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Post by MoreToJack on Aug 10, 2019 16:34:10 GMT
Talking of power cuts, how come just the Victoria line was knocked out during nationwide power issues on 9th August 2019?
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Post by MoreToJack on Aug 10, 2019 16:40:33 GMT
Without going into too much detail, the issue was similar to that experienced on Thameslink/Great Northern - trains temporarily disabled as a result of the power surge, as opposed to a loss of traction power. All trains were successfully reset and on the move within thirty minutes (unlike GTR).
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Post by phil on Aug 10, 2019 18:25:11 GMT
Without going into too much detail, the issue was similar to that experienced on Thameslink/Great Northern - trains temporarily disabled as a result of the power surge, as opposed to a loss of traction power. All trains were successfully reset and on the move within thirty minutes (unlike GTR). As far as I am aware Victoria line trains do not use OLE and Siemens multiple units. The reason for the chaos on Thameslink north of City Thameslink is entirely down to the design of the Siemens class 700 / 717 stock when working from OLE. Acording to informed sources, the problem with the 700s and 717s was not the loss of power, or the rebooting. It was the premature rebooting before the overheads were reset that caused the problem. If they don't detect line voltage, the pantograph will automatically drop after 90 seconds. Try that three times and the 4 quadrant chopper, part of the power equipment, will think there's a problem and will lock itself out. It can then only be reset with a laptop. Now, it doesn’t take a genius to realise that if drivers were not awere of this (and most weren't) their attempts to get moving before the OLE power was properly restored means you now have large quantities of trains without air conditioning, working toilets, proper lighting stranded all over the place - blocking junctions, inside tunnels etc. Neuther GTR nor NR have vast armies of technicians with laptops standing by - and those few that GTR do have at Hornsy or Three Bridges are going to take a long time to getting to the trains stuck, particularly the further away they are. Additionally you have to remember that if de-training occurs (either supervised by NR / the TOC or unauthorised as passengers get fed up staying on trains with no power for hours) then the railway must be closed to train movements. Hence even though LNER and East Midlands Trains rolling stock was not affected by the outage - the mass stranding of the GTR / GN fleet still resulted in line closures with no services permitted south of Bedford / Peterborough for a considerable period of time.
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Post by MoreToJack on Aug 10, 2019 20:31:19 GMT
Please let’s not stray into the issues that happened elsewhere on this thread, which is for the Victoria line. The issue has been reported widely for people to be aware of it, but by all means create a new topic if you want to discuss them in more depth (although I would posit the NR delays are off topic for this forum).
I’ve provided as much information as I am willing to share into the public domain. The current collection method and manufacture of the rolling stock is irrelevant; the issues that immobilised the trains were similar, but were successfully solved by tripping and resetting certain systems.
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Post by spsmiler on Aug 10, 2019 23:05:14 GMT
Aha! I only saw the news headlines which talked about power cuts and showed the Victoria line (plus other affected places) - so I did not appreciate that it was a safety system designed to prevent damage from a power surge which brought the trains to a halt. I wonder, had the 1967 stock still been in use would they have been damaged by the power surge - or would they have just carried on regardless.
The news reports I saw showed people on the Victoria line train using mobile devices for illumination. Maybe this was just the camera angle but its a shame that the emergency battery powered lighting was not shown as well. The news media report was somewhat generic, nevertheless the impression gained was that the trains would have been pitch black without the light from the tablets etc. I cannot imagine this having been the situation! Also mentioned were subterranean station passageways where passengers had been left in the dark but I think the news report was referring to stations other than those on the London Underground.
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Post by norbitonflyer on Aug 11, 2019 5:08:47 GMT
Also mentioned were subterranean station passageways where passengers had been left in the dark but I think the news report was referring to stations other than those on the London Underground. The BBC News showed people blundering about in the darkened subway at Clapham Junction, which is definitely not on the London Underground
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class411
Operations: Normal
Posts: 2,724
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Post by class411 on Aug 11, 2019 7:06:18 GMT
Without going into too much detail, the issue was similar to that experienced on Thameslink/Great Northern - trains temporarily disabled as a result of the power surge, as opposed to a loss of traction power. All trains were successfully reset and on the move within thirty minutes (unlike GTR). As far as I am aware Victoria line trains do not use OLE and Siemens multiple units. The reason for the chaos on Thameslink north of City Thameslink is entirely down to the design of the Siemens class 700 / 717 stock when working from OLE. Presumably OLE = Overhead Line <Electric, Electrical, Equipment> GTR = ??
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futurix
Formerly Alex F
The cows are not what they seem.
Posts: 75
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Post by futurix on Aug 11, 2019 7:14:20 GMT
I suspect it's Govia Thameslink Railway.
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Post by phil on Aug 11, 2019 7:38:41 GMT
GTR = Grater Thameslink Railway, the holding company that runs Southern, Gatwick Express, Thameslink and Great Northern brands
OLE = Overhead line electrification.
The reason I gave the detailed explanation of the national rail problems was the implication that GTR were lazy / incompetent in restoring the service compared to London Underground when in reality the failure modes experienced were different and thus impacted service recovery times accordingly.
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DWS
every second count's
Posts: 2,418
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Post by DWS on Aug 11, 2019 8:46:11 GMT
Also mentioned were subterranean station passageways where passengers had been left in the dark but I think the news report was referring to stations other than those on the London Underground. The BBC News showed people blundering about in the darkened subway at Clapham Junction, which is definitely not on the London Underground Why are the subways at Clapham Junction not fitted with emergency lighting, or if not the station should have be closed .
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Post by superteacher on Aug 11, 2019 9:26:09 GMT
GTR = Grater Thameslink Railway, the holding company that runs Southern, Gatwick Express, Thameslink and Great Northern brands OLE = Overhead line electrification. The reason I gave the detailed explanation of the national rail problems was the implication that GTR were lazy / incompetent in restoring the service compared to London Underground when in reality the failure modes experienced were different and thus impacted service recovery times accordingly. I don’t believe there was any implication that GTR were lazy in MoreToJack’s post. Nevertheless, your explanation clarified the issues well.
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DWS
every second count's
Posts: 2,418
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Post by DWS on Aug 11, 2019 9:58:54 GMT
Who were the builders of the present Victoria Line stock ?
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Post by will on Aug 11, 2019 10:03:08 GMT
Who were the builders of the present Victoria Line stock ? Bombardier built the 2009 stock 😊
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Post by spsmiler on Aug 11, 2019 10:24:04 GMT
GTR = Grater Thameslink Railway, the holding company that runs Southern, Gatwick Express, Thameslink and Great Northern brands OLE = Overhead line electrification. The reason I gave the detailed explanation of the national rail problems was the implication that GTR were lazy / incompetent in restoring the service compared to London Underground when in reality the failure modes experienced were different and thus impacted service recovery times accordingly. Phil, your explanation was very much much appreciated. I would hope that lessons from what happened can be learnt, and train control systems are altered so that if ever a similar power supply system occurs again the train drivers will be able to restart the trains without needing laptop support. I also hope that the same ' three attempts and you are out' issue does not also apply to the trains when travelling in third rail mode through the tube train subterranean section between Moorgate and Drayton Park. Its a shame that higher tech introduces new problems that work against speedy service recovery after power supply events.
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class411
Operations: Normal
Posts: 2,724
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Post by class411 on Aug 11, 2019 15:58:08 GMT
Without going into too much detail, the issue was similar to that experienced on Thameslink/Great Northern - trains temporarily disabled as a result of the power surge, as opposed to a loss of traction power. All trains were successfully reset and on the move within thirty minutes (unlike GTR). As far as I am aware Victoria line trains do not use OLE and Siemens multiple units. The reason for the chaos on Thameslink north of City Thameslink is entirely down to the design of the Siemens class 700 / 717 stock when working from OLE. Acording to informed sources, the problem with the 700s and 717s was not the loss of power, or the rebooting. It was the premature rebooting before the overheads were reset that caused the problem. If they don't detect line voltage, the pantograph will automatically drop after 90 seconds. Try that three times and the 4 quadrant chopper, part of the power equipment, will think there's a problem and will lock itself out. It can then only be reset with a laptop. Now, it doesn’t take a genius to realise that if drivers were not awere of this (and most weren't) their attempts to get moving before the OLE power was properly restored means you now have large quantities of trains without air conditioning, working toilets, proper lighting stranded all over the place - blocking junctions, inside tunnels etc. Neuther GTR nor NR have vast armies of technicians with laptops standing by - and those few that GTR do have at Hornsy or Three Bridges are going to take a long time to getting to the trains stuck, particularly the further away they are. Additionally you have to remember that if de-training occurs (either supervised by NR / the TOC or unauthorised as passengers get fed up staying on trains with no power for hours) then the railway must be closed to train movements. Hence even though LNER and East Midlands Trains rolling stock was not affected by the outage - the mass stranding of the GTR / GN fleet still resulted in line closures with no services permitted south of Bedford / Peterborough for a considerable period of time. Does this imply that the motors run on (transformed) 50hz thus each quadrant of a cycle is chopped individually for greater smoothness. I'd always assumed that the power was rectified, then converted to a higher frequency, which would be easier to regulate. Although I suppose that that would not require GTO {Gate Turn Off} thyristors.
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