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| Avonmouth / St. Andrews query 02/01/2012 at 15:56 #26651 | |
DaveHarries
1269 posts |
Hi all, Just a thought but if a signal was yellow (IRL) would it still show up on the controlling panel as green? My reason for asking is that, at Avonmouth, signal SA5 does not, IRL, show anything other than either red or amber. Thanks. Dave Log in to reply |
| Re: Avonmouth / St. Andrews query 02/01/2012 at 20:43 #26675 | |
jc92
3630 posts |
on an NX panel, signals only show as green (off) or red (on) despite what they will show to the driver. think of them like repeaters in a mechanical box, its only important that the signaller knows the signal has cleared.
"We don't stop camborne wednesdays" Log in to reply |
| Re: Avonmouth / St. Andrews query 02/01/2012 at 20:54 #26677 | |
Late Turn
696 posts |
Given that you've got SA5 indicating a yellow (not amber!!), you can't have 'panel signals' ticked in the F3 menu (which would mean you'd only see red or green). I suspect that SA5's not cleared beyond a yellow for no reason other than that the "crossing keeper" looking after the LCs on the Avonmouth line doesn't get the barriers down at St Andrews LC until the train has passed SA5, thus SA7 doesn't clear in time to get a green at SA7. As above, you only need to know whether the signal's displaying a proceed aspect or not - the most important thing is knowing that it's gone back to Danger! Tom Last edited: 02/01/2012 at 20:55 by Late Turn Log in to reply |
| Re: Avonmouth / St. Andrews query 02/01/2012 at 21:31 #26684 | |
DriverCurran
683 posts |
Do know of one signal that shows the actual aspect out of the 3 possible on the signallers equipment shelf. Paul You have to get a red before you can get any other colour Log in to reply |
| Re: Avonmouth / St. Andrews query 02/01/2012 at 21:44 #26686 | |
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Late Turn
696 posts |
I think the Southern was quite keen to provide an indication of the actual aspect displayed, so it wasn't too uncommon around those parts. Our three-aspect colour-light distants on the preserved GCR are indicated on the block shelf in the same way. I'm not sure what the Signalman gains from it though!
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| Re: Avonmouth / St. Andrews query 02/01/2012 at 22:32 #26692 | |
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BoxBoyKit
166 posts |
Frame with colourlights I work has a signal that can only display Red or Yellow (or white) and on the block shelf, the inidcator is a Red or Yellow light. The others (3 or 4 aspect signals) display Red or Green (or white)...I admit it's only on a preserved railway and was built in the 70s/80s...but I would have assumed it was the same on BR and now NR?
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| Re: Avonmouth / St. Andrews query 02/01/2012 at 22:56 #26696 | |
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Late Turn
696 posts |
Generally that's all that would be provided, as that's all the Signalman needs. Sometimes the additional aspects are indicated though, as Paul's example above and the GC - for reasons that aren't entirely clear to me!
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| Re: Avonmouth / St. Andrews query 03/01/2012 at 12:16 #26710 | |
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kbarber
1712 posts 
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This is yet another generational/company of origin one. After nationalisation, the BR regions tended to continue the practices of the former owning companies until something intervened to stop them. With exceptions (I'll come on to that), all companies used a red visual for a signal at danger. Not sure about GWR practice where colour light signals existed. At Cardiff there were WB&SCo style L lever frames and Mark Adlington records that red and green were used to show "on" and "off" respectively (see here http://www.wbsframe.mste.co.uk/public/Cardiff_West.html ). Not sure whether there were any working distants in that installation, nor how shunt signals were indicated. Of course the GWR didn't go in for multi-aspect signalling, but used colour lights to repeat the night indications of semaphores. The LNER and BR(E) used red & green for "on" and "off", the green indication showing for any possible off indication (I have an idea this may have applied to subsidiary signals as well but would welcome confirmation). The LMR (presumably LMS too?) used red for "on" and a white stencil reading "OFF" for off, for both main and subsidiary aspects. The SR and BR(S) repeated the signal aspect in full. Very impressive with 4-aspect signalling on a large L frame such as Clapham B, where it was possible to have 2 or more successive trains in the controlled area. However, the standard was a lever for every route from a signal (similar to semaphore practice). At a signal with multiple routes, only the lever for the main route had the signal aspects repeated behind it. For other routes the lever had no indication for signal on and an illuminated arrow (if memory serves black on white) pointing in the direction of the junction indicator for "off", while the indicator behind the main route lever stepped up to the aspect being shown even though that lever was normal. The SR also used something different for subsidiary signals. In general these were Westinghouse-style discs (solenoid driven) and accordingly the indication in the box was a red band on an illuminated white background, horizontal for "on" and inclined for "off". (In the same vein I've an idea I once saw two small whites - or was it red & white? - but it wasn't that distinct anyway) horizontally for a PL shunt "on" and two whites