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Dunblane down slot / Greenloaning DGL 30/12/2012 at 22:00 #39877 | |
grahamj42
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Dunblane requests the slot before describing the train. I gave the slot, was sent an early-running freight and decided to put it in the loop. Working in mechanical mode, I got a clearing point violation. IMHO, given that there are points within the clearing point of the first controlled signal, one must have the description before the slot is requested, if one is not to delay trains by witholding the slot until the description is received. Graham Log in to reply |
Dunblane down slot / Greenloaning DGL 30/12/2012 at 23:19 #39878 | |
Peter Bennet
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Or if it's a goods train await it hoving up to GL5 before changing the points. The early slot request is so you get the train entering at line speed, and not from a standing start. You have plenty of time to decide what to do with it once it's entered. Peter I identify as half man half biscuit - crumbs! Log in to reply |
Dunblane down slot / Greenloaning DGL 30/12/2012 at 23:41 #39880 | |
Danny252
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And there are/were plenty of locations where setting the route into a goods loop would not be a valid clearing point at all (though I haven't the faintest what the actual situation is/was at Dunblane).
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Dunblane down slot / Greenloaning DGL 31/12/2012 at 11:22 #39889 | |
kbarber
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Let's get this right: swinging points in advance of the home signal gave a clearing point violation? It wouldn't necessarily be so in real life. The (G)WR was very particular about not permitting facing points within the clearing point to be altered until after an approaching train had come to a stand. The LMR - certainly the former MR - permitted it (there's a GA instruction that refers to it so presumably it happened elsewhere too). Typically, there's an inconsistency - a literal reading of the Block Regs supports the GW interpretation but the GA supports the more liberal view; there were locations on the MR where it would have been impossibe to work the traffic if the Block Regs had been followed too literally. I don't know what ScR practice was; it may be they were Block Reg literalists like the GW, in which case the violation would be absolutely correct. I wonder if Peter had a chance to see the actual working at Greenloaning? It would be easy to go weeks without this arising these days, so he may not have done. Log in to reply |
Dunblane down slot / Greenloaning DGL 31/12/2012 at 13:11 #39897 | |
jc92
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" said:Let's get this right: swinging points in advance of the home signal gave a clearing point violation?it is my understanding that points can be unbolted and moved provided "it is safe to do so" and they provide a new, safe clearing point. the definition of it being safe is open, eg if the block section is 10 miles long and the train hasnt yet entered section, why not? but if the train is clearly approaching, then probably not. I would have said the scenario at greenloaning would only be a violation if the loop is not a legitimate clearing point. if it is, then to my mind the signaller has provided a suitable alternative within a safe period of time. "We don't stop camborne wednesdays" Log in to reply |
Dunblane down slot / Greenloaning DGL 31/12/2012 at 14:26 #39899 | |
Late Turn
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I don't think anyone (including the instructors at signalling school!) has ever given me a definitive answer to the question of whether it's ok to swing points within the clearing point. I can't find anything in the current Rule Book that forbids it, though I did have to read very deeply into some of the regs to come to that conclusion. Personally I'm happy to do it, as long as there's no train closely approaching - after all, what's the chance of the points failing halfway and the approaching train running past the signal and going on far enough, and fast enough, to cause a problem?
