Discussion:
Signal failure at Victoria
(too old to reply)
Graeme Wall
2018-07-05 08:58:26 UTC
Permalink
Just when you thought it couldn't get any worse…

<https://www.bbc.co.uk/news/uk-england-london-44721415>
--
Graeme Wall
This account not read.
eastender
2018-07-05 10:20:35 UTC
Permalink
To be accurate it's a power outage in Streatham.
Roland Perry
2018-07-05 10:28:31 UTC
Permalink
Post by Graeme Wall
Just when you thought it couldn't get any worse…
<https://www.bbc.co.uk/news/uk-england-london-44721415>
I smell a rat.

It's extremely unlikely that Network Rail has experienced the
simultaneous failure of three separate incoming grid feeds, nor would it
take all day to get just one of them re-instated.

This sounds like the *Network Rail* equipment which merges the three
feeds into the supply to the signalling centre has gone up in smoke.

Any other electricity supply issues reported overnight in Stretham?
--
Roland Perry
Anna Noyd-Dryver
2018-07-05 11:50:20 UTC
Permalink
Post by Roland Perry
Post by Graeme Wall
Just when you thought it couldn't get any worse…
<https://www.bbc.co.uk/news/uk-england-london-44721415>
I smell a rat.
It's extremely unlikely that Network Rail has experienced the
simultaneous failure of three separate incoming grid feeds, nor would it
take all day to get just one of them re-instated.
This sounds like the *Network Rail* equipment which merges the three
feeds into the supply to the signalling centre has gone up in smoke.
Any other electricity supply issues reported overnight in Stretham?
Presumably you’re referring to the tweet referenced in that article
“Passengers are advised not to travel from the South into London this
morning due to total loss of signalling power that Network Rail has
experienced on 3 separate supplies in Streatham area.”? I see no
suggestion that it’s external rather than railway-internal power supplies
which have failed.


Anna Noyd-Dryver
Roland Perry
2018-07-05 12:34:01 UTC
Permalink
Post by Anna Noyd-Dryver
Post by Roland Perry
Post by Graeme Wall
Just when you thought it couldn't get any worse…
<https://www.bbc.co.uk/news/uk-england-london-44721415>
I smell a rat.
It's extremely unlikely that Network Rail has experienced the
simultaneous failure of three separate incoming grid feeds, nor would it
take all day to get just one of them re-instated.
This sounds like the *Network Rail* equipment which merges the three
feeds into the supply to the signalling centre has gone up in smoke.
Any other electricity supply issues reported overnight in Stretham?
Presumably you’re referring to the tweet referenced in that article
“Passengers are advised not to travel from the South into London this
morning due to total loss of signalling power that Network Rail has
experienced on 3 separate supplies in Streatham area.”? I see no
suggestion that it’s external rather than railway-internal power supplies
which have failed.
It's one signalling centre which is without power, thus the "three
supplies" must be those for that centre.

Here's another report from Network Rail (via Simon Calder):

"A generator has been sourced to isolate the power feed and is
expected to arrive at the signalling centre later this morning.
Once the generator arrives, the situation will be re-assessed."

Note, not three generators, one for each of hypothetically three
separate sites.
--
Roland Perry
Roland Perry
2018-07-05 13:45:05 UTC
Permalink
Post by Roland Perry
Post by Anna Noyd-Dryver
Post by Roland Perry
Post by Graeme Wall
Just when you thought it couldn't get any worse…
<https://www.bbc.co.uk/news/uk-england-london-44721415>
I smell a rat.
It's extremely unlikely that Network Rail has experienced the
simultaneous failure of three separate incoming grid feeds, nor would it
take all day to get just one of them re-instated.
This sounds like the *Network Rail* equipment which merges the three
feeds into the supply to the signalling centre has gone up in smoke.
Any other electricity supply issues reported overnight in Stretham?
Presumably you’re referring to the tweet referenced in that article
“Passengers are advised not to travel from the South into London this
morning due to total loss of signalling power that Network Rail has
experienced on 3 separate supplies in Streatham area.”? I see no
suggestion that it’s external rather than railway-internal power supplies
which have failed.
It's one signalling centre which is without power, thus the "three
supplies" must be those for that centre.
"A generator has been sourced to isolate the power feed and is
expected to arrive at the signalling centre later this morning.
Once the generator arrives, the situation will be re-assessed."
Note, not three generators, one for each of hypothetically three
separate sites.
Note that I've seen the post-mortems of various data centre power
outages. They typically have two grid power feeds, plus generators/UPS
on site. What almost always goes wrong (apart from there being no fuel
in the generator tanks because they've been doing too much test-running)
is that occasionally the fail-over mechanisms, err, fail. [When they
work, few outsiders get to hear about it]

