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Post by A60stock on Dec 18, 2023 23:37:47 GMT
Travelling back at around 730, got to harrow around 740. Informed the line is shut with only Uxbridge trains running as normal with the mainline (fast and slows) suspended Harrow to northwood, due to a signal failure around the Pinner area. Announcements at Harrow saying both Chiltern and met are suspended. However, I did see one south bound Chiltern train turn up at 752, although delayed by 20 mins.
Waited around 20 to 30 mins. Uxbridge trains running as usual and finally an Amersham all stations turns up. It waited a while but finally got a move on. It took 15 mins to get between North Harrow and Pinner as the train had to be talked through 2 or 3 signals using the 'trip' method. I'm not sure if these were the only affected signals because as the train left Pinner, it did the same thing, being tripped by the next signal.
I've taken a look right now and the issue has still not been sorted out so looks like it's something quite serious and definitely not specific to the slows or fasts as both lines are affected and I did notice a number of trains parked on the fast lines southbound when I was on the amersham train.
On exiting Pinner, the station was actually shut for entry and I saw no southbound locals so clearly despite my train running, the section of the line was officially shut. Sorry, this is a long post but my questions are as follows:
1. What actually happened?
2. The Amersham I was on appeared to be the only train which went through, as the service remained suspended officially. If this managed to get through, why not run some sort of service? Or another way of putting it I guess is why did they let that one go through? Did any others get through?
3. The aforementioned Chiltern service which I saw at Harrow at 752, how did this get through?
4. A number of not in service trains turned up at Harrow southbound (assuming having been supposed to have come from Watford, Amersham or Chesham) but for some reason occupied both platforms 5 and 6 for a while, holding up a que of trains coming from Uxbridge. Why not move these trains to Wembley/neasden via the fasts rather than have them block both platforms at harrow?
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DWS
every second count's
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Post by DWS on Dec 19, 2023 0:29:44 GMT
Failure of signal equipment at Pinner can occur for a number of reasons, the Met Line north of Finchley Road is still awaiting to be updated so this existing equipment is more likely to cause delays.
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Post by Dstock7080 on Dec 19, 2023 5:14:07 GMT
Loss of signal power 18.55, signals remain at danger both main and local lines.
Suspected failure in Northwood substation at 400v circuit.
Much investigation work to find the cause.
Shuttle service implemented Northwood-Amersham/Chesham/Watford 19.35
Limited non-advertised trains running under failure conditions through area.
22.00 3 train shuttle service in operation (461 Amersham-Watford; 465 Rickmansworth-Chesham; 435 Amersham-Northwood)
Fuses changed 23.30 and power restored.
Service remained advertised suspended Northwood-Harrow until close of day.
One stalled MET on approach to Moor Park NB, arrived Moor Park 19.50.
One stalled Chiltern on approach to Harrow SB, arrived Harrow 19.48.
One stalled Chiltern on approach to Pinner NB.
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rincew1nd
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Post by rincew1nd on Dec 28, 2023 20:50:23 GMT
In my mind, a "stalled" train is one off the juice, another word for the situation being "gapped".
How does a diesel powered Chiltern train get stalled?
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Colin
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Post by Colin on Dec 29, 2023 14:32:11 GMT
2. The Amersham I was on appeared to be the only train which went through, as the service remained suspended officially. If this managed to get through, why not run some sort of service? Or another way of putting it I guess is why did they let that one go through? There's a number of reasons for pushing a train through a multiple signal failure. Whilst not an exhaustive list, some that spring to mind are: A) Could have been a Rickmansworth based driver so was facilitating getting that driver back to their home location. B) It may have been used as a "test train" to see if a fix had worked. C) Could have been used to drop off technical staff or run technical staff through the area to see if they can spot an obvious reason for the failure. As for why not run more than one train through.......well it depends on the number of signals that have failed for starters. The signaller has to speak to each driver at each signal to authorise them forward - this causes a high workload which aside from creating a higher risk of a mistake being made, takes time to do for each train and then each train when it is moving is doing so at less than 10mph for at least two minutes at a time - often longer. Then there's the nature of the failure - on this occasion the whole signal main was lost - the signaller can't even see where the trains are, so from a safety/risk management point of view, its not desirable to pump trains into an area you can't see or maintain full control of. And if you did push enough trains through the failure area, how long will it be before they return back to the part of the railway that's operating normally? It's about balancing the need of the whole line rather than allowing the failed part to overly affect the non failed part. 3. The aforementioned Chiltern service which I saw at Harrow at 752, how did this get through? A, B or C above could equally apply to this train (obviously wouldn't be a Rickmansworth based driver but could still be facilitating getting them to wherever they are based). It may also have been the case that the train was too far south to be able to reverse anywhere so was simply pushed forward via signaller authorisation. 