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Dunblane down slot / Greenloaning DGL 31/12/2012 at 16:40 #39907 | |
clive
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" said:after all, what's the chance of the points failing halfway and the approaching train running past the signal and going on far enough, and fast enough, to cause a problem?This is the logic behind swinging overlaps on TCB. While I haven't delved through the manuals in detail, it would seem that the same logic applies to AB as well - the clearing point is just another kind of overlap. Log in to reply |
Dunblane down slot / Greenloaning DGL 01/01/2013 at 10:54 #39924 | |
kbarber
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" said:" said:after all, what's the chance of the points failing halfway and the approaching train running past the signal and going on far enough, and fast enough, to cause a problem?This is the logic behind swinging overlaps on TCB. While I haven't delved through the manuals in detail, it would seem that the same logic applies to AB as well - the clearing point is just another kind of overlap. Exactly. But the (G)W did things its own way and was insistent that an AB clearing point wasn't altered until the approaching train had come to a stand. So much so that Bewdley North (SVR, but very much based on WR practice) had a special authority in the footnotes - because the clearing point was halfway along the down main - single line crossover, it was permitted to unlock & move the Xover provided Train Entering Section had not been received from the South box. I think there may also have been a degree of difference between local areas & between inspectors. A friend on John Hinson's "Blower" has written that he was rather strongly challenged by a newly-arrived inspector for moving the clearing point in that way at Finchley Road; the inspector conceded that it would be impossible to run the service to time if the points had to remain locked until the train had stopped at the home. But the inspector concerned had previously been on the GN section (Kings X), where lines are paired by direction and it would be rare to have the kind of conflicting move that was the raison d'etre at Finchley Road (Hitchin was the only place it might regularly cause problems, and Jim's patch had been nearer London). In the end, the only way to be sure what the situation is at Greenloaning is to ask the signalmen who actually work the box (or strike lucky and be there to see it happen). Until then (and perhaps after as well, if they do use the stricter interpretation) the only way is to bring the approaching train to a stand at the home before setting the road into the loop. Log in to reply |
Dunblane down slot / Greenloaning DGL 01/01/2013 at 17:48 #39931 | |
Danny252
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" said:So much so that Bewdley North (SVR, but very much based on WR practice) had a special authority in the footnotes - because the clearing point was halfway along the down main - single line crossover, it was permitted to unlock & move the Xover provided Train Entering Section had not been received from the South box."Had"? Pretty sure it's still in there! And yes, I think the (G)WR influences on the SVR shew on occasion... Log in to reply |
Dunblane down slot / Greenloaning DGL 01/01/2013 at 23:27 #39949 | |
Ron_J
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" said:In the end, the only way to be sure what the situation is at Greenloaning is to ask the signalmen who actually work the box (or strike lucky and be there to see it happen). Until then (and perhaps after as well, if they do use the stricter interpretation) the only way is to bring the approaching train to a stand at the home before setting the road into the loop. Greenloaning box has been permanently switched out* for a few years now. Moving facing points in the clearing point with a train approaching is certainly frowned upon in the Perth area, but Greenloaning comes under Stirling so I'm not sure which view prevails there. *Not quite permanent; it's opened only for the usual cyclic FPL testing. Log in to reply |
Dunblane down slot / Greenloaning DGL 02/01/2013 at 00:24 #39955 | |
jc92
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at darley dale the moving of the points is governed by the position of the train relative to them. (bear in mind of course this is light railway order 25mph territory). As a rule of thumb, if the treadle hasnt rung to indicate the trains arrival is imminent (allows us to open the gates at the correct time) then the points are free to be moved about. after the treadle we have to wait until the train has been brought to a stand before altering them. an interesting point to note is that a lot of panels allow points to be swung in front of trains. take wincobank junction as an example, say the overlap from S199 on the down main has its overlap set across the junction towards P2. if the signaller sets a route from meadowhall P3, the overlap (and points within it) are thrown across to P4. "We don't stop camborne wednesdays" Log in to reply |
Dunblane down slot / Greenloaning DGL 02/01/2013 at 10:45 #39969 | |
Danny252
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" said:an interesting point to note is that a lot of panels allow points to be swung in front of trains. take wincobank junction as an example, say the overlap from S199 on the down main has its overlap set across the junction towards P2. if the signaller sets a route from meadowhall P3, the overlap (and points within it) are thrown across to P4.But there are locations where that isn't possible when a train is close to the signal and the points are located very close to it - KX certainly has a few examples with Fast/Slow crossovers. Log in to reply |
Dunblane down slot / Greenloaning DGL 02/01/2013 at 15:08 #39990 | |
kbarber
