WS4336 at Penkridge

[brick60000]

Hi all,

I noticed this afternoon that signal WS4336 at Penkridge in the up direction on P2 does not display a YY aspect, jumping straight from Y to G. Is this intended, or is there a failure with the other LED bulb that should show the second yellow (since the space is there on the signal)?

I look forward to any replies!

Thanks,

Brick60000

 

[Lrd]

I don't know the area but it could be a three aspect signal, meaning that there is no double yellow. Only red, yellow and green.

Not all areas use four aspect signalling (R, Y, YY, G), it depends on a whole variety of things to determine what signalling to use.

 

[Railsigns]

The signalling plan reveals nothing unusual about the signals in that area. It looks as though a standard four-aspect sequence applies and WS4336 ought to be able to display YY.

 

[HarleyDavidson]

Depends on the signal ahead of it & what it can display.

 

[Bald Rick]

I wondered if there was a double red ahead, but that appears not to be the case. Perhaps the braking distance to WS4332 is not quite sufficient for linespeed (125?) so there are consecutive single yellows.

Or the top yellow is out

 

[driver_m]

Next time you go past the signal, have a look if the second one after it to see if it is a controlled signal. (ID plate is black with a white WS43XX and nothing else) That could be why. Theres no issue with distances at that point so no consecutive yellows and the top yellow shouldn't be going out on LED's anyway, that happens with filaments but an S&T worker can answer that better.

 

[Railsigns]

Next time you go past the signal, have a look if the second one after it to see if it is a controlled signal. (ID plate is black with a white WS43XX and nothing else) That could be why.

The next two signals beyond are automatic. The one beyond those two is plated as an auto but is a controlled signal.

 

[headshot119]

Next time you go past the signal, have a look if the second one after it to see if it is a controlled signal. (ID plate is black with a white WS43XX and nothing else) That could be why. Theres no issue with distances at that point so no consecutive yellows and the top yellow shouldn't be going out on LED's anyway, that happens with filaments but an S&T worker can answer that better.

You can lose an aspect on an LED driven signal, doesn't have to be the LEDs themselves which have gone, but the transformer, or a fuse etc.

 

[driver_m]

You can lose an aspect on an LED driven signal, doesn't have to be the LEDs themselves which have gone, but the transformer, or a fuse etc.

If a top yellow goes on a traditional 60's filament signal, I was told it doesn't show as a failure in the SB the way the lower yellow would and thus you can go green-yellow (wrong side failure) on 4 aspect signalling. I was guessing that by now the LED signalling should have some sort of fail safe technology to prevent this. (I've had the scenario above happen to me)

 

[Emblematic]

If a top yellow goes on a traditional 60's filament signal, I was told it doesn't show as a failure in the SB the way the lower yellow would and thus you can go green-yellow (wrong side failure) on 4 aspect signalling. I was guessing that by now the LED signalling should have some sort of fail safe technology to prevent this. (I've had the scenario above happen to me)

Single yellow instead of double is a right-side failure, even if a little disconcerting coming off green. You still have another yellow before red, so there's nothing unsafe.

 

[SpacePhoenix]

Aren't the LED aspects actually a grid/matrix of LEDs so one individual LED going shouldn't have any affect? How busy was the line at the time?

 

[Crossover]

If a top yellow goes on a traditional 60's filament signal, I was told it doesn't show as a failure in the SB the way the lower yellow would and thus you can go green-yellow (wrong side failure) on 4 aspect signalling. I was guessing that by now the LED signalling should have some sort of fail safe technology to prevent this. (I've had the scenario above happen to me)

A right side failure, surely? It's failed more safe than it needs to be, which is good.

I think I have read (probably on here) similar about the second yellow not showing as a failure

Aren't the LED aspects actually a grid/matrix of LEDs so one individual LED going shouldn't have any affect? How busy was the line at the time?

Even if they are, there could be some other fault that takes out the entire matrix

 

[driver_m]

It needs an rt3185 filling in and appropriate action taken. It is definitely a signalling irregularity. It really should send the previous signal to two yellows to be a right side failure. The next signal will be yellow but that's not the issue when you go past the errant single yellow not expecting it.

