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Post by chilsie on Mar 19, 2024 23:50:13 GMT
I was surprised at the magnitude of what happened, though I kind of had an inkling that something was wrong quite quickly. I was at Fulham Broadway leaving a football game when we were held on the platform for about five minutes with the driver informing us we were “waiting for the signalling system to pick the train up”, which was immediately a sign of something wrong. I then saw three trains unusually close to each other on the opposite side as we headed towards West Brompton, though the biggest whopper came when we arrived at High Street Ken, the train’s terminus, and were informed that the entire Edgware Road-Earl’s Court section had been completely suspended!
Would anyone be able to share further knowledge on what happened to the system which caused such carnage?
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Post by Dstock7080 on Mar 20, 2024 6:45:26 GMT
The failure first occurred on Saturday 16 March at 0600 when VCC4 Vehicle Control Centre crashed, and trains were unable operate across the boundary between 3 and 4 Monument, 4 and 5 Sloane Square.
All trains stopped communicating with the Control Centre.
Unfortunately a trespasser compounded the attempts to move trains manually (one at a time) away from the failure area to reboot the VCC.
After 0900 the boundary were reset and train were moved away from the boundary conflict points.
The VCC was rebooted at 1035 and movement was regained.
Unfortunately the failure reoccurred at 1745 when an engineers train came across the boundary from VCC3, which was under possession for the weekend.
Services resumed around 1830 with severe delays advertised until close of traffic.
Sunday 17 March; VCC4 failure reoccurred 1420, service suspended West Ham-Ealing/Richmond/Wimbledon and Edgware Road service.
Service resumed between Upminster and Whitechapel 2130 but remained suspended for passengers on rest of Line until close of traffic. Test trains were run empty from across the suspended section during the evening.
It was concluded that engineers trains working within the weekend possession Wembley Park-Aldgate East, which included VCC3 Euston Square-Monument/Stepney Green had sometimes incorrectly used their CBTC equipment for movement, disrupting the interface between the passenger trains along the District part of SMA3.
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Post by brigham on Mar 20, 2024 8:27:39 GMT
"It was concluded that engineers trains.../ /... had sometimes incorrectly used their CBTC equipment for movement".
I hope that the cause of the odd behaviour of these trains has been investigated.
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Post by zbang on Mar 20, 2024 15:37:15 GMT
I rather expect that some of the software folks are all over this.
Me- "When I do YYY, the system crashes."
Programmer- "Well, don't do that."
Me- "Don't let me."
(actual conversation I've had multiple times with software developers)
I'd also love to hear about the root cause, but that's unlikely.
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gefw
Gone - but still interested
Posts: 201
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Post by gefw on Mar 21, 2024 15:38:53 GMT
Bearing in mind that it is a safety critical system. I tend to concur with the failsafe principle being employed when an unacceptable/unexpected condition has occured.
The term "software crash" may not be a suitable description - one would expect the system to go into a "protected state", hopefully giving error messages and requiring some intervention to resume/reset/ignore.
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Tom
Administrator
Signalfel?
Posts: 4,196 
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Post by Tom on Mar 21, 2024 22:02:32 GMT
I rather expect that some of the software folks are all over this They are. (Obviously can't say much more.) |
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class411
Operations: Normal
Posts: 2,743
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Post by class411 on Mar 22, 2024 15:11:48 GMT
Bearing in mind that it is a safety critical system. I tend to concur with the failsafe principle being employed when an unacceptable/unexpected condition has occured. The term "software crash" may not be a suitable description - one would expect the system to go into a "protected state", hopefully giving error messages and requiring some intervention to resume/reset/ignore. On the railways, "I'm sorry Dave, I can't do that", is acceptable, given an unsupported exception condition. On an Airbus, less so. |
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Post by ijmad on May 29, 2024 16:36:44 GMT
Same thing again today? Or a different problem?
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Post by starlight73 on May 29, 2024 19:22:21 GMT
Not sure if it affected the circle line equally badly - I got the impression the Circle line’s disruption recovered faster. (It was on ‘minor delays’ while the affected branch of the district was still on ‘severe delays’, but as has been discussed here before, those messages are what TfL choose to report)
in fact - the Circle line has no reported disruption now and the District is still suspended between High Street Kensington and Edgware Road. Is it a problem with either the District’s side of the triangle, or its Edgware Road platform?
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DWS
every second count's
Posts: 2,487
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Post by DWS on May 29, 2024 19:27:29 GMT
The District Line has had no service between High Street Kensington and Edgware Road for most of today.
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Colin
Advisor
My preserved fire engine!
Posts: 11,346
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Post by Colin on May 29, 2024 23:30:53 GMT
Same thing again today? Or a different problem? Different issue entirely - point failure in the High Street Kensington area. |
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Post by ijmad on May 31, 2024 13:06:27 GMT
Same thing again today? Or a different problem? Different issue entirely - point failure in the High Street Kensington area. Ah fair enough, it initially came up on the status boards as a signal failure. Thanks for clarifying. |
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Post by t697 on May 31, 2024 16:50:22 GMT
Likely points detection or locking, which falls into the Signals category.
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