2006 Cts on 2012 IRSE tables

[dorothy.pipet]

Attempt for comments.
I would not have achieved these in the time available.

[PJW]

Yes it is definitely a tough speed challenge; whether or not it should be, it has always been thus.
However do remember that you don't need to get full marks; if you do three quarters then that is a distinction. [Actually it can be easier than being given one simple route and one simple point but being expected to get them perfect- hence being very heavily penalised should you get any little thing not completely correct!]

Your notes were very comprehensive, but probably too too long to write.
Think about being more economical

Combine the first two bullets-
Practice: UK mainline (SSI, NX panel)

and use lttle tables
e.g.
SET LOCK DETECT
$32 Y
$37 Y Y Y
Doesn't save much on those two, but if you need others as well then there is payback

Also slightly modifying (because you can define what you want them to mean)-
Replacement:
#1 First wheel
#3 Auto facility
#4 Last wheel
#5 Once occ and cleared

Just started looking at the CTs themselves; not fully checked but the points seem good (actually 234 looks easy, wonder what we are both missing?).
As ever I would not have shown CG in the route holding as I regard as superfluous and untestable; I'd be test logging it on a real job but if this is your practice for the exam I'll not disturb.

Fr 225 I can't work out why you have shown 122C(S) but not 124A(S); can see arguments to include or exclude but would have treated the two the same.

I'll return to update this evening

Attempt for comments.
I would not have achieved these in the time available.

[dorothy.pipet]

IMO showing CG is consistent with SSI practice because SSI data tests TCG clear for the deadlocking, but the sectional route locking test is on the appropriate sub-route free.
While it might save the odd second to not write these tracks in, it is a strong habit and I don't think I could become consistent at leaving them out, which is perhaps a greater sin!

[PJW]

It very much depends on the philosophical question: are Control Tables
a) a high level document specifying in the abstract what is required, independent of technology?
or
b) a specification from which the detailed design can be derived and therefore a step along the way of the "Vee diagram" from user requirements to implementation.

I agree in recent years with the new 11202 SSI CTs that we are certainly going down the road of b).

Keep with what you are comfortable with; as a tester wanting to get ticks on the CT, I happen to disagree!

IMO showing CG is consistent with SSI practice because SSI data tests TCG clear for the deadlocking, but the sectional route locking test is on the appropriate sub-route free.
While it might save the odd second to not write these tracks in, it is a strong habit and I don't think I could become consistent at leaving them out, which is perhaps a greater sin!

[PJW]

Sorry, work priorities and other ife intervened.

122A(M)
Overall pretty good, however
a) You put all points in the overlap to be $32 and defined that to be "set only"- this is not the traditional NR practice. I am aware that recent standards have moved away from detecting facing points in the overlap, but was unaware that this logic had extended to trailing points as well (but then I have only been back on the surface from the Underground for a month so may not be up to date). It does look a bit odd to have a column for the facing points in the overlap for bridging the detection out whilst swinging if indeed they are never detected in the first place!
If you really did mean what you wrote (and I guess you do) to cover yourself as a candidaate then I'd have put a # note explictly referring to latest NR practice not to detect (as some of the examiners at least may like me not be completely up to the most recent practice and you wouldn't want it being viewed as a mistake)

b) What is definitely wrong is that you have failed to look far enough for your opposing locking; there is an overlap-overlap conflict. Opposing locking after 175 timing out on AG should be shown.

c) As you pointed out, you forgot to use your # refs regarding stick disengagement / asppect replacement!


122A(W)
Given that you intended the $32 this is fine; there is no conflict from 175.


122A( C)
Again this is good.
I regard the requirement to have relevant track occupied at time of route setting should however have been shown, in addition to the aspect level control.

I note that it is the latter which you have shown and have included a "time to stand value" which traditionally would not have been provided but again I think does probably accord with the most recent practice- unlike the $32 I don't feel that this needs a nudging note to the examiners because this time it doesn't look like a possible mistake and it doesn't make a real difference to the operability of the layout- in the past (possibly because in RRI it would require a separate timing relay) we didn't feel it worth imposing the control of a time delay whereas now "it is only data" we feel better to do so.

You showed the aspect as "Sub" following the route box; it loooks a bit incongruous given the modernity of other elements of your Control Tables and I might have "interpreted" this to be PL; however a case of being damned if you do, damned if you don't! To me this is what exposes the "follow your own principles, but do follow our layout with all its inbuilt assumptions" difficulty inherent in the IRSE module.