While I'm not speculating about the precise cause of this particular
incident, what's happened before is one of two alternate power feeds
failing for a random reason (the kind of back-hoe or other incident
which is why you have two feeds in the first place), then the "fuses
blowing" on the second feed, because instead of the feeds being sized
for (say) 40% each in normal circumstances, thus 80% when one is
operating alone; they turn out to have been supplying 60% each, and
when one fails the other can't supply 120%.

Anyway, here's a recent example of failing fail-over in a different
transport industry:

<https://www.theregister.co.uk/2017/06/02/british_airways_data_centre_co
nfiguration/>
--
Roland Perry
Anna Noyd-Dryver
2018-07-06 11:39:51 UTC
Permalink
Post by Roland Perry
Post by Anna Noyd-Dryver
Post by Roland Perry
Post by Graeme Wall
Just when you thought it couldn't get any worse…
<https://www.bbc.co.uk/news/uk-england-london-44721415>
I smell a rat.
It's extremely unlikely that Network Rail has experienced the
simultaneous failure of three separate incoming grid feeds, nor would it
take all day to get just one of them re-instated.
This sounds like the *Network Rail* equipment which merges the three
feeds into the supply to the signalling centre has gone up in smoke.
Any other electricity supply issues reported overnight in Stretham?
Presumably you’re referring to the tweet referenced in that article
“Passengers are advised not to travel from the South into London this
morning due to total loss of signalling power that Network Rail has
experienced on 3 separate supplies in Streatham area.”? I see no
suggestion that it’s external rather than railway-internal power supplies
which have failed.
It's one signalling centre which is without power, thus the "three
supplies" must be those for that centre.
"A generator has been sourced to isolate the power feed and is
expected to arrive at the signalling centre later this morning.
Once the generator arrives, the situation will be re-assessed."
Note, not three generators, one for each of hypothetically three
separate sites.
Right, here’s some Actual Facts copied from another forum.

<quote>
As I understand it, it was loss of all signalling power to Streatham
Junction Remote Interlocking area. Ex-Southern Region area signalling
installations usually have three seperate incoming power supply sources,
but in this case there was a catastrophic failure of a part of common
equipment. Other sources state that NR has had to bypass the equipment in
hard wiring to get it working again, but before it could do that it first
had to determine what had caused the original failure, and also monitor the
temporary setup to make sure a hidden fault didn't reoccur and cause even
more damage.

Apparently the incident is subject to a formal inquiry which will report
back to the NR Board and the DfT.

Edit to add: This just in from GTR journeycheck:

“The electrical supply that maintains this areas signalling system failed.
The failure has been traced to a faulty power supply cable which feeds off
the national grid.”

Well, that must of given the changeover switchgear a good bang
</quote>

And from another post in the same place:

“Signal power feed triple redundant 3 input BUT the changeover swiitch
(single point of failure) was what burnt out”


