Answers to 2000 Part A Q1 & Q2

[alexgoei]

Hello Peter,

Appended please find my answers to the 2000 paper.

The layout for this paper has a single slip so the answer to Point 311 involves point-to-point with 310. Do look forward to your comments on this as putting a slip is very much favoured as a feature in the Module 3 layout.

One other question, can you confirm that there is no need to prove alight the Limit of Shunt and buffer stop lights in any of the signal controls?

Thank you and do look forward to your reply.

Regards

[PJW]

Hello Peter,

Appended please find my answers to the 2000 paper.

The layout for this paper has a single slip so the answer to Point 311 involves point-to-point with 310. Do look forward to your comments on this as putting a slip is very much favoured as a feature in the Module 3 layout.

One other question, can you confirm that there is no need to prove alight the Limit of Shunt and buffer stop lights in any of the signal controls?

Thank you and do look forward to your reply.

Regards

Quick answer re lamp proving:
1. ALWAYS prove alight a Limit of Shunt.

2. Similarly lamp prove any GPL which acts as one- i.e. when ON would stop a wrong direction movement continuing into the wide blue yonder on a line that is not signalled for that direction. Typical example is a GPL at the tips of a trailing crossover between running lines which only has a route reading over points Reverse to get train onto its right line- if ON then there would be a high chance of the points being normal and if passed at danger (because invisible) train would be going say in the down direction on the up line- ready for a head-on collision with oncoming train.

3. Don't lamp prove other PLs.

4. Don't prove buffer stops.

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Let's hope I am equally quiet at Sheffield this weekend as I was at Derby last weekend to have time to look at CTs.

In the meantime, in good "Blue Peter" fashion "here is one I did earlier".
A former student's attempt at 311 with my comments on their work. If your's differs it is not necessarily wrong but may well be......

[PJW]

Let's hope I am equally quiet at Sheffield this weekend as I was at Derby last weekend to have time to look at CTs.

Thank you to WRSL for arranging things so that I had enough free time over the weekend to look at these CTs for you and also some written answers for others and still getting the commissioning in on time!

Shades of Drake.....not sure how well you know the tales of English history.....

Perhaps you yourslf ran out of time; no 112B (I usually just look at the ones you send rather than check for completeness but for some reason I noticed this omission)
PJW

[alexgoei]

Hello Peter,

Thank you once again for your effort to review my submissions. Your turnaround time for most submissions are less than 7 days and if there is any QoS to meet you would have done well.

Gone through your review comments for this year's paper and have some questions.

These questions are the ones in red text in the appended file especially showing point-to-point. Your suggestion to show this under Points N > R or R > N is only possible if the routes called/locked always have the point-to-point in the same throw. However this is not the case as my answers show.

Look forward to your comments.

Thank you and Regards

[PJW]

Hello Peter,

Gone through your review comments for this year's paper and have some questions.


Thank you and Regards

There are 2 overlaps for 112B(M), the first to the POL towards the sidings and the second (which I would regard as the non-preferred) out to the Passenger Loop.
The first requires 303N (trapping), 304N, AA clear.
The second requires 303N (trapping), 304R, BA clear, AA clear.

Hence when written in combination the requirement is:
304 [written in the N or R or swinging column]
303N, AA clear, (BA clear or 304N)

You may find it an odd way of writing the logic- it is because as I have said the CTs still have the presumption of relay circuits embedded within them. SSI data would consider there were 2 overlaps and put a positive statement of which each needed (part of my fight to update 11202 to relect- I am winning but not there yet!); RRI has a single aspect relay and effectively puts in a long series path anything that may be needed in any overlap before puttting in parallel paths around various elements to condition them out when not needed. A good exercise in Boolean algebra......

[PJW]

Hello Peter,
Gone through your review comments for this year's paper and have some questions.
Thank you and Regards

If there are two tracks (usually within a platform) on which the opposing route locking or overlap point locking is to be timed out, they are summated and one timer provided. Hence the time value is for their combined length

[PJW]

Hello Peter,
Gone through your review comments for this year's paper and have some questions.

Your suggestion to show this under Points N > R or R > N is only possible if the routes called/locked always have the point-to-point in the same throw. However this is not the case as my answers show.

Thank you and Regards

Think about 310 and 311.
a) 310N, 311N is a valid combination- parallel moves along the various running lines
b) 310R, 311N is a valid combination- e.g. 109B simultaneously with 118A
c) 310R, 311R is a valid combination- e.g. 118C
d) 310N, 311R is not useful as any move over 311R must also want 310R. Had there been a move in the opposite direction along the same path (imagine 109 reading to a LOS at the DH/DJ joint) then whilst that train on DG 311 would have to be locked R but 310 could be normalised thus allowing traffic on the Branch.

The point-to-point that could be provided is
a) the requirement for 311 to ensure that 310 already R before 311 could go R
b) the requirement for 310 to ensure that 311 already N before 310 could go N
since never want 311R without 310R. Such point-to-point would lead to slightly excessive locking on 310 had there been a move to the imagined LOS (but we'd have lived with this) but without any such a move existing then it is not restrictive (other than effect on the event of a detection fault).

From a route calling of points perspective (i.e. pseudo point-to-point) then the thing that you need to see that you should do is "any route that calls 310N should also call 311N". So if doing 311's CT, it is a prompt to look at routes such as those from 112 that you might otherwise have forgotten about; hey presto you get the marks for recognising that 311 provides flank protection.

You were right in what you were saying- what that was telling you was that you were attempting to place inappropriate point-to-point!

Does the above clarify?

[PJW]

Hello Peter,
Gone through your review comments for this year's paper and have some questions.
Thank you and Regards

114- As post re 2002 CTs, suggest naming signals at which a SPAD would endanger the route in the Remarks column. Nothing to do with A/L; totally different comment about same route.

[PJW]

Hello Peter,

Gone through your review comments for this year's paper and have some questions.

Thank you and Regards

My error- platform tracks of course are DD or DE.
I could blame it on being distracted by having actually to do some commisioning relevant work on the shift, I could claim it was deliberate ploy to see whether you actually reading my replies, I could claim as the French do "that an error slipped itself in", or I could just admit it!

[PJW]

Hello Peter,
Gone through your review comments for this year's paper and have some questions.
Thank you and Regards

Yes I contend that 209A(S) would certainly be a non-permissive shunt. Given the distance of the move to modern standards I can't see that a PL aspect would be tolerable nowadays. It it were the only (S) move within the CTs asked to do then I'd probably note "I have signalled it to show shunt characteristics but in my experience it should have been provided as a main aspect and even if provided as a PL should probably operate as if a (M) class route". If I had already done a "real" (S) then I think I'd have given it (M) class controls and have annotated CTs to that effect as being appropriate to a running move of some 1500m!