On 06/12/2023 16:34, Tweed wrote:
> <Muttley@dastardlyhq.com> wrote:
>> On Wed, 6 Dec 2023 12:50:08 +0100
>> Bob <bob@domain.com> wrote:
>>> As a high voltage AC electrification system, the 15 kV system, on
>>> direct-to-the-railway basis is much closer in cost to the 25 kV 50 Hz
>>> system, and does not have the kinds of power limitations that make DC
>>> systems unsuited to higher speed running or heavy freight haulage (300
>>
>> Actually DC is actually better for high voltage for transfering power as
>> there are lower losses. National Grid has built some DC interconnects to
>> other countries for example. These days if building a railway from scratch
>> you could probably do worse than 25KV *DC* given converting it down to lower
>> DC voltages is now a solved problem with modern electronics. Of course you
>> wouldn't get the nice hum for the catenary in the rain :)
>>
>>
>
> Swings and roundabouts for “better”. See here
>
> https://www.cencepower.com/blog-posts/hvdc-transmission-systems#:~:text=Therefore%2C%20DC%20power%20is%20inherently,underwater%20it%27s%20about%2024%20%2D%2050km.
>
> One of the main reasons for our undersea cables being DC is it removes the
> need to synchronise our grid frequency to continental Europe.
>

One reason yes, but "main" I am not so sure about. We have a major
windfarm being built (will be fully operational next year) and the link
from Shetland to the mainland in Caithness is DC with the associated
converter stations at each end (Kergord in Shetland).

--
Colin

On 07/12/2023 10:47, ColinR wrote:
> On 06/12/2023 16:34, Tweed wrote:
>> <Muttley@dastardlyhq.com> wrote:
>>> On Wed, 6 Dec 2023 12:50:08 +0100
>>> Bob <bob@domain.com> wrote:
>>>> As a high voltage AC electrification system, the 15 kV system, on
>>>> direct-to-the-railway basis is much closer in cost to the 25 kV 50 Hz
>>>> system, and does not have the kinds of power limitations that make DC
>>>> systems unsuited to higher speed running or heavy freight haulage (300
>>>
>>> Actually DC is actually better for high voltage for transfering power as
>>> there are lower losses. National Grid has built some DC interconnects to
>>> other countries for example. These days if building a railway from
>>> scratch
>>> you could probably do worse than 25KV *DC* given converting it down
>>> to lower
>>> DC voltages is now a solved problem with modern electronics. Of
>>> course you
>>> wouldn't get the nice hum for the catenary in the rain :)
>>>
>>>
>>
>> Swings and roundabouts for “better”. See here
>>
>> https://www.cencepower.com/blog-posts/hvdc-transmission-systems#:~:text=Therefore%2C%20DC%20power%20is%20inherently,underwater%20it%27s%20about%2024%20%2D%2050km.
>>
>> One of the main reasons for our undersea cables being DC is it removes
>> the
>> need to synchronise our grid frequency to continental Europe.
>>
>
> One reason yes, but "main" I am not so sure about. We have a major
> windfarm being built (will be fully operational next year) and the link
> from Shetland to the mainland in Caithness is DC with the associated
> converter stations at each end (Kergord in Shetland).
>

https://www.electricaltechnology.org/2020/06/advantages-of-hvdc-over-hvac-power-transmission.html