 

[Railsigns]

It is definitely a signalling irregularity.

Not necessarily.

There is a possible explanation for why WS4336 could jump straight from Y to G.

The second signal beyond WS4336 (WS4332) is provided with a banner repeater (WS4332BR). If WS4332 is a red but the 'on' indication in WS4332BR has failed, the stop signal in rear (WS4334) will be held at red until WS4332 clears and its banner repeater is, accordingly, able to show an 'off' indication. WS4336 will therefore jump straight from Y to G when signals WS4332 and WS4334 both clear simultaneously.

This is not an irregularity but a case of graceful degradation. Drivers are being prevented from seeing an unlit banner repeater and they are presented with a correct aspect sequence at all times.

 

[driver_m]

Not necessarily.

There is a possible explanation for why WS4336 could jump straight from Y to G.

The second signal beyond WS4336 (WS4332) is provided with a banner repeater (WS4332BR). If WS4332 is a red but the 'on' indication in WS4332BR has failed, the stop signal in rear (WS4334) will be held at red until WS4332 clears and its banner repeater is, accordingly, able to show an 'off' indication. WS4336 will therefore jump straight from Y to G when signals WS4332 and WS4334 both clear simultaneously.

This is not an irregularity but a case of graceful degradation. Drivers are being prevented from seeing an unlit banner repeater and they are presented with a correct aspect sequence at all times.

I'm referring to a signalling sequence, for instance g-g-g-yy-y-r is entirely correct on 4 aspect signalling. g-g-y-y-r on 4 aspect signalling is not.

To muddy the waters a bit more. When the line was initially resignalled to take control from wolves PSB that signal on Penkridge on the Up was the only traditional signal put in place. All others were LED's. Can't remember the reason why, when Stafford was resignalled though it was changed to an LED. Whether it's got something to do with fringing from Rugby ROC to WM SC at Saltley I wouldn't know. One for someone who works the signalling down there to explain better than me.

This is the trouble with labelling signals by route. It blurs who controls the actual signal. The same problem occurs at Brandon where control changes from WM SC to Rugby SCC, where control changes but the signals are labelled RC. (I bet this really confusing some people now!)

 

[Railsigns]

I'm referring to a signalling sequence, for instance g-g-g-yy-y-r is entirely correct on 4 aspect signalling. g-g-y-y-r on 4 aspect signalling is not.

We have no evidence that a G-G-Y-Y-R aspect sequence was displayed. That was just an assumption on your part. We don't know what any other signal was displaying while WS4336 was at Y.

All we know from the information given by the OP is that WS4336 changed directly from Y to G. This is not in itself an irregularity. A 4-aspect signal may legitimately change from Y to G.

 

[driver_m]

We have no evidence that a G-G-Y-Y-R aspect sequence was displayed. That was just an assumption on your part. We don't know what any other signal was displaying while WS4336 was at Y.

All we know from the information given by the OP is that WS4336 changed directly from Y to G. This is not in itself an irregularity. A 4-aspect signal may legitimately change from Y to G.

Let's clear this up. I never said it was a failure. I've not assumed anything
The OP asked why it went Y to G. The signal in front obviously steps up from red to at least two yellows for 4336 to go Y-G.

I was showing an example of what happens if the top yellow does fail which it had on a SEPARATE signal somewhere else. Not WS4336. My example was due to a transformer failure with the signal, which I found out later on some time after the event.

Correct signal sequence from green to red on 4 aspects is g-yy-y-r which most of us already know. What I'm saying should not happen on 4 aspects is to get a green aspect then receive a single yellow in the next one. That's what happened to me at this other signal. If you look at a NR 3185 form which deals with signalling irregularities it is there in black and white as encountering a more severe aspect than expected.

As I've said. There is a changeover of signalling control around the Penkridge area. It could be the interlocking between the boxes. But on that I am guessing. I have never said that the sequence is wrong though.

 

[ComUtoR]

I noticed this afternoon that signal WS4336 at Penkridge in the up direction on P2 does not display a YY aspect,

Can you confirm that it "does not" or that it "did not" ? there is a significant difference between the two.

jumping straight from Y to G. Is this intended,

Signals can "step up" to a less restrictive aspect and its not an issue and happens regularly. The layout of the track and if a train is in the section or not will determine what is seen by the Driver. A signal going Y to G just means that the section went from occupied/protected to clear.

