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Signal failure at Victoria
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. |
Signal failure at Victoria
To be accurate it's a power outage in Streatham.
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Signal failure at Victoria
In message , at 09:58:26 on Thu, 5 Jul 2018,
Graeme Wall remarked: 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 |
Signal failure at Victoria
In message , at 09:58:26 on Thu, 5 Jul 2018,
Graeme Wall remarked: 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 |
Signal failure at Victoria
Roland Perry wrote:
In message , at 09:58:26 on Thu, 5 Jul 2018, Graeme Wall remarked: 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 |
Signal failure at Victoria
In message , at 11:50:20 on Thu, 5 Jul 2018,
Anna Noyd-Dryver remarked: Roland Perry wrote: In message , at 09:58:26 on Thu, 5 Jul 2018, Graeme Wall remarked: 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 |
Signal failure at Victoria
In message , at 13:34:01 on Thu, 5 Jul
2018, Roland Perry remarked: In message , at 11:50:20 on Thu, 5 Jul 2018, Anna Noyd-Dryver remarked: Roland Perry wrote: In message , at 09:58:26 on Thu, 5 Jul 2018, Graeme Wall remarked: 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. 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/2017/0...data_centre_co nfiguration/ -- Roland Perry |
Signal failure at Victoria
On 05/07/2018 11:28, Roland Perry wrote:
In message , at 09:58:26 on Thu, 5 Jul 2018, Graeme Wall remarked: 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. |
Signal failure at Victoria
On 05/07/2018 14:50, Jim Chisholm wrote:
On 05/07/2018 11:28, Roland Perry wrote: In message , at 09:58:26 on Thu, 5 Jul 2018, Graeme Wall remarked: 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. |
Signal failure at Victoria
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Signal failure at Victoria
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Signal failure at Victoria
On 5 Jul 2018 16:11:54 GMT
Jeremy Double wrote: wrote: On 05/07/2018 14:50, Jim Chisholm wrote: On 05/07/2018 11:28, Roland Perry wrote: In message , at 09:58:26 on Thu, 5 Jul 2018, Graeme Wall remarked: 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. |
Signal failure at Victoria
On 05/07/18 17:28, Jim Chisholm wrote:
On 05/07/2018 17:11, Jeremy Double wrote: wrote: On 05/07/2018 14:50, Jim Chisholm wrote: On 05/07/2018 11:28, Roland Perry wrote: In message , at 09:58:26 on Thu, 5 Jul 2018, Graeme Wall remarked: 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. |
Signal failure at Victoria
On 05/07/2018 12:08, Roland Perry wrote:
In message , at 09:58:26 on Thu, 5 Jul 2018, Graeme Wall remarked: 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). 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 |
Signal failure at Victoria
" Wrote in message:
On 05/07/2018 14:50, Jim Chisholm wrote: On 05/07/2018 11:28, Roland Perry wrote: In message , at 09:58:26 on Thu, 5 Jul 2018, Graeme Wall remarked: 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 cluster**** 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... -- |
Signal failure at Victoria
Roland Perry wrote:
In message , at 11:50:20 on Thu, 5 Jul 2018, Anna Noyd-Dryver remarked: Roland Perry wrote: In message , at 09:58:26 on Thu, 5 Jul 2018, Graeme Wall remarked: 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. 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 |
Signal failure at Victoria
In message , at 11:39:51 on Fri, 6 Jul 2018,
Anna Noyd-Dryver remarked: Roland Perry wrote: In message , at 11:50:20 on Thu, 5 Jul 2018, Anna Noyd-Dryver remarked: Roland Perry wrote: In message , at 09:58:26 on Thu, 5 Jul 2018, Graeme Wall remarked: 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. 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” 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 |
Signal failure at Victoria
Roland Perry wrote:
In message , at 11:39:51 on Fri, 6 Jul 2018, Anna Noyd-Dryver remarked: Roland Perry wrote: In message , at 11:50:20 on Thu, 5 Jul 2018, Anna Noyd-Dryver remarked: Roland Perry wrote: In message , at 09:58:26 on Thu, 5 Jul 2018, Graeme Wall remarked: 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. 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” 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 |
Signal failure at Victoria
In message , at 13:01:35 on Fri, 6 Jul 2018,
Anna Noyd-Dryver remarked: 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. 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” 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 |
Signal failure at Victoria
Roland Perry wrote:
In message , at 13:01:35 on Fri, 6 Jul 2018, Anna Noyd-Dryver remarked: 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” 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” 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 |
Signal failure at Victoria
In message , at 14:33:57 on Fri, 6 Jul 2018,
Anna Noyd-Dryver remarked: Roland Perry wrote: In message , at 13:01:35 on Fri, 6 Jul 2018, Anna Noyd-Dryver remarked: 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” 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? 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” 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 |
Signal failure at Victoria
On 2018-07-06 15:05:43 +0000, Roland Perry said:
In message , at 14:33:57 on Fri, 6 Jul 2018, Anna Noyd-Dryver remarked: Roland Perry wrote: In message , at 13:01:35 on Fri, 6 Jul 2018, Anna Noyd-Dryver remarked: 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” 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. |
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