On 8 Dec 2023 15:10:25 GMT
Marland <gemehabal@btinternet.co.uk> wrote:
><Muttley@dastardlyhq.com> wrote:
>> 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.
>>
>>
>
>In many houses swapping the neutral with earth in the plug won’t make much
>difference to how a device works though the you may end up with a small
>potential on the properties earth circuits. Neutral and earth are bonded
>together where the mains supply enters the property .
>The suppliers return is then also utilised as the earth and is connected to
>earth at regular intervals .
>Saves running another conductor and you can often see properties supplied
>by overhead suppies with just two conductors,examination of the poles
>carrying them will show a wire running down the pole connecting the neutral
>to ground.
>Known as PME or protective multiple earthings.
>We are on such a supply.

So if you plug something in that is earthed to its metal casing that could
actually be connected indirectly to its own transformer. What could
possibly go wrong.

On Fri, 8 Dec 2023 10:14:16 -0000 (UTC), 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.
>
It often will depending on how your supply is wired. Not all circuits
will have RCCBs in them.

On 8 Dec 2023 15:10:25 GMT, Marland <gemehabal@btinternet.co.uk>
wrote:

><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.
>>
>>
>
>In many houses swapping the neutral with earth in the plug won’t make much
>difference to how a device works though the you may end up with a small
>potential on the properties earth circuits. Neutral and earth are bonded
>together where the mains supply enters the property .
>
Not with a TN-S system.
https://en.wikipedia.org/wiki/Earthing_system
<snip>

Charles Ellson <charlesellson@btinternet.com> wrote:
> On 8 Dec 2023 15:10:25 GMT, Marland <gemehabal@btinternet.co.uk>
> wrote:
>
>> <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.
>>>
>>>
>>
>> In many houses swapping the neutral with earth in the plug won’t make much
>> difference to how a device works though the you may end up with a small
>> potential on the properties earth circuits. Neutral and earth are bonded
>> together where the mains supply enters the property .
>>
> Not with a TN-S system.
> https://en.wikipedia.org/wiki/Earthing_system
> <snip>
>

Which is why I said many and not all.

GH

On 9 Dec 2023 09:38:50 GMT, Marland <gemehabal@btinternet.co.uk>
wrote:

>Charles Ellson <charlesellson@btinternet.com> wrote:
>> On 8 Dec 2023 15:10:25 GMT, Marland <gemehabal@btinternet.co.uk>
>> wrote:
>>
>>> <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.
>>>>
>>>>
>>>
>>> In many houses swapping the neutral with earth in the plug won?t make much
>>> difference to how a device works though the you may end up with a small
>>> potential on the properties earth circuits. Neutral and earth are bonded
>>> together where the mains supply enters the property .
>>>
>> Not with a TN-S system.
>> https://en.wikipedia.org/wiki/Earthing_system
>> <snip>
>>
>
>Which is why I said many and not all.
>
The second sentence can easily be read as a follow-on to the first.

Late to this party but I switched my main computer a few months ago and
I've only just got round to installing a newsreader. So using this post
as an excuse to test a reply...

On 2023-12-05 17:51, Muttley@dastardlyhq.com wrote:
> On 5 Dec 2023 14:54:45 GMT
> Marland <gemehabal@btinternet.co.uk> wrote
>> would have looked quite complicated because of the need to have large
>> neutral sections where one phase crossed another, trolley buses have them
>> as well where + and - wires cross but they only need a few inches for a
>> trolley head whereas pantographs are a lot wider.
>
> Problem with trolley wires is they need their own little points to guide the
> pole onto the correct wire which I imagine makes route setting as complex as
> any tram system. Perhaps today with smarter AI systems the bus could move the
> pole appropriately itself.

Unless I'm misunderstanding what you're saying here, trolley points are
already controlled by the bus itself, and don't rely on any remote
route-setting system or infrastructure.

The two mechanisms I'm aware of - one based on the angle of the poles,
another based on the power draw.

In the first system, it relies on the fact that if the bus is turning,
one of the poles will be leading the other slightly; this can be
detected by one pole crossing a contactor/switch earlier than the other,
which then automatically switches the point to the diverging route.

In the other system, the driver controls it more directly by applying
power; if the bus is coasting, the points will be in the default
direction, if it is drawing power it energises the solenoid that
switches the points.