Signals "stepping down" should always happen in sequence. G-YY-Y-R or G-Y-R

g-g-y-y-r on 4 aspect signalling is not.

I understand where your going (sequence stepping down correctly) but its entirely possible (and happens regularly on my TOC) for that sequence to happen. As above a normal 4 aspect sequence should always be G-YY-Y-R but you can transition from 3 aspect to 4 aspect and you can get your G-G-Y-Y-R sequence. From the drivers perspective you will get a 4 aspect signal showing a 3 aspect sequence.

 

[Tomnick]

If you look at a NR 3185 form which deals with signalling irregularities it is there in black and white as encountering a more severe aspect than expected.

The top of the RT3185, though, clearly carries the following exemption from the requirement to use the form to report an irregularity though:

unless the fault is clearly right side or the Signaller is aware of the circumstances and
can explain the failure or irregularity

I'd argue that a G, Y (vice YY), Y, R sequence isn't a wrong side failure at all, as the aspect displayed at each signal is at least as restrictive as it should be. It's obviously not good from the driver's point of view, and should definitely be reported (plus, of course, you probably won't know what the next signal in advance is doing at that moment anyway), but it's a right side failure as far as the signalling's concerned.

 

[driver_m]

Can you confirm that it "does not" or that it "did not" ? there is a significant difference between the two.



Signals can "step up" to a less restrictive aspect and its not an issue and happens regularly. The layout of the track and if a train is in the section or not will determine what is seen by the Driver. A signal going Y to G just means that the section went from occupied/protected to clear.

Signals "stepping down" should always happen in sequence. G-YY-Y-R or G-Y-R



I understand where your going (sequence stepping down correctly) but its entirely possible (and happens regularly on my TOC) for that sequence to happen. As above a normal 4 aspect sequence should always be G-YY-Y-R but you can transition from 3 aspect to 4 aspect and you can get your G-G-Y-Y-R sequence. From the drivers perspective you will get a 4 aspect signal showing a 3 aspect sequence.

I work some sections where we go from 3 aspect to 4 and vice versa, even 2 aspect in parts. Stone is one example where a 4 aspect signal won't show 2 yellows when the next signal is a 3 aspect showing single yellow. If you're on solid 4 aspects though it just shouldnt happen.
--- old post above --- --- new post below ---

The top of the RT3185, though, clearly carries the following exemption from the requirement to use the form to report an irregularity though:

I'd argue that a G, Y (vice YY), Y, R sequence isn't a wrong side failure at all, as the aspect displayed at each signal is at least as restrictive as it should be. It's obviously not good from the driver's point of view, and should definitely be reported (plus, of course, you probably won't know what the next signal in advance is doing at that moment anyway), but it's a right side failure as far as the signalling's concerned.

That's for code 2 AWS failures where you get horn sound on a green aspect instead of a bell. That's a right side failure.

Its a stop immediately and report job if you get an incorrect signalling sequence. I appreciate its not the same as getting an AWS bell sound on a caution/stop aspect which is a definite wrong side failure, but you tell any driver doing 100mph+ that going past 1 yellow in fog when at worst you should have got 2 is not something to be dismissed as a right side failure. To a signaller or s&t maybe, but they can see the bigger picture. A driver can't. The signalling system should make the signal in rear go back to two yellows if this happens to make it right.

 

[ComUtoR]

If you're on solid 4 aspects though it just shouldnt happen.

Agreed. (and posted)

I hope that a Signaller can talk about the sequence seen on the "Up Lewisham"

 

[Tomnick]

Its a stop immediately and report job if you get an incorrect signalling sequence. I appreciate its not the same as getting an AWS bell sound on a caution/stop aspect which is a definite wrong side failure, but you tell any driver doing 100mph+ that going past 1 yellow in fog when at worst you should have got 2 is not something to be dismissed as a right side failure. To a signaller or s&t maybe, but they can see the bigger picture. A driver can't. The signalling system should make the signal in rear go back to two yellows if this happens to make it right.