--
Colin

ColinR <rail@greystane.shetland.co.uk> wrote:
> On 07/12/2023 10:47, ColinR wrote:
>> On 06/12/2023 16:34, Tweed wrote:
>>> <Muttley@dastardlyhq.com> wrote:
>>>> On Wed, 6 Dec 2023 12:50:08 +0100
>>>> Bob <bob@domain.com> wrote:
>>>>> As a high voltage AC electrification system, the 15 kV system, on
>>>>> direct-to-the-railway basis is much closer in cost to the 25 kV 50 Hz
>>>>> system, and does not have the kinds of power limitations that make DC
>>>>> systems unsuited to higher speed running or heavy freight haulage (300
>>>>
>>>> Actually DC is actually better for high voltage for transfering power as
>>>> there are lower losses. National Grid has built some DC interconnects to
>>>> other countries for example. These days if building a railway from
>>>> scratch
>>>> you could probably do worse than 25KV *DC* given converting it down
>>>> to lower
>>>> DC voltages is now a solved problem with modern electronics. Of
>>>> course you
>>>> wouldn't get the nice hum for the catenary in the rain :)
>>>>
>>>>
>>>
>>> Swings and roundabouts for “better”. See here
>>>
>>> https://www.cencepower.com/blog-posts/hvdc-transmission-systems#:~:text=Therefore%2C%20DC%20power%20is%20inherently,underwater%20it%27s%20about%2024%20%2D%2050km.
>>>
>>> One of the main reasons for our undersea cables being DC is it removes
>>> the
>>> need to synchronise our grid frequency to continental Europe.
>>>
>>
>> One reason yes, but "main" I am not so sure about. We have a major
>> windfarm being built (will be fully operational next year) and the link
>> from Shetland to the mainland in Caithness is DC with the associated
>> converter stations at each end (Kergord in Shetland).
>>
>
> https://www.electricaltechnology.org/2020/06/advantages-of-hvdc-over-hvac-power-transmission.html
>

Yes there are other reasons - capacitive losses in seawater, no skin effect
and no need to run three phase conductors. However the UK - Continent links
could never have been considered if grid synchronisation was a requirement,
even over the short channel route. The Shetland link is probably benefiting
from electronic DC converter stations being now a tried and trusted
technology.

There’s serious talk of a 1000km Iceland - UK interconnector. Even with DC
I’m surprised there’s anything left after such a long run, but clearly
someone thinks there is.

On Thu, 7 Dec 2023 10:55:53 +0000
ColinR <rail@greystane.shetland.co.uk> wrote:
>On 07/12/2023 10:47, ColinR wrote:
>> One reason yes, but "main" I am not so sure about. We have a major
>> windfarm being built (will be fully operational next year) and the link
>> from Shetland to the mainland in Caithness is DC with the associated
>> converter stations at each end (Kergord in Shetland).
>>
>
>https://www.electricaltechnology.org/2020/06/advantages-of-hvdc-over-hvac-power
>-transmission.html

"in case of HVDC that can utilize the earth as the return path"

Huh? How on earth can you use the ground as a return path for DC? There'd be
so much resistance you'd get no power whatsover.

<Muttley@dastardlyhq.com> wrote:
> On Thu, 7 Dec 2023 10:55:53 +0000
> ColinR <rail@greystane.shetland.co.uk> wrote:
>> On 07/12/2023 10:47, ColinR wrote:
>>> One reason yes, but "main" I am not so sure about. We have a major
>>> windfarm being built (will be fully operational next year) and the link
>>> from Shetland to the mainland in Caithness is DC with the associated
>>> converter stations at each end (Kergord in Shetland).
>>>
>>
>> https://www.electricaltechnology.org/2020/06/advantages-of-hvdc-over-hvac-power
>> -transmission.html
>
> "in case of HVDC that can utilize the earth as the return path"
>
> Huh? How on earth can you use the ground as a return path for DC? There'd be
> so much resistance you'd get no power whatsover.
>
>
>

It’s a known and implemented method

https://www.mdpi.com/1996-1073/16/14/5349

On Thu, 7 Dec 2023 11:40:55 -0000 (UTC)
Tweed <usenet.tweed@gmail.com> wrote:
><Muttley@dastardlyhq.com> wrote:
>> On Thu, 7 Dec 2023 10:55:53 +0000
>> ColinR <rail@greystane.shetland.co.uk> wrote:
>>> On 07/12/2023 10:47, ColinR wrote:
>>>> One reason yes, but "main" I am not so sure about. We have a major
>>>> windfarm being built (will be fully operational next year) and the link
>>>> from Shetland to the mainland in Caithness is DC with the associated
>>>> converter stations at each end (Kergord in Shetland).
>>>>
>>>
>>>
>https://www.electricaltechnology.org/2020/06/advantages-of-hvdc-over-hvac-power
>
>>> -transmission.html
>>
>> "in case of HVDC that can utilize the earth as the return path"
>>
>> Huh? How on earth can you use the ground as a return path for DC? There'd be
>> so much resistance you'd get no power whatsover.
>>
>>
>>
>
>It’s a known and implemented method
>
>https://www.mdpi.com/1996-1073/16/14/5349

Well I guess if they want to waste huge amounts of power heating up the
ground or the water. Ohms law doesn't change just because you're using very
high voltages.