Anna Noyd-Dryver
Roland Perry
2018-07-06 12:36:30 UTC
Permalink
Post by Anna Noyd-Dryver
Post by Roland Perry
Post by Anna Noyd-Dryver
Post by Roland Perry
Post by Graeme Wall
Just when you thought it couldn't get any worse…
<https://www.bbc.co.uk/news/uk-england-london-44721415>
I smell a rat.
It's extremely unlikely that Network Rail has experienced the
simultaneous failure of three separate incoming grid feeds, nor would it
take all day to get just one of them re-instated.
This sounds like the *Network Rail* equipment which merges the three
feeds into the supply to the signalling centre has gone up in smoke.
Any other electricity supply issues reported overnight in Stretham?
Presumably you’re referring to the tweet referenced in that article
“Passengers are advised not to travel from the South into London this
morning due to total loss of signalling power that Network Rail has
experienced on 3 separate supplies in Streatham area.”? I see no
suggestion that it’s external rather than railway-internal power supplies
which have failed.
It's one signalling centre which is without power, thus the "three
supplies" must be those for that centre.
"A generator has been sourced to isolate the power feed and is
expected to arrive at the signalling centre later this morning.
Once the generator arrives, the situation will be re-assessed."
Note, not three generators, one for each of hypothetically three
separate sites.
Right, here’s some Actual Facts copied from another forum.
<quote>
As I understand it, it was loss of all signalling power to Streatham
Junction Remote Interlocking area. Ex-Southern Region area signalling
installations usually have three seperate incoming power supply sources,
but in this case there was a catastrophic failure of a part of common
equipment. Other sources state that NR has had to bypass the equipment in
hard wiring to get it working again, but before it could do that it first
had to determine what had caused the original failure, and also monitor the
temporary setup to make sure a hidden fault didn't reoccur and cause even
more damage.
Apparently the incident is subject to a formal inquiry which will report
back to the NR Board and the DfT.
“The electrical supply that maintains this areas signalling system failed.
The failure has been traced to a faulty power supply cable which feeds off
the national grid.”
Well, that must of given the changeover switchgear a good bang
</quote>
“Signal power feed triple redundant 3 input BUT the changeover swiitch
(single point of failure) was what burnt out”
That confirms everything I was saying about the cause, thanks.

It appears to differ from Network Rail's originally announced quick-fix
of generators, unless that's what they used ahead of working out it was
safe to hard-wire one of the two remaining grid feeds.

Thus they still have quite a big project ahead of them - reinstating the
three-way failover equipment (as well as the grid having to make 3/3
rather than 2/3 of the supplies operational).
--
Roland Perry
Anna Noyd-Dryver
2018-07-06 13:01:35 UTC
Permalink
Post by Roland Perry
Post by Anna Noyd-Dryver
Post by Roland Perry
Post by Anna Noyd-Dryver
Post by Roland Perry
Post by Graeme Wall
Just when you thought it couldn't get any worse…
<https://www.bbc.co.uk/news/uk-england-london-44721415>
I smell a rat.
It's extremely unlikely that Network Rail has experienced the
simultaneous failure of three separate incoming grid feeds, nor would it
take all day to get just one of them re-instated.
This sounds like the *Network Rail* equipment which merges the three
feeds into the supply to the signalling centre has gone up in smoke.
Any other electricity supply issues reported overnight in Stretham?
Presumably you’re referring to the tweet referenced in that article
“Passengers are advised not to travel from the South into London this
morning due to total loss of signalling power that Network Rail has
experienced on 3 separate supplies in Streatham area.”? I see no
suggestion that it’s external rather than railway-internal power supplies
which have failed.
It's one signalling centre which is without power, thus the "three
supplies" must be those for that centre.
"A generator has been sourced to isolate the power feed and is
expected to arrive at the signalling centre later this morning.
Once the generator arrives, the situation will be re-assessed."
Note, not three generators, one for each of hypothetically three
separate sites.
Right, here’s some Actual Facts copied from another forum.
<quote>
As I understand it, it was loss of all signalling power to Streatham
Junction Remote Interlocking area. Ex-Southern Region area signalling
installations usually have three seperate incoming power supply sources,
but in this case there was a catastrophic failure of a part of common
equipment. Other sources state that NR has had to bypass the equipment in
hard wiring to get it working again, but before it could do that it first
had to determine what had caused the original failure, and also monitor the
temporary setup to make sure a hidden fault didn't reoccur and cause even
more damage.
Apparently the incident is subject to a formal inquiry which will report
back to the NR Board and the DfT.
“The electrical supply that maintains this areas signalling system failed.
The failure has been traced to a faulty power supply cable which feeds off
the national grid.”
Well, that must of given the changeover switchgear a good bang
</quote>
“Signal power feed triple redundant 3 input BUT the changeover swiitch
(single point of failure) was what burnt out”
That confirms everything I was saying about the cause, thanks.
It appears to differ from Network Rail's originally announced quick-fix
of generators, unless that's what they used ahead of working out it was
safe to hard-wire one of the two remaining grid feeds.
Thus they still have quite a big project ahead of them - reinstating the
three-way failover equipment (as well as the grid having to make 3/3
rather than 2/3 of the supplies operational).
It also confirms that it’s local equipment, not at the signalling centre
itself.