The signalling system's working exactly as it's designed though, that's what I mean (and why it's not a wrong side failure). Whether the design is any good is another question altogether! I agree that it's much much less than desirable from the driver's point of view, and I'd guess that the top yellow is indeed proved on new installations nowadays - but, back then, the extra complexity with all the additional relays probably couldn't be justified (at one point, not sure if any still exist, you could have a single yellow reading onto a black signal on some schemes?).

Agreed. (and posted)

I hope that a Signaller can talk about the sequence seen on the "Up Lewisham"

What is the sequence seen on the Up Lewisham?

 

[ComUtoR]

What is the sequence seen on the Up Lewisham?

YY - Y - Y - R (protects Jn)

You get Y-Y on Auto's with NO trains in the section. You can see both Y-Y clearly. I was told that they are broken due to some work that took place many moons ago so you always see Y-Y I was told that the second yellow cannot show YY so its always left as Y-Y and not YY-Y

I'd love to know what the real reason why the sequence is fixed or what is actually happening. Its fun watching the faces of new Drivers when they first see it.

*edit* and you also frequently get Y-Y-G

 

[driver_m]

The signalling system's working exactly as it's designed though, that's what I mean (and why it's not a wrong side failure). Whether the design is any good is another question altogether! I agree that it's much much less than desirable from the driver's point of view, and I'd guess that the top yellow is indeed proved on new installations nowadays - but, back then, the extra complexity with all the additional relays probably couldn't be justified (at one point, not sure if any still exist, you could have a single yellow reading onto a black signal on some schemes?).

With the same type of signalling, (4 aspect 60's filament) if a signal that should be red goes black, the signal in rear only goes one yellow if it's an auto. Yes it is or certainly was around very recently. Liverpool and Brum still have 60s 4 aspects. (Again from previous experience). That is a wrong side failure for me. I could run into the back of another train with that if assuming the AWS magnet also failed and I missed the black signal for whatever reason. That's the reason why I'm not convinced about it being a 'right side failure'

 

[Tomnick]

YY - Y - Y - R (protects Jn)

You get Y-Y on Auto's with NO trains in the section. You can see both Y-Y clearly. I was told that they are broken due to some work that took place many moons ago so you always see Y-Y I was told that the second yellow cannot show YY so its always left as Y-Y and not YY-Y

I'd love to know what the real reason why the sequence is fixed or what is actually happening. Its fun watching the faces of new Drivers when they first see it.

*edit* and you also frequently get Y-Y-G

Possibly inadequate braking distance from the second yellow to the red? Can you see Y-Y-G all at once, or is it just that you're getting brought up to the junction signal (YY-Y-Y-R) as above and it's then clearing at some point after passing the last Y.

With the same type of signalling, (4 aspect 60's filament) if a signal that should be red goes black, the signal in rear only goes one yellow if it's an auto. Yes it is or certainly was around very recently. Liverpool and Brum still have 60s 4 aspects. (Again from previous experience). That is a wrong side failure for me. I could run into the back of another train with that if assuming the AWS magnet also failed and I missed the black signal for whatever reason. That's the reason why I'm not convinced about it being a 'right side failure'

Thanks. That's obviously a quite different scenario - potential for an unprotected wrong side failure, albeit inherent in the design? In the first example, though, everything's 'safe' (except possibly the driver's clothing!) with the proper braking distance from the first Y (vice YY) to the R and any possible conflict beyond.

 

[driver_m]

Possibly inadequate braking distance from the second yellow to the red? Can you see Y-Y-G all at once, or is it just that you're getting brought up to the junction signal (YY-Y-Y-R) as above and it's then clearing at some point after passing the last Y.


Thanks. That's obviously a quite different scenario - potential for an unprotected wrong side failure, albeit inherent in the design? In the first example, though, everything's 'safe' (except possibly the driver's clothing!) with the proper braking distance from the first Y (vice YY) to the R and any possible conflict beyond.