4. A number of not in service trains turned up at Harrow southbound (assuming having been supposed to have come from Watford, Amersham or Chesham) but for some reason occupied both platforms 5 and 6 for a while, holding up a que of trains coming from Uxbridge. Why not move these trains to Wembley/neasden via the fasts rather than have them block both platforms at harrow? Harrow is a driver relief point - if trains are turning up off timetable or relief drivers are still on trains stuck in a failure area, it doesn't take much for the booked driver reliefs to start going awry. This will obviously impact the ability to keep trains moving. In my mind, a "stalled" train is one off the juice, another word for the situation being "gapped". How does a diesel powered Chiltern train get stalled? A stalled train, in railway vernacular, is a train between stations that cannot be moved because of an external factor not caused by the train itself such as a train in the section ahead or rear preventing further movement, a failure of points not in favour of the route required, a signal failing to clear, traction current turned off, physical obstruction on the track, etc. Where a train cannot be moved because it is the direct cause of the issue, such as a being gapped, having an onboard defect, person ill on the train, no relieving driver, etc.......we call that a sit down. |
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Post by d7666 on Dec 29, 2023 17:39:00 GMT
In my mind, a "stalled" train is one off the juice, another word for the situation being "gapped". How does a diesel powered Chiltern train get stalled? A stalled train, in railway vernacular, LU railway vernacular yes. BR/NR main line no. Since the immediate question was about a (main line) Chiltern train, a perfectly valid question to ask. Informally AIUI on main line away from LU a stalled train means one that has slipped to a stand or can not move off from standing start due to to poor adhesion but not other use, such as a gapped train, or any of the many other causes. And, I am not only saying that from my own view of it, but a Chiltern driver I know said this is something that is supposed to be imparted in their general training that "stalled" has different meaning on LU infrastructure. Not sure where the LU term came from, or why LU has to be different. Is it an imported north American terms like signal "cabin" on LU but "box" to the rest of the country ? Digressing a bit, but in the same sort of failure scenario, another term with different meaning is "blocking back". I have often heard on LU "blocking back" when a train has "stalled" and there are a number of trains queued behind it. In main line terminology 'blocking back' has a totally totally different meaning under BR Absolute Block (and equivalent signalling block) regulations - and I am not going into it here save to say it has nothing whatsoever to do with queued trains. |
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tut
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Post by tut on Dec 29, 2023 19:49:02 GMT
Digressing a bit, but in the same sort of failure scenario, another term with different meaning is "blocking back". I have often heard on LU "blocking back" when a train has "stalled" and there are a number of trains queued behind it. In main line terminology 'blocking back' has a totally totally different meaning under BR Absolute Block (and equivalent signalling block) regulations - and I am not going into it here save to say it has nothing whatsoever to do with queued trains. Indeed we block back most mornings. And it does kind of have something to do with queued trains, in as much as we do it to keep the Up line clear for the steady stream of trains to pass while the driver of our train out of the sidings changes ends on the Down and waits for a platform to become available to join the queue  I don't think I've ever heard stalled trains used for trains stuck between stations either on the main line, I think 'stranded' or 'trapped' is perhaps more common at least these days. Not sure where the LU term came from, or why LU has to be different. Is it an imported north American terms like signal "cabin" on LU but "box" to the rest of the country ? I believe the North Eastern Railway also used the term 'signal cabin' and probably quite a few others, it's not just an LU term.
Getting back towards the topic, on the main line we would have the option of (traditionally) temporary block working or (now very much the preferred option) "emergency special working", although they are not trivial to implement (temporary block working especially) and we don't have tripcocks to worry about, although there is TPWS which has to be isolated, but that's not a problem for us. LU is a different animal though with its own considerations. The service is a very dense, comparatively short-distance metro service (even an Amersham to Aldgate is hardly the Inverness to Euston sleeper!) where it doesn't always make sense to doggedly force trains into a huge failure as the costs compared to benefits don't really justify it.
Chiltern however are a main line operator and I'm not too surprised they made it through because at the end of the day they need to get back onto the main line, they can't really be imprisoned by LU's failure nor can they be stuck in the sidings at Rickmansworth for the night. It also would have become very expensive very quickly.