We have quite a few of these switches in Bucharest. From reading
local-language groups, my understanding is that the exact mechanism of
operation here is that if you draw power for more than X (let's say 5)
seconds inside the "control" zone (a few metres before the switch), that
is what triggers the switch. So if you want to make the turn, you make
sure to draw power for 5 seconds (if you're stuck in traffic, it's
enough to depress the accelerator while holding on the brake), and if
you want to go straight ahead you make sure not to hold the accelerator
any longer than a couple of seconds while in that zone. On this rather
blurry Google Streetview shot you can see the white sign "Macaz cu
comanda dreapta" (roughly translated "Switch commanding right-turn")
which marks the beginning of the control zone:

https://maps.app.goo.gl/ymnptCPRy7ArhKmj9

And here you can see the switch itself, a few metres further down the road:

https://maps.app.goo.gl/kRKsLFtpYNDU1PwA8

The "straight ahead" route actually switches the poles to the left,
while for the right-turn they stay on the same wires.

(Not brilliant pictures, Google's cameras don't appear to be well
optimised for pointing up, and the wires are also a bit complicated here
because you've got trams and trolleys sharing the same street.)

It seems to work pretty reliably, despite general Bucharest
infrastructure maintenance standards, and the fact the wires and switch
are normally buried amid tree foliage. In a near decade of fairly
regularly taking the 79 & 86 trolleybuses (which diverge right here) and
70 (which doesn't), I think I can only remember one occasion where the
driver got it wrong and had to get out and switch the poles.

Clank <clank75@googlemail.com> wrote:
> Late to this party but I switched my main computer a few months ago and
> I've only just got round to installing a newsreader. So using this post
> as an excuse to test a reply...
>
> On 2023-12-05 17:51, Muttley@dastardlyhq.com wrote:
>> On 5 Dec 2023 14:54:45 GMT
>> Marland <gemehabal@btinternet.co.uk> wrote
>>> would have looked quite complicated because of the need to have large
>>> neutral sections where one phase crossed another, trolley buses have them
>>> as well where + and - wires cross but they only need a few inches for a
>>> trolley head whereas pantographs are a lot wider.
>>
>> Problem with trolley wires is they need their own little points to guide the
>> pole onto the correct wire which I imagine makes route setting as complex as
>> any tram system. Perhaps today with smarter AI systems the bus could move the
>> pole appropriately itself.
>
> Unless I'm misunderstanding what you're saying here, trolley points are
> already controlled by the bus itself, and don't rely on any remote
> route-setting system or infrastructure.
>
> The two mechanisms I'm aware of - one based on the angle of the poles,
> another based on the power draw.
>
> In the first system, it relies on the fact that if the bus is turning,
> one of the poles will be leading the other slightly; this can be
> detected by one pole crossing a contactor/switch earlier than the other,
> which then automatically switches the point to the diverging route.
>
> In the other system, the driver controls it more directly by applying
> power; if the bus is coasting, the points will be in the default
> direction, if it is drawing power it energises the solenoid that
> switches the points.
>
>
> We have quite a few of these switches in Bucharest. From reading
> local-language groups, my understanding is that the exact mechanism of
> operation here is that if you draw power for more than X (let's say 5)
> seconds inside the "control" zone (a few metres before the switch), that
> is what triggers the switch. So if you want to make the turn, you make
> sure to draw power for 5 seconds (if you're stuck in traffic, it's
> enough to depress the accelerator while holding on the brake), and if
> you want to go straight ahead you make sure not to hold the accelerator
> any longer than a couple of seconds while in that zone. On this rather
> blurry Google Streetview shot you can see the white sign "Macaz cu
> comanda dreapta" (roughly translated "Switch commanding right-turn")
> which marks the beginning of the control zone:
>
> https://maps.app.goo.gl/ymnptCPRy7ArhKmj9
>
> And here you can see the switch itself, a few metres further down the road:
>
> https://maps.app.goo.gl/kRKsLFtpYNDU1PwA8
>
> The "straight ahead" route actually switches the poles to the left,
> while for the right-turn they stay on the same wires.
>
> (Not brilliant pictures, Google's cameras don't appear to be well
> optimised for pointing up, and the wires are also a bit complicated here
> because you've got trams and trolleys sharing the same street.)
>
>
> It seems to work pretty reliably, despite general Bucharest
> infrastructure maintenance standards, and the fact the wires and switch
> are normally buried amid tree foliage. In a near decade of fairly
> regularly taking the 79 & 86 trolleybuses (which diverge right here) and
> 70 (which doesn't), I think I can only remember one occasion where the
> driver got it wrong and had to get out and switch the poles.
>
>
>

