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Post by Dstock7080 on Jan 28, 2024 11:51:18 GMT
26 trains cancelled at 1500, 28 at 1800; from 73 scheduled.
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Post by pgb on Jan 29, 2024 6:52:30 GMT
26 trains cancelled at 1500, 28 at 1800; from 73 scheduled. Interesting, thank you |
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Post by scheduler on Feb 4, 2024 17:49:22 GMT
At about 16.45, that would be peak service. Peak service Bank-Holborn should be a train every 1.75 mins. So a 10 minute gap would be about 6 trains missing.
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gefw
Gone - but still interested
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Post by gefw on Feb 5, 2024 9:01:47 GMT
At about 16.45, that would be peak service. Peak service Bank-Holborn should be a train every 1.75 mins. So a 10 minute gap would be about 6 trains missing. Although the (severe) shortage of about 35% of trains would not help - there would have been other factors (eg passenger incident) - A 10 min gap would normally be managed out by central control (by holding trains at turn or turning short). The new temporary timetable based on less trains will help a lot (with short trip additional/specials inserted during busy times if more trains available) |
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Post by Dstock7080 on Feb 7, 2024 15:20:31 GMT
A trial is shortly to start with up to two 8-car trains having the middle traction package isolated via the Traction Control Cut-Out Switch TCCOS.
The trains will operate on the Hainault-Woodford shuttle only.
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Post by xtmw on Feb 7, 2024 16:21:14 GMT
Interesting. Good to see stuff happening which might help remedy the service.
I've been on train before where the car I was in sounded like there weren't any motors at all, acceleration was sluggish for the train, no door chimes nor announcements. Is this a symptom of a traction motor being 'isolated' or just one of the many bugs on the 92s?
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gefw
Gone - but still interested
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Post by gefw on Feb 7, 2024 16:56:18 GMT
I see that the Central line service status in now only "minor delays" .
Does this mean they are on top of the quality/flash over mitigation issues or is it because the reduced timetable is now in place (so the "bar is lower)
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Post by Dstock7080 on Feb 7, 2024 17:05:14 GMT
a further reduced timetable is not yet in operation, planned for 4 March 2024.
The mitigation mentioned above is very imminent.
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Post by Westinghouse on Feb 7, 2024 17:30:03 GMT
I see that the Central line service status in now only "minor delays" . Does this mean they are on top of the quality/flash over mitigation issues or is it because the reduced timetable is now in place (so the "bar is lower) I wont get too far into it, But the minor delays is nonsensical and purely political. The service was no better this morning than it has been all week with 25 minute gaps between trains through central london and 40 minute gaps to all of the branches at various points. Unfortunatly Wood Lane can only do so much, and are now being ignored when trying to advertise the true extent of the service to the customers! |
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Post by t697 on Feb 7, 2024 17:49:55 GMT
Interesting. Good to see stuff happening which might help remedy the service. I've been on train before where the car I was in sounded like there weren't any motors at all, acceleration was sluggish for the train, no door chimes nor announcements. Is this a symptom of a traction motor being 'isolated' or just one of the many bugs on the 92s? Cutting out the traction with the TCCOS or the propulsion system self isolating shouldn't prevent door chimes and announcements. Probably something else wrong on that one as well. |
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Post by spsmiler on Feb 7, 2024 22:32:43 GMT
A few days ago I was at Stratford at about 4pm and eastbound trains were coming through so frequently that they were stopping on the up ramp before entering the station (possibly also queuing further back) and departing with a white signal
20+ minute gaps during the day for central London is absurd.
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Post by xtmw on Feb 7, 2024 23:21:12 GMT
You could have a frequent service on that section of the line, but westbound on that section could be a different story.
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Post by xtmw on Feb 8, 2024 16:11:55 GMT
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gefw
Gone - but still interested
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Post by gefw on Feb 8, 2024 18:18:36 GMT
Unfortunately it seems rather random which trains in the current timetable are cancelled (thus leaving inbalanced gaps)
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DWS
every second count's
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Post by DWS on Feb 8, 2024 20:11:19 GMT
Tonight’s Evening Standard has an article about the problem with the Central Line trains, .
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Post by xtmw on Feb 8, 2024 20:19:17 GMT
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gefw
Gone - but still interested
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Post by gefw on Feb 9, 2024 19:29:02 GMT
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Chris M
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Post by Chris M on Feb 10, 2024 2:05:15 GMT
This is despite no reason yet given for the significant/sudden increase in flashed over motors. Last I was aware, the root cause wasn't known or at least wasn't known with certainty. This blog post from 2008 (of unknown reliability) suggests brushes wearing out as one possible cause, although my gut feeling is that if it were that simple then there would be a lot more certainly about how to fix the issue and how long disruption will last. |
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brigham
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Post by brigham on Feb 10, 2024 8:35:51 GMT
So you can't cut out a defective motor?