Anna Noyd-Dryver
Roland Perry
2018-07-06 14:00:28 UTC
Permalink
Post by Anna Noyd-Dryver
Post by Roland Perry
Post by Anna Noyd-Dryver
Right, here’s some Actual Facts copied from another forum.
<quote>
As I understand it, it was loss of all signalling power to Streatham
Junction Remote Interlocking area. Ex-Southern Region area signalling
installations usually have three seperate incoming power supply sources,
but in this case there was a catastrophic failure of a part of common
equipment. Other sources state that NR has had to bypass the equipment in
hard wiring to get it working again, but before it could do that it first
had to determine what had caused the original failure, and also monitor the
temporary setup to make sure a hidden fault didn't reoccur and cause even
more damage.
I wonder what it was - they'd have pretty quickly been able to eliminate
back-hoes, smoking substations, and National Grid technicians with
finger trouble.
Post by Anna Noyd-Dryver
Post by Roland Perry
Post by Anna Noyd-Dryver
Apparently the incident is subject to a formal inquiry which will report
back to the NR Board and the DfT.
“The electrical supply that maintains this areas signalling system failed.
The failure has been traced to a faulty power supply cable which feeds off
the national grid.”
Well, that must of given the changeover switchgear a good bang
</quote>
“Signal power feed triple redundant 3 input BUT the changeover swiitch
(single point of failure) was what burnt out”
That confirms everything I was saying about the cause, thanks.
It appears to differ from Network Rail's originally announced quick-fix
of generators, unless that's what they used ahead of working out it was
safe to hard-wire one of the two remaining grid feeds.
Thus they still have quite a big project ahead of them - reinstating the
three-way failover equipment (as well as the grid having to make 3/3
rather than 2/3 of the supplies operational).
It also confirms that it’s local equipment, not at the signalling centre
itself.
"A generator has been sourced to isolate the power feed and is
expected to arrive at the signalling centre later this morning.
Once the generator arrives, the situation will be re-assessed."

So it's just a co-incidence that the signalling centre still had power,
yet they needed to locate a generator there to re-energise the local
equipment?
--
Roland Perry
Anna Noyd-Dryver
2018-07-06 14:33:57 UTC
Permalink
Post by Roland Perry
Post by Anna Noyd-Dryver
Post by Roland Perry
Post by Anna Noyd-Dryver
Right, here’s some Actual Facts copied from another forum.
<quote>
As I understand it, it was loss of all signalling power to Streatham
Junction Remote Interlocking area. Ex-Southern Region area signalling
installations usually have three seperate incoming power supply sources,
but in this case there was a catastrophic failure of a part of common
equipment. Other sources state that NR has had to bypass the equipment in
hard wiring to get it working again, but before it could do that it first
had to determine what had caused the original failure, and also monitor the
temporary setup to make sure a hidden fault didn't reoccur and cause even
more damage.
I wonder what it was - they'd have pretty quickly been able to eliminate
back-hoes, smoking substations, and National Grid technicians with
finger trouble.
From the end of my post:

“Signal power feed triple redundant 3 input BUT the changeover swiitch
(single point of failure) was what burnt out”
Post by Roland Perry
Post by Anna Noyd-Dryver
Post by Roland Perry
Post by Anna Noyd-Dryver
Apparently the incident is subject to a formal inquiry which will report
back to the NR Board and the DfT.
“The electrical supply that maintains this areas signalling system failed.
The failure has been traced to a faulty power supply cable which feeds off
the national grid.”
Well, that must of given the changeover switchgear a good bang
</quote>
“Signal power feed triple redundant 3 input BUT the changeover swiitch
(single point of failure) was what burnt out”
That confirms everything I was saying about the cause, thanks.
It appears to differ from Network Rail's originally announced quick-fix
of generators, unless that's what they used ahead of working out it was
safe to hard-wire one of the two remaining grid feeds.
Thus they still have quite a big project ahead of them - reinstating the
three-way failover equipment (as well as the grid having to make 3/3
rather than 2/3 of the supplies operational).
It also confirms that it’s local equipment, not at the signalling centre
itself.
"A generator has been sourced to isolate the power feed and is
expected to arrive at the signalling centre later this morning.
Once the generator arrives, the situation will be re-assessed."
So it's just a co-incidence that the signalling centre still had power,
yet they needed to locate a generator there to re-energise the local
equipment?
Or that you/we are being over-specific about the terminology used in a
statement that’s probably third-hand when it gets published by someone
who’s not technical staff; and the generator is actually at the site in
Streatham where the problem seems to have occurred, rather than at Three
Bridges ROC which controls the area.


Anna Noyd-Dryver
Roland Perry
2018-07-06 15:05:43 UTC
Permalink
Post by Anna Noyd-Dryver
Post by Roland Perry
Post by Anna Noyd-Dryver
Post by Roland Perry
Post by Anna Noyd-Dryver
Right, here’s some Actual Facts copied from another forum.
<quote>
As I understand it, it was loss of all signalling power to Streatham
Junction Remote Interlocking area. Ex-Southern Region area signalling
installations usually have three seperate incoming power supply sources,
but in this case there was a catastrophic failure of a part of common
equipment. Other sources state that NR has had to bypass the equipment in
hard wiring to get it working again, but before it could do that it first
had to determine what had caused the original failure, and also monitor the
temporary setup to make sure a hidden fault didn't reoccur and cause even
more damage.
I wonder what it was - they'd have pretty quickly been able to eliminate
back-hoes, smoking substations, and National Grid technicians with
finger trouble.
“Signal power feed triple redundant 3 input BUT the changeover swiitch
(single point of failure) was what burnt out”
I meant - what caused it to burn out? Just old age, or was it my
suggestion that when one of the grid feeds failed for a random reason
(they do, which is why one has three) the subsequent load via two of the
contacts on the contact breakers was too high?
Post by Anna Noyd-Dryver
Post by Roland Perry
Post by Anna Noyd-Dryver
Post by Roland Perry
Post by Anna Noyd-Dryver
Apparently the incident is subject to a formal inquiry which will report
back to the NR Board and the DfT.
“The electrical supply that maintains this areas signalling system failed.
The failure has been traced to a faulty power supply cable which feeds off
the national grid.”
Well, that must of given the changeover switchgear a good bang
</quote>
“Signal power feed triple redundant 3 input BUT the changeover swiitch
(single point of failure) was what burnt out”
That confirms everything I was saying about the cause, thanks.
It appears to differ from Network Rail's originally announced quick-fix
of generators, unless that's what they used ahead of working out it was
safe to hard-wire one of the two remaining grid feeds.
Thus they still have quite a big project ahead of them - reinstating the
three-way failover equipment (as well as the grid having to make 3/3
rather than 2/3 of the supplies operational).
It also confirms that it’s local equipment, not at the signalling centre
itself.
"A generator has been sourced to isolate the power feed and is
expected to arrive at the signalling centre later this morning.
Once the generator arrives, the situation will be re-assessed."
So it's just a co-incidence that the signalling centre still had power,
yet they needed to locate a generator there to re-energise the local
equipment?
Or that you/we are being over-specific about the terminology used in a
statement that’s probably third-hand when it gets published by someone
who’s not technical staff; and the generator is actually at the site in
Streatham where the problem seems to have occurred, rather than at Three
Bridges ROC which controls the area.
Perhaps it's a case of over-reading "signalling centre" to mean "ROC",
when what they mean is a portacabin on the trackside somewhere in
Stretham.