On 07/12/2023 15:50, Muttley@dastardlyhq.com wrote:
> On Thu, 7 Dec 2023 11:40:55 -0000 (UTC)
> Tweed <usenet.tweed@gmail.com> wrote:
>> <Muttley@dastardlyhq.com> wrote:
>>> On Thu, 7 Dec 2023 10:55:53 +0000
>>> ColinR <rail@greystane.shetland.co.uk> wrote:
>>>> On 07/12/2023 10:47, ColinR wrote:
>>>>> One reason yes, but "main" I am not so sure about. We have a major
>>>>> windfarm being built (will be fully operational next year) and the link
>>>>> from Shetland to the mainland in Caithness is DC with the associated
>>>>> converter stations at each end (Kergord in Shetland).
>>>>
>> https://www.electricaltechnology.org/2020/06/advantages-of-hvdc-over-hvac-power
>>
>>>> -transmission.html
>>>
>>> "in case of HVDC that can utilize the earth as the return path"
>>>
>>> Huh? How on earth can you use the ground as a return path for DC? There'd be
>>> so much resistance you'd get no power whatsover.
>>
>> It’s a known and implemented method
>>
>> https://www.mdpi.com/1996-1073/16/14/5349
>
> Well I guess if they want to waste huge amounts of power heating up the
> ground or the water. Ohms law doesn't change just because you're using very
> high voltages.

It may not change, but it does take into account the fact that you have
a very wide conductor. Plus you get free fried fish.

On Thu, 7 Dec 2023 16:43:55 +0000
Certes <Certes@example.org> wrote:
>On 07/12/2023 15:50, Muttley@dastardlyhq.com wrote:
>> On Thu, 7 Dec 2023 11:40:55 -0000 (UTC)
>> Tweed <usenet.tweed@gmail.com> wrote:
>>> <Muttley@dastardlyhq.com> wrote:
>>>> On Thu, 7 Dec 2023 10:55:53 +0000
>>>> ColinR <rail@greystane.shetland.co.uk> wrote:
>>>>> On 07/12/2023 10:47, ColinR wrote:
>>>>>> One reason yes, but "main" I am not so sure about. We have a major
>>>>>> windfarm being built (will be fully operational next year) and the link
>>>>>> from Shetland to the mainland in Caithness is DC with the associated
>>>>>> converter stations at each end (Kergord in Shetland).
>>>>>
>>>
>https://www.electricaltechnology.org/2020/06/advantages-of-hvdc-over-hvac-power
>
>>>
>>>>> -transmission.html
>>>>
>>>> "in case of HVDC that can utilize the earth as the return path"
>>>>
>>>> Huh? How on earth can you use the ground as a return path for DC? There'd
>be
>>>> so much resistance you'd get no power whatsover.
>>>
>>> It’s a known and implemented method
>>>
>>> https://www.mdpi.com/1996-1073/16/14/5349
>>
>> Well I guess if they want to waste huge amounts of power heating up the
>> ground or the water. Ohms law doesn't change just because you're using very
>> high voltages.
>
>It may not change, but it does take into account the fact that you have
>a very wide conductor. Plus you get free fried fish.

Beyond a certain point (probably inches) I suspect conductor width has little
influence on the resistence but feel free to test it with a single wire, a
torch bulb and battery using the ground as the return.

