Why do we use overhead lines in this country, given we experience windy weather conditions? Would third rail be better?

[WAO]

ISTR that BR supplied its Mark3b OLE system to the Kowloon Canton Railway in Typhoon proof mode in 1982. Doesn't seem to cause problems.

Also the ECML OLE was designed for the lower power needs and for the (higher) maintenance capability of BR in the 1980's, not the privatised system of today. All the pre 2000 systems are/have been modernised for robustness, increased power and better control etc.

Time moves on.

WAO

 

[Trainbike46]

Still not worth the extra costs DC will amount to. The ECML catenary is also sub-standard and was done quite cheaply its not a proper use case here.
The amount of substations required to accommodate a 3rd rail DC electrification between Kings Cross and Peterborough would amount to 72miles / 3.5miles(Average distance required per substation on a dc route) which equals about 21 Substations. I'd not want to find out how much that would cost let alone the rest of changes required just to mitigate wind disruption and gain much more drawbacks.

The failures on the GWR section where on the older electrification that also uses the less reliable wires hanging of wires design similar to the ECML.

installing more reliable kit when replacing or changing OHLE should help reduce the frequency of these significant dewirement events

 

[Samzino]

The failures on the GWR section where on the older electrification that also uses the less reliable wires hanging of wires design similar to the ECML.

installing more reliable kit when replacing or changing OHLE should help reduce the frequency of these significant dewirement events

Indeed, a lot of these sections one will find have been lacking the much needed upgrades for a decade and will only get worse till an upgrade to the new series is actually done.

 

[renegademaster]

Thameslink North of the river does anecdotally seem a lot less reliable than it south of the river

 

[coppercapped]

The failures on the GWR section where on the older electrification that also uses the less reliable wires hanging of wires design similar to the ECML.

installing more reliable kit when replacing or changing OHLE should help reduce the frequency of these significant dewirement events

Headspan suspension of the contact and catenary wires is not necessarily less reliable than individual suspension from masts or gantries. As always the results depend on the design choices made, the materials, installation and maintenance.

The German railways use headspan construction almost exclusively and even in areas with quite extreme weather conditions it works reliably. This link (not my photo) shows a train leaving München Hbf and it is clear that over this very busy multi-track area headspans are used.

 

[AM9]

Tell RAIB the concerns re 3rd rail are noted but pass come 1st.

RAIB does put passenger concerns first, that's it has have prevented any significant expansion of a more hazardous electrification method. That will probably premanently override any occasional inconvenience through OLE vulnerabilities in stormy weather.
So unless you think that running inter-city services like metro and LU services at metro speeds, are OK, you will be using OLE powered trains for the forseeable future, except on those ex SR lines where grandfather rights exist.

 

[zwk500]

Tell RAIB the concerns re 3rd rail are noted but pass come 1st.

Go read the RSSB report, they tell you quite clearly what is needed to keep passengers safe.

 

[Nicholas Lewis]

Headspan suspension of the contact and catenary wires is not necessarily less reliable than individual suspension from masts or gantries. As always the results depend on the design choices made, the materials, installation and maintenance.

The German railways use headspan construction almost exclusively and even in areas with quite extreme weather conditions it works reliably. This link (not my photo) shows a train leaving München Hbf and it is clear that over this very busy multi-track area headspans are used.

Indeed and those heaspans are across many many more tracks than you will find anywhere in the UK and are reliable albeit they don't use them on higher speed sections though.

RAIB does put passenger concerns first, that's it has have prevented any significant expansion of a more hazardous electrification method. That will probably premanently override any occasional inconvenience through OLE vulnerabilities in stormy weather.

thats the ORR thats thwarting further extensions

 

[WAO]

RAIB does put passenger concerns first, that's it has have prevented any significant expansion of a more hazardous electrification method.

Has this ever been quantified and set against the additional hazards of travelling by other modes and the economic costs of less rail usage?

It is dangerous to use a ladder (such as in installing OLE) but it is a necessity of life and covered by training.

Covering one's Institution for zero risk by doing nothing is bad engineering; comparable to taking the advice of reclusive maiden aunts and housebound spinsters (we shall all be murdered in our beds!).

I do agree that more could be done to improve dc safety but if it were sincere, it would be applied across all dc lines not just new ones.

WAO

 

[AM9]

Has this ever been quantified and set against the additional hazards of travelling by other modes and the economic costs of less rail usage?