ps Kudos for being the first person to note the ROC isn't in Stretham.
--
Roland Perry
Sam Wilson
2018-07-06 15:25:18 UTC
Permalink
Post by Roland Perry
Post by Anna Noyd-Dryver
Post by Roland Perry
Post by Anna Noyd-Dryver
Right, here’s some Actual Facts copied from another forum.
<quote>
As I understand it, it was loss of all signalling power to Streatham
Junction Remote Interlocking area. Ex-Southern Region area signalling
installations usually have three seperate incoming power supply sources,
but in this case there was a catastrophic failure of a part of common
equipment. Other sources state that NR has had to bypass the equipment in
hard wiring to get it working again, but before it could do that it first
had to determine what had caused the original failure, and also monitor the
temporary setup to make sure a hidden fault didn't reoccur and cause even
more damage.
I wonder what it was - they'd have pretty quickly been able to eliminate
back-hoes, smoking substations, and National Grid technicians with
finger trouble.
“Signal power feed triple redundant 3 input BUT the changeover swiitch
(single point of failure) was what burnt out”
I meant - what caused it to burn out? Just old age, or was it my
suggestion that when one of the grid feeds failed for a random reason
(they do, which is why one has three) the subsequent load via two of
the contacts on the contact breakers was too high?
We had an incident not long ago during an electrical refurbishment
where, IIRC, the main switch "fell apart". It took several days for a
replacement to be sourced from abroad (Germany, I think) and during
that time a major site ran on generators (parts of it didn't run at all
for some of the time).

Sam
--
The University of Edinburgh is a charitable body, registered in
Scotland, with registration number SC005336.
Jim Chisholm
2018-07-05 13:50:47 UTC
Permalink
Post by Roland Perry
Post by Graeme Wall
Just when you thought it couldn't get any worse…
<https://www.bbc.co.uk/news/uk-england-london-44721415>
I smell a rat.
Of course it could be a rat (probably fried)
&
I bet a lot of equipment cabinets are not designed to dissipate the sort
of heat we currently have. I remember building simple circuits and
seeing how tolerant they were to both low and high temperatures as they
were to be in a field.
h***@yahoo.co.uk
2018-07-05 14:45:00 UTC
Permalink
Post by Jim Chisholm
Post by Roland Perry
Post by Graeme Wall
Just when you thought it couldn't get any worse…
<https://www.bbc.co.uk/news/uk-england-london-44721415>
I smell a rat.
Of course it could be a rat (probably fried)
&
I bet a lot of equipment cabinets are not designed to dissipate the sort
of heat  we currently have. I remember building simple circuits and
seeing how tolerant they were to both low and high temperatures as they
were to be in a field.
I wonder how often failures like this occur in India due to heat?