On 07/12/2023 16:43, Certes wrote:
> On 07/12/2023 15:50, Muttley@dastardlyhq.com wrote:
>> On Thu, 7 Dec 2023 11:40:55 -0000 (UTC)
>> Tweed <usenet.tweed@gmail.com> wrote:
>>> <Muttley@dastardlyhq.com> wrote:
>>>> On Thu, 7 Dec 2023 10:55:53 +0000
>>>> ColinR <rail@greystane.shetland.co.uk> wrote:
>>>>> On 07/12/2023 10:47, ColinR wrote:
>>>>>> One reason yes, but "main" I am not so sure about. We have a major
>>>>>> windfarm being built (will be fully operational next year) and the
>>>>>> link
>>>>>> from Shetland to the mainland in Caithness is DC with the associated
>>>>>> converter stations at each end (Kergord in Shetland).
>>>>>
>>> https://www.electricaltechnology.org/2020/06/advantages-of-hvdc-over-hvac-power
>>>
>>>>> -transmission.html
>>>>
>>>> "in case of HVDC that can utilize the earth as the return path"
>>>>
>>>> Huh? How on earth can you use the ground as a return path for DC?
>>>> There'd be
>>>> so much resistance you'd get no power whatsover.
>>>
>>> It’s a known and implemented method
>>>
>>> https://www.mdpi.com/1996-1073/16/14/5349
>>
>> Well I guess if they want to waste huge amounts of power heating up the
>> ground or the water. Ohms law doesn't change just because you're using
>> very
>> high voltages.
>
> It may not change, but it does take into account the fact that you have
> a very wide conductor.  Plus you get free fried fish.

Only on Fridays.
--
Graeme Wall
This account not read.

On 07/12/2023 17:03, Muttley@dastardlyhq.com wrote:
> On Thu, 7 Dec 2023 16:43:55 +0000
> Certes <Certes@example.org> wrote:
>> On 07/12/2023 15:50, Muttley@dastardlyhq.com wrote:
>>> On Thu, 7 Dec 2023 11:40:55 -0000 (UTC)
>>> Tweed <usenet.tweed@gmail.com> wrote:
>>>> <Muttley@dastardlyhq.com> wrote:
>>>>> On Thu, 7 Dec 2023 10:55:53 +0000
>>>>> ColinR <rail@greystane.shetland.co.uk> wrote:
>>>>>> On 07/12/2023 10:47, ColinR wrote:
>>>>>>> One reason yes, but "main" I am not so sure about. We have a major
>>>>>>> windfarm being built (will be fully operational next year) and the link
>>>>>>> from Shetland to the mainland in Caithness is DC with the associated
>>>>>>> converter stations at each end (Kergord in Shetland).
>>>>>>
>>>>
>> https://www.electricaltechnology.org/2020/06/advantages-of-hvdc-over-hvac-power
>>
>>>>
>>>>>> -transmission.html
>>>>>
>>>>> "in case of HVDC that can utilize the earth as the return path"
>>>>>
>>>>> Huh? How on earth can you use the ground as a return path for DC? There'd
>> be
>>>>> so much resistance you'd get no power whatsover.
>>>>
>>>> It’s a known and implemented method
>>>>
>>>> https://www.mdpi.com/1996-1073/16/14/5349
>>>
>>> Well I guess if they want to waste huge amounts of power heating up the
>>> ground or the water. Ohms law doesn't change just because you're using very
>>> high voltages.
>>
>> It may not change, but it does take into account the fact that you have
>> a very wide conductor. Plus you get free fried fish.
>
> Beyond a certain point (probably inches) I suspect conductor width has little
> influence on the resistence but feel free to test it with a single wire, a
> torch bulb and battery using the ground as the return.
>

Torch bulb? Where do you find one of those?
--
Graeme Wall
This account not read.