inclined for "off". Wish I could recall where it was. As the earliest panels were built for the LNER it's hardly surprising they used red/green for on/off indications of main aspects. I'm not quite sure whether they used white for subsidiaries in early installations - as signal configurations were painted onto the panel in full it was easy to use separate lamps for main & sub repeaters. The earliest NX panels (Metro Vickers-GRS) showed signal indications through the entrance switches and were restricted to red & green whatever the signal displayed. The late (1961) MV-GRS panel at Barking used that aperture for filament failure indications and had small red & green indications adjacent to the entrance switch for signal indicating; IIRC there was a green on the opposite side of the line to the red for a main aspect and one on the same side for a subsidiary, with both provided where the signal was capable of displaying both; IIRC the red was extinguished even where the signal showed red with cats-eyes. By this time Westinghouse was definitely using green for main aspect and white for any subsidiary off, with red for on; this was found on both OCS and NX panels and became standard when BR settled on the push-push NX panel. I think the WR turn-push domino panels had adopted these standard indications from the start; certainly that was what Old Oak Common had when I saw it in 1979. Just to be different, the Underground power frames had a red indication for "on" but no indication at all for "off". There would be a small white visual to indicate route set at a junction signal. However the diagram would repeat the full indication of some signals, including PLJIs. I have no idea what the criteria were for choosing which to repeat in this manner; I couldn't see any obvious reason for the choices in the boxes I saw. So broadly, you pays your money & you takes your choice! Log in to reply The following users said thank you: Forest Pines, BarryM, maxand |
| Re: Avonmouth / St. Andrews query 07/01/2012 at 17:57 #26901 | |
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DaveHarries
1269 posts |
" said:Given that you've got SA5 indicating a yellow (not amber!!), you can't have 'panel signals' ticked in the F3 menu (which would mean you'd only see red or green). I suspect that SA5's not cleared beyond a yellow for no reason other than that the "crossing keeper" looking after the LCs on the Avonmouth line doesn't get the barriers down at St Andrews LC until the train has passed SA5, thus SA7 doesn't clear in time to get a green at SA7. I don't have "Panel Signals" ticked in option F3: you are right there. I don't know if St. Andrews Road (SA) is an NX panel though. Anyway, here's something to prove my point with SA5 being only dual-aspect IRL:  SA5 at Avonmouth, cleared for FGW150127 to proceed with the 1516hrs Bristol TM - Severn Beach. 07-Jan-2012. I see the point about only needing to know that the signal has cleared though. Dave Log in to reply |
| Re: Avonmouth / St. Andrews query 07/01/2012 at 18:27 #26904 | |
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Late Turn
696 posts |
Thanks for the pic Dave, confirms that the signal can't clear beyond a single yellow (rather than just being prevented from doing so by the operation of the next signal). Presumably the additional circuitry to determine the aspect of the next signal couldn't be justified if it wasn't normally intended to clear until the train had passed this signal.
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| Re: Avonmouth / St. Andrews query 07/01/2012 at 20:42 #26910 | |
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DaveHarries
1269 posts |
" said:Thanks for the pic Dave, confirms that the signal can't clear beyond a single yellow (rather than just being prevented from doing so by the operation of the next signal). Presumably the additional circuitry to determine the aspect of the next signal couldn't be justified if it wasn't normally intended to clear until the train had passed this signal. The next signal towards Severn Beach after SA5 is located just before the Docks LC. It is also concealed by a curve and therefore not visible to a train departing Avonmouth for Severn Beach. The box at St. Andrews is not a gate box as it also signals the layout for the coal terminal. I don't know how the next signal works but I am certain that when one crossing is closed the other one is closed at the same time. Once when I was doing a photo of the box at St. Andrews Road. The signalman closed the gates at Avonmouth station before closing the gates at the docks LC and from where I was I could hear the siren from the back of the traffic signals at Avonmouth station when the sequence there was started. HTIOI, Dave Last edited: 07/01/2012 at 20:50 by DaveHarries Log in to reply |
| Re: Avonmouth / St. Andrews query 08/01/2012 at 08:42 #26924 | |
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Late Turn
696 posts |
" said:[quote="Late Turn" post=26904]The box at St. Andrews is not a gate box as it also signals the layout for the coal terminal. Correct in reality, but in Simsig it appears to have been simulated as a gate box. Even if St. Andrews crossing was lowered at the same time, presumably the circuitry previously mentioned still wasn't justified to allow SA5 to clear to green, given the low speed nature of the operation (was the Severn Beach branch beyond Avonmouth ever - recently - OTW with staff?). Also of interest are the panel photos on John Tilly's website (www.tillyweb.biz), which show that there's two panels (Avonmouth and St Andrews) within the signal box - that might contribute to the complexity of allowing SA5 to step up to green? Just a few thoughts! Tom Log in to reply |