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Post by dave1 on Feb 9, 2017 12:52:24 GMT
Another one of those what for questions I'm afraid. I was shown a photo of the IMR at Baker Street Bakerloo/Jubilee and apart from all the types of indications I noticed that one set of points had an additional indication.
There was an indication for all points normal or reverse but 3 points had an additional indication for the A end being normal, these are the points from the SB Jubilee to the SB Bakerloo any idea what this indication was for other than the obvious.
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Post by railtechnician on Feb 9, 2017 20:46:29 GMT
Another one of those what for questions I'm afraid. I was shown a photo of the IMR at Baker Street Bakerloo/Jubilee and apart from all the types of indications I noticed that one set of points had an additional indication. There was an indication for all points normal or reverse but 3 points had an additional indication for the A end being normal, these are the points from the SB Jubilee to the SB Bakerloo any idea what this indication was for other than the obvious. Baker Street Jubilee was one of my maintenance sites so I spent time there maintaining 3A and 10? (IIRC) turnouts while Bakerloo signals maintained 3B and the other end of 10. I really can't recall anything special as such, however, you have to remember that, that frame is controlled by two signal operators independently as separate Bakerloo and Jubilee lines from the appropriate regulating rooms i.e. the Bakerloo control room and the Met/Jub SCC (assuming that is still the case, the old Jub may now be controlled from Neasden along with the JLE but I don't know). When looking at IMR diagrams it is important to note the placement of the various control indications. It is not sufficient to simply say that 3W are indicated normal and reverse and 3A had an additional Normal indication. The 3NW and 3RW indications indicate the actual lay of the points while the separate 3AW(N) indication may indicate the 'called for'/'not called for' condition i.e. a non-safety indication of 'slotting' as the Bakerloo signal operator would have to allow 3AW to be thrown reverse (offering the 'slot'), the Bakerloo signal operator controlling 3W lever, when the route to the Bakerloo is called by the Jubilee signal operator. I think the Bakerloo also controlled 10W lever and so that is why there is no 'slot' and no 10? non-safety indication, Bakerloo having full control of the route to the Jubilee. This makes sense as originally the Bakerloo was the running line and the Jubilee was still under construction. I worked at Baker Street resignalling for the Jubilee for several weeks n 1977/8, my section being St.John's Wood to Baker Street and my job rewiring trainstops and relays etc at all the locations on the commissioning changeover. I can tell you no more than that, if I had the IMR bookwiring in front of me I would be able to give a 100% definitive answer to your question but I don't think my explanation is wide of the mark. These days memories are fading fast I'm afraid as most of my concentration lies with my other hobbies. |
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Post by dave1 on Feb 10, 2017 15:34:59 GMT
Another one of those what for questions I'm afraid. I was shown a photo of the IMR at Baker Street Bakerloo/Jubilee and apart from all the types of indications I noticed that one set of points had an additional indication. There was an indication for all points normal or reverse but 3 points had an additional indication for the A end being normal, these are the points from the SB Jubilee to the SB Bakerloo any idea what this indication was for other than the obvious. Baker Street Jubilee was one of my maintenance sites so I spent time there maintaining 3A and 10? (IIRC) turnouts while Bakerloo signals maintained 3B and the other end of 10. I really can't recall anything special as such, however, you have to remember that, that frame is controlled by two signal operators independently as separate Bakerloo and Jubilee lines from the appropriate regulating rooms i.e. the Bakerloo control room and the Met/Jub SCC (assuming that is still the case, the old Jub may now be controlled from Neasden along with the JLE but I don't know). When looking at IMR diagrams it is important to note the placement of the various control indications. It is not sufficient to simply say that 3W are indicated normal and reverse and 3A had an additional Normal indication. The 3NW and 3RW indications indicate the actual lay of the points while the separate 3AW(N) indication may indicate the 'called for'/'not called for' condition i.e. a non-safety indication of 'slotting' as the Bakerloo signal operator would have to allow 3AW to be thrown reverse (offering the 'slot'), the Bakerloo signal operator controlling 3W lever, when the route to the Bakerloo is called by the Jubilee signal operator. I think the Bakerloo also controlled 10W lever and so that is why there is no 'slot' and no 10? non-safety indication, Bakerloo having full control of the route to the Jubilee. This makes sense as originally the Bakerloo was the running line and the Jubilee was still under construction. I worked at Baker Street resignalling for the Jubilee for several weeks n 1977/8, my section being St.John's Wood to Baker Street and my job rewiring trainstops and relays etc at all the locations on the commissioning changeover. I can tell you no more than that, if I had the IMR bookwiring in front of me I would be able to give a 100% definitive answer to your question but I don't think my explanation is wide of the mark. These days memories are fading fast I'm afraid as most of my concentration lies with my other hobbies. RT I love your posts and you may remember some of the questions I have asked and these covered IMRs which I always find very interesting. I have only ever seen the one that is at Covent Garden. I have attached a photo.  |
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Post by railtechnician on Feb 10, 2017 16:43:01 GMT
Dave,
Scotch what I said about about the reason for the 3AW(N) indication, clearly it is a safety signalling WKE for the lay of 3A points normal as it resides in the point indications area of the diagram and not in the non-safety KEs.
