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Module 3 Answers
#1
My answers to Module 3 are attached


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#2
(04-05-2010, 09:10 AM)Andrew Lockyear Wrote: My answers for Module 3

Somewhat similar answer to the others received and included in the amalgam.

The question could be interpreted as:
a) the route has already been set and locked, now what needs to be proved in tthe aspect level prior to allowing the signal to clear,
or
b) what needs to be proved before a movement authority can be given and since setting the route is a pre-requisite also include these considerations.

I don't think it really matters how you answer; however a short introduction to let the examiner know that you are aware of the (probably deliberate- after all not all candidates would answer from a railway featuring route setting panels / VDUs) ambiguity would certainly have been very wise. Similarly you should have stated the railway whose practices you were going onto describe; in the absence of this I'll assume modern NR practice as a default.

Certainly if including both route level (at time of setting) and aspect level (effectively continuous proving) then you should have separated the two separate elements; however in your answer they seemed to be mixed indistinguishably.

2nd bullet in section i): whereas the exit signal is proved alight for Main and Warners, generally it is not for call-ons and shunts; the entrance signal isn't proved; route indicators are genreally proved, but again not always. Hence more detail would be required to explain more precisely.

3rd bullet- could also do with more explanation.

5th bullet- You fortunately defined what you meant by "logical problems" as that is a term with which I am unfamiliar. Be careful theough- I think you mean "from the same exit which do not conflict due to different point calling"- the Main / Warning / Call-on routes will actually utilise different exit butttons and anyway there could be a shunt route to an intermediate GPL that would also need to be similarly (but not 100% identically) locked.

6th bullet- this is also too glib- AWS is not proved, other than the AWS of the next signal being proved "not supressed by an opposite direction move"; it is the TPWS of the exit signal which is proved - and this only when the signal is supposed to be displaying red of course.

You didn't mention anything about proving points were actually detected in the correct position, Ground Frames locked, level crossings closed to the road user, conflicting releases not given etc. so I am sure you'd lose some marks for that (I wouldn't want to travel on your railway if that is not a practice!)

section ii):

I am not quite sure why you decided to treat oppposing routes differently in this section than previously; I suppose you were thinking that routes from opposite direction signals falling within one's route will be directly opposