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Post by norbitonflyer on Jan 30, 2011 20:53:33 GMT
The distinction that I am drawing is between a 'technical' SPAD and a 'non-technical' SPAD - which is indeed scenario B. In no way am I attempting to give the impression that an over-run is a trivial matter, merely that some are less worse than others. Indeed the RAIB categorises SPADs as being of four types - three of which are "unavoidable" (caused by a signal going to red in front of a train for example due to emergency or technical fault,) and with no less than 28 degrees of seriousness based on the potential or actual consequences, including how far into or beyond the overlap the train went. The general public rarely understand that "running a red" on a railway is a very different matter to doing so on the roads. In normal use a railway signal should never go to red ahead of a driver, as it does on the roads - leading to "amber-gambling", which can save a driver a several minutes at some junctions. In contrast, there is nothing to be gained by passing a red signal on the rails: if the signal is red the line is simply not ready for the train for some reason: at best, you will end up going the wrong way. The difference is best realised bt thinking about the difference between amber/yellow signals in the two environments. On the roads, an amber signal is a warning to approaching drivers that it is about to go red. On the rails, if it changes in front of an approaching driver at all, it will be to green. |
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Post by andypurk on Jan 30, 2011 21:59:52 GMT
The distinction that I am drawing is between a 'technical' SPAD and a 'non-technical' SPAD - which is indeed scenario B. In no way am I attempting to give the impression that an over-run is a trivial matter, merely that some are less worse than others. Indeed the RAIB categorises SPADs as being of four types - three of which are "unavoidable" (caused by a signal going to red in front of a train for example due to emergency or technical fault,) and with no less than 28 degrees of seriousness based on the potential or actual consequences, including how far into or beyond the overlap the train went. The general public rarely understand that "running a red" on a railway is a very different matter to doing so on the roads. In normal use a railway signal should never go to red ahead of a driver, as it does on the roads - leading to "amber-gambling", which can save a driver a several minutes at some junctions. In contrast, there is nothing to be gained by passing a red signal on the rails: if the signal is red the line is simply not ready for the train for some reason: at best, you will end up going the wrong way. The difference is best realised bt thinking about the difference between amber/yellow signals in the two environments. On the roads, an amber signal is a warning to approaching drivers that it is about to go red. On the rails, if it changes in front of an approaching driver at all, it will be to green. Legally though, the amber on the road is more restrictive than that, as it means stop unless it is not safe to do so or you are already over the stop line. Of course, this gets heavily abused and many people now seem to consider that it is just a warning. The amber is also used as a warning that the lights are about to go green, either when it appears along with the red, or at pedestrian crossings to warn that pedestrians may still be there. |
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Post by mcmaddog on Jan 30, 2011 22:24:46 GMT
Does anyone have news of Dollis Hill-Stanmore commissioning and/or a new WTT to take advantage of the new capabilities?
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Post by version3point1 on Jan 31, 2011 20:28:16 GMT
Defective train today. Services suspended between London Bridge and Stratford when I traveled at around 3PM I think. We initially suspended Stratford – Green Park after a train became defective at North Greenwich Platform 1. After we lost this road, trains began to run via Platform 2, only for the second departure to stall between North Greenwich and Canary Wharf. Can't really go into any more details, but it has been established that there may be a defect in the loop in the NGW – CWF area as trains have been having problems departing WB or developing problems after leaving for Canary Wharf on a day-to-day basis. NGW have also lost use of the RTDIs since Thursday and this may indicate the same root cause. We're waiting for somebody to get back to us about it, though a whole bunch of Thales guys and Tube Lines TOs did turn up to have a walkabout. |
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Post by flippyff on Jan 31, 2011 22:22:29 GMT
I was almost caught in the Jubbly suspension yesterday, I got off the ELL at Canada Water (so much for all those announcements possible on a 378) and just as I reached the bottom of the escalated a station control room announcement was made saying the line was suspended between Green Park and Stratford - the people coming down the escalator behind me hadn't heard it and rushed for the trains. The westbound train then departed and the announcement was then made that there were no eastbound trains.
(Back on the ELL to Shadwell, help a confused Hammers fan find the DLR and DLR it down to Woolwich instead of North Greenwich).
Simon
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Post by Bighat on Jan 31, 2011 22:31:05 GMT
Defective train today. Services suspended between London Bridge and Stratford when I traveled at around 3PM I think. We initially suspended Stratford – Green Park after a train became defective at North Greenwich Platform 1. After we lost this road, trains began to run via Platform 2, only for the second departure to stall between North Greenwich and Canary Wharf. Can't really go into any more details, but it has been established that there may be a defect in the loop in the NGW – CWF area as trains have been having problems departing WB or developing problems after leaving for Canary Wharf on a day-to-day basis. NGW have also lost use of the RTDIs since Thursday and this may indicate the same root cause. We're waiting for somebody to get back to us about it, though a whole bunch of Thales guys and Tube Lines TOs did turn up to have a walkabout. What's all this 'Tube Lines' nonsense?  Surely they are no more??? ;D ;D ;D |
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Tom
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Post by Tom on Jan 31, 2011 23:56:11 GMT
What's all this 'Tube Lines' nonsense? Surely they are no more??? ;D ;D ;D Quite the opposite; Tube Lines is a Wholly-Owned subsidiary of TfL and legally has to be maintained as a separate company from LU. |
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Post by edwin on Jan 31, 2011 23:57:04 GMT
I have two questions.
1) When the new platform at Stratford comes into fore, will Willesden Green/West Hampstead/Wembley Park reversers end?
2) What is the speed limit on the line under ATO? I remember reading on here that the JLE has no speed limits... Whats the speed limit on the JLE now?
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Post by Tom on Feb 1, 2011 0:06:34 GMT
I have two questions. 1) When the new platform at Stratford comes into fore, will Willesden Green/West Hampstead/Wembley Park reversers end? 2) What is the speed limit on the line under ATO? I remember reading on here that the JLE has no speed limits... Whats the speed limit on the JLE now? I take it you mean Stanmore? I'm not too sure on the line speed now, but all railways have a maximum speed (known as Vmax) which comes from the Track Engineer. This takes into account things like track curvature, clearances, cants (and change of cant) etc. |
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Post by abe on Feb 1, 2011 8:17:57 GMT
It's by a company called Thales... say it out loud. It's pronounced Tallis, or Tarlis (I've heard both used). |
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Post by mrfs42 on Feb 1, 2011 13:34:37 GMT
I have two questions. 1) When the new platform at Stratford comes into fore, will Willesden Green/West Hampstead/Wembley Park reversers end? I suspect that the West Hampstead ones will vanish into rusty rail manœuvres as that is the least used of the lot - there is a definite pattern of NOG - WmP shorties during the run up to evening busy. The booked usage of the other two flip-flops to a regular pattern of Stanmore/Willesden Green/Stanmore/Wembley Park and repeat. Even with the third platform at Stanmore, I suspect that some element of Wembley Park reversers will continue, quite possibly as a continuation of the NOG - WmP 'shuttles'. It's by a company called Thales... say it out loud. It's pronounced Tallis, or Tarlis (I've heard both used). Rhymes with Neanderthal, as in 'tʰāles'. There is vestigial residual aspiration of the dental 't': tʰ and there is lengthening of the 'a' hence the macron. |
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Post by Deleted on Feb 2, 2011 19:03:58 GMT
Once again as a non regular tube user, I am behind the trend. But I took the Jub for the first time since TBTC has been introduced. I have to say I was very impressed. I travelled from Southwark to Bond Street. Southwark to Waterloo was a little of the heavy acceleration then cruise (jerky effect) that has been mentioned. I have to say I found it a little ironic as it's probably the shortest distance between two stations on the Jub. After that the acceleration and so average speed was ratcheted up and the ride became very smooth. I was particularly impressed with Westminster to Green Park and then Green Park to Bond Street.The journey was so much improved, I was 5 minutes earlier than I had wanted. Now for a journey that prior to TBTC took me about 15 minutes tops when a 'good service' was in operation during rush hour, that is very good going!
While it's taken a long time to arrive and the service isn't fully operational, am thinking this bodes well for Jub and Northern line passengers.
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Dom K
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Post by Dom K on Feb 2, 2011 19:33:50 GMT
Looks like TBTC has died tonight, "Signal System Failure" reported on TFL website! Oh dear, sounds chaotic!
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Post by plasmid on Feb 2, 2011 20:15:35 GMT
Looks like TBTC has died tonight, "Signal System Failure" reported on TFL website! Oh dear, sounds chaotic! I wouldn't say it's "chaotic". TFL can't say there are delays because of a signal failure because there are no more signals on most of the line hence "signal systems failure". I believe this term will become more significantly used. And even since the new signalling has been introduced on the majority of the line, I feel as if there have been less delays. With the old system, a signal failure seemed to be a daily occurrence. |
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Post by jswallow on Feb 2, 2011 20:33:01 GMT
Seeing as the entire line was suspended as a result, chaotic sounds a pretty good definition to me - even if it were only for a short time.
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Post by Deleted on Feb 2, 2011 21:27:52 GMT
So this system doesn't have light bulbs then? That's sure a good thing. Having a line brought down because a bulb has blown is too glass jaw to be funny.
Hopefully, this is just teething trouble. Remember the bathtub curve. And hopefully, the system doesn't run on Windows Server 2008.
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Post by Deleted on Feb 4, 2011 5:44:27 GMT
I'm pretty sure the Seltrac system that San Francisco bought runs on OS/2. No idea about the Jubilee one, hopefully they used a more sensible operating system that will still be maintainable in 10 years.
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Ben
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Post by Ben on Feb 4, 2011 15:31:00 GMT
How warped  |
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Post by Chris M on Feb 4, 2011 16:13:48 GMT
Embedded system operating systems are different to (and differently supported than) the standard consumer OSes they are based on. Basically they are supported until the end of the life of whatever they're embedded in, and are often based on relatively old OSes as the key requirement is stability and reliability rather than flexibility and the ability to cope with new hardware/software.