It is dangerous to use a ladder (such as in installing OLE) but it is a necessity of life and covered by training.

Covering one's Institution for zero risk by doing nothing is bad engineering; comparable to taking the advice of reclusive maiden aunts and housebound spinsters (we shall all be murdered in our beds!).

I do agree that more could be done to improve dc safety but if it were sincere, it would be applied across all dc lines not just new ones.

WAO

Not sure what your point is there. The RAIB/ORR has made the case that there have to be overriding reasons for extending DC coverage, and so far there hasn't been a case made since the metro scheme of the South London loop on the Overground network. With such a metro line, the 'hazards' of other modes don't really have any relevance.
OLE hasn't been installed using ladders for at least 30 years and it is unlikely that it would in the future.
There's no cynical protecting the 'Institution', it's just the higher safety standards of 21st century work required to meet HaSAW legislation.
I agree that there is a risk in the grandfather rights granted to the existing DC network, but making it non-standard would push a lot of footfall onto other modes of transport for decades.

 

[zwk500]

Has this ever been quantified and set against the additional hazards of travelling by other modes and the economic costs of less rail usage?

Presumably yes, thats why its not been ripped out. But where of the potential DC extensions would lead to substantive modal shift to outweigh the additional risk of the third rail?

It is dangerous to use a ladder (such as in installing OLE) but it is a necessity of life and covered by training.

hence why OLE is now installed from aerial platforms and cherry pickers not ladders.

I do agree that more could be done to improve dc safety but if it were sincere, it would be applied across all dc lines not just new ones.

cost is the factor here.

 

[WAO]

Presumably yes, thats why its not been ripped out. But where of the potential DC extensions would lead to substantive modal shift to outweigh the additional risk of the third rail?

hence why OLE is now installed from aerial platforms and cherry pickers not ladders.

cost is the factor here.

1 You would not consider electrification if that were not so.

2 Agreed that platforms are preferred but ladders are not extinct.

3 It's not cost but cost-benefit that counts and the quantified safety benefits for avoiding dc are evidently too small.

Having said that, I think that the some recent dc upgrades ideally should have better been conversions to ac - Pirbright Jn to Weymouth and Merseyrail for instance.

WAO

 

[AM9]

... Agreed that platforms are preferred but ladders are not extinct.

They are much nearer to extinction thatyou may think, especially in the workplace, where the consensus is that standing on a ladder to do work is condered outside what an employee should be expected to do.

Having said that, I think that the some recent dc upgrades ideally should have better been conversions to ac - Pirbright Jn to Weymouth and Merseyrail for instance.

It's unfortunate that the extension of electrification from Bournemouth to Weymouth in 1988 was only considered for DC because the flaws of an extended DC route became all too clear in less than 10 years. With forsight,an ac schem could have been a good showcase of why ac should be expanded and we may well have a serious programme extending that back to Pirbright Junction, and that might have included delaying the Eastleigh/Southampton/Portsmout scheme until Soton was ac with a switch over at (Cosham). The SWML has always been a far better route than DC allows.

 

[zwk500]

1 You would not consider electrification if that were not so.

There's plenty of routes where Electrification would drive substantial reduction in road traffic, just not the lines most often talked about for 3rd rail conversion. And abstraction from roads and the reduction in accidents is certainly part of rail scheme appraisal.

2 Agreed that platforms are preferred but ladders are not extinct.

Not extinct but certainly on their way out.

3 It's not cost but cost-benefit that counts and the quantified safety benefits for avoiding dc are evidently too small.

No, it's overall cost as well. The government would have to borrow the money to pay for it, and it's a rather expensive job to stop all the trains for however long to flip everything over (ask the Belgians who've just switched 3kv DC OLE to 25kv AC DC near the French/Lux border).

Having said that, I think that the some recent dc upgrades ideally should have better been conversions to ac - Pirbright Jn to Weymouth and Merseyrail for instance.

Merseyrail is one of the few areas where if you were electrifying it brand new you'd still consider third rail (though bottom contact) tbh. Agree that Weymouth should have been OLE in an ideal world.

 

[Trainbike46]

There's plenty of routes where Electrification would drive substantial reduction in road traffic, just not the lines most often talked about for 3rd rail conversion. And abstraction from roads and the reduction in accidents is certainly part of rail scheme appraisal.

what are some electrification schemes you would put high on the list for reducing road traffic?

