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".
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".
(16-07-2013, 06:03 AM)PJW Wrote: I'll return to update this evening
PJW