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"Hidden" signal lamp failure 02/12/2015 at 15:41 #78311 | |
WesternChampion
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Had a curious incident when running Rugby Centre today. I had a notification of a signal lamp failure in the Hanslope area. I checked the display but all seemed normal. A few minutes later I got a call from a train on the Up Fast reporting an adverse change of aspect. Looking again I saw that signal KR3266 was showing a blank display. This is the last signal on the left hand side of the display and the signal is actually under the control (albeit an auto signal) of Rugby South. It appears that the yellow light was out, so a train following closely behind another went from green at KR3278 to yellow rather than double yellow at KR3276. While I was still pondering what to do, the same thing happened to the following train - ouch! Could anyone advise me what I should have done to avoid the ACOA. The signal affected, KR3266, shows grey unless the actual aspect is yellow, so was not easily detectable. Log in to reply |
"Hidden" signal lamp failure 02/12/2015 at 18:16 #78319 | |
GeoffM
![]() 6344 posts |
In this case I would suggest holding signal KR3276 at danger (using the replacement button) until KR3274 shows green. The headway will be reduced but it should avoid a following train from receiving a change of aspect. If you're playing multiplayer then you could coordinate with the south panel and use KR3274 instead of KR3276 to determine when to release the next train. SimSig Boss Log in to reply The following users said thank you: pedroathome, WesternChampion |
"Hidden" signal lamp failure 02/12/2015 at 20:36 #78324 | |
Jersey_Mike
![]() 250 posts |
" said:In this case I would suggest holding signal KR3276 at danger (using the replacement button) until KR3274 shows green. The headway will be reduced but it should avoid a following train from receiving a change of aspect.Does this happen in real life? If so does this happen as frequently as it does in the sim? Are bulb-out circuits really necessary, especially on automatic signals that are also protected by AWS? Log in to reply |
"Hidden" signal lamp failure 02/12/2015 at 21:01 #78328 | |
GeoffM
![]() 6344 posts |
" said:" said:Traditional filament lamps had two filaments. If the primary filament failed then the technician would get a "first filament failure" alarm but the signal would still work, albeit not quite as bright with the second filament. If the second filament fails then the lamp out occurs. How often that happens probably relates to a large number of factors, but I have heard that the first filament burning out fairly often takes the second one out as well, due to their proximity.In this case I would suggest holding signal KR3276 at danger (using the replacement button) until KR3274 shows green. The headway will be reduced but it should avoid a following train from receiving a change of aspect.Does this happen in real life? If so does this happen as frequently as it does in the sim? Are bulb-out circuits really necessary, especially on automatic signals that are also protected by AWS? With LEDs I believe there is current sensing to ensure x% of LEDs are lit before it becomes a bad aspect and thus a failure. Back on (at least) the Midland and Southern regions, a lamp failure would cause the signal on the approach to the failed one to show yellow instead of red if the black signal should have been showing a proceed aspect. As for additional relay circuitry, I don't think there is much. Certainly for CBIs it's virtually no cost. SimSig Boss Log in to reply |
"Hidden" signal lamp failure 03/12/2015 at 00:02 #78351 | |
pedroathome
![]() 906 posts ![]() |
" said:" said:Don't forget here that AWS will sound the same tone for both a cautionary aspecct (yellow, double yellow) as it would with a red aspect. Only a green aspect gets a different soundIn this case I would suggest holding signal KR3276 at danger (using the replacement button) until KR3274 shows green. The headway will be reduced but it should avoid a following train from receiving a change of aspect.Does this happen in real life? If so does this happen as frequently as it does in the sim? Are bulb-out circuits really necessary, especially on automatic signals that are also protected by AWS? Log in to reply |
"Hidden" signal lamp failure 03/12/2015 at 12:29 #78359 | |
WesternChampion
![]() 173 posts |
Thanks for all the responses. My problem was that I couldn't see the signal to which it related to take the appropriate action. Would it be unprototypical for the signal lamp failure alert to specify the signal rather than the area?
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"Hidden" signal lamp failure 03/12/2015 at 12:38 #78361 | |
KymriskaDraken
![]() 963 posts |
" said:Thanks for all the responses. My problem was that I couldn't see the signal to which it related to take the appropriate action. Would it be unprototypical for the signal lamp failure alert to specify the signal rather than the area?I'm not sure how the modern system deals with this, but on an NX panel the first clue we got that a lamp was out was a train calling in at a signal that was being held at Danger for no obvious reason. If it was a controlled signal that had failed we might spot that the repeater lamp in the signal control switch was out, or indeed was being held at Danger because the signal in advance had failed. Sometimes the Sick & Tired would be in the panel to watch some trains go though an area where they knew there was a lamp on Standby to try and work out which aspect of which signal was faulty. Log in to reply |
"Hidden" signal lamp failure 08/12/2015 at 13:14 #78533 | |
Jersey_Mike
![]() 250 posts |
" said:" said:An improperly displayed signal should be treated as if it is displaying it's most restrictive indication. Bulb out protection isn't necessary if the drivers simply follow the rules. In the remote chance that they fail to follow the rules the AWS would provide additional warning if the signal were was failing to display a restrictive indication. That should mitigate almost all the remaining risk." said:Don't forget here that AWS will sound the same tone for both a cautionary aspecct (yellow, double yellow) as it would with a red aspect. Only a green aspect gets a different soundIn this case I would suggest holding signal KR3276 at danger (using the replacement button) until KR3274 shows green. The headway will be reduced but it should avoid a following train from receiving a change of aspect.Does this happen in real life? If so does this happen as frequently as it does in the sim? Are bulb-out circuits really necessary, especially on automatic signals that are also protected by AWS? Log in to reply |
"Hidden" signal lamp failure 08/12/2015 at 13:47 #78536 | |
RainbowNines
![]() 272 posts |
I don't think it makes any difference does it? Proving is a thing regardless so a lamp "failing to prove" will naturally be reported. What would the gain be from not having it as such? Cost?
