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| Points keying question 11/07/2013 at 13:39 #46999 | |
clive
2789 posts |
Geoff and I aren't clear about some details to do with points keying. I could spend hours poring over circuit diagrams, but I don't really have the time. Can anyone here answer this either from knowledge of design, or by trying it out on a real panel? [In the latter case, DO NOT DO ANYTHING THAT COULD GET YOU INTO TROUBLE. This isn't important enough for that - nothing in SimSig is.] Take a set of points which has main class routes without approach control across both the normal and reverse directions. It doesn't matter whether the routes are from the same signal or not, or even in the same direction or not. Call the route across the normal position route A and the route across the reverse position route B. * Set route A. * Key the points reverse. I'd expect the points to stay normal, the route up, and the entrance signal clear. * Cancel route A (or let a train pass over it). I'd expect the points to stay normal. * Re-stroke route A. I'm not sure whether I'd expect the route to set or not. * If it set, cancel it again. * Set route B. I would expect that the route couldn't be set. I've written my expectations there, based on the assumption that you can't pre-select keying. But I'd like to know what actually happens on the ground in real life. (I repeat: this is not important enough for anyone to get into trouble over.) Log in to reply |
| Points keying question 11/07/2013 at 16:06 #47004 | |
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Colourlight
117 posts |
Having never worked a Panel this really needs a Panel Operator to answer your question. However, if you set route A which is through the points in the normal position and the protecting signal clears I don,t understand why you would want to reverse the points.
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| Points keying question 11/07/2013 at 16:59 #47006 | |
jc92
3685 posts |
" said:Having never worked a Panel this really needs a Panel Operator to answer your question. However, if you set route A which is through the points in the normal position and the protecting signal clears I don,t understand why you would want to reverse the points.you could key the wrong point in error? "We don't stop camborne wednesdays" Log in to reply |
| Points keying question 11/07/2013 at 18:33 #47008 | |
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Colourlight
117 posts |
It should not be possible to move points on a route that is set. Otherwise it could cause a derailment or a head on collision.
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| Points keying question 11/07/2013 at 18:39 #47009 | |
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Ron_J
331 posts |
" said:Take a set of points which has main class routes without approach control across both the normal and reverse directions. It doesn't matter whether the routes are from the same signal or not, or even in the same direction or not. Call the route across the normal position route A and the route across the reverse position route B.Correct. Quote: * Cancel route A (or let a train pass over it). I'd expect the points to stay normal. Nope, route A will not set Quote: * If it set, cancel it again.Correct. The points need to be keyed normal, then either centre or reverse before route B will set. Note this is with a Scottish Region Geographical interlocking and a Westinghouse M4 NX panel. Log in to reply |
| Points keying question 11/07/2013 at 19:29 #47011 | |
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Late Turn
699 posts |
" said:Having never worked a Panel this really needs a Panel Operator to answer your question. However, if you set route A which is through the points in the normal position and the protecting signal clears I don,t understand why you would want to reverse the points. Clearly you wouldn't want to. However, it'd be nice to think that the sim would respond in an appropriate manner (in terms of setting subsequent routes) if you did choose to do so. Log in to reply |
| Points keying question 12/07/2013 at 09:24 #47032 | |
GeoffM
6376 posts |
Note that the question is not about trying to move points within a locked route, but what happens to the points request after the route has cancelled. UK rail has never liked pre-selection.
SimSig Boss Log in to reply |
| Points keying question 12/07/2013 at 09:37 #47034 | |
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clive
2789 posts |
" said:However, it'd be nice to think that the sim would respond in an appropriate manner (in terms of setting subsequent routes) if you did choose to do so.That's the reason behind the question. What is "appropriate"? Log in to reply |
| Points keying question 12/07/2013 at 09:39 #47035 | |
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clive
2789 posts |
" said:Keyed normal as well? Interesting. (JOOI: is this from experimenting or from circuit diagrams?) Thanks very much for the answers. Log in to reply |
| Points keying question 12/07/2013 at 10:24 #47038 | |
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Late Turn
699 posts |
" said:" said:However, it'd be nice to think that the sim would respond in an appropriate manner (in terms of setting subsequent routes) if you did choose to do so.That's the reason behind the question. What is "appropriate"? Exactly, that was my understanding - others seemed to have missed the point slightly. I'm back at work this afternoon anyway, so could direct any further queries towards my colleague two boxes away, who has two NX panels at his disposal. Log in to reply |
| Points keying question 12/07/2013 at 12:54 #47042 | |
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UKTrainMan
1803 posts |
FWIW, I recall some time ago having previously asked a real signaller about keying the points in the opposite direction to hopefully speed up the route calling/setting for a following train - I believe the response was something along the lines of 'I would never do that, in-case some kind of failure cropped up and resulted in the points swinging underneath a train actively using that set of points'; so no actual mention of it strictly not being possible to do so (as is in SimSig).
