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| Signal 539 (Potters Bar Down Fast) 02/11/2012 at 00:23 #37158 | |
Josie
310 posts |
When the DF>DS points at Potters Bar are set reverse with a route set ahead from signal 539 (the platform signal on the Down Fast), that signal only shows danger, unless there is a train between the points and the signal. I'm assuming a quirk this specific is a representation of the signal's actual behaviour rather than a bug - but why does this happen?
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| Signal 539 (Potters Bar Down Fast) 02/11/2012 at 02:13 #37159 | |
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Firefly
521 posts |
It's called INSELL lock and is described as:- Quote: A means of holding a SIGNAL in advance of a diverging junction at red where there is a risk of misreading or READING THROUGH. Log in to reply The following user said thank you: Josie |
| Signal 539 (Potters Bar Down Fast) 02/11/2012 at 02:45 #37160 | |
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Josie
310 posts |
Thanks for that. I haven't noticed anything similar anywhere else on the King's Cross sim*; is there a specific risk with this signal/location? (*I'd noticed it at Westerleigh Junction on Bristol as well, and had assumed that was the reason for it in that case.) Log in to reply |
| Signal 539 (Potters Bar Down Fast) 02/11/2012 at 08:00 #37164 | |
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clive
2789 posts |
" said:Thanks for that. I haven't noticed anything similar anywhere else on the King's Cross sim*; is there a specific risk with this signal/location?The Down Slow signal isn't visible because of the curvature of the line and the station canopy, while the DF one is. The risk is that the driver will pass the junction signal, then see the green ahead of him and think that the DS signal has cleared since he passed the yellow or double yellow. If he can see a train there he's much less likely to make the mistake. Log in to reply The following user said thank you: Josie |
| Signal 539 (Potters Bar Down Fast) 02/11/2012 at 20:54 #37182 | |
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jrr
95 posts |
The risk at Westerleigh junction is for trains heading north to approach too fast for the junction. The signal stays red until the train MUST be going slow enough to take the curve. When I travelled it regularly in 1975 the start of the curve was 30mph whereas the up Paddington it left was a lot higher! jrr Log in to reply |
| Signal 539 (Potters Bar Down Fast) 02/11/2012 at 21:53 #37183 | |
GeoffM
6377 posts |
" said:The risk at Westerleigh junction is for trains heading north to approach too fast for the junction. The signal stays red until the train MUST be going slow enough to take the curve. When I travelled it regularly in 1975 the start of the curve was 30mph whereas the up Paddington it left was a lot higher!I think two different applications of two different signals are being confused here. Signal B115 before Westerleigh is approach controlled (flashing yellow) because of the 30mph diversion speed compared to 100mph straight ahead. But signal UB106A after Westerleigh is held at red if the diamond is reversed IIRC, to prevent a train heading towards Yate from seeing UB106A show a proceed aspect - reading through. SimSig Boss Log in to reply |
| Signal 539 (Potters Bar Down Fast) 03/11/2012 at 01:16 #37184 | |
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Josie
310 posts |
" said:I think two different applications of two different signals are being confused here. Signal B115 before Westerleigh is approach controlled (flashing yellow) because of the 30mph diversion speed compared to 100mph straight ahead. But signal UB106A after Westerleigh is held at red if the diamond is reversed IIRC, to prevent a train heading towards Yate from seeing UB106A show a proceed aspect - reading through.Right - it was the latter I was referring to in this case. Going slightly off topic, does anyone know whether 'reading through' is a railway-specific term? There's a road junction near me where it happens often (a pedestrian crossing just after a crossroads causes drivers to see a green light at the crossing and miss the red light at the crossroads) and I've referred to it as 'reading through' before and got confused looks in return; am I using railway jargon without realising? :S Log in to reply |
| Signal 539 (Potters Bar Down Fast) 03/11/2012 at 10:41 #37185 | |
jc92
3690 posts |
" said:" said:there is a junction outside my house where this could happen, as a result the lights are both set to change together to prevent reading through, so it certainly isnt just a railway application, not sure about the jargon though.I think two different applications of two different signals are being confused here. Signal B115 before Westerleigh is approach controlled (flashing yellow) because of the 30mph diversion speed compared to 100mph straight ahead. But signal UB106A after Westerleigh is held at red if the diamond is reversed IIRC, to prevent a train heading towards Yate from seeing UB106A show a proceed aspect - reading through.Right - it was the latter I was referring to in this case. "We don't stop camborne wednesdays" Log in to reply |
| Signal 539 (Potters Bar Down Fast) 03/11/2012 at 11:16 #37187 | |
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benstafford
88 posts |
There are several round here. They have hoods to block amber and green but not red to prevent reading through.
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| Signal 539 (Potters Bar Down Fast) 03/11/2012 at 12:10 #37190 | |
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Danny252
1461 posts |
" said:amberNever heard of issues with reading through traffic lights being a problem on the railway! (Or did you mean "yellow", which is a colour of lamp in railway signals?) Log in to reply |
| Signal 539 (Potters Bar Down Fast) 03/11/2012 at 12:40 #37193 | |
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Josie
310 posts |
I think he was describing an issue with reading through traffic lights being a problem on the roads...!