On 07/12/2023 17:03, Muttley@dastardlyhq.com wrote:
> On Thu, 7 Dec 2023 16:43:55 +0000
> Certes <Certes@example.org> wrote:
>>On 07/12/2023 15:50, Muttley@dastardlyhq.com wrote:
>>> On Thu, 7 Dec 2023 11:40:55 -0000 (UTC)
>>> Tweed <usenet.tweed@gmail.com> wrote:
>>>> <Muttley@dastardlyhq.com> wrote:
>>>>> On Thu, 7 Dec 2023 10:55:53 +0000
>>>>> ColinR <rail@greystane.shetland.co.uk> wrote:
>>>>>> On 07/12/2023 10:47, ColinR wrote:
>>>>>>> One reason yes, but "main" I am not so sure about. We have a major
>>>>>>> windfarm being built (will be fully operational next year) and the link
>>>>>>> from Shetland to the mainland in Caithness is DC with the associated
>>>>>>> converter stations at each end (Kergord in Shetland).

The biggest reason for undersea cables is the capacitance, and therefore
losses, of the cable. Surprisingly, there's a 33 kV AC cable between the
Isle of Man and Blackpool.

>>>>>> https://www.electricaltechnology.org/2020/06/advantages-of-hvdc-over-hvac-power-transmission.html
>>>>>
>>>>> "in case of HVDC that can utilize the earth as the return path"
>>>>>
>>>>> Huh? How on earth can you use the ground as a return path for DC? There'd be
>>>>> so much resistance you'd get no power whatsover.

500 MW between Tasmania and Victoria. It has environmental disadvantages but
is cheaper to build.

>>>> It's a known and implemented method
>>>>
>>>> https://www.mdpi.com/1996-1073/16/14/5349
>>>
>>> Well I guess if they want to waste huge amounts of power heating up the
>>> ground or the water. Ohms law doesn't change just because you're using very
>>> high voltages.
>>
>>It may not change, but it does take into account the fact that you have
>>a very wide conductor. Plus you get free fried fish.
>
> Beyond a certain point (probably inches) I suspect conductor width has little
> influence on the resistence but feel free to test it with a single wire, a
> torch bulb and battery using the ground as the return.

Not much point in all those low impedance earths that safety people keep
insisting on then.

<Muttley@dastardlyhq.com> wrote in message news:ukkstc$3fmr0$1@dont-email.me...
>I was standing at farringdon today and watched a Thameslink train come into the
> platform. Under the footbridge the 25KV wire looked like it was mere inches
> above the roof of the train.
>
> Given that EMUs seem to be around 6 inches lower than most locos in the UK
> what on earth would happen if say a 12'9 class 66 or worse a 13ft high class
> 60 headed down there? I presume certain stock must be banned from the route
> for this reason.

Or not it would seem...

Dec 8th *

quote:

Passengers stuck for hours on Elizabeth Line after cables damaged

:unquote

https://www.bbc.co.uk/news/uk-67655656

bb

On 08/12/2023 08:33, billy bookcase wrote:
> <Muttley@dastardlyhq.com> wrote in message news:ukkstc$3fmr0$1@dont-email.me...
>> I was standing at farringdon today and watched a Thameslink train come into the
>> platform. Under the footbridge the 25KV wire looked like it was mere inches
>> above the roof of the train.
>>
>> Given that EMUs seem to be around 6 inches lower than most locos in the UK
>> what on earth would happen if say a 12'9 class 66 or worse a 13ft high class
>> 60 headed down there? I presume certain stock must be banned from the route
>> for this reason.
>
> Or not it would seem...
>
> Dec 8th *
>
> quote:
>
> Passengers stuck for hours on Elizabeth Line after cables damaged
>
> :unquote
>
> https://www.bbc.co.uk/news/uk-67655656
>
>

What has that got to do with Farringdon?

--
Graeme Wall
This account not read.

Graeme Wall <rail@greywall.demon.co.uk> wrote:
> On 08/12/2023 08:33, billy bookcase wrote:
>> <Muttley@dastardlyhq.com> wrote in message news:ukkstc$3fmr0$1@dont-email.me...
>>> I was standing at farringdon today and watched a Thameslink train come into the
>>> platform. Under the footbridge the 25KV wire looked like it was mere inches
>>> above the roof of the train.
>>>
>>> Given that EMUs seem to be around 6 inches lower than most locos in the UK
>>> what on earth would happen if say a 12'9 class 66 or worse a 13ft high class
>>> 60 headed down there? I presume certain stock must be banned from the route
>>> for this reason.
>>
>> Or not it would seem...
>>
>> Dec 8th *
>>
>> quote:
>>
>> Passengers stuck for hours on Elizabeth Line after cables damaged
>>
>> :unquote
>>
>> https://www.bbc.co.uk/news/uk-67655656
>>
>>
>
> What has that got to do with Farringdon?
>

Apparently the EL core operation came to a halt as a consequence of above
ground OHLE damage outside of Paddington.

