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| Redbridge starter signal 781 stays red 16/02/2012 at 12:21 #29564 | |
maxand
1637 posts |
I noticed that Redbridge signal 781 indicates correct aspect when a route is set from it along the Down Main towards Brockenhurst. (Panel signals Off revealing 4-aspect signalling.) However, when a route is set from it to Romsey, the signal remains red even though a route has been cleared, until the train reaches it, when it turns green   Maybe this has something to do with the fact that the next signal (861, down Test Valley) appears to be controlled by Romsey (remains grey). FWIW, 1V94 does not stop at Redbridge - just passes through. Thanks for any explanation. I'm sure it's a simple one. Last edited: 16/02/2012 at 12:28 by maxand Log in to reply |
| Re: Redbridge starter signal 781 stays red 16/02/2012 at 12:32 #29565 | |
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GB
64 posts |
The signal is approach released...meaning the approaching train has to occupy the track circuit for a period of time before the signal comes off. Its to make sure (as best as possible) that the train reduces enough speed before taking a diverging (slower) route. Standard set up amongst UK signalling.
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| Re: Redbridge starter signal 781 stays red 16/02/2012 at 12:32 #29566 | |
Peter Bennet
5402 posts |
At a guess it's approach released which I think we have covered before. Peter I identify as half man half biscuit - crumbs! Log in to reply |
| Re: Redbridge starter signal 781 stays red 16/02/2012 at 12:33 #29567 | |
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Josie
310 posts |
That's normal behaviour for what's called 'approach control from red'. It's usually used when the speed restriction on facing points is low, and the train needs to be slowed down before crossing them. A full diagram explaining it (as well as various other ways of signalling junctions) is on Clive's website. And in this case the fact that the route leads to an adjacent box is a red herring - this is purely about the junction. Log in to reply |
| Re: Redbridge starter signal 781 stays red 16/02/2012 at 12:35 #29568 | |
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Late Turn
699 posts |
Max, A very well illustrated example of approach control! The permissible speed through the divergence towards Romsey will be rather lower than the speed for the route straight ahead (no idea of the actual numbers in this case), so you need some way of ensuring that 1V94 is aware that he's been signalled over the diverging route. Bear in mind that you can't rely on the Driver 'knowing' that he's booked to go that way - the route could have been set in error for a Brockenhurst train, or the diverging route could be an acceptable alternative to the straight-ahead route. The most common means of ensuring that his speed is reduced is to hold the signal protecting the junction at Danger until the train is proved to be at a pre-determined distance from the signal (usually achieved by requiring a certain TC occupied for a specified time), and thus well under control and preparing to come to a stand at the junction signal. There are other methods (approach control from yellow, flashing yellows), but I'm sure you'll come across these in due course! Tom Log in to reply The following user said thank you: maxand |
| Re: Redbridge starter signal 781 stays red 16/02/2012 at 12:36 #29569 | |
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ExDistrictDriver
30 posts |
I can't say for certain, but I suspect the route over the junction is the reason. The signal you're referring to is more than likely approach controlled for the route over that junction. Just my guess looking at your screenshots. Log in to reply |
| Re: Redbridge starter signal 781 stays red 16/02/2012 at 12:38 #29570 | |
lazzer
636 posts |
Despite many signals being approach control on the Western region, the management don't like us referring to them as such, because they think that drivers will assume the signal will come off as they approach it and have a SPAD if it doesn't! But we all know they're approach-controlled, so it's a complete waste of time on their part ... Last edited: 16/02/2012 at 12:42 by lazzer Log in to reply |
| Re: Redbridge starter signal 781 stays red 16/02/2012 at 12:39 #29571 | |
nroberts
227 posts |
