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Incorrect Aspect Sequnce

You are here: Home > Forum > Miscellaneous > The real thing (signalling) > Incorrect Aspect Sequnce

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Incorrect Aspect Sequnce 28/07/2010 at 19:26 #1517
Ianno
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28 posts 		For the last week or so there's been an incorrect sequence of aspects between New Beckenham and Lower Sydenham stations (See picture below - you will need to zoom in to see):



In short, L372 (nearest the camera) is showing a double yellow, with L370 (the Lower Sydenham down starter) 'in Advance' showing green. Does anyone know why this might be? It's always otherwise been the standard R/Y/YY/G sequence.
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Incorrect Aspect Sequnce 28/07/2010 at 19:26 #10300
Ianno
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28 posts 		For the last week or so there's been an incorrect sequence of aspects between New Beckenham and Lower Sydenham stations (See picture below - you will need to zoom in to see):



In short, L372 (nearest the camera) is showing a double yellow, with L370 (the Lower Sydenham down starter) 'in Advance' showing green. Does anyone know why this might be? It's always otherwise been the standard R/Y/YY/G sequence.
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Incorrect Aspect Sequnce 28/07/2010 at 19:29 #10301
deanbean10
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36 posts 		thats spooky....
have you contacted Network Rail over this to report it? So they can look into it more?
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Incorrect Aspect Sequnce 28/07/2010 at 19:35 #10304
Ianno
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28 posts 		No, not contacted NR (even though I work for them!), but I'd be surprised if drivers hadn't reported it already, given it's passed by up to six trains per hour.

Might try and work out who I should e-mail tomorrow...
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Incorrect Aspect Sequnce 28/07/2010 at 21:13 #10308
clive
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2789 posts 		My guesses:
(1) It's conventional relay interlocking and the HHR feed from 370, which would feed the DR relay on 372, is broken. So 372 thinks 370 is showing single yellow.
(2) The signals are driven by SSI modules and the automated testing has found that the green lamp has failed, so the module has automatically dropped back to the next aspect that's working. Better than 372 being out and drivers having to be talked past 374 at red.
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Incorrect Aspect Sequnce 28/07/2010 at 21:46 #10314
DriverCurran
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688 posts 		My thought is that the signal has been restricted to show no more than 2 yellows. This is quite common if drivers have been reporting a right side AWS fault on that signal and will be like that until the techs find and rectify the orginal fault.
You have to get a red before you can get any other colour
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Incorrect Aspect Sequnce 29/07/2010 at 07:23 #10320
kaiwhara
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587 posts 		119 Signal (down stop and stay intermediate) between Auckland and Newmarket in New Zealand was doing that for a while after the new Westinghouse Signalling system was installed at Newmarket. When 202 Down Home Signal at Newmarket was displaying a proceed indication of any kind (either caution or clear at either normal or medium speed) the appropriate indication was not displayed 119 signal in the rear (which in this case should either be green over red or yellow over green as appropriate). However, as 202 signal is around a tight right hand curve it is provided with a Banner Indicator which can clearly be seen at the far end of the Parnell Tunnel when passing 119 signal. The drivers had been reporting the issue to our faults desk for weeks (although no-one told us in the box till ages afterwards...), but it took a rather large amount of headscratching before a fix was found.

Evidently the issue was the old interlocking "not talking to the new stuff"...
Sorry guys, I am in the business of making people wait!
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Incorrect Aspect Sequnce 29/07/2010 at 11:46 #10322
panelbeater
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11 posts 		DriverCurran said:
My thought is that the signal has been restricted to show no more than 2 yellows. This is quite common if drivers have been reporting a right side AWS fault on that signal and will be like that until the techs find and rectify the orginal fault.