On Thu, 7 Dec 2023 17:59:33 +0000
Graeme Wall <rail@greywall.demon.co.uk> wrote:
>On 07/12/2023 17:03, Muttley@dastardlyhq.com wrote:
>> On Thu, 7 Dec 2023 16:43:55 +0000
>> Certes <Certes@example.org> wrote:
>>> On 07/12/2023 15:50, Muttley@dastardlyhq.com wrote:
>>>> On Thu, 7 Dec 2023 11:40:55 -0000 (UTC)
>>>> Tweed <usenet.tweed@gmail.com> wrote:
>>>>> <Muttley@dastardlyhq.com> wrote:
>>>>>> On Thu, 7 Dec 2023 10:55:53 +0000
>>>>>> ColinR <rail@greystane.shetland.co.uk> wrote:
>>>>>>> On 07/12/2023 10:47, ColinR wrote:
>>>>>>>> One reason yes, but "main" I am not so sure about. We have a major
>>>>>>>> windfarm being built (will be fully operational next year) and the link
>
>>>>>>>> from Shetland to the mainland in Caithness is DC with the associated
>>>>>>>> converter stations at each end (Kergord in Shetland).
>>>>>>>
>>>>>
>>>
>https://www.electricaltechnology.org/2020/06/advantages-of-hvdc-over-hvac-power
>
>>>
>>>>>
>>>>>>> -transmission.html
>>>>>>
>>>>>> "in case of HVDC that can utilize the earth as the return path"
>>>>>>
>>>>>> Huh? How on earth can you use the ground as a return path for DC? There'd
>
>>> be
>>>>>> so much resistance you'd get no power whatsover.
>>>>>
>>>>> It’s a known and implemented method
>>>>>
>>>>> https://www.mdpi.com/1996-1073/16/14/5349
>>>>
>>>> Well I guess if they want to waste huge amounts of power heating up the
>>>> ground or the water. Ohms law doesn't change just because you're using very
>
>>>> high voltages.
>>>
>>> It may not change, but it does take into account the fact that you have
>>> a very wide conductor. Plus you get free fried fish.
>>
>> Beyond a certain point (probably inches) I suspect conductor width has little
>
>> influence on the resistence but feel free to test it with a single wire, a
>> torch bulb and battery using the ground as the return.
>>
>
>Torch bulb? Where do you find one of those?

LED then.

On Thu, 7 Dec 2023 22:09:10 +0000
Roger Lynn <usenet@rilynn.me.uk> wrote:
>On 07/12/2023 17:03, Muttley@dastardlyhq.com wrote:
>> Beyond a certain point (probably inches) I suspect conductor width has
>little
>> influence on the resistence but feel free to test it with a single wire, a
>> torch bulb and battery using the ground as the return.
>
>Not much point in all those low impedance earths that safety people keep
>insisting on then.

You do realise there's a difference between an earth and return? Next time
you change a plug wire the live or neutral to earth instead and see how well
your device works.

On Fri, 8 Dec 2023 08:33:56 -0000
"billy bookcase" <billy@anon.com> wrote:
><Muttley@dastardlyhq.com> wrote in message news:ukkstc$3fmr0$1@dont-email.me...
>
>>I was standing at farringdon today and watched a Thameslink train come into
>the
>> platform. Under the footbridge the 25KV wire looked like it was mere inches
>> above the roof of the train.
>>
>> Given that EMUs seem to be around 6 inches lower than most locos in the UK
>> what on earth would happen if say a 12'9 class 66 or worse a 13ft high class
>> 60 headed down there? I presume certain stock must be banned from the route
>> for this reason.
>
>Or not it would seem...
>
>Dec 8th *
>
>quote:
>
>Passengers stuck for hours on Elizabeth Line after cables damaged
>
>:unquote
>
>https://www.bbc.co.uk/news/uk-67655656

I don't know why people wait so long. I'd be pulling the emergency door
release after an hour and just walk to the next station. I did it once on
Thameslink (albeit we were sitting at a station at the time) when the driver
refused to open the doors to let us off because we'd officially left the
station even though we'd only moved about 20m to the end of the platform.

On Fri, 8 Dec 2023 09:16:26 -0000 (UTC)
Tweed <usenet.tweed@gmail.com> wrote:
>Graeme Wall <rail@greywall.demon.co.uk> wrote:
>>> Passengers stuck for hours on Elizabeth Line after cables damaged
>>>
>>> :unquote
>>>
>>> https://www.bbc.co.uk/news/uk-67655656
>>>
>>>
>>
>> What has that got to do with Farringdon?
>>
>
>Apparently the EL core operation came to a halt as a consequence of above
>ground OHLE damage outside of Paddington.

God forbid they should start running reversers to paddington in the core and
let the passengers off the train before 4 hours. And wasn't it 8 hours on
a eurostar the other week stuck outside folkstone?

The railways in this country really are run by absolute fucking clowns.

On 08/12/2023 10:14, Muttley@dastardlyhq.com wrote:
> On Thu, 7 Dec 2023 22:09:10 +0000
> Roger Lynn <usenet@rilynn.me.uk> wrote:
>> On 07/12/2023 17:03, Muttley@dastardlyhq.com wrote:
>>> Beyond a certain point (probably inches) I suspect conductor width has
>> little
>>> influence on the resistence but feel free to test it with a single wire, a
>>> torch bulb and battery using the ground as the return.
>>
>> Not much point in all those low impedance earths that safety people keep
>> insisting on then.
>
> You do realise there's a difference between an earth and return? Next time
> you change a plug wire the live or neutral to earth instead and see how well
> your device works.

Because Usenet has readers of varying experience:
Please, please do not try this dangerous experiment at home.

Tweed <usenet.tweed@gmail.com> wrote:
> Graeme Wall <rail@greywall.demon.co.uk> wrote:
>> On 08/12/2023 08:33, billy bookcase wrote:
>>> <Muttley@dastardlyhq.com> wrote in message news:ukkstc$3fmr0$1@dont-email.me...
>>>> I was standing at farringdon today and watched a Thameslink train come into the
>>>> platform. Under the footbridge the 25KV wire looked like it was mere inches
>>>> above the roof of the train.
>>>>
>>>> Given that EMUs seem to be around 6 inches lower than most locos in the UK
>>>> what on earth would happen if say a 12'9 class 66 or worse a 13ft high class
>>>> 60 headed down there? I presume certain stock must be banned from the route
>>>> for this reason.
>>>
>>> Or not it would seem...
>>>
>>> Dec 8th *
>>>
>>> quote:
>>>
>>> Passengers stuck for hours on Elizabeth Line after cables damaged
>>>
>>> :unquote
>>>
>>> https://www.bbc.co.uk/news/uk-67655656
>>>
>>>
>>
>> What has that got to do with Farringdon?
>>
>
> Apparently the EL core operation came to a halt as a consequence of above
> ground OHLE damage outside of Paddington.
>
>

Yes, I noticed some trains had been held for 30-50 minutes during a
westbound trip across the capital; I'm surprised there isn't a plan in
place to turn everything at Paddington in that situation and keep the
service moving across the centre.

Still unrelated to previous discussion about OLE heights on Thameslink at
Farringdon, though!