My guess is that the signal since it's now about to indicate a diverging route with a slower-than-line speed over the point is approach released. Maybe you should check out: =approach&s[]=control]http://www.SimSig.co.uk/dokuwiki/doku.php?id=signallingprinciples&s[]=approach&s[]=control or the heading "junction working" in =approach&s[]=control]http://www.SimSig.co.uk/dokuwiki/doku.php?id=usertrack:mans:stafford&s[]=approach&s[]=controll Whilst the next signal (in this case down Test Valley) could well be showing a non-clear aspect, I would throw my chips in with the approach release. Also a bit of searching (not a very complicated task) throws up (among other results): http://www.SimSig.co.uk/index.php?option=com_kunena&func=view&catid=23&id=26218&Itemid=145#26218 NR BTW the search box is at the top right. Last edited: 16/02/2012 at 12:39 by nroberts Reason: grammar correction Log in to reply |
| Re: Redbridge starter signal 781 stays red 16/02/2012 at 12:41 #29572 | |
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Josie
310 posts |
Six answers for the price of one! We're a helpful bunch 
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| Re: Redbridge starter signal 781 stays red 16/02/2012 at 12:47 #29573 | |
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lazzer
636 posts |
" said:Six answers for the price of one! We're a helpful bunch ;) I have a feeling we'll be needed in the future - Max likes to ask questions about everything new thing he comes across ... Log in to reply |
| Re: Redbridge starter signal 781 stays red 16/02/2012 at 13:07 #29574 | |
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maxand
1637 posts |
I think the ayes have it - approach release! Thanks a lot, everyone. I understood the concept, but just didn't recognize it in action here across facing points. As they say, one picture (or three in this case) is worth a thousand words. Your excellent, clear explanations should help other newcomers too. Quote: BTW the search box is at the top right. That's the trick - you have to know what you're searching for before you can start searching for it.  But thanks for the links. Last edited: 16/02/2012 at 13:16 by maxand Log in to reply |
| Re: Redbridge starter signal 781 stays red 16/02/2012 at 13:38 #29577 | |
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clive
2789 posts |
" said:The permissible speed through the divergence towards Romsey will be rather lower than the speed for the route straight ahead (no idea of the actual numbers in this case)50 straight, 30 round the corner. Log in to reply The following user said thank you: maxand |
| Re: Redbridge starter signal 781 stays red 16/02/2012 at 14:11 #29580 | |
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AndyG
1842 posts |
also in glossary at http://www.SimSig.co.uk/dokuwiki/doku.php?id=usertrack:glossary:approach_control
I can only help one person a day. Today's not your day. Tomorrow doesn't look too good either. Log in to reply |
| Re: Redbridge starter signal 781 stays red 16/02/2012 at 14:13 #29581 | |
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Peter Bennet
5402 posts |
" said:" said:Which is fair enough provided it's done in a non-confrontational manner- which this was.Six answers for the price of one! We're a helpful bunch ;) Peter I identify as half man half biscuit - crumbs! Log in to reply |
| Re: Redbridge starter signal 781 stays red 17/02/2012 at 12:01 #29624 | |
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Aurora
183 posts |
" said:" said:Six answers for the price of one! We're a helpful bunch ;) Not such a bad thing, especially if it's not particularly simple to know. I like reading through these explanations. Thanks all. :) EDIT: My Fiftieth post. Nil. Last edited: 17/02/2012 at 12:04 by Aurora Reason: Number Fifty Log in to reply |
| Re: Redbridge starter signal 781 stays red 18/02/2012 at 15:44 #29666 | |
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kbarber
1743 posts |
" said:" said:Six answers for the price of one! We're a helpful bunch ;) Given that he's taken on - and made substantial progress on - a task that none of us has been able to make much inroad into (Wiki editing/creation), I'm all for encouraging Max to ask questions! Last edited: 18/02/2012 at 15:45 by kbarber Reason: My 400th post... coincidence or what?!! Log in to reply The following users said thank you: ralphjwchadkirk, Sam Tugwell, maxand |
| Re: Redbridge starter signal 781 stays red 18/02/2012 at 15:48 #29667 | |
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lazzer
636 posts |
" said:" said:" said:Six answers for the price of one! We're a helpful bunch ;) I think I should have put a smiley after my post quoted above.
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