147A(S)
Opposing route locking after 122A(M/WC) should have released once platform tracks occupied for time; this is surely a large part of what the signal is there for! Similarly I beleive that it should only include tracks AE and AD in the aspect.

Again I know where you are coming from; NR's latest standards tend to treat shunt signals in many ways as if they are main aspects. In reality it does depend on the operational use needed from the layout; if you knew that the only need for 147 was to put a multiple unit train that had been stored in the Up Siding into an empty platform then your Control Tables are right to latest practice- your error though was you failed to state this as an assumption.

I'd actually advise signalling to the standards of say 10 years ago when it was taken for granted that shunt signals would be used for shunting in the widest sense including joining and splitting and therefore as a default making them prove less. Rationale for this is-
a) this is what the examiners inherently expect
b) as a candidate in the IRSE exam you are attempting to show your knowledge and experience- respond to the fact that the reason why the question gives you examples of the different classes of routes is to permit you to display that you know that "one size does not fit all"- exploit the differences as a way of showing off your understanding
c) think why are the platforms split into two track sections whereas the through roads are not. They are used by 2 separate trains; there are call-on moves into the platforms. If it is ok to share a platform between 2 passsenger trains, perhaps to join or perhaps not), why on earth would it not be sensible to have a train in the platform and add another unit onto it from the sidings. Indeed looking at your CT for the 122 call-on, you permit this; therefore why not the other way around. Seems inconsistent.

All I am pointing out really is that it is in your best interests as a candidate to convince the examiner you have thought about it and come to a sensible conclusion- it actually doesn't what that is since this will depend upon the standards being adopted, but somehow you should get across that you recognise there is a decision to be made. The way you tackled the BG/BH joint position for 122A(W) was perfect; brief note made clear the basis on which you were continuing.

I don't see why you have included 227N in the route availability. IFor there to be a train it must have come from 159 and that would call 227N anyway. I can sjust about ee the sense in including (perhaps only $32) in the aspect level to prevent a through reading issue if 159 set to a different destination, but there is in fact no obvious risk, there is no parallel signal, the train from 159 is either already on a PL proceeding only as far as the line is clear or on a main aspect reading far further than 147

162A(S)
Probably should have made up some nomenclature for the route exit.
Rediculuous to have made this route work auto; never sensible for a PL aspect and onto a branch with OTW! Examiner thinks candidate has not engaged brain.
Just because there is an A in a circle against a signal, it doesn't mena that all of its routes have an auto facility, just that one (or possibly occasionally more, but practically never all) have that facility.
The #10 note certainly does apply at route level but I think I'd also have as an aspect level control and so I would have reworded the note slightly to reflect- possibly also stengthened the note give an outline explanation of how that works. "Once a train has passed taken 162A(S) then OTW held occupied until a sequence of track occupation and treadle indicates that a train has left the branch; it is train crew responsibility to ensure that trains which pass 175 are indeed complete with taillamp".

I'll return to update this evening

[StrongLifts5x5]

Hi Peter

I have been working through the control tables for the 2006 exam however if you could address some concerns I have?

171A(M) do you not have to take into consideration opposing locking from 122D(M)?? also if the signalman keys 228R then sets the route the route would the route not set up to 225B locking 225N? So therefore you need to consider 122C(S) as well?

It a horrendous set of controls to complete in an hour, my first attempt took around an hour excluding the point controls.

My experience is with NIR controls so most of our interlocking would not contain complex swinging overlaps.

Cheers,

Darren

---

Also I am unsure about the route setting from 175 signal coming of the branch, does this set to 159 signal and if it did would the O/L of 159 therefore not conflict with 122A(M), and would we not put 175A in the route normal for 122A(M) or prove train is timed to a stand at AG tc??

[StrongLifts5x5]

Probably best to explain some of my reasoning so its easy for you to correct it, when I had the first attempt at 171A(M) I resoned that if the signaller had keyed 225N and 228R the route would set up to 225B.

Therefore 122C(S) to 138 signal would conflict with the route, i reasoned it would therefore be appropriate to have 122C(S) normal and free of sectional locking or the train timed to a stand at CP tc, my reasoning is there could a movement into the goods yard from 142 at the same time the route is set from 171 and at the same time there is a shunting movement from 122 to 138.