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gefw
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Post by gefw on Jan 2, 2024 10:56:57 GMT
2. The Amersham I was on appeared to be the only train which went through, as the service remained suspended officially. If this managed to get through, why not run some sort of service? Or another way of putting it I guess is why did they let that one go through? There's a number of reasons for pushing a train through a multiple signal failure. Whilst not an exhaustive list, some that spring to mind are... I appreciate the logic to what you say but unfortunately it doesn't seem to be particularly customer focused ie getting the driver "home". Perhaps the need for the Signalman to seperately authorise a train past successive Auto signals might worth consideration/proceedure change Quote modified - if you can try to be more selective in your quoting, rather than quoting whole posts verbatim, it makes reading your post easier. (Tom) |
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Colin
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Post by Colin on Jan 2, 2024 16:35:24 GMT
I appreciate the logic to what you say but unfortunately it doesn't seem to be particularly customer focused ie getting the driver "home". Perhaps the need for the Signalman to seperately authorise a train past successive Auto signals might worth consideration/proceedure change Once the railway falls into failure mode, the railway can't always remain 100% customer focussed. There has to be a balance with attempting to resolve the root cause of the failure and also preparing operationally for resumption after a failure. Having said that, getting that driver back to their home location could potentially mean you now have a member of staff in position ready to give an earlier resumption of service - ditto with any rolling stock that has been moved through a failure area - so it could be argued in a roundabout way that there was customer focussed decision making going on; albeit not immediately obvious. As for the need for the signaller to authorise separately past each signal......I'm not particularly familiar with the part of the Metropolitan line covered by the incident that led to this thread so unsure of exact type of signals in that area, but to perhaps expand a bit on your suggested potential corner cutting..... In the case of automatic signals on LU........drivers must stop at each one, and unless previously advised that the signal is known to have failed, must wait two minutes before attempting to seek information as to why the signal is remaining at danger. The information they receive may be to continue to remain at that signal, or it may be that they're authorised to pass the signal at danger. If they cannot garner any further information after waiting those two minutes they can then pass that signal at danger under their own authority. Drivers must then proceed at a speed where they can stop short of an obstruction (ie. walking pace) for two consecutive stop signals showing a proceed aspect. If they were unable to gain any information, they must further attempt to do so at the earliest opportunity. If they come across another auto signal at danger, the process starts again. Failure to follow this basic procedure correctly has led to collisions in the past - perhaps the most famous being on the Central line at Leyton back in the 80's when a train went into the back of another. Semi automatic signals on LU are controlled by the signaller and often involve points, etc so drivers absolutely must get authorisation from the signaller before proceeding past a semi auto signal on LU. If a signaller were to attempt to authorise me past two or three signals in one go I would politely refuse their authorisation and request it individually at each signal. The same proceed at a speed where they can stop short of an obstruction for two consecutive stop signals showing a proceed aspect procedure then applies. On the TBTC/CBTC ATO areas (Jubilee, Northern and much of the SSR) drivers can only ever be authorised from one fixed point to the next fixed point and never ever through multiple fixed points in one go. Passing signals at danger is a safety critical action and anyone who attempts to speed the process up by cutting corners is opening themselves up to a catastrophic error that could easily put a train on the deck. I've seen it happen more than once. Especially with drivers receiving instructions in a train cab where it's often not written down and done "on the fly". They forget what they were told or get the instructions mixed up in their mind. Slow and steady always wins the race! |
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gefw
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Post by gefw on Jan 4, 2024 19:41:39 GMT
I appreciate the logic to what you say but unfortunately it doesn't seem to be particularly customer focused ie getting the driver "home". Perhaps the need for the Signalman to seperately authorise a train past successive Auto signals might worth consideration/proceedure change As for the need for the signaller to authorise separately past each signal......I'm not particularly familiar with the part of the Metropolitan line covered by the incident that led to this thread so unsure of exact type of signals in that area, but to perhaps expand a bit on your suggested potential corner cutting..... In the case of automatic signals on LU........drivers must stop at each one, and unless previously advised that the signal is known to have failed, must wait two minutes before attempting to seek information as to why the signal is remaining at danger. The information they receive may be to continue to remain at that signal, or it may be that they're authorised to pass the signal at danger. If they cannot garner any further information after waiting those two minutes they can then pass that signal at danger under their own authority. Drivers must then proceed at a speed where they can stop short of an obstruction (ie. walking pace) for two consecutive stop signals showing a proceed aspect. If they were unable to gain any information, they must further attempt to do so at the earliest opportunity. If they come across another auto signal at danger, the process starts again. Thanks Colin for the further clarification of the existing procedures, confirming that my "suggestion" is already covered. So it further strengthens A60's first post suggesting surprise at the line controllers publicised and ongoing declaration of "service suspension" of both fast and slow line lines (as Pinner is an Auto area on all lines). So much so that A60 (who appears to be a rail person and familiar with the area) did not use an alternative route ( Rayners Lane + bus). Lets all hope the 4LM signalling rollout progresses to cover this area soon (expecting it removes the aged/deteriorated equipment associated with this failure (signal main cable/link boxes that have previously caused similar problems) as well as putting the signallers/line controllers in the same room this aiding decision making, communications etc). |
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