We do have hot summers and cold winters -- perhaps not to the same
degree and length, respectively, as India and Russia, but nonetheless we
are hit with weather extremes.
martin.coffee
2018-07-05 15:35:01 UTC
Permalink
Post by h***@yahoo.co.uk
Post by Jim Chisholm
Post by Roland Perry
Post by Graeme Wall
Just when you thought it couldn't get any worse…
<https://www.bbc.co.uk/news/uk-england-london-44721415>
I smell a rat.
Of course it could be a rat (probably fried)
&
I bet a lot of equipment cabinets are not designed to dissipate the
sort of heat  we currently have. I remember building simple circuits
and seeing how tolerant they were to both low and high temperatures as
they were to be in a field.
I wonder how often failures like this occur in India due to heat?
We do have hot summers and cold winters -- perhaps not to the same
degree and length, respectively, as India and Russia, but nonetheless we
are hit with weather extremes.
Even if the equipment is designed for these temperatures it is being
stressed in a way that faults not normally apparat will emerge so it is
not surprising that that there are heat related problems.
Jeremy Double
2018-07-05 16:11:54 UTC
Permalink
Post by h***@yahoo.co.uk
Post by Jim Chisholm
Post by Roland Perry
Post by Graeme Wall
Just when you thought it couldn't get any worse…
<https://www.bbc.co.uk/news/uk-england-london-44721415>
I smell a rat.
Of course it could be a rat (probably fried)
&
I bet a lot of equipment cabinets are not designed to dissipate the sort
of heat  we currently have. I remember building simple circuits and
seeing how tolerant they were to both low and high temperatures as they
were to be in a field.
I wonder how often failures like this occur in India due to heat?
We do have hot summers and cold winters -- perhaps not to the same
degree and length, respectively, as India and Russia, but nonetheless we
are hit with weather extremes.
The annual temperature ranges in the UK are nowhere near as large as in
(say) Siberia or Chicago. The UK has a maritime climate, which means a
relatively small variation from winter to summer.
--
Jeremy Double
Jim Chisholm
2018-07-05 16:28:37 UTC
Permalink
Post by Jeremy Double
Post by h***@yahoo.co.uk
Post by Jim Chisholm
Post by Roland Perry
Post by Graeme Wall
Just when you thought it couldn't get any worse…
<https://www.bbc.co.uk/news/uk-england-london-44721415>
I smell a rat.
Of course it could be a rat (probably fried)
&
I bet a lot of equipment cabinets are not designed to dissipate the sort
of heat  we currently have. I remember building simple circuits and
seeing how tolerant they were to both low and high temperatures as they
were to be in a field.
I wonder how often failures like this occur in India due to heat?
We do have hot summers and cold winters -- perhaps not to the same
degree and length, respectively, as India and Russia, but nonetheless we
are hit with weather extremes.
The annual temperature ranges in the UK are nowhere near as large as in
(say) Siberia or Chicago. The UK has a maritime climate, which means a
relatively small variation from winter to summer.
That means it is not (normally) economical viable to 'design' for
extreme temperatures. We didn't used to point heaters or paint them
white! I don't know if I dare mention Climate (variation).
martin.coffee
2018-07-05 18:32:06 UTC
Permalink
Post by Jim Chisholm
Post by Jeremy Double
Post by h***@yahoo.co.uk
Post by Jim Chisholm
Post by Roland Perry
Post by Graeme Wall
Just when you thought it couldn't get any worse…
<https://www.bbc.co.uk/news/uk-england-london-44721415>
I smell a rat.
Of course it could be a rat (probably fried)
&
I bet a lot of equipment cabinets are not designed to dissipate the sort
of heat  we currently have. I remember building simple circuits and
seeing how tolerant they were to both low and high temperatures as they
were to be in a field.
I wonder how often failures like this occur in India due to heat?
We do have hot summers and cold winters -- perhaps not to the same
degree and length, respectively, as India and Russia, but nonetheless we
are hit with weather extremes.
The annual temperature ranges in the UK are nowhere near as large as in
(say) Siberia or Chicago.  The UK has a maritime climate, which means a
relatively small variation from winter to summer.
That means it is not (normally) economical viable to 'design' for
extreme temperatures. We didn't used to point heaters or paint them
white! I don't know if I dare mention Climate (variation).
The extreme temperatures will produce faults in equipment designed for
such temperatures but still capable of operating quite satisfactorily
the rest of the time.
b***@cylonHQ.com
2018-07-05 18:25:53 UTC
Permalink
On 5 Jul 2018 16:11:54 GMT
Post by Jeremy Double
Post by h***@yahoo.co.uk
Post by Jim Chisholm
Post by Roland Perry
Just when you thought it couldn't get any worse