 

[CarrotPie]

what are some electrification schemes you would put high on the list for reducing road traffic?

Infill AC electrification for rail freight (Electric Spine *cough*)

 

[zwk500]

what are some electrification schemes you would put high on the list for reducing road traffic?

Birmingham, Bristol, Manchester, Leeds suburban electrifications.

 

[AM9]

what are some electrification schemes you would put high on the list for reducing road traffic?

I would suggest Stowmarket to Cambridge/Ely, Norwich to Ely, Ely to Peterborough and the lines providing a freight routes through to the WCML. Then there's the Birmingham (actually Bromsgrove) to Bristol (Westerleigh juction triangle), taking some freight and passenger traffic from the M5.

 

[WAO]

At the risk of labouring the point, first cost is not the main issue in investment; issues such as the Nett Present Value and the Internal Rate of Return are the key.

It can be much more expensive to do nothing, even with zero first cost. If you don't have the cash, a merchant bank can provide it and its interest simply goes into the cost of capital. A good business follows this rule, even for small items.

The problem with UK railway investment is the Treasury's need for an "optimism bias" - a polite way of saying it doesn't believe the figures submitted, historically for good reason.

WAO

 

[Technologist]

Thread is insufficiently ambitious, third rail is a retrograde step.

Suggest that the true replacement for both third rail and overhead line is a wireless transmission.It's already used on maglevs and has been demonstrated on moving cars.

While windings and power electronics are more expensive than wires at £4 million per mile to electrify UK tracks we could spend £1k per m on a wireless charging pad and still come out ahead of OHL by having a lower install cost.

I would also assume that O&M costs would eventually be lower as it's a non contact system.

In maglev innovation, Chinese researchers transfer power wirelessly

Although a maglev train is driven forward by magnetic force, much of the equipment on board requires electricity, and current methods have their drawbacks.

www.scmp.com

 

[AM9]

Thread is insufficiently ambitious, third rail is a retrograde step.

Suggest that the true replacement for both third rail and overhead line is a wireless transmission.It's already used on maglevs and has been demonstrated on moving cars.

While windings and power electronics are more expensive than wires at £4 million per mile to electrify UK tracks we could spend £1k per m on a wireless charging pad and still come out ahead of OHL by having a lower install cost.

I would also assume that O&M costs would eventually be lower as it's a non contact system.

In maglev innovation, Chinese researchers transfer power wirelessly

Although a maglev train is driven forward by magnetic force, much of the equipment on board requires electricity, and current methods have their drawbacks.

www.scmp.com

So with this new wonder scheme:

how efficent is the power transfer?​

what is its EMC profile?​

how much capital to convert (say) the Brighton Main Line?​

I'm sure there are plenty of other unanswered questions before there will be any serious debate on the possibility of adoption.

 

[stuu]

Thread is insufficiently ambitious, third rail is a retrograde step.

Suggest that the true replacement for both third rail and overhead line is a wireless transmission.It's already used on maglevs and has been demonstrated on moving cars.

While windings and power electronics are more expensive than wires at £4 million per mile to electrify UK tracks we could spend £1k per m on a wireless charging pad and still come out ahead of OHL by having a lower install cost.

I would also assume that O&M costs would eventually be lower as it's a non contact system.

In maglev innovation, Chinese researchers transfer power wirelessly

Although a maglev train is driven forward by magnetic force, much of the equipment on board requires electricity, and current methods have their drawbacks.

www.scmp.com

Why would you replace OHLE with a less-efficient solution? Whole life costs do matter

 

[miklcct]

It is generally accepted that overhead lines are a superior way of electrification. They can support high speed running with less energy loss (while 3rd rail is practically limited at 160 km/h). They are also safer as well.

 

[fandroid]

One of the main reasons for using ole rather than 3rd rail is that much higher voltages can be safely used. Higher voltages mean higher power through a smaller cross-section of conductor using smaller currents. Power=voltage x current. Smaller currents mean smaller losses during transmission along the line to the train. As well as reducing costly losses overall, that means the power can be fed into the railway at points much further apart. That in turn makes getting power to the railway cheaper overall

 

[Technologist]

So with this new wonder scheme:

how efficent is the power transfer?​

what is its EMC profile?​

how much capital to convert (say) the Brighton Main Line?​

I'm sure there are plenty of other unanswered questions before there will be any serious debate on the possibility of adoption.