In tramway days, if a motor became defective, you simply cut it out using the reversing handle, and continued on one.
A lot less power in that case, obviously; but when you have 32 I doubt that cutting one out ewould even be noticed.
Another useful feature 'rationalized-out'?
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Post by jimbo on Feb 10, 2024 9:13:00 GMT
A trial is shortly to start with up to two 8-car trains having the middle traction package isolated via the Traction Control Cut-Out Switch TCCOS. The trains will operate on the Hainault-Woodford shuttle only. Just what effect will "having the middle traction package isolated" have on a train, given the reference to 32 motors on an 8-car train? Is this a way of trialing use of a defective 2-car unit in service before it is repaired? |
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Post by Dstock7080 on Feb 10, 2024 9:34:19 GMT
Using the TCCOS would isolate two cars of motors and the associated rheostatic/regenerative braking on those cars.
Yes, it is a way of using defective units in passenger service, without having them piled up in depots.
There is no suggestion currently of using them on other parts of the Line.
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Post by Dstock7080 on Feb 10, 2024 9:44:45 GMT
So you can't cut out a defective motor? Traditionally on the Underground all motors on individual motor cars could be isolated by using the TCOS Traction Control Cut-Out Switch (nicknamed ’Ten Point’) in that car. 1973 Stock and subsequent Stock have dual wired traction circuits and it would be possible to use from the cab to reduce the available motors by half, not necessarily individual units (D Stock would be cars 1+4 or 3+6). |
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gefw
Gone - but still interested
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Post by gefw on Feb 10, 2024 10:30:11 GMT
Yes the problem is certainly related to the interaction between the motor brushes, the Commutators and surrounding grounded metalwork, "Flash over" being the culmination of deterioration/build up of debris. So yes queries should have started with Brush/spring quality (they are frequently checked/replaced) and the Commutator refurb (regularly undertaken by various contractors both in situe & and during motor rebuilds at Acton). The issue appears to annually peak during the winter /cold spells. Would also be interested if the there has been any changes/drift to regen voltages and brush current control/limitation arrangements. No doubt/hopefully plenty of FRACAS/Root cause analysis sessions already done over the years - I've heard of the long standing method of identifying and tracking the motors with higher flash over probability - but the worsening and higher priority of the problem may have broadened the diversity of participation and investigations - With a tweaking of the process on the new Asset Record system (Maximo)? |
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Post by jimbo on Feb 10, 2024 10:35:20 GMT
A trial is shortly to start with up to two 8-car trains having the middle traction package isolated via the Traction Control Cut-Out Switch TCCOS. The trains will operate on the Hainault-Woodford shuttle only. This is a trial on two 8-car Hainault shuttles only, so would only release a maximum two units, or half a train. Will only help reduce the train shortfall if it proves successful and is extended to the whole line. |
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towerman
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Post by towerman on Feb 10, 2024 11:59:19 GMT
Is there a “ shed day” as part of 92TS maintenance regime?On older stocks this was done around every 36 weeks and included checking brushes on all rotating machines eg motors MAs and compressors.
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Post by d7666 on Feb 10, 2024 21:30:17 GMT
The issue appears to annually peak during the winter /cold spells. Often wondered if Sandite is a cause. Could get drawn in. You really do not want any of that in a commutator. Even a tiny bit is damaging. Failures out of phase with sandite season : accumulative fault, so lags i.e. sandite ~ 0ctober to December, does the damage but takes time to develop into faults => December onwards peaking in cold weather but not necessarily a result of it. Just saying. |
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Post by xtmw on Feb 14, 2024 22:25:51 GMT
TfL on the recent disruption (maybe we could rename this thread to the new misery line....)
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Post by greatkingrat on Feb 14, 2024 22:39:53 GMT
Why do they need to change the signalling or the power supply in order to run a new timetable with fewer trains?
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Post by wonderwaller on Feb 14, 2024 23:16:52 GMT
Why do they need to change the signalling or the power supply in order to run a new timetable with fewer trains? It’s more likely new signalling data needs to be provided to Wood Lane in order for the timetable to run Power control is most likely the various engineering and protection publications are updated with new last trains and potentially different switch off and switch on times to ensure the safety of staff going trackside in engineering hours |
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Post by xtmw on Feb 15, 2024 16:27:06 GMT
As well as the trains having some issues, problems with the signalling system also appear to be taking shape...
There was a signalling problem at Bank a few days ago, and today a signal failure at Leytonstone has ruined the service.
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