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| I need a little signal help 14/04/2010 at 00:25 #1117 | |
cohiba
3 posts |
Could someone please explain in rather laymans terms what the signals with the red triangles are and how they work? Thank you.
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| I need a little signal help 14/04/2010 at 00:25 #8477 | |
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cohiba
3 posts |
Could someone please explain in rather laymans terms what the signals with the red triangles are and how they work? Thank you.
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| I need a little signal help 14/04/2010 at 00:39 #8478 | |
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AndyG
1842 posts |
They are shunt signals, see here and here on the WIKI.
I can only help one person a day. Today's not your day. Tomorrow doesn't look too good either. Log in to reply |
| I need a little signal help 14/04/2010 at 00:40 #8479 | |
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UKTrainMan
1803 posts |
The signals you so eloquently describe are known as Shunt Signals. You may have seen them before, they often exhibit a red and white light along the bottom and then an unlit light above the red - when the route is set from them and cleared the red light extinguishes and the unlit light above it lights up white, which is basically authority to proceed. Some may say "LOS" next to them which means they are a Limit of Shunt signal - these only display double reds and nothing more and they cannot be passed. Some main signals (i.e: two aspects, three aspects or four aspects) may also have a shunt signal below or next to them however these are often unlit until a shunt route is set from them and it clears - although if a main route is set then they will still remain unlit and the main signal aspects will be used). EDITED TO ADD: Damn, AndyG beat me to it! 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. Log in to reply |
| I need a little signal help 14/04/2010 at 00:43 #8480 | |
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lpeters
160 posts |
Some signals may display double red and change to a single white upon the route being set. Some LOS will also display 3 reds in the format of a triangle. http://farm4.static.flickr.com/3175/2376676309_b48f4342b8.jpg?v=0 <--- one that I described http://www.scalewaysignals.com/products/col_light/CLGS.jpg <--- the 2+1 that Andy described http://www.scalewaysignals.com/products/col_light/CLLS.jpg <--- the LOS that Andy described Log in to reply |
| I need a little signal help 14/04/2010 at 00:49 #8481 | |
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cohiba
3 posts |
Thanks guys, I guess I missed that part of the WIKI somhow. My apologies. Log in to reply |
| I need a little signal help 14/04/2010 at 09:39 #8487 | |
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kbarber
1743 posts 
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UKTrainMan said:The signals you so eloquently describe are known as Shunt Signals. You may have seen them before, they often exhibit a red and white light along the bottom and then an unlit light above the red - when the route is set from them and cleared the red light extinguishes and the unlit light above it lights up white, which is basically authority to proceed. That arrangement is rapidly becoming history even if it hasn't quite got there yet; the modern standard requires 2 red lights horizontally displayed for the "on" indication, the smae indication as an LOS (remains 2 white at 45degrees for "proceed"  and there is a programme to alter all existing shunt signals. (Incidentally, historically the "on" aspect was 2 white lights and I believe that, when one of these was provided as a facing shunt in a main route, it wasn't cleared when the main signal cleared - it was passed at "on" under the authority of the main signal.)UKTrainMan said: Some main signals (i.e: two aspects, three aspects or four aspects) may also have a shunt signal below or next to them however these are often unlit until the route it set from them and cleared. These are always unlit when "on" as the red of the main signal is the "stop" aspect for them; they also remain unlit when a main aspect proceed indication is shown. Log in to reply |
| I need a little signal help 14/04/2010 at 11:42 #8496 | |
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Late Turn
699 posts |
lpeters said:Some signals may display double red and change to a single white upon the route being set. Some LOS will also display 3 reds in the format of a triangle. GPLs displaying a 'double red' will still clear to the two whites diagonally. None of them, including LOSs, display 3 reds. Log in to reply |
| I need a little signal help 14/04/2010 at 14:06 #8502 | |
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UKTrainMan
1803 posts |
kbarber said:UKTrainMan said:Yes, I am aware of the new type of shunt signal however I specifically didn't mention it as in my experience most shunt signals are still the older type I originally described, not the newer type, therefore I didn't want to mention the newer type and confuse someone.The signals you so eloquently describe are known as Shunt Signals. You may have seen them before, they often exhibit a red and white light along the bottom and then an unlit light above the red - when the route is set from them and cleared the red light extinguishes and the unlit light above it lights up white, which is basically authority to proceed. kbarber said: UKTrainMan said:Seems I may have incorrectly worded that - I will make the appropriate adjustments now. Thanks for pointing this outSome main signals (i.e: two aspects, three aspects or four aspects) may also have a shunt signal below or next to them however these are often unlit until the route it set from them and cleared. 
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. Log in to reply |
| I need a little signal help 15/04/2010 at 09:09 #8522 | |
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kbarber
1743 posts
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UKTrainMan said:
That's interesting; all the shunt signals I ever see these days have the 2-reds for "on" configuration (and discussion elsewhere seemed to suggest that was true across most of the country), so much so that I'd thought maybe the replacement programme was complete and the old red/white configuration was truly history. Incidentally the changeover programme is a bit of a rarity; my experience is that, when a standard changes, existing installations are left pretty much untouched until there's a need for significant replacement. (In fact it's not that unusual to see several generations of equipment, all built to different standards/principles and with different meanings to match, at one location.) Log in to reply |
| I need a little signal help 15/04/2010 at 09:27 #8525 | |
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AndyG
1842 posts |
Getting a bit off topic for a Newcomer's thread really, as the originator's question has been answered.
I can only help one person a day. Today's not your day. Tomorrow doesn't look too good either. Log in to reply |
| I need a little signal help 15/04/2010 at 09:28 #8526 | |
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Forest Pines
525 posts |
kbarber said:(In fact it's not that unusual to see several generations of equipment, all built to different standards/principles and with different meanings to match, at one location.)In fact, the shunt signal replacement programme has made it very common indeed! (it's been a few years now since I've seen a shunt signal showing red/white for on, but I haven't been a great explorer of the network over that period). Log in to reply |
| I need a little signal help 15/04/2010 at 10:29 #8527 | |
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clive
2789 posts |
If I remember correctly, the requirement is that you mustn't have shunt signals of the two different types (R/W and R/R) visible to a driver. Thus you have to change all Down signals at a site simultaneously, and all Up signals simultaneously, but you can have Up and Down being different types and you can have different types at opposite ends of a station or otherwise well-spaced apart. Ah: "Where independent position light signals that display [two reds when ON] are to be added to an existing signalling layout that includes independent position light signals that display a different form of ON aspect, the signalling layout shall be designed so that: a) Drivers will not observe the different forms of ON aspect at the same time during train movements, and b) The transition between the different forms of ON aspect is clearly defined." Log in to reply |