With you mentioning the relays and proving and it being an unjustifiable cost back then, maybe that kind of signalling is now a priority for being got rid of and deemed a manageable risk that is very unlikely to cause an accident. The 2 places I mentioned are both due to go soon. Again I'm guessing but that kind of signalling would just not be allowed now. I've seen that sequence mentioned at Lewisham a few times but not for very long, seems unusual to leave it. Code 2 AWS faults usually result in a signal being restricted to one/two yellows at best if the problem can't be quickly rectified, but that scenario sounds unusual to have been left for so long.

 

[ComUtoR]

Possibly inadequate braking distance from the second yellow to the red? Can you see Y-Y-G all at once,

You always see the Y-Y sequence as the junction signal is out of view. There is lots of curvature. It may be a braking distance thing as the linespeed goes (20-60-25) in a very short distance

or is it just that you're getting brought up to the junction signal (YY-Y-Y-R) as above and it's then clearing at some point after passing the last Y.

I accept that as that happens many many times to our frustration

In this instance the Jn signal is usually held at red because your going onto a busier line (up catford loop) and the up lewisham is low usage but you can see a Y-G sequence when the Jn is clear. If it is stepping up then its timed to such a point where you never see the red. I don't know but even if it was approach controlled then you should still see the red ? I have never seen an approach control signal where you don't see the red before it steps up. I'll have a really close look next time but I could swear you do see Y-G.

It's the second yellow that is alleged to not be capable of showing YY In my 10+ years I have never seen it show YY or a correct sequence (YY-Y-R) to the red. As they are both auto signals then why doesn't it show in the correct sequence ? The sequence does appear to be locked to Y-Y-R
--- old post above --- --- new post below ---

(at one point, not sure if any still exist, you could have a single yellow reading onto a black signal on some schemes?).

Yes. There was a SPAD last year iirc where a Driver went through a blank signal. If you receive the correct sequence then your expected to stop at the next signal and even if you don't see it you are expected to know where it is and bring your train to a stand.

 

[Tomnick]

I think it is (or at least was) permissible for a signal, approach released from red, to clear before it comes into the driver's view, as long as the main aspect doesn't become visible to the driver before the route indication. If it's low speed (is that the 25mph that you refer to?) through the junction with no other higher speed routes available, I'm not sure why it'd be approach released though.

Have you ever had greens right through at that location?

 

[ComUtoR]

If it's low speed (is that the 25mph that you refer to?) through the junction with no other higher speed routes available, I'm not sure why it'd be approach released though.

Technically it does go up to 60 but its one of those speeds where 60 wouldn't be possible anyway. The 25mph is the exit speed onto the loop. 20mph out of lewisham and up onto the bank, up to 60mph then drops onto the 25mph into the loop.

Have you ever had greens right through at that location?

Never. As I say. In the 10+ years I have driven that route that signal has only ever shown a single yellow or a red (extremely rare) I was told that there was some work done and they went through a cable or something and ever since then it has always been Y-Y Its something we always point out to route learners because of the Y-Y and as you pass them you see them plated as auto's. If I got greens I'd be pretty worried due to the the 60 onto a 25 and the Jn. It wouldn't be the first signal that's protected due to speed but you would only need to restrict the linespeed and remove the 60mph as no one ever goes that fast up or down.

Its under London Bridge box so I wonder what will happen when the box goes bye bye.

It's always been an oddity. We have so many odd sequences and signals you need to tell the route learners and newbies that what they see in the rule book is very different out on the line.

We have :
4 aspect signalling with a random 3 aspect in the middle
Colour light AB
4 aspect with a random distant signal
signals that never show main aspect (always have a lunar)

And single head LED's still freak me out a little

As long as I don't see G-R or YY-R then I'm content to let the signals do as they wish.

Mostly I'm very curious in my old age as to why such anomalies exist.

Cheers for the help Tomnick

 

[Crossover]

I work some sections where we go from 3 aspect to 4 and vice versa, even 2 aspect in parts. Stone is one example where a 4 aspect signal won't show 2 yellows when the next signal is a 3 aspect showing single yellow. If you're on solid 4 aspects though it just shouldnt happen.

Just curious, how far do you take that? What would be wrong with Y-Y on 4 aspect and then Y on 3 aspect? Also, does that mean that you have a 4 aspect signal that only ever shows 3 aspects (or is this the junction where one way is 3 and the other is 4 aspect signalling)?