I believe it may possibly be for Route Securing i.e. a guarantee that 3AW lie normal such that BM2 signal can be passed at danger under rule in the event of a track or signal failure.
Without the full diagram it is difficult to deduce but clearly I can just see that the Jubilee signal operator controls the route BM1(2), BM2(2), the crossover to the Bakerloo, so the additional 3AW(N) indication would make sense from a route securing viewpoint but without the bookwiring I am guessing.
My recollection is that 3AW were a set of chairlock points and the starting signal was originally BM1 back in 1978 and don't know if that is the original diagram from the day the Jubilee came into service or a later one after signalling alterations although it is the one I recall from my days doing point maintenance there from 1998 onward.
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Post by dave1 on Feb 10, 2017 19:01:37 GMT
Dave, Scotch what I said about about the reason for the 3AW(N) indication, clearly it is a safety signalling WKE for the lay of 3A points normal as it resides in the point indications area of the diagram and not in the non-safety KEs. I believe it may possibly be for Route Securing i.e. a guarantee that 3AW lie normal such that BM2 signal can be passed at danger under rule in the event of a track or signal failure. Without the full diagram it is difficult to deduce but clearly I can just see that the Jubilee signal operator controls the route BM1(2), BM2(2), the crossover to the Bakerloo, so the additional 3AW(N) indication would make sense from a route securing viewpoint but without the bookwiring I am guessing. My recollection is that 3AW were a set of chairlock points and the starting signal was originally BM1 back in 1978 and don't know if that is the original diagram from the day the Jubilee came into service or a later one after signalling alterations although it is the one I recall from my days doing point maintenance there from 1998 onward. Thanks, I am a mere novice with these sort of things but you mention route securing as a possible reason but what about the NB Bakerloo as that is facing points. |
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Post by railtechnician on Feb 11, 2017 10:30:13 GMT
Dave,
I just knew you would ask me that and I have no definitive answer for you. The biggest problem with LT signalling is that despite standard signalling principles being used throughout every controlled site is unique. There is also the factor of a number of generations of LT signalling over the years leading to improved standards and changes of circuitry due to the use of different relay types, different no-safety signalling from relay, through electronic to computer such that two practically identical sites from a diagrammatic standpoint would be signalled to the same principles but appear quite different as far as circuitry is concerned. The only way to know exactly what is what is to have the bookwiring to hand, the site bookwiring being the unique bible for just the one site.
Generally there is no universal update to bring sites up to new standards except for planned line resignalling, changes to track layout such as installing additional tracks and points or as a result of a wrong side failure identified as an issue that could occur at other sites and corrected with a change in circuit principle and/or equipment. Thus many standards from the past can still be found where there was no necessity to upgrade them.
I don't know if all lines have route securing, the Picc certainly does, of course I know that because I was a Picc maintenance TO and had occasion to test it at various sites and from the control room. I would expect all tunnel sections with points to have route securing to ease the delays caused by track and signal failures that cannot be resolved in traffic hours but I don't know the whys and wherefores of it being installed in some places or on some lines and perhaps not others. If I had complete information on current LT signalling principles I would surely have an answer for you but my signalling principles info stopped at 1997 except for anything that followed on from a couple of wrong side failure issues.
As I say the definitive answer to the question will be found in the unique site bookwiring, clearly there was/is a need to know specifically the lay of 3A points, a point failure would quite often result in no point indication at all so the 3W crossover indication would be extinguished both normal and reverse, such occurs when neither switch is 'up' to either stock rail. Thus my thought about route securing which is only relevant to the normal route i.e. the main running line and the turnout in the route must be indicated normal for route securing to be enabled. My recollection of 3AW was as I said that they are chairlock points while I'm sure that 3BW would be trailing 4' layout without facing point locks. If that is so it 'might' be a reason for the separate 3AW(N) indication because the indication circuitry of the two layouts is different, the 3WKR requires both ends of the crossover proved to be normal or both proved reverse in order to give a normal or reverse indication otherwise there will be no indication. Thus if a point failure leaves the 3BW turnout reverse or not normal when 3's lever is normal or is restored to normal an indication that 3AW is normal and locked can still be given via the additional 3AW(N) indication which I presume is fed via an additional relay, perhaps 3A NWLR.