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" said:
This is called a swinging overlap; the detection is bridged out for up to seven seconds as the points motor across so there's no change of aspect while points in the overlap are unlocked (and if they haven't been detected by the end of 7 seconds the signal drops to red). Edge Hill panel as built had selectable overlaps for the main fast - slow crossovers. When setting a route (if I recall correctly - I visited only once, 35 years ago), there was an option if a conflicting move was in the offing to use the overlap button as an exit rather than the usual signal button and this would swing the crossovers to trap the route being set and allow the conflicting move. I think it was the case that, when the conflicting move had passed clear, the desired route could then be set in the usual way (with the protecting signal as the entrance button). I believe the original double crosssovers were later remodelled as a set of single leads but I don't know whether the selectable overlaps survived. Nor do I know whether the swinging overlaps were inhibited if the train was closely approaching. Log in to reply |
Dunblane down slot / Greenloaning DGL 03/02/2013 at 18:17 #41110 | |
Gwasanaethau
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Hi all, I wonder if you can help me. I have come across a second issue with the Greenloaning loops (as per the original post), and that is if a goods train is sitting in the DGL at Greenloaning (waiting at shunt signal GL16), swinging the points to let it leave the loop causes a “Clearing point violation at Inverkeillor 6[‽]”. I have had a look at the clearing points document in the wiki and those points are not covered by any of the clearing points in the Greenloaning area (besides, I thought if trains were stationary then the clearing points no longer applied). Is there a problem there or am I misunderstanding the idea of the clearing points? In any case, the violation occurs at Greenloaning, not Inverkeillor. I am not sure if it is related, by I also got a message saying there was a “Clearing point violation at Inverkeillor 12” during the whole process of trying to get the goods train into the loop and allowing a passenger train to pass. There were trains in the Inverkeillor region at the time, but they were simply passing each other on adjacent lines, so I cannot see where the violation occurred. Sorry about the long post. Gwasanaethau (Mark). Log in to reply |
Dunblane down slot / Greenloaning DGL 03/02/2013 at 18:54 #41113 | |
Steamer
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Gwasanaethau said:Have you accepted a train from Dunblane? If so, I've made a mistake writing the document. If not, something else must be at work. "Don't stress/ relax/ let life roll off your backs./ Except for death and paying taxes/ everything in life.../ is only for now." (Avenue Q) Last edited: 03/02/2013 at 18:54 by Steamer Log in to reply |
Dunblane down slot / Greenloaning DGL 03/02/2013 at 19:34 #41116 | |
Peter Bennet
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" said:Hi all, I wonder if you can help me.Have checked the data and can see nothing that links Greenloaning to the report you got. Peter I identify as half man half biscuit - crumbs! Log in to reply |
Dunblane down slot / Greenloaning DGL 04/02/2013 at 21:56 #41153 | |
Gwasanaethau
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" said:Have you accepted a train from Dunblane? If so, I've made a mistake writing the document. If not, something else must be at work. At the point where the message about the clearing point violation appeared, I had the goods train stationary in the loop and a passenger train had already passed the loop and was well on its way to Blackford. There was nothing coming from Dunblane at that moment. " said: Have checked the data and can see nothing that links Greenloaning to the report you got.I have attached an SSG save file for you if it helps. If you try swinging the points on the exit to the loop (PGL17B I believe), the message I described earlier pops up… Post has attachments. Log in to view them. Log in to reply |
Dunblane down slot / Greenloaning DGL 04/02/2013 at 23:46 #41156 | |
BarryM
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" said:" said:Running the save, the only violation I got was "Clearing point violation at Inverkeillor 6".Have you accepted a train from Dunblane? If so, I've made a mistake writing the document. If not, something else must be at work. Barry Barry, Sydney, New South Wales, Australia Log in to reply The following user said thank you: Gwasanaethau |
Dunblane down slot / Greenloaning DGL 09/02/2013 at 15:29 #41361 | |
Gwasanaethau
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I think I have managed to get nearer to the trigger for the “Clearing point violation at Inverkeillor 12” issue too. This one occurs when a route is set from AH45 to IK12 even though there are no trains in the Inverkeillor region to trigger it. This seems to occur if points PGL17B in Greenloaning (the ones that trigger the “Inverkeillor 6” message) are reversed. Normalising those points before setting the route stops the “Inverkeillor 12” message appearing. In fact, when PGL17B are reversed, setting a route from US10 to IK6 will trigger the “Inverkeillor 6” message. It seems that the presence of a train in the loop at Greenloaning has nothing to do with it. I have attached a new save for you to experiment with. Try reversing PGL17B and then setting routes between AH45 and IK12, and US10 and IK6 to get the relevant message to appear. Try normalising the points and resetting the routes and the neither of the messages should appear. Reversing the points with the routes set should cause both messages to appear together. If you need more information, let me know and I will try to provide it if I can. Post has attachments. Log in to view them. Log in to reply |