[PJW]

Yes I agree that for setting 171A(M) there is a need to prove that 122D(M) route locking is normal, or at least the overlap locking on EL and EK has timed out, should 228 be locked Normal.

However if 228 are free then 171A(M) is available to set and, when it does so, then 228 will be called Reverse. 228 will subsequently be locked Reverse by "counter-conditional locking" until such time as one or other of the mutually opposing overlaps has been released.

Therefore in the route level of 171 there should be an "or" condition "228 R or free to go" conditioning out the opposing route locking entry.

You are correct that if 228 are set R by the signaller initially then the route will set with overlap as described. I do now note that 122C(S) has been given a shunt overlap as far as CL and therefore yes I agree that this presents a similar situation- I am somewhat old in the tooth and thus giving shunts overlaps is not something that comes naturally to me!

Yes it is horrendous- suggest you adopt NIR practice and dispense with the complexity of Swinging Overlaps. Indeed Network Rail seems to be coming to much the same view after a few particular nasties when attempting to implement is SSI or SSI-like data; hence the "NoticeBoard 125 entitled "Simple Is Effective".

The route from 175 would read to 159 and there is no stated requirement that 159 be off, although I agree that this is something that could have been adopted. Whereas any GPL in line of route from one running signal to another would be pre-set (effectively false fed to a proceed aspect when the main signal is ready-to-clear and then proved actually to be OFF before the main signal actually does clear), then this would not be done for another main aspect. Typically any control is at aspect level, the signaller setting the routes in either order, but the first signal not clearing until the one to which it reads has itself cleared- this would be implemented when a particular risk is believed to exist should the exit of the first route suffer a SPAD.

In scenario in which this does not apply, 175 reads to 159 which can be at Red and yes sections AF and AE are locked as its overlap in the Down direction. 175 is required as route normal in 122A(M) but not 122A(W); similarly its associated route locking should be shown as {AF, AE [AJ, AH AG or (AG occ for t)]}, so yes you are right.
122A(W) only locks AD as its overlap and this abutts end-on the overlap AF, AE beyond 159 so in this case there is no conflict with the route from 175.

Hi Peter

I have been working through the control tables for the 2006 exam however if you could address some concerns I have?

171A(M) do you not have to take into consideration opposing locking from 122D(M)?? also if the signalman keys 228R then sets the route the route would the route not set up to 225B locking 225N? So therefore you need to consider 122C(S) as well?

It a horrendous set of controls to complete in an hour, my first attempt took around an hour excluding the point controls.

My experience is with NIR controls so most of our interlocking would not contain complex swinging overlaps.

Cheers,

Darren

---

Also I am unsure about the route setting from 175 signal coming of the branch, does this set to 159 signal and if it did would the O/L of 159 therefore not conflict with 122A(M), and would we not put 175A in the route normal for 122A(M) or prove train is timed to a stand at AG tc??

[PJW]

Indeed there can certainly be the parallel moves which you describe; there would be no need for the signaller to have keyed any points as should 142 be routed into the Goods yard then the mere setting of 171 to 151 would have to call 228R and 225N since that would be the only available overlap.

Hence when considering 122C(S) as a potentially opposing route when producing the Control Table for 171 then the availability entry recording this locking would need to be qualified by "or 228 Normal or Free to go".

So certainly you seem t understand the issues- I hope my comments have assisted rather than confused.

Probably best to explain some of my reasoning so its easy for you to correct it, when I had the first attempt at 171A(M) I resoned that if the signaller had keyed 225N and 228R the route would set up to 225B.

Therefore 122C(S) to 138 signal would conflict with the route, i reasoned it would therefore be appropriate to have 122C(S) normal and free of sectional locking or the train timed to a stand at CP tc, my reasoning is there could a movement into the goods yard from 142 at the same time the route is set from 171 and at the same time there is a shunting movement from 122 to 138.

[StrongLifts5x5]

Thanks Peter for your advice, I'm from a maintenance/install background but I do finds control tables interesting probably in a sadistic way!

If I stated in my assumptions that I am answering to the railway standard I am familiar with- Northern Ireland Railways- would the examiner be aware that I don't have experience with complex swinging overlaps or should I state that I don't?? My experiences would be NX panels, TDM over PCM transmission and RRI.