<https://www.bbc.co.uk/news/uk-england-london-44721415>
I smell a rat.
Of course it could be a rat (probably fried)
&
I bet a lot of equipment cabinets are not designed to dissipate the sort
of heat  we currently have. I remember building simple circuits and
seeing how tolerant they were to both low and high temperatures as they
were to be in a field.
I wonder how often failures like this occur in India due to heat?
We do have hot summers and cold winters -- perhaps not to the same
degree and length, respectively, as India and Russia, but nonetheless we
are hit with weather extremes.
The annual temperature ranges in the UK are nowhere near as large as in
(say) Siberia or Chicago. The UK has a maritime climate, which means a
relatively small variation from winter to summer.
I think its fair to say the climate has changed in the last couple of
decades and the changes are becoming more pronounced. One can argue the
toss over whether its man made or natural, but either way equipment needs
to be made resilient against this whether than involved upgrading installed
equipment or replacing it with new kit.
Clank
1970-01-01 00:00:00 UTC
Permalink
Post by h***@yahoo.co.uk
Post by Jim Chisholm
Post by Roland Perry
Just when you thought it couldn't get any worse

<https://www.bbc.co.uk/news/uk-england-london-44721415>
I smell a rat.
Of course it could be a rat (probably fried)
&
I bet a lot of equipment cabinets are not designed to dissipate the sort
of heat we currently have. I remember building simple circuits and
seeing how tolerant they were to both low and high temperatures as they
were to be in a field.
I wonder how often failures like this occur in India due to heat?
We do have hot summers and cold winters -- perhaps not to the same
degree and length, respectively, as India and Russia, but nonetheless we
are hit with weather extremes.
The 'normal' annual range here is about 60c, from lows at around -20c in winter to highs of around 40c in summer. A couple of years ago we had an absolute stinker of a winter and they recorded a low of -33 in Brasov; last summer it was crazy hot, notable not so much for the temperature (> 40c, but that's to be expected at least a day or two every year) but that it was that easy for days at a time. Somewhat concerned this year could be a repeat - when I left the house at 9.30 this morning it was already north of 31c by the weather station on my balcony :-).

Our datacentre has never had a cooling related outage ;-). Actually, thinking about it, it's never had an outage at all.


I am reminded though of a monumental clusterfuck that happened to the Netherlands (Schipol) datacentre of a certain large satellite broadcaster while I was working there... Power was lost, so the generators kicked in and everything worked smoothly as planned. Until one of the power control units gave up in a shower of sparks. No problem, the backup was ok... Until 5 minutes later it did exactly the same thing. And the whole datacentre was down...

Root cause was sort-of aircon. The UPS+Power control kit was in shipping containers outside the datacentre, with their own cooling system. At some point this cooling system had failed, and an on-site genius had solved the problem by propping the doors of the containers open and letting fresh air do the job. This worked well enough that evidently nobody ever got round to fixing the aircon...

The problem wasn't that the power control units overheated. It was that moist (salty, being right next to the North Sea) spray/moisture had been getting into to the power control unit all the time those doors had been propped open, corroding the circuit boards, and leading to both units failing identically one after the other...






--
Roland Perry
2018-07-05 11:08:31 UTC
Permalink
Post by Graeme Wall
Just when you thought it couldn't get any worse…
<https://www.bbc.co.uk/news/uk-england-london-44721415>
It just did:

11:23
Disruption expected until 7am tomorrow

National Rail has now said disruption will continue until at least 7am
tomorrow morning (Friday, July 6).
--
Roland Perry
Clive Page
2018-07-05 21:10:29 UTC
Permalink
Post by Roland Perry
Post by Graeme Wall
Just when you thought it couldn't get any worse…
<https://www.bbc.co.uk/news/uk-england-london-44721415>
11:23
Disruption expected until 7am tomorrow
National Rail has now said disruption will continue until at least 7am tomorrow morning (Friday, July 6).
I can see why the Thameslink services on the Sutton-Wimbledon loop are affected, as well as others that use that part of the system. But this morning at least the Bedford-Brighton/Gatwick trains appeared to be getting through more or less on-time as presumably the route from Blackfriars to London Bridge and then East Croydon wasn't affected at all. So two questions to which I can't find an answer:

(1) Why didn't they tell people who couldn't get trains from Victoria to Gatwick or Brighton just to take the circle line a few stops to Blackfriars and get on a working Thameslink train?

(2) Why has the Thameslink service gone tits-up this evening - I see a gap of more than 2 hours between successive northbound trains to Bedford. There seems no obvious reason.
--
Clive Page
Loading...