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| Signal 539 (Potters Bar Down Fast) 03/11/2012 at 16:08 #37199 | |
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benstafford
88 posts |
Which is why I used amber rather than yellow. When it comes to read through on the rails, I always have issues working out which signal is which in the distance on the line north from Purley but I suspect driver route knowledge will help here as they know whether to expect fast and slow or just slow signals. Log in to reply |
| Signal 539 (Potters Bar Down Fast) 03/11/2012 at 16:53 #37201 | |
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GeoffM
6377 posts |
" said:I think he was describing an issue with reading through traffic lights being a problem on the roads...!There was a story some time ago of a female driver stopping at a red light on a motorway in Ireland - which was a railway signal. I don't know whether that's an urban myth or a true story. SimSig Boss Log in to reply |
| Signal 539 (Potters Bar Down Fast) 03/11/2012 at 17:18 #37204 | |
Peter Bennet
5402 posts |
" said:" said:I have seen temporary road work lights very close to railway lines - don't know how confusing that could be in the dark.I think he was describing an issue with reading through traffic lights being a problem on the roads...!There was a story some time ago of a female driver stopping at a red light on a motorway in Ireland - which was a railway signal. I don't know whether that's an urban myth or a true story. Peter I identify as half man half biscuit - crumbs! Log in to reply |
| Signal 539 (Potters Bar Down Fast) 03/11/2012 at 19:21 #37206 | |
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Signalhunter
177 posts |
Approaching Settle Junction, from Carnforth, the railway runs alongside the A65, (from Kendal and the M6, J.36 to Skipton) road. I have seen car drivers brake for SJ11(?) on foggy/early mornings. Certainly, I refer to reading through, at traffic lights but, I'm not sure if any other (road) drivers would know what I meant. Log in to reply |
| Signal 539 (Potters Bar Down Fast) 03/11/2012 at 19:31 #37209 | |
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Danny252
1461 posts |
Ah, there was a lack of a quote so I didn't pick up on the discussion having kept on the "road"-y theme. One I've always thought is a risk is yellow street lamps - a signal with a significant background of those could be confusing if the signal itself is showing yellow, as the colours seem quite similar. Log in to reply |
| Signal 539 (Potters Bar Down Fast) 03/11/2012 at 21:11 #37211 | |
postal
5265 posts 
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" said:One I've always thought is a risk is yellow street lamps - a signal with a significant background of those could be confusing if the signal itself is showing yellow, as the colours seem quite similar.Actually covered in the Rule Book - S3, Section 3.3. To quote, a driver is instructed that "If a signal is difficult to see because of sunlight, streetlights or light reflections, you must tell the signaller immediately stopping the train specially if necessary." The signaller is then instructed that "If a driver reports that a signal is difficult to see because of sunlight, streetlights or light reflections, you must: • tell Operations Control who will arrange for the signalling technician to check the sighting of the signal • tell the driver of the next approaching train what has happened • instruct that driver to report the state of the signal • signal the train in the normal way. If the driver you have instructed to check the signal reports to you that the signal is not difficult to see, you may signal the following trains in the normal way. However, if that driver reports that the signal is difficult to see because of sunlight, streetlights or light reflections, you must treat the signal as defective and carry out the instructions in module T1A Work on signalling equipment and module T1B Movement of trains during failure of, or when working on, signalling equipment." “In life, there is always someone out there, who won’t like you, for whatever reason, don’t let the insecurities in their lives affect yours.” – Rashida Rowe Last edited: 03/11/2012 at 21:12 by postal Log in to reply |
| Signal 539 (Potters Bar Down Fast) 04/11/2012 at 09:24 #37220 | |
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Stephen Fulcher
2084 posts |
Quite often a signal will have a much larger than standard backboard to compensate for things like this. One that stands out to me was LN51R approaching Milverton Junction on the Down. When this signal was yellow, it was hard to tell which yellow light was actually the signal at night due to all the street lights behind it. Green was obvious enough however. Log in to reply |
| Signal 539 (Potters Bar Down Fast) 04/11/2012 at 10:37 #37221 | |
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AndyG
1842 posts |
" said:One I've always thought is a risk is yellow street lamps - a signal with a significant background of those could be confusing if the signal itself is showing yellow, as the colours seem quite similar.Occasionally you will (still) find a street-light with a backboard, to prevent it being seen from the railway; modern designs of street lights have a improved light cut-off design and so it's less of a problem these days. I can only help one person a day. Today's not your day. Tomorrow doesn't look too good either. Log in to reply |
| Signal 539 (Potters Bar Down Fast) 04/11/2012 at 12:08 #37222 | |
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Hooverman
306 posts |
The new road traffic lights on the Coulsdon by-pass adjacent to the Quarry Lines near Purley had be switched off for nearly a year while contractors for TFL sorted out the light pollution spillover onto the nearby railway signals. We had a spate of complaints from drivers that the railway signals were getting lost into the road traffic ones, having said that other drivers had no problems with them and said it was all down to route knowledge.
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| Signal 539 (Potters Bar Down Fast) 04/11/2012 at 13:30 #37224 | |
DriverCurran
688 posts |
During the time I was driving services up the Catford Loop there was a set of traffic lights between Croften Road Junction and Denmark Hill where the line curved to the left, however I never felt this was a problem. As a professional driver I was aware of this potential SPAD trap and having the required route knowledge I knew that there could be an issue there and therefore ascertained that I had infact spotted the real signal rather than the road traffic signal. Paul You have to get a red before you can get any other colour Log in to reply |
| Signal 539 (Potters Bar Down Fast) 04/11/2012 at 14:17 #37227 | |
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TimTamToe
664 posts |
" said:The new road traffic lights on the Coulsdon by-pass adjacent to the Quarry Lines near Purley had be switched off for nearly a year while contractors for TFL sorted out the light pollution spillover onto the nearby railway signals. We had a spate of complaints from drivers that the railway signals were getting lost into the road traffic ones, having said that other drivers had no problems with them and said it was all down to route knowledge.I had always wondered why the road traffic lights had been switched off. If only they would sort out the stupid positioning of the (road) speed limit changes on the by-pass... Log in to reply |