Any views and / or opinions expressed by myself are from me personally and do not represent those of any company I either work for or am a consultant for. Last edited: 12/07/2013 at 12:57 by UKTrainMan Log in to reply |
| Points keying question 12/07/2013 at 14:16 #47045 | |
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GeoffM
6376 posts |
" said:FWIW, I recall some time ago having previously asked a real signaller about keying the points in the opposite direction to hopefully speed up the route calling/setting for a following train - I believe the response was something along the lines of 'I would never do that, in-case some kind of failure cropped up and resulted in the points swinging underneath a train actively using that set of points'; so no actual mention of it strictly not being possible to do so (as is in SimSig).One should not provoke an interlocking, no. It's an issue for ARS as that has to have knowledge of route availability, including points free to move. Even then, its information can be out of date by a second or so, so theoretically it could exploit a weakness. As to speeding up routesetting, a call on the points while not free to move would not do anything, as the points have to be free to move at the time of the request (the no pre-selection bit I mentioned earlier). However, the keying that Clive is talking about is an interesting subject. SimSig Boss Log in to reply |
| Points keying question 12/07/2013 at 14:26 #47046 | |
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Stephen Fulcher
2078 posts |
Preselection is not possible in Western Region E10k interlocking, there is a back contact of the LR in the WZCR circuit which will keep a feed on the WZCR, thus preventing the LR from picking and the points being able to move, until the first call is removed from the points. The point switch will have to be in the CENTRE position to remove the call, even if it is the wrong one. Clive, if you like I can send you some notes on this issue. Log in to reply |
| Points keying question 12/07/2013 at 14:51 #47048 | |
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TomOF
452 posts |
I have a follow on question,Stephen. If you move the IPS quickly from reverse to normal will the points be centred at any point while the switch is moving? I realise the switch will go briefly to the centre position, but are there any timing factors at play?
Last edited: 12/07/2013 at 14:52 by TomOF Reason: Grammar Log in to reply |
| Points keying question 12/07/2013 at 14:55 #47049 | |
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Stephen Fulcher
2078 posts |
Theoretically it will be centered, but in practice it rarely works that way. The switch being centered will trigger relays to change state - you need to allow time for this to happen before moving the switch away from the centre position, or nothing will happen. With local relays it might not take too long, but if TDM links are involved a second or so may be required. Log in to reply |
| Points keying question 12/07/2013 at 20:55 #47057 | |
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Firefly
521 posts |
Quote:Set route A. Absolutely Quote: * Cancel route A (or let a train pass over it). I'd expect the points to stay normal.Correct, you mustn't be able to preselect Quote: * Re-stroke route A. I'm not sure whether I'd expect the route to set or not.The route should set. As far as the interlocking is concerned the points are still set, locked and detected normal I'm rather surpsied by Ron_J's answer here. This must be a feature of Scottish geographical as it's not the case with GEC, Westpac, SW67, or Western E10k. Quote: * If it set, cancel it again.Correct, as above the points are still set, locked and detected normal. Also the key is not in the centre position which is a requirement for the points to move reverse Quote: have a follow on question,Stephen. If you move the IPS quickly from reverse to normal will the points be centred at any point while the switch is moving? I realise the switch will go briefly to the centre position, but are there any timing factors at play?No, as any signaller will tell you, if you move the switch too quickly the points will not move. You have to deliberately pause in the centre position to give the relays time to react or the electronic interlocking time to register the key position. One of the tests that we carry out when testing points is to move the switch quickly to the opposite direction. We can then confirm that any functions requiring the points in a certain position are locked by the Vital NLR/RLR relays and not the non-vital NR/RR relays which are simply a repeat of the point key position. FF Log in to reply |
| Points keying question 13/07/2013 at 14:46 #47093 | |
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Ron_J
331 posts |
" said:" said:Experimentation. I suspect it's a quirk of ScR Geographical.Keyed normal as well? Interesting. Log in to reply |
| Points keying question 14/07/2013 at 08:09 #47121 | |
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Firefly
521 posts |
So on your panel, if say points are keyed Normal and you then key reverse too quickly for it to register do you have to go back to centre, then reverse or do you need to go normal, centre, reverse to get them to swing?
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| Points keying question 14/07/2013 at 11:43 #47133 | |
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Ron_J
331 posts |
You have to key normal again, then centre (pause), reverse. It's well known about by the signallers and is referred to as "letting the panel catch up".
Log in to reply The following user said thank you: Firefly |
| Points keying question 14/07/2013 at 12:01 #47135 | |
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Firefly
521 posts |
Very interesting. I don't believe I've come across that before. It's certainly not the norm Clive. FF Log in to reply |
| Points keying question 18/07/2013 at 07:37 #47305 | |
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Hooverman
306 posts |
Clive I will pm you my results.
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