The draw power for one route setting method was used by British systems and
I think a couple used
the other method you mentioned, that still left a lot that were manually
controlled by pulling down a handle on a roadside pole for the diverging
route against a spring which held the frog for the main one. The
traditional British layout with an open rear platform and a conductor
helped as they could easily step off to go and work the handle and step
back on once the trolley heads were past the frogs. At really busy
intersections a member of staff was stationed roadside when it was
busy,often someone like an ex serviceman who had got injured in the war and
could not return driving or conducting. In winter he may even had a small
brazier to keep warm.
This was getting on for around 70+ years ago in the UK so other traffic was
much lighter , nowadays
stepping of a vehicle approaching a turning then making ones way to the
roadside and then back to a bus which has stopped again would soon see an
impatient motorist or cyclist collide with the conductor. And lets face it,
with various modern methods available why would one need to.

GH

On 2023-12-30 19:32, Marland wrote:
> Clank <clank75@googlemail.com> wrote:
>>
>> It seems to work pretty reliably, despite general Bucharest
>> infrastructure maintenance standards, and the fact the wires and switch
>> are normally buried amid tree foliage. In a near decade of fairly
>> regularly taking the 79 & 86 trolleybuses (which diverge right here) and
>> 70 (which doesn't), I think I can only remember one occasion where the
>> driver got it wrong and had to get out and switch the poles.
>
> The draw power for one route setting method was used by British systems and
> I think a couple used
> the other method you mentioned, that still left a lot that were manually
> controlled by pulling down a handle on a roadside pole for the diverging
> route against a spring which held the frog for the main one. The
> traditional British layout with an open rear platform and a conductor
> helped as they could easily step off to go and work the handle and step
> back on once the trolley heads were past the frogs. At really busy
> intersections a member of staff was stationed roadside when it was
> busy,often someone like an ex serviceman who had got injured in the war and
> could not return driving or conducting. In winter he may even had a small
> brazier to keep warm.
> This was getting on for around 70+ years ago in the UK so other traffic was
> much lighter , nowadays
> stepping of a vehicle approaching a turning then making ones way to the
> roadside and then back to a bus which has stopped again would soon see an
> impatient motorist or cyclist collide with the conductor.

I wonder if that's really true? On the continent it's quite common
where the tram lines are in the outside lane of a road for them to stop
and let passengers off directly into the inside lane, and traffic is
expected to be disciplined enough not to run people over. Not just in
the wild east, but in civilised places like (IIRC the most recent place
I noticed) Munich. One does wonder from time to time if the UK takes
things too far in attempting to regulate absolutely all risk out of life...

> And lets face it,
> with various modern methods available why would one need to.

Well, indeed. I presume with a new trolley system you could come up
with a smarter method of driver-controlled points - something like using
a simple power-line networking protocol to allow the bus to communicate
its intentions to the switch (which you could also use to do things like
getting priority at traffic lights and the like.)

On 30/12/2023 20:15, Clank wrote:
> On 2023-12-30 19:32, Marland wrote:
>> Clank <clank75@googlemail.com> wrote:
>>>
>>> It seems to work pretty reliably, despite general Bucharest
>>> infrastructure maintenance standards, and the fact the wires and switch
>>> are normally buried amid tree foliage.  In a near decade of fairly
>>> regularly taking the 79 & 86 trolleybuses (which diverge right here) and
>>> 70 (which doesn't), I think I can only remember one occasion where the
>>> driver got it wrong and had to get out and switch the poles.
>>
>> The draw power for one route setting method was used by British
>> systems and
>> I think a couple used
>> the other method you mentioned, that still left a lot that were manually
>> controlled by pulling down a handle on a roadside pole for the diverging
>> route against a spring which held the frog for the main one.   The
>> traditional British layout with an open rear platform and a conductor
>> helped as they could easily step off to go and work the handle and step
>> back on once the trolley heads were past the frogs. At really busy
>> intersections a member of staff was stationed roadside when it was
>> busy,often someone like an ex serviceman who had got injured in the
>> war and
>> could not return driving or conducting. In winter he may even had a small
>> brazier to keep warm.
>> This was getting on for around 70+ years ago in the UK so other
>> traffic was
>> much lighter , nowadays
>> stepping of a vehicle approaching a turning then making ones way to the
>> roadside and then back to a bus which has stopped again would soon see an
>> impatient motorist or cyclist collide with the conductor.
>
> I wonder if that's really true?  On the continent it's quite common
> where the tram lines are in the outside lane of a road for them to stop
> and let passengers off directly into the inside lane, and traffic is
> expected to be disciplined enough not to run people over.  Not just in
> the wild east, but in civilised places like (IIRC the most recent place
> I noticed) Munich.  One does wonder from time to time if the UK takes
> things too far in attempting to regulate absolutely all risk out of life...