Any computer system will continue to do what it did on day one as well as it did it on day one until the hardware fails, in the absence of any other changes. This is an exceedingly rare environment for a home computer system (massively more so since the internet became common), but is the norm for embedded systems.
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Post by Deleted on Feb 4, 2011 17:52:44 GMT
There is some value to extensibility though. I'm not sure what that value would be to a railway line, but when it comes to managing an offshore installation, new bits are added and old bit are taken away all the time.
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Post by Deleted on Feb 5, 2011 4:02:15 GMT
From what I've heard, the San Francisco system has been end-of-lifed by the vendor, and Muni can't really do much about it, because it's impossible for them to modify it. While this sort of thing is a problem with traditional signalling too, the life cycles with computers are much shorter and the systems are harder to get inside and fix. At least with relay-based logic, LU has the whole wiring diagram and can replace individual components and rewire individual sections. And I imagine more conventional CBI has some kind of logic table, such that you can make a new one if the track layout changes. From what I've heard about SelTrac, everything in there is hardcoded, so any change requires a recompile, and Thales doesn't give out the source code. It's not extensible at all, just a black box that LU gets with a sticker saying "no user-serviceable parts inside, opening the box voids warranty". So if the Met or Bakerloo get new signal systems, I can imagine there will be some difficulty. And I can imagine even more difficulty when the line gets new trains with new and potentially incompatible on-board computers.
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Post by Deleted on Feb 5, 2011 10:16:52 GMT
I see that following yet another complete breakdown on the Jubilee Line in the morning rush hour, Mayor Boris Johnson asked for a "complete report" from Commissioner Hendy on his desk by the end of the day. www.bbc.co.uk/news/uk-england-london-12367400I wonder if the "complete report" will do what TfL usually do, and say "Good Service" about all those times people were unable to even get into infrequent and overloaded trains? Meanwhile, I was driving off to a business meeting yesterday, and at 09.00 Commissioner Hendy came on the car radio in what is apparently a regular appearence on one of the radio stations, and the subject of what was happening on the Jubilee Line came up, which was being reported on the travel news. Mr Hendy tried to say that it was just unfortunate that it had happened that morning and that things were all going well on the Jubilee Line - which someone who telephoned the radio programme then rebutted, and described the never-ending issues. As someone who has seen the constant disruptions to morning business meetings at Canary Wharf since the New Year and the new signals, I just wonder how there can be this difference in view. It could be that the Commissioner is just trying to gloss over reality, which would be unacceptable. On the other hand it could be that as news of yet another breakdown is passed up the layers of management is is progressively sanitised at each stage, until what is described to him bears little relationship to what is going on - the "Good Service" syndrome, of course. I do wonder what the report actually said in the end. If it lists all the occasions when things on the Jubilee Line have been badly disrupted over the last 12 months, I hope the printer in the TfL office has been loaded with plenty of paper. |
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Post by Deleted on Feb 5, 2011 23:07:03 GMT
I'm sure what he actually said was that the service had been working better than the old system, on the whole.
You never know, this could be true. The old system was hardly the most reliable system ever!
On the other hand, it'll be nice when the Jubilee is actually known widely as being reliable
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Post by Deleted on Feb 5, 2011 23:11:40 GMT
Its doing worse than the Northern line at the moment! But I suppose any new computer based stuff is gona have problems at first. Anyone know how smoothly the Central line upgrade went?
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Post by jamesb on Feb 7, 2011 2:52:56 GMT
There seem to have been a number of service suspensions at the Stratford end recently - Friday morning, Friday evening, Sunday evening.
How do defective trains become defective in the context of the signaling? I read somewhere that they 'stop talking to the signaling requiring the system to be reset'. What does this actually mean?
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Post by Deleted on Feb 7, 2011 6:39:34 GMT
Another morning, another faulty train...
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Post by Deleted on Feb 7, 2011 12:45:17 GMT
Disorganisation of the Jubilee Line both last Friday morning and this morning are the principal topic around Canary Wharf this morning. I would say topic "over coffee", but nobody seems to have any time for that today due to being late in again. At least it's not as bad as last Friday apparently was (I was elsewhere) when there was a huge loss of productivity and people missing from early meetings.
Apparently in a Teleconference with Russia (3 hours ahead) last Friday, the absences were described and the Muscovites said annoyedly "your Metro all broken yet again?". For which the answer was 'Yes'.
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Post by Deleted on Feb 9, 2011 13:45:29 GMT
Interesting snippet on the BBC Transport Blog today talking about the "inability to reverse" under the new system. There's a number of different ways to read that, so is that really suggesting that Wrong Direction Movement isn't possible now? |
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Post by Deleted on Feb 9, 2011 14:30:21 GMT
I would imagine WDMs are possible under restricted manual.
The DLR is bi-directional for the most of it, using SelTrac, so I don't see why the Jub couldn't have been given this!
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Post by littlebrute on Feb 9, 2011 15:56:37 GMT
Probably Tube Lines trying to save money by not including the reversing facility
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