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| Flashing Red Aspect 23/05/2013 at 20:49 #45076 | |
Joe_T
56 posts |
Hi all I was watching a video that a mate of mine did and there was an empty coal train heading north and the southbound signal on P3 Carlisle was flashing. Can some kind soul please tell me what the Flashing Red Aspect means?
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| Flashing Red Aspect 23/05/2013 at 21:09 #45077 | |
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TomOF
452 posts |
Hi Joe, It means a controlled signal has been replaced to danger and is timing out. This is to mitigate a train being unable to stop in time and overrunning the signal. Log in to reply |
| Flashing Red Aspect 23/05/2013 at 21:09 #45078 | |
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UKTrainMan
1803 posts |
I'm only aware of flashing red aspects being found on SPAD Indicators.
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 |
| Flashing Red Aspect 23/05/2013 at 21:10 #45079 | |
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Backup
89 posts |
Could we please see the video ourselves, in order to better answer the question?
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| Flashing Red Aspect 23/05/2013 at 21:12 #45080 | |
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UKTrainMan
1803 posts |
The only case I'm aware of of where you'd find a flashing red aspect 'in the field'/'on the ground' would be as part of a SPAD Indicator - quite a few videos of these can be found on YouTube. http://www.youtube.com/watch?v=xje3coP9-IM http://www.youtube.com/watch?v=kj_1mf5ZuGg (Railway modelling layout) P.S.: How are you? 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: 23/05/2013 at 21:20 by UKTrainMan Log in to reply |
| Flashing Red Aspect 23/05/2013 at 21:25 #45081 | |
Steamer
3985 posts 
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I think it may be something to do with the camera's sampling rate and the 50Hz AC supply to the signal lamp (especially if it's an LED lamp), which produces an illusion of flickering that someone looking at the lamp directly wouldn't notice. I don't know anymore than this though, so I won't speculate further.
"Don't stress/ relax/ let life roll off your backs./ Except for death and paying taxes/ everything in life.../ is only for now." (Avenue Q) Last edited: 23/05/2013 at 21:26 by Steamer Log in to reply |
| Flashing Red Aspect 23/05/2013 at 21:28 #45082 | |
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Joe_T
56 posts |
Hi here is the video http://www.youtube.com/watch?v=hLoOZRU9qdc The time where you see the train going north and the south faceing signal is at 6m 45s. Thanks for the replies so far 
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| Flashing Red Aspect 23/05/2013 at 21:36 #45083 | |
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UKTrainMan
1803 posts |
Direct link to a good time to start at - http://www.youtube.com/watch?v=hLoOZRU9qdc&t=6m43s
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: 23/05/2013 at 21:38 by UKTrainMan Log in to reply |
| Flashing Red Aspect 23/05/2013 at 21:45 #45084 | |
Peter Bennet
5402 posts
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At about 9 minutes it appears to be out then flickers into life. Peter I identify as half man half biscuit - crumbs! Log in to reply |
| Flashing Red Aspect 23/05/2013 at 21:58 #45086 | |
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TomOF
452 posts |
My apologies, I thought you where referring to the Carlisle sim. :blush:
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| Flashing Red Aspect 23/05/2013 at 22:28 #45088 | |
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Backup
89 posts |
This puzzles me. To my limited awareness: It's too slow and incorrectly laid-out to be a SPAD indicator. It's not sunlight reflecting off the wagon roofs, since its pace remains steady even as the trains slows to a stop. My best guess would be agreeing with Steamer's assumption of some form of video artefact. Sorry I can't be more helpful. Log in to reply |
| Flashing Red Aspect 23/05/2013 at 22:33 #45089 | |
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Firefly
521 posts |
it seems to coincide with the train movement. Dodgy cable or lose connection being vibrated by the passing train?
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| Flashing Red Aspect 23/05/2013 at 22:43 #45090 | |
BarryM
2158 posts |
Is it a repeater of the line being closed. There is a shot of the adjacent lines being closed with flashing red lights attached to the railheads. Barry Barry, Sydney, New South Wales, Australia Log in to reply |
| Flashing Red Aspect 23/05/2013 at 23:07 #45091 | |
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Noisynoel
989 posts |
It looks to me as though the filaments in the lamp are failing, there is some form of defect there though
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| Flashing Red Aspect 24/05/2013 at 03:34 #45092 | |
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Danny252
1461 posts |
" said:Is it a repeater of the line being closed. There is a shot of the adjacent lines being closed with flashing red lights attached to the railheads.Now we really are getting to silly and outlandish ideas - normal running signals don't interact with those flashing "Stop" signs at all. Even if they did, the very section of the video showing the flashing has a train running on the line the signal applies to! Edit: I misread the "Is it" as a more stateful "It is" - however, the fact that there wasn't a question mark on the end of the question didn't help! Last edited: 24/05/2013 at 19:10 by Danny252 Log in to reply |
| Flashing Red Aspect 24/05/2013 at 08:06 #45094 | |
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Firefly
521 posts |
I think all we can say on the matter is that it's not supposed to happen, and that it's a fault of some description. FF Log in to reply |
| Flashing Red Aspect 24/05/2013 at 12:57 #45098 | |
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john havenhand
58 posts |
Ithink its actually the video itself
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| Flashing Red Aspect 24/05/2013 at 14:36 #45100 | |
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Underwood
748 posts |
