current and power loss issues due to the lower voltages required, 1MW @ 750V is 1,333A but only 40A @ 25kV and the higher the current the higher the heating losses in the transmission system (which is just wasted power). You'd need a decent anount more power available if you switched to 3rd rail at 750V and none of that extra power would be doing anything useful.

Third rail is a much larger cross section than overhead line, which will mitigate this effect.

 

[Elecman]

Third rail is a much larger cross section than overhead line, which will mitigate this effect.

Bigger cross sectional area yes!! but made of a far less conductive material than copper so far higher resistive losses than the copper ole conductor

 

[Pat31]

Simple answer is no. Power loss and lower speeds limit it's usefulness on a modern railway.

 

[Dr Hoo]

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?

Tonbridge-Redhill (and other Channel Tunnel traffic related works) was put in hand as part of the follow-up to the Treaty of Canterbury in 1986, so was already 'in hand' by the time that the Electricity at Work Act 1989 came into effect on 1 April 1990, even though it wasn't completed until afterwards.

It will either be that or the last of the Merseyrail projects of the 1990s, Chester was 1993 and Ellesmere Port was 1994.

This is if you assume the ~mile of new rail installed as part of the East London Line project is not significant.

The Chester and Ellesmere Port extensions had also been announced in 1989, before the Electricity at Work Act came into effect (although the formal financial go-ahead was actually only snuck out just before Christmas 1990).

A crash or derailment will almost certainly trip out the power supply anyway. How many trespassers get electrocuted each year? Can't be many or the media would be jumping up and down about it. My son is seven. He understands that messing about on the track is a bad idea. And he's someone that absolutely loves to push boundaries.

I know that I've mentioned my own experience on here before but this sort of stuff doesn't actually 'get real' until you personally have to attend the Inquest into the death of a nine-year-old boy who got onto a third rail line through a hole in the fence made by rail staff to create a shortcut to a depot.

And then, within few months have a very experienced Electric Track Maintenance (ETM) colleague electrocuted whilst working right next to me because of an appalling set of procedural lapses.

Believe me - third rails can be lethal. They are not 'the future'.

 

[Lurcheroo]

I know that I've mentioned my own experience on here before but this sort of stuff doesn't actually 'get real' until you personally have to attend the Inquest into the death of a nine-year-old boy who got onto a third rail line through a hole in the fence made by rail staff to create a shortcut to a depot.

And then, within few months have a very experienced Electric Track Maintenance (ETM) colleague electrocuted whilst working right next to me because of an appalling set of procedural lapses.

Believe me - third rails can be lethal. They are not 'the future'.

I’m very sorry to hear that.

I see it a lot on here from non-railway staff, the railway is a seriously dangerous place and the industry, as I’m sure you know, is safety first in everything that we do.
And it is us the employees who must adopt that same safety first mindset to make it safe.

I agree 3rd rail is not the future and if 3rd rail was gotten rid of in favour of OLE, subsequently removing that risk, it would only be a good thing in my eyes.

 

[Mike Machin]

Because we don't have evidence of many years of total failure to deliver third rail electrification despite promises to the contrary.

The 25kV programme has failed catastrophically, the third rail programme has not yet done so (as it does not yet exist), so it has a greater chance of not failing.
By about 2018 (Kent RUS from before coronavirus), even Network Rail admitted that third rail was cheaper than 25kV, and 25kV has kept climbing in price since then.


== Doublepost prevention - post automatically merged: 10 Jan 2024 ==



Given current capabilities and budgets, it will be impossible for any government to deliver sufficient 25kV electrification to matter before road transport decarbonisation renders the diesel railway an irrelevance.

Starmer isn't going to pay £4m/stkm+ to electrify to Hull or wherever when he wants that money for the triple lock or Nurse pay rises. Meanwhile, the window of opportunity for the railway to stake its claim to a major role in the post carbon world slips away with every electric car to drive out of a dealership

Exactly! Unfortunately there will need to be strong fiscal restraint on capital expenditure for many years, by which time the electric car will be the norm and diesel-powered railways will, quite rightly, be shunned by the general public.

I have however seen various videos of hydrogen-powered multiple units being tested and operating in continental Europe, so maybe this could be the best way forward?

The heavy plant equipment manufacturer JCB certainly believes that hydrogen is how they will be making their products eco-friendly, so if this proves successful this would probably offer better value to the taxpayer and also offer a better product for the consumer too.

 

[Dr Hoo]

I’m very sorry to hear that.

I see it a lot on here from non-railway staff, the railway is a seriously dangerous place and the industry, as I’m sure you know, is safety first in everything that we do.
And it is us the employees who must adopt that same safety first mindset to make it safe.