Agreed
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Incorrect Aspect Sequnce 29/07/2010 at 18:05 #10330
ralphjwchadkirk
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275 posts 		It's not a really major problem anyway. If it was Green - Red then that is very serious, but stepping up an aspect is unusual but not a major problem in itself.
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Incorrect Aspect Sequnce 30/07/2010 at 12:06 #10338
kbarber
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1742 posts 		I believe that part of the world is all relay interlockings (& I suspect these are relay driven autos) thus far more likely to be broken HHR feed or restricted by S&T.
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Incorrect Aspect Sequnce 31/07/2010 at 18:23 #10375
Firefly
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521 posts 		Any temporary speed restrictions nearby? If there are, AWS magnets have to be prevented from giving a bell. One method of achieving this is to restrict the signal to YY. Otherwise as has already been mentioned it could be that the AWS electro magnet has failed and the signal has been deliberately restricted. Failing that the next most likely scenario is that there is a fault on the DR circuit.
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Incorrect Aspect Sequnce 31/07/2010 at 19:02 #10382
DriverCurran
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688 posts 		Firefly said:
Any temporary speed restrictions nearby? If there are, AWS magnets have to be prevented from giving a bell. One method of achieving this is to restrict the signal to YY.
Not sure where abouts you're from mate, but certainly on the south eastern division and the few parts of the central division that I've driven over the magnets are always disconnected rather than restricting the aspect, would be interested to know if that would be standard practice else where though

Paul
You have to get a red before you can get any other colour
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Incorrect Aspect Sequnce 31/07/2010 at 19:56 #10384
Firefly
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521 posts 		Hi Paul.

I've worked on most regions. Restricting a signal to YY is a "quick fix" that I've seen used on SSI areas. You can effect this disconnection from the technicians terminal at the signal box whereas you cannot disconnect an AWS from the techs terminal, you'd have to go lineside.

Maybe not standard practice, wouldn't be my preference but I've seen it done.

Kev
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Incorrect Aspect Sequnce 31/07/2010 at 23:00 #10393
DriverCurran
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688 posts 		Ah maybe have just never been in the area when they have done that then Kev, certainly the only time i've encountered signal restriction is where there has been a rightside AWS failure :)

Paul
You have to get a red before you can get any other colour
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Incorrect Aspect Sequnce 31/07/2010 at 23:47 #10395
Danny252
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1461 posts 		Excuse my ignorance here, but "disconnected AWS" and a "right-side AWS failure" both sound the same to me, in that the driver should always get a warning.

I believe I'm right in thinking AWS has a permanent magnet, and an electromagnet which, when powered, cancels the magnetic field - magnetic field means warning, cancelled field means no warning.

A right side failure would be that the AWS always gives a warning - that's the definition! But surely by disconnecting the AWS, the permanent magnet is never cancelled and always gives a warning as well?
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Incorrect Aspect Sequnce 01/08/2010 at 01:50 #10396
mfcooper
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707 posts 		AWS can give 2 types of warning. If a Green aspect is displayed, it gives a bell warning that the driver does NOT have to cancel in-cab. If a stop or any kind of cautionary (Y or YY) aspect is shown, then a horn warning is given which the driver has to cancel in-cab promptly or the brakes will apply automatically. The permanent magnet gives the horn warning, and the electromagnet is only activated by a Green aspect to give the bell warning. Hence, when the electromagnet fails, one will always get the horn warning. This is a right-side failure as it makes the driver think the signal ahead is displaying a more restrictive aspect than it actually is (if the signal is showing green). If the bell sounded instead of the horn, then you have a potentially dangerous wrong-sided failure as the driver would be expecting a Green aspect at a signal that could be showing Red!
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Incorrect Aspect Sequnce 01/08/2010 at 13:49 #10398
deanbean10
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36 posts 		mfcooper said:
AWS can give 2 types of warning. If a Green aspect is displayed, it gives a bell warning that the driver does NOT have to cancel in-cab. If a stop or any kind of cautionary (Y or YY) aspect is shown, then a horn warning is given which the driver has to cancel in-cab promptly or the brakes will apply automatically. The permanent magnet gives the horn warning, and the electromagnet is only activated by a Green aspect to give the bell warning. Hence, when the electromagnet fails, one will always get the horn warning. This is a right-side failure as it makes the driver think the signal ahead is displaying a more restrictive aspect than it actually is (if the signal is showing green). If the bell sounded instead of the horn, then you have a potentially dangerous wrong-sided failure as the driver would be expecting a Green aspect at a signal that could be showing Red