It looks like 90% plus is possible over 100-200mm distance, which puts it into the space of feasible. You'd also get most of the efficiency gap between it and OHL back with aero improvements from getting rid of pantograph and assorted acne on the train roof.

EMC question is one where you'd have to be elbow deep in the design of the system to answer, obviously various Maglev people have got it to work but that may have involved design features on the vehicle itself to protect it. It's obviously not propagating serious EMI beyond the lines to any great range. The beauty of said system is that it only operates under the train using it so old trains can run without being affected.

Again you'd need to design it to get costs but it is an interesting idea and very much in the direction of societal/technological megatrends are going. By this I mean that compared to existing solutions this is full of sensors, active controls and power electronics, all things which used to be expensive and now aren't.

The pads would be 20m sections, volume produced, which would get to cost trending down to a small multiple of the cost of materials. The instal costs would be limited to screwing the pads to sleepers and connecting the ends up. Ergo the site specific engineering and man hours for the instal are reduced, which are now the expensive stuff. Once properly developed such a system should be reliable as it has no moving pieces and no contacts.

I could see some issues as to what the power density will be. I have found some references to car based wireless charging systems for moving vehicles with a min target of 10KW per m2. Which doesn't sound like much, however looking at IET energy consumption of 4600KWh for a 162min trip between London and Newcastle averages less than 0.5MW for a 5 car Class 800

If we had a 1m wide wireless pad this would need to be only 50m long. In practice I don't see why this wouldn't be nearly the whole length of the train (unlike a pantograph there is no issue with running multiple pads). While this wouldn't cope with peak power I expect that in the longer term most trains will end up being battery EMUs as the cost of batteries is now incredibly low and the masses required to operate significant distances off the wires are comparable to bi mode trains anyway.

The other advantage of operating this with a BEMU is that it can be highly discontinuous. So old signalling and points can be avoided if necessary, it could even be interrupted when the new wireless power train is passing an older train which doesn't like it. (This assumes EMC is an issue, it might not be)

I'd previously estimated a 2.2MWh battery would fit into the mass that a 5 car class 801 reserves for it's diesel and it's fuel. Looking at EV batteries these are capable of 7C discharges which would mean that we could potentially draw 15.4MW (or 22 Tesla Plaid Model S) from that battery. Easily enough to allow the train to accelerate like a demon, you could if you want design our class 801 surrogate to accelerate to 90mph at 1.3ms/s fully loaded.

Not saying that this would work but it would be the sort of thing that GBRs research programme should be looking at.

 

[To the trains]

The East Coast Mainline and the part of the Great Western Mainline between Paddington and the spur to Heathrow have electrification held up by headspans which fail if even feather blows over them, the rest of the GWML hasn't had such problems because the gantries, albeit ugly are much more resilient. 3rd rail also struggles to hit 100mph, requires lots of substations, runs at a low voltage and high current, making it less efficient, is worse affected by ice and snow and has fallen firmly out of favour worldwide, except for low-speed metro systems.

 

[CarrotPie]

3rd rail also struggles to hit 100mph, requires lots of substations, runs at a low voltage and high current, making it less efficient, is worse affected by ice and snow and has fallen firmly out of favour worldwide, except for low-speed metro systems.

The Bay Area Rapid Transit (BART) system in California uses 1000V DC third rail and reaches speeds of 70mph (previously 80mph). I wouldn't call that low-speed.

 

[stuu]

The Bay Area Rapid Transit (BART) system in California uses 1000V DC third rail and reaches speeds of 70mph (previously 80mph). I wouldn't call that low-speed.

Yes but no one would build it like that now, which is the point the poster was making

 

[Trainbike46]

The Bay Area Rapid Transit (BART) system in California uses 1000V DC third rail and reaches speeds of 70mph (previously 80mph). I wouldn't call that low-speed.

but still very much below the hard-to-reach 100 mph maximum encountered in England - the limitations at higher speeds are a key reason to avoid third rail on some lines

 

[AM9]

but still very much below the hard-to-reach 100 mph maximum encountered in England - the limitations at higher speeds are a key reason to avoid third rail on some lines

And of course much of the main lines from London to the South Coast would benefit from removing the restriction of 3rd rail power collection, especially the SWML.