Speculation keeps my little grey cells churning but I have expended my thought process on this particular question now!
However, one last thought taking another look at the diagram! There is no route securing shown at 2G or 8G which rather blows my theory. I have also just noticed that 8(1) route from Bakerloo to Jubilee is not over a crossover but via a diverging junction 9W and a converging junction 11W. I used to maintain 11W which is a trailing 4' layout although until I looked at the diagram for some reason I had 10?W in mind and just assumed 10s crossover. Clearly this is a siding which can hold a train although none of this helps with your questions.
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Post by dave1 on Feb 12, 2017 10:01:02 GMT
Dave, I just knew you would ask me that and I have no definitive answer for you. The biggest problem with LT signalling is that despite standard signalling principles being used throughout every controlled site is unique. There is also the factor of a number of generations of LT signalling over the years leading to improved standards and changes of circuitry due to the use of different relay types, different no-safety signalling from relay, through electronic to computer such that two practically identical sites from a diagrammatic standpoint would be signalled to the same principles but appear quite different as far as circuitry is concerned. The only way to know exactly what is what is to have the bookwiring to hand, the site bookwiring being the unique bible for just the one site. Generally there is no universal update to bring sites up to new standards except for planned line resignalling, changes to track layout such as installing additional tracks and points or as a result of a wrong side failure identified as an issue that could occur at other sites and corrected with a change in circuit principle and/or equipment. Thus many standards from the past can still be found where there was no necessity to upgrade them. I don't know if all lines have route securing, the Picc certainly does, of course I know that because I was a Picc maintenance TO and had occasion to test it at various sites and from the control room. I would expect all tunnel sections with points to have route securing to ease the delays caused by track and signal failures that cannot be resolved in traffic hours but I don't know the whys and wherefores of it being installed in some places or on some lines and perhaps not others. If I had complete information on current LT signalling principles I would surely have an answer for you but my signalling principles info stopped at 1997 except for anything that followed on from a couple of wrong side failure issues. As I say the definitive answer to the question will be found in the unique site bookwiring, clearly there was/is a need to know specifically the lay of 3A points, a point failure would quite often result in no point indication at all so the 3W crossover indication would be extinguished both normal and reverse, such occurs when neither switch is 'up' to either stock rail. Thus my thought about route securing which is only relevant to the normal route i.e. the main running line and the turnout in the route must be indicated normal for route securing to be enabled. My recollection of 3AW was as I said that they are chairlock points while I'm sure that 3BW would be trailing 4' layout without facing point locks. If that is so it 'might' be a reason for the separate 3AW(N) indication because the indication circuitry of the two layouts is different, the 3WKR requires both ends of the crossover proved to be normal or both proved reverse in order to give a normal or reverse indication otherwise there will be no indication. Thus if a point failure leaves the 3BW turnout reverse or not normal when 3's lever is normal or is restored to normal an indication that 3AW is normal and locked can still be given via the additional 3AW(N) indication which I presume is fed via an additional relay, perhaps 3A NWLR. Speculation keeps my little grey cells churning but I have expended my thought process on this particular question now! However, one last thought taking another look at the diagram! There is no route securing shown at 2G or 8G which rather blows my theory. I have also just noticed that 8(1) route from Bakerloo to Jubilee is not over a crossover but via a diverging junction 9W and a converging junction 11W. I used to maintain 11W which is a trailing 4' layout although until I looked at the diagram for some reason I had 10?W in mind and just assumed 10s crossover. Clearly this is a siding which can hold a train although none of this helps with your questions. I suspect that if there is one of something then it is the standard despite lots of similar things. The bookwirings would like you say have the answer or at least point in the right direction. I don't know if the route securing was down to H&S or that lines in tube tunnels or even both. I have been sent a photo which show the area with details of which routes have route securing and you theory I'm afraid does go but it was a good one.  |
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Post by railtechnician on Feb 12, 2017 14:42:10 GMT
It's nice to see that I was correct about route securing on 2(1), my thought regarding 3AW(N) therefore stands. I'm sure that additional point indication is strictly for route securing circuitry.
It is interesting that route securing is indicated as remote securing, which it is, however, it can also be done locally within the IMR, there are usually local keys for those functions on the lever frame.