Car drivers in the UK are certainly far more ill disciplined than German
ones.

>
>> And lets face it,
>> with various modern methods available why would one need to.
>
> Well, indeed.  I presume with a new trolley system you could come up
> with a smarter method of driver-controlled points - something like using
> a simple power-line networking protocol to allow the bus to communicate
> its intentions to the switch (which you could also use to do things like
> getting priority at traffic lights and the like.)
>

On 31/12/23 01:10, Clank wrote:

> The two mechanisms I'm aware of - one based on the angle of the poles,
> another based on the power draw.
>
>
Power / coast point controllers are very common on tramways. Largely
replaced now by coded radio transponders as modern 'LRV's with their air
conditioners don't place nice with them. When the air-conditioning is
drawing more power than traction, 'coasting' under the sensor,
significant power is still being drawn.

On double-ended trams with pantographs, the driver has to we aware of
when end the pantograph is over, so they can adjust their 'power-coast'
appropriately to select the route. (Some systems equipped their
bi-directional trams with 2 pantographs, and when changing ends, they
would change pantographs - so the relationship between the pantograph
and the driver was always the same.)

Trolley buses just move the points to the overhead as they have no
track. But largely the same technology was used to select the route.
Same 'problem' , same solution.

On Sat, 30 Dec 2023 16:10:30 +0200, Clank <clank75@googlemail.com>
wrote:

>Late to this party but I switched my main computer a few months ago and
>I've only just got round to installing a newsreader. So using this post
>as an excuse to test a reply...
>
>On 2023-12-05 17:51, Muttley@dastardlyhq.com wrote:
>> On 5 Dec 2023 14:54:45 GMT
>> Marland <gemehabal@btinternet.co.uk> wrote
>>> would have looked quite complicated because of the need to have large
>>> neutral sections where one phase crossed another, trolley buses have them
>>> as well where + and - wires cross but they only need a few inches for a
>>> trolley head whereas pantographs are a lot wider.
>>
>> Problem with trolley wires is they need their own little points to guide the
>> pole onto the correct wire which I imagine makes route setting as complex as
>> any tram system. Perhaps today with smarter AI systems the bus could move the
>> pole appropriately itself.
>
>Unless I'm misunderstanding what you're saying here, trolley points are
>already controlled by the bus itself, and don't rely on any remote
>route-setting system or infrastructure.
>

There are the occasional photographs of junctions with manually set
points (lever at the bottom of the pole, rodding up the pole,
direction indicator part way up the pole). AFAIR they were usually at
permanently-staffed locations such as depots or terminals, presumably
anything more complicated being regarded as unnecessary when a Mk.1
human was always available. ISTR there was also the element that the
points weren't 100% efficient which could have added to local staff
being regarded as a better way of switching.

Am 30.12.2023 um 21:15 schrieb Clank:
> On 2023-12-30 19:32, Marland wrote:
>> Clank <clank75@googlemail.com> wrote:
>>>
>>> It seems to work pretty reliably, despite general Bucharest
>>> infrastructure maintenance standards, and the fact the wires and switch
>>> are normally buried amid tree foliage.  In a near decade of fairly
>>> regularly taking the 79 & 86 trolleybuses (which diverge right here) and
>>> 70 (which doesn't), I think I can only remember one occasion where the
>>> driver got it wrong and had to get out and switch the poles.
>>
>> The draw power for one route setting method was used by British
>> systems and
>> I think a couple used
>> the other method you mentioned, that still left a lot that were manually
>> controlled by pulling down a handle on a roadside pole for the diverging
>> route against a spring which held the frog for the main one.   The
>> traditional British layout with an open rear platform and a conductor
>> helped as they could easily step off to go and work the handle and step
>> back on once the trolley heads were past the frogs. At really busy
>> intersections a member of staff was stationed roadside when it was
>> busy,often someone like an ex serviceman who had got injured in the
>> war and
>> could not return driving or conducting. In winter he may even had a small
>> brazier to keep warm.
>> This was getting on for around 70+ years ago in the UK so other
>> traffic was
>> much lighter , nowadays
>> stepping of a vehicle approaching a turning then making ones way to the
>> roadside and then back to a bus which has stopped again would soon see an
>> impatient motorist or cyclist collide with the conductor.
>
> I wonder if that's really true?  On the continent it's quite common
> where the tram lines are in the outside lane of a road for them to stop
> and let passengers off directly into the inside lane, and traffic is
> expected to be disciplined enough not to run people over.  Not just in
> the wild east, but in civilised places like (IIRC the most recent place
> I noticed) Munich.  One does wonder from time to time if the UK takes
> things too far in attempting to regulate absolutely all risk out of life...