Anna Noyd-Dryver

On 08.12.2023 11:19, Muttley@dastardlyhq.com wrote:
> On Fri, 8 Dec 2023 09:16:26 -0000 (UTC)
> Tweed <usenet.tweed@gmail.com> wrote:
>> Graeme Wall <rail@greywall.demon.co.uk> wrote:
>>>> Passengers stuck for hours on Elizabeth Line after cables damaged
>>>>
>>>> :unquote
>>>>
>>>> https://www.bbc.co.uk/news/uk-67655656
>>>>
>>>>
>>>
>>> What has that got to do with Farringdon?
>>>
>>
>> Apparently the EL core operation came to a halt as a consequence of above
>> ground OHLE damage outside of Paddington.
>
> God forbid they should start running reversers to paddington in the core and
> let the passengers off the train before 4 hours. And wasn't it 8 hours on
> a eurostar the other week stuck outside folkstone?
>
> The railways in this country really are run by absolute fucking clowns.

The reversing siding for turning trains at Paddington is on the surface
beyond the station, it is likely the power supply there was equally
affected.

Robin

On Fri, 08 Dec 2023 10:14:16 +0000, Muttley wrote:

> On Thu, 7 Dec 2023 22:09:10 +0000 Roger Lynn <usenet@rilynn.me.uk>
> wrote:
>>On 07/12/2023 17:03, Muttley@dastardlyhq.com wrote:
>>> Beyond a certain point (probably inches) I suspect conductor width has
>>little
>>> influence on the resistence but feel free to test it with a single
>>> wire, a torch bulb and battery using the ground as the return.
>>
>>Not much point in all those low impedance earths that safety people keep
>>insisting on then.
>
> You do realise there's a difference between an earth and return? Next
> time you change a plug wire the live or neutral to earth instead and see
> how well your device works.

See "single-wire earth return" on Wikipedia for example.

nib

On Fri, 8 Dec 2023 11:07:39 -0000 (UTC)
nib <news@ingram-bromley.co.uk> wrote:
>On Fri, 08 Dec 2023 10:14:16 +0000, Muttley wrote:
>
>> On Thu, 7 Dec 2023 22:09:10 +0000 Roger Lynn <usenet@rilynn.me.uk>
>> wrote:
>>>On 07/12/2023 17:03, Muttley@dastardlyhq.com wrote:
>>>> Beyond a certain point (probably inches) I suspect conductor width has
>>>little
>>>> influence on the resistence but feel free to test it with a single
>>>> wire, a torch bulb and battery using the ground as the return.
>>>
>>>Not much point in all those low impedance earths that safety people keep
>>>insisting on then.
>>
>> You do realise there's a difference between an earth and return? Next
>> time you change a plug wire the live or neutral to earth instead and see
>> how well your device works.
>
>See "single-wire earth return" on Wikipedia for example.

I guess they don't mind wasting huge amounts of energy in some situations
to save a few pennies.

"Anna Noyd-Dryver" <anna@noyd-dryver.com> wrote in message
news:ukut2q$1ndio$1@dont-email.me...
>
> Still unrelated to previous discussion about OLE heights on Thameslink at
> Farringdon, though!

Which would of course be a perfectly valid point were it the case that
the only circumstances under which the overhead wire height - the actual
topic under discussion I believe - could ever represent a problem, would
be at Farringdon Station.

Whereas the TfL spokesperson for one, would appear to disagree

quote:

Transport for London (TfL) said the power lines were damaged by another
rail operator's train.

:unquote

https://www.bbc.co.uk/news/uk-67655656

bb

On 08/12/2023 12:22, billy bookcase wrote:
> "Anna Noyd-Dryver" <anna@noyd-dryver.com> wrote in message
> news:ukut2q$1ndio$1@dont-email.me...
>>
>> Still unrelated to previous discussion about OLE heights on Thameslink at
>> Farringdon, though!
>
> Which would of course be a perfectly valid point were it the case that
> the only circumstances under which the overhead wire height - the actual
> topic under discussion I believe - could ever represent a problem, would
> be at Farringdon Station.
>
> Whereas the TfL spokesperson for one, would appear to disagree
>
> quote:
>
> Transport for London (TfL) said the power lines were damaged by another
> rail operator's train.
>
> :unquote
>
> https://www.bbc.co.uk/news/uk-67655656
>
>
> bb
>
>
>
>

But not at Farringdon and not on Thameslink.

--
Graeme Wall
This account not read.