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Post by dave1 on Feb 13, 2017 15:37:00 GMT
It's nice to see that I was correct about route securing on 2(1), my thought regarding 3AW(N) therefore stands. I'm sure that additional point indication is strictly for route securing circuitry. It is interesting that route securing is indicated as remote securing, which it is, however, it can also be done locally within the IMR, there are usually local keys for those functions on the lever frame. I suppose remote might be because of being done by a control room rather than a signal box? |
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Post by Nortube on Feb 13, 2017 23:47:03 GMT
I think that remote route securing was generally used where it was thought to have the most benefit for the cost. On the Northern line, Kennington and Camden Town make sense because of the time that it could take to get on site and manually secure the route.
I'm not sure why the reason for Stockwell and Tooting Broadway, as both places would only need one point end secured and there is easy access just off the platform for both of them. Perhaps it's because of the frequency of rush hour trains and the less delay the better.
Morden makes sense because there are more points to secure (2 normal for Y27 and three normal for Y2(1) ) and every second counts when there's a rush hour delay. Mind you, Morden would be well and truly screwed anyway, especially in rush hour. The simplest way of running the service is Y2 to platform 2, detrain, then run to either depot bank road then come back into service via platform 5.
Remote route securing was commissioned on the Northern line on 31 May 1999 for the following locations:
Morden
Y2 (1) - SB junction signal to platform 2
Y27 - platform 5 to NB
Tooting Broadway
W2A - SB outer home
W12B - NB intermediate home
Stockwell
U1B – SB inner home
U10 – NB starter
Kennington
B3(1) - SB platform 2 via loop
B3(2) - SB platform 2 to Oval
B31A(1) – NB to platform 1
B31A(2) – NB to platform 3
B31/1B - NB inner home from main to platform 1
B33 – NB before exit from siding
B36B – NB inner home from loop to platform 1
Camden Town / Mornington Crescent
E32B - SB before crossover at Mornington Crescent
E34 – SB CX ex Edgware branch before junction
E37(1) – SB platform 4 starter via CX
E37(2) – SB platform 4 starter via City
E39 – SB CX ex Barnet branch before junction
E41(1) – SB platform 2 starter via CX
E41(2) – SB platform 2 starter via City
E2 – NB starter Mornington Crescent
E4(1) – NB CX junction to Edgware branch
E4(2) – NB junction to Barnet branch
E6 – NB inner home CX to platform 1
E9B – NB inner home CX to platform 3
E11B(1) – NB City inner home to platform 1
E11B(2) – NB City inner home to platform 3
All signals were the last signal before a crossover and each signal was provided with a sign that was illuminated when remote route securing was set up by the signalman for that route. The sign (in the standard small square internally illuminated box) was either Route secured, Route 1 secured, or Route 2 secured as appropriate.
For info, to quote from information to drivers:
“Remote route securing is available at various locations on the line. A ROUTE SECURED sign can only be illuminated if the points are detected as locked in their correct position and a train is stopped at that signal. Therefore, an illuminated route secured sign means that the points are detected as working normally and there is no need for them to be secured by scotch and clip before the train moves over them.
Remote route securing is normally put into operation when there is a signal failure. If there is a points failure or a points and signal failure, route secured cannot be bought into use as the route secured sign cannot be illuminated. The points must then be secured by scotch and clip.
An illuminated route secured sign does not give permission for any signals to be passed at danger – this must be given in the usual way. Where the signal is a junction signal, the appropriate route number will also be shown on the sign.”
Route proving that was introduced on the Northern line ten years later was a sort of similar thing, but was based on the fact that if a certain signal was displaying a green aspect, then the points involved must be being detected in their correct position. The main difference was that the driver had no visible indication (no illuminated sign).
The driver was given instructions (usually via the train radio) to pass the signal at danger and that the route ahead was being proved secure with no need for the points to be scotched and clipped. The proving was done by the driver of another train that was standing at the green signal that was proving the route.
Route proving could only be done on a simple layout and was used at all locations on the Northern line where there were emergency crossovers.
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Post by dave1 on Feb 14, 2017 17:09:05 GMT
All these route secured signals came in when the lines went OPO? Having thought about it and I could be wrong but I take it securing a route could take some time so providing certain conditions were met then remote route securing was a way around it to minimise delays? Route proving that is interesting you say it applied to a simple layout but thinking about it somewhere like Wembley Park where you more than one route in the same direction could this not be used at such layouts like you say there was a signal showing green with the affected points.
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