" said:" said:I see your point, and whilst I like Barry I'm not taking anyone's side, but to be fair BarryM doesn't reside in this country and is probably just trying to help, not knowing if it's right or wrong. At least by saying so on here he would now know that would never happen however if he had not guessed, he would never know if that's something that can happen or not...if you see my point.Is it a repeater of the line being closed. There is a shot of the adjacent lines being closed with flashing red lights attached to the railheads.Now we really are getting to silly and outlandish ideas - normal running signals don't interact with those flashing "Stop" signs at all. I'm not raising my voice nor having a go at you at Danny, just adding my opinion and letting you know he lives in Australia. James. Log in to reply The following user said thank you: BarryM |
| Flashing Red Aspect 24/05/2013 at 15:06 #45101 | |
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Danny252
1461 posts |
" said:" said:My problem was mainly that his statement was so matter of fact - not even an "I think that...". It would be pretty easy for someone who doesn't know to come along and read only that post, then perpetuate the idea - and then in 40 years, when some future signalling historian looks back, there's suddenly a book published stating that flashing red aspects had a meaning!" said:I see your point, and whilst I like Barry I'm not taking anyone's side, but to be fair BarryM doesn't reside in this country and is probably just trying to help, not knowing if it's right or wrong. At least by saying so on here he would now know that would never happen however if he had not guessed, he would never know if that's something that can happen or not...if you see my point.Is it a repeater of the line being closed. There is a shot of the adjacent lines being closed with flashing red lights attached to the railheads.Now we really are getting to silly and outlandish ideas - normal running signals don't interact with those flashing "Stop" signs at all. (I've certainly seen stranger myths perpetuated in published books...) Log in to reply |
| Flashing Red Aspect 24/05/2013 at 15:32 #45102 | |
jc92
3690 posts |
To bring this back to the matter at hand... how would this kind of fault show on a panel? would the signal detect as failed consistently, or would the alarm/indicator flicker on and off in line with the signals behaviour? "We don't stop camborne wednesdays" Log in to reply |
| Flashing Red Aspect 24/05/2013 at 15:35 #45103 | |
Gwasanaethau
509 posts |
I would bet money on it being a near coincidence of the sample rate of the camera and the frequency of the electric current in the bulbs (as Steamer mentioned). At 6:45 onwards, you can see all the red lights from all the visible signals pulsing at the same time even before the train passes under them. It also accounts for them appearing to be unlit at about 9:00 (as Peter pointed out). I downloaded the first few seconds of the video and used Nautilus (in Linux) to get some information on the video. It has a sample rate of 25 frames per second = 25Hz, which is exactly half of the AC frequency of the electricity feeding the lights (50Hz). This means that the every time the camera took a snapshot of the world, the red lights had essentially switched on and off twice. However, in the real world, nothing is perfect. The camera probably sampled at very close to 25Hz, but I doubt the electricity was exactly 50Hz, especially if that circuit fed quite a few other things as well. Any variation in either or both of these values will result in the camera taking a snapshot at a slightly different point in the lights’ ‘switching-on-and-off cycle’. In fact, the pulses in the video appear to be 5 seconds long. This enables us to figure out how far off they are. If you divide 1 by this 5 second value, you get a frequency of 0.2Hz, or one fifth of a cycle every second. This means that the sample rate of the camera and the frequency of the lights are out by 0.2Hz. This could be: Camera: 25 frames per second Lights: 50.2Hz or Camera: 24.9 frames per second Lights: 50.1Hz and so on… I hope that helps to try and explain it a bit. Log in to reply |
| Flashing Red Aspect 24/05/2013 at 15:45 #45104 | |
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Gwasanaethau
509 posts |
" said:… In fact, it is more likely to be: Camera: 25 frames per second Lights: 49.8Hz as loading on AC circuits will make the frequency reduce – not increase – from 50Hz. Log in to reply |
| Flashing Red Aspect 24/05/2013 at 16:16 #45105 | |
GeoffM
6377 posts |
" said:My problem was mainly that his statement was so matter of fact - not even an "I think that...".He did start by saying "Is it..." " said: which is exactly half of the AC frequency of the electricity feeding the lights (50Hz)I thought signals lamps used 12v DC but could be wrong. SimSig Boss Last edited: 24/05/2013 at 16:16 by GeoffM Log in to reply The following user said thank you: BarryM |
| Flashing Red Aspect 24/05/2013 at 16:35 #45106 | |
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Late Turn
699 posts
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" said:To bring this back to the matter at hand... It should flicker between 'in order' and 'failed' indications, as you suggest, to reflect the signal's actual state. I visited one of the last boxes in our area to use paraffin lamps, shortly before the line was resignalled, and one of the lamps was burning a little low. The indicator kept swinging to 'lamp out' (accompanied by a buzzer which had to be acknowledged) then back to 'lamp in' (accompanied by the same buzzer which had to be acknowledged again) repeatedly. It was a rather tiring exercise after a few minutes! Obviously the method of indication will be different at Carlisle, and I don't know whether there'd be any alarm to acknowledge, but the principle ought to remain the same. Log in to reply |
| Flashing Red Aspect 24/05/2013 at 16:55 #45107 | |
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Gwasanaethau
509 posts |
" said:" said:which is exactly half of the AC frequency of the electricity feeding the lights (50Hz)I thought signals lamps used 12v DC but could be wrong. I did a little bit of digging and every source I found confirmed that signals are indeed powered by either 12V or 24V DC. I was just about to give up and donate to a sim for making a fool out of myself and losing my bet (with myself :whistle:), when I found this little gem. It seems some signals run off a 110V AC feed transformed down from a 230V/240V AC mains connection (at 50Hz). Phew! That’ll teach me to never make assumptions! Aside: This seems to confirm that both AC and DC are used for signals; even those with LEDs. Log in to reply |