Well matt you do work in signalling lol
so you will know
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Incorrect Aspect Sequnce 01/08/2010 at 17:30 #10404
Firefly
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521 posts 		I should correct myself before someone corrects me.

You can't restrict a signal to YY from a SSI techs terminal.
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Incorrect Aspect Sequnce 01/08/2010 at 18:24 #10405
DriverCurran
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688 posts 		Danny - I would say the main difference is that a disconnected AWS is where the electromagnet has been disconnected under controlled conditions by the signal & telegraph tech's (If you're the same Danny as from last nights mp on kx you will enjoy many hours with these people doing work around your box) and a right side failure is where the equipment itself has a fault and causes a warning indication, the 'normal' cause being a blown fuse in the respective location case.

Paul
You have to get a red before you can get any other colour
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Incorrect Aspect Sequnce 11/08/2010 at 13:09 #10650
Mattyq
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259 posts 		Another reason is that the Green aspect has failed (IE: blacked out) and, for whatever reason, the Signal Electricians are unable to immediately fix it. The safe option is to restrict the signal to maximum double yellow so that the signal will always show an aspect. Since, here in QLD, trains must be authorised past Red or failed signals on written authority (which can take up to 10 minutes), quicker to have a restrictive proceed aspect than none at all.

To make matters worse, the Electrical Safety boffins here have changed the live exclusion zone from 2.75 metres to 3 metres. As a result, many signals cannot now be repaired immediately, requiring the overhead wiring to be shut off, which is a huge undertaking in itself.
Not fat ..... fluffy!! (G Iglesias)
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Incorrect Aspect Sequnce 24/11/2010 at 22:22 #12629
c0mputerc4m
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4 posts 		There looks to be a signal at this end of the platform, if you look closely it just shines through the trees
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Incorrect Aspect Sequnce 24/11/2010 at 22:52 #12630
UKTrainMan
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1803 posts 		c0mputerc4m said:
There looks to be a signal at this end of the platform, if you look closely it just shines through the trees
I feel pretty confident to say that there isn't for a number of reasons;

1: If there was a signal there then it wouldn't be so obscured by trees as that'd probably be against the rules having the signal obscured by a tree branch/foliage

2: If there was a signal there then what aspect do you think it is displaying - if the signal clearly visible closest to the camera is double yellow then it really can only be displaying a single yellow, but then why would it be doing that if the next signal is green (unless of-course this signal you think is there has been restricted to only display Y).

3: The distance between the YY signal and the G signal is so small that another signal in between them would surely be pointless.

And I'm sure there are a number of other reasons I've missed.

It is most likely a passenger information system / screen / display / board 'thing' on the platform showing the next few trains, they often have orange-coloured text.
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.
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Incorrect Aspect Sequnce 25/11/2010 at 10:58 #12634
kbarber
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1742 posts 		UKTrainMan said:
c0mputerc4m said:
There looks to be a signal at this end of the platform, if you look closely it just shines through the trees
I feel pretty confident to say that there isn't for a number of reasons;

<snip>

It is most likely a passenger information system / screen / display / board 'thing' on the platform showing the next few trains, they often have orange-coloured text.
Seconded. The illumination referred to is set back some way from the lineside - if 'twere a signal it would be much closer, mounted on a bracket if necessary (and in that location probably a gallows bracket, which would be very obvious). It's approximately halfway along the platform, which is where you tend to find those displays. The colour is closer to orange than the yellow shown by the signal in the foreground (and the SE area does have orange LED indicators).
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