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"Hidden" signal lamp failure 08/12/2015 at 13:51 #78537 | |
KymriskaDraken
![]() 963 posts |
" said:"If" is a very deadly word. IF everyone followed the rules, IF that train didn't happen to be just there at the same time as the other one, IF that old wire hadn't just happened to touch the relay... Things are set up on the modern railway to mitigate against the IF - there should always be a second, or even third line of defence - just in case. After all, if Drivers never allowed their attention to wander we wouldn't need AWS; if Signalmen never allowed their attention to wander we wouldn't need interlocking. I'm possibly over-generalising here, but I think that a significant proportion of railway accidents are caused by human error of some sort, whether that's a Driver missing a signal or the Signalman forgetting about a train or whatever. When I was a Signalman I sometimes got very stressed when the job was up the wall, and I made mistakes, but I had confidence that the interlocking would stop me from doing something that would kill people, and I still think that the Railway should have things like lamp-proving to try and mitigate the consequences of someone making a mistake. I would rather have 100 minutes of delay by stopping trains to talk them past a failed signal, than saving a few minutes and having a crash because someone made a mistake. Kev Last edited: 08/12/2015 at 13:52 by KymriskaDraken Reason: Minor edit Log in to reply The following user said thank you: BarryM |
"Hidden" signal lamp failure 09/12/2015 at 09:47 #78574 | |
kbarber
![]() 1723 posts |
" said:" said:Indeed Kev. IF is all very well, but too many IFs lead to the sort of nasty they had near Clayton Tunnel (late'70s I think?) where one of the 1932 signals was dark (they didn't have lamp proving of any kind in those days) resulting in a rear-end."If" is a very deadly word. IF everyone followed the rules, IF that train didn't happen to be just there at the same time as the other one, IF that old wire hadn't just happened to touch the relay... Things are set up on the modern railway to mitigate against the IF - there should always be a second, or even third line of defence - just in case. After all, if Drivers never allowed their attention to wander we wouldn't need AWS; if Signalmen never allowed their attention to wander we wouldn't need interlocking. In any case, without lamp proving the signal in rear will continue to offer an unrestricted clear, leading to a train approaching the dark signal too fast to stop. You only need a bit of fog in the mix... Log in to reply |
"Hidden" signal lamp failure 09/12/2015 at 15:13 #78584 | |
WesternChampion
![]() 173 posts |
In the case that I experienced, a train received an adverse change of aspect because, although one of the lamps had failed, the signal in the rear did not switch to red all of the time, only when that particular light (one of the yellows) should have been displayed. This was driven by the proximity of one train to another and once two were the "right" distance apart for the signal in advance to change from red to the failed yellow aspect, the signal in the rear changed from yellow to red. Given what is written above, should the signal in the rear not display a red aspect whatever the aspect of the signal in advance to prevent an ACOA? Log in to reply |
"Hidden" signal lamp failure 09/12/2015 at 15:34 #78585 | |
Steamer
![]() 3958 posts ![]() |
" said:In the case that I experienced, a train received an adverse change of aspect because, although one of the lamps had failed, the signal in the rear did not switch to red all of the time, only when that particular light (one of the yellows) should have been displayed. This was driven by the proximity of one train to another and once two were the "right" distance apart for the signal in advance to change from red to the failed yellow aspect, the signal in the rear changed from yellow to red.No. If the signal in front is lit, the signal in rear will show the appropriate aspect. If the signal in front is unlit, the signal in rear shows red. A lot of extra circuitry/code would be needed for the signal in rear to behave as you've suggested. You'll be able to use the replacement buttons to make sure everything's spaced properly to prevent an ACOA though. "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: 09/12/2015 at 15:36 by Steamer Log in to reply |
"Hidden" signal lamp failure 09/12/2015 at 16:43 #78588 | |
Finger
![]() 220 posts |
" said:In the case that I experienced, a train received an adverse change of aspect because, although one of the lamps had failed, the signal in the rear did not switch to red all of the time, only when that particular light (one of the yellows) should have been displayed. This was driven by the proximity of one train to another and once two were the "right" distance apart for the signal in advance to change from red to the failed yellow aspect, the signal in the rear changed from yellow to red.That would be nearly impossible, because the lamp is being proved only when alight. There's no proving of yellow when red is shown, so it's understandable the signal in rear shows yellow then. Having said that... " said: If the signal in front is lit, the signal in rear will show the appropriate aspect. If the signal in front is unlit, the signal in rear shows red. A lot of extra circuitry/code would be needed for the signal in rear to behave as you've suggested.I don't think you need "lot of extra circuitry" to make the signalling much more sane in case of filament failure. Here in Czechia, all signals just degrade their aspect one step lower in case of such failure and such ACOAs can't occur. The way it's done is quite simple, the relay doing the lamp proving also cuts current to the circuits showing the more restrictive aspects. BTW I wonder why Simsig doesn't simulate other possible failures of signals, like failure of the junction indicator. Or does it? Log in to reply |