Apart from the fact that 'tram stop in the outside lane' is incompatible
with modern accessibility requirements that typically require a raised
platform, it used to be best practice in Germany that the tram stops
were traffic-light protected, allowing passengers to exit and cross to
the pavement safely.

I remember one situation as a car driver at an unprotected tram stop in
the early 1990's that caused me to read the German highway code: you
were allowed to pass a stopped tram at walking speed ready to stop if
necessary in such situations, i.e. similar to a zebra crossing with the
added challenge that you don't see the person jumping onto the road in
front of you.

Rolf

Rolf

On Mon, 8 Jan 2024 15:40:07 +0100, Rolf Mantel wrote:

> Am 30.12.2023 um 21:15 schrieb Clank:
>> I wonder if that's really true?  On the continent it's quite common
>> where the tram lines are in the outside lane of a road for them to stop
>> and let passengers off directly into the inside lane, and traffic is
>> expected to be disciplined enough not to run people over.  Not just in
>> the wild east, but in civilised places like (IIRC the most recent place
>> I noticed) Munich.  One does wonder from time to time if the UK takes
>> things too far in attempting to regulate absolutely all risk out of
>> life...
>
> Apart from the fact that 'tram stop in the outside lane' is incompatible
> with modern accessibility requirements that typically require a raised
> platform, it used to be best practice in Germany that the tram stops
> were traffic-light protected, allowing passengers to exit and cross to
> the pavement safely.
>

The great city of Munich would like to interject that it doesn't give a
rat's arse about your modern accessibility requirements or best practices:

https://maps.app.goo.gl/d6jsiFobjkEuCcyk7

(You will note the position of the tram rails, the position of the stop
for the number 16 and 17 tram routes, and a complete absence of protecting
traffic lights.)

Then again, I suppose not giving a rat's arse about German best practices
is rather the Bavarian way ;-).

Am 08.01.2024 um 16:19 schrieb Clank:
> On Mon, 8 Jan 2024 15:40:07 +0100, Rolf Mantel wrote:
>
>> Am 30.12.2023 um 21:15 schrieb Clank:
>>> I wonder if that's really true?  On the continent it's quite common
>>> where the tram lines are in the outside lane of a road for them to stop
>>> and let passengers off directly into the inside lane, and traffic is
>>> expected to be disciplined enough not to run people over.  Not just in
>>> the wild east, but in civilised places like (IIRC the most recent place
>>> I noticed) Munich.  One does wonder from time to time if the UK takes
>>> things too far in attempting to regulate absolutely all risk out of
>>> life...
>>
>> Apart from the fact that 'tram stop in the outside lane' is incompatible
>> with modern accessibility requirements that typically require a raised
>> platform, it used to be best practice in Germany that the tram stops
>> were traffic-light protected, allowing passengers to exit and cross to
>> the pavement safely.
>>
>
> The great city of Munich would like to interject that it doesn't give a
> rat's arse about your modern accessibility requirements or best practices:
>
> https://maps.app.goo.gl/d6jsiFobjkEuCcyk7
>
> (You will note the position of the tram rails, the position of the stop
> for the number 16 and 17 tram routes, and a complete absence of protecting
> traffic lights.)

The term 'Grandfather rights' springs to mind. Heidelberg has one
similar tram-stop left but secured by traffic lights (note the cobbles
between the tram tracks); maybe the traffic lights were an additional
safety requirement for running on 'Bundesstraße' (A-Road) only.

https://maps.app.goo.gl/iZp3nZvnhduDBZQm7

The rest was re-built within the last decade to

https://maps.app.goo.gl/JMV2kYJb68BtGf3PA

or

https://maps.app.goo.gl/yQVVJZXQXXW3F3Pb9

>
> Then again, I suppose not giving a rat's arse about German best practices
> is rather the Bavarian way ;-).
>
;-)