I agree 3rd rail is not the future and if 3rd rail was gotten rid of in favour of OLE, subsequently removing that risk, it would only be a good thing in my eyes.

Thank you.

 

[Snow1964]

Isn't 3rd rail more susceptible to issues caused by ice and snow?

Snow, not really, it is either wet snow which isn that much different to drizzle as got wet top surface, or powder snow which blows around more but heavy shoe gear generally sweeps out of the way as it is dry.

If get deep snow or drifts (which weather forecast says might happen next Wednesday) then tend to have more general problems of blocked points etc.

Ice is different matter, it effectively creates a non conducive barrier between the pick up shoe and conductor rail. Frost tends to see arcing. Freezing rain forming deeper ice will usually cause trains to struggle or stop

 

[Lurcheroo]

I have however seen various videos of hydrogen-powered multiple units being tested and operating in continental Europe, so maybe this could be the best way forward?

I haven’t looked into it too extensively but I think I remember seeing that Germany had ditched their hydrogen train programme.

With electric trains, you have regenerative braking and can feed back either to onboard battery’s or the system. This makes electric trains much more efficient.

Storing Compressed hydrogen gas in a tank on a train is also potentially dangerous, much more so than diesel. I have worked on the railway a short time and know several incidents where fuel tanks have been repaired by some sort of debris that a train has hit. Most resulted in just a fuel leak (not great for the environment but not instant death either) I do wonder if it was hydrogen would it cause an explosion.

Lastly, it’s worth mentioning that producing Hydrogen (via electrolysis at least) is very energy intensive, so in my opinion, might as well just have the trains electric if that’s the case.

 

[Mat17]

I have often wondered how safe hydrogen trains are. If it is the elemental gas stored in tanks then yes I'd be uncomfortable travelling on such a vehicle. Hydrogen is very volatile, how would it react in a derailment or crash? I suspect an explosion would be the most likely scenario.

 

[Wolfie]

Not without reform of ORR at any rate.

ORR are applying a logical interpretation of primary legislation. If a "reformed ORR" was to approve more third rail installation the first fatality would inevitably result in litigation citing the previous ruling as primary evidence.

I hardly imagine that senior decision makers would wish to find themselves justifying a measure apparently reducing safety precautions under cross-examination from a KC.

 

[trebor79]

I have however seen various videos of hydrogen-powered multiple units being tested and operating in continental Europe, so maybe this could be the best way forward?

Nope. Way too expensive, and horrific end to end energy efficiency (which just compounds the cost issue).

== Doublepost prevention - post automatically merged: 11 Jan 2024 ==

I have often wondered how safe hydrogen trains are. If it is the elemental gas stored in tanks then yes I'd be uncomfortable travelling on such a vehicle. Hydrogen is very volatile, how would it react in a derailment or crash? I suspect an explosion would be the most likely scenario.

Do you feel uncomfortable travelling in a petrol powered car with a plastic tank full of petrol beneath your bum?
There are many good reasons to not use hydrogen. Safety isn't one of them.

 

[yorksrob]

ORR are applying a logical interpretation of primary legislation. If a "reformed ORR" was to approve more third rail installation the first fatality would inevitably result in litigation citing the previous ruling as primary evidence.

I hardly imagine that senior decision makers would wish to find themselves justifying a measure apparently reduced safety precautions under cross-examination from a KC.

Frankly the legislation should be amended to enable these extensions and infills (although it's hardly surprising that such a lack of consideration was shown in the original bill by Major's circus government).

 

[Wolfie]

Frankly the legislation should be amended to enable these extensions and infills (although it's hardly surprising that such a lack of consideration was shown in the original bill by Major's circus government).

Any such amended legislation could itself be the subject of legal challenge.

 

[LBMPSB]

Okay enough of this Third Rail is better OHL and vice-versa. How about marrying the two together. What I hear you say??

Conductor Beams, are aluminium beams hung from OH supports and have the un-stressed contact wire attached to the base of the beam.The conductor beam is installed laterally in a sinusoidal wave rather than the usual staggering profile used on wired OHL. It is in use, and has been since 2013, in the the Thameslink Core. It was originally developed by Balfour Beaty because of the reduced height in the Thameslink Tunnels and to eliminate the use of the bulky weight system to stress the contact wire. As there is no tension in the system, it reduces the loading that is imposed by the electrification equipment onto the surrounding infrastructure, a problem they had before with the conventional OHL system in the Thameslink Core. Because the contact wire is not under stress, it has an extend life of over 10% over the convential OHL. Conductor beam will not be brought down by a defective pantograph unlike the convential system. I do not know though if there is increased wear on the carbon heads on the pantographs.

I believe there maybe some tunnels around the country that have these fitted, especially in new installations. Maximum speed these are designed for at the moment is 250kph (around 155mph). Furrer + Frey are the major company incvolved with this now and they are redesigning for speeds up to 320kph (nearly 200mph).

There are Aluminium conductor rails that have stainless steel contact surfaces that improve the transmission efficiency on third rail systems. Other options for third rail are encased third rail, such as side contact (Bury -Manchester route years ago), bottom contact (Docklands Light Railway). But all mean changing what is already in place and having compatible traction units or having to convert. Likewise, converting OHL to Third Rail and vice versa has the same issues. It is impossible to switch over from one system to the other with out a very long transition period where both systems exist, and new traction purchased or existing traction converted. Then there is the signalling system and immunising it from stray AC/DC currents.

I suspect both systems will be in existance for evermore unless someone with a huge sum of money is willing to invest and change it, which rules the Government out.

 

[yorksrob]

Any such amended legislation could itself be the subject of legal challenge.

Perhaps that's the best forum for the issue to be decided. At least the courts could consider the disadvantages of diesel islands and non-standard rolling stock against the marginal safety benefit of a marginally smaller third rail network.

It's patently obvious that no such consideration has gone into this situation to date.

 

[Lurcheroo]

Safety isn't one of them

I’m sorry but it absolutely is. Petrol is flammable, compressed Hydrogen is explosive.

As I’ve already mentioned SAFETY IS THE NUMBER 1 PRIORITY ON THE RAILWAY.
It is drummed into us over and over and over, so yes safety IS one of them.

 

[trebor79]

I’m sorry but it absolutely is. Petrol is flammable, compressed Hydrogen is explosive.

As I’ve already mentioned SAFETY IS THE NUMBER 1 PRIORITY ON THE RAILWAY.
It is drummed into us over and over and over, so yes safety IS one of them.

That's nonsense. A tank of hydrogen has no oxygen in it, it can't explode. It can burn when released to the atmosphere but it can't explode.
A tank of petrol has vapour and oxygen in the empty part of the tank and very much can explode, and/or can then get heated in a fire and result in a BLEVE.
What about the LPG vehicles that we've had running around for a couple of decades, or the bottles of LPG slung under restaurant/kitchen coaches on the railway? Way more dangerous fuel than hydrogen.

 

[Lurcheroo]

That's nonsense. A tank of hydrogen has no oxygen in it, it can't explode. It can burn when released to the atmosphere but it can't explode.
A tank of petrol has vapour and oxygen in the empty part of the tank and very much can explode, and/or can then get heated in a fire and result in a BLEVE.
What about the LPG vehicles that we've had running around for a couple of decades, or the bottles of LPG slung under restaurant/kitchen coaches on the railway? Way more dangerous fuel than hydrogen.

Well interestingly OSHA state :
“Hydrogen used in the fuel cells is a very flammable gas and can cause fires and explosions if it is not handled properly. Hydrogen fires are invisible and if a worker believes that there is a hydrogen leak, it should always be presumed that a flame is present”

Seems pretty dangerous to me.

 

[Meerkat]

Even without fancy segmentation of the system, a lot of lines would allow the third rail to be dead for a substantial fraction of the day.

Taking the example of Gillingham on the West of England line, there is a five hour gap in service overnight during the week. It's more like seven and a half hours on sundays.

When you add up all the gaps in service with earlier stops on weekends and public holidays, you probably have the rail dead a quarter of the time.
That would have a significant impact on risk to tresspassers and trackside staff.

Which way would the impact be?
I would think of ticketing and how social media and gossip has told people about doughnutting and refunding tickets and that they wont get caught etc.
Once rumours go round..."yeah mate its fine, they switch the electricity off when there isn't a train"

PS How easy is it to cut 3rd rail and get it in the back of a transit?

 

[zwk500]

Even without fancy segmentation of the system, a lot of lines would allow the third rail to be dead for a substantial fraction of the day.

Taking the example of Gillingham on the West of England line, there is a five hour gap in service overnight during the week. It's more like seven and a half hours on sundays.

When you add up all the gaps in service with earlier stops on weekends and public holidays, you probably have the rail dead a quarter of the time.
That would have a significant impact on risk to tresspassers and trackside staff.

Anywhere likely to be able to switch off for several hours a day is unlikely to be worthwhile electrifying unless there are further external factors.

If you're switching it off for 20 minutes between a half-hourly service every hour that's a lot of potential times for the power not to come back when asked, as well as the risk of residual current unless some programme is put in place to fit automatic earthing equipment. And, as @Meerkat says, you introduce other risks as you complicate the messaging, as well as not saving too much because staff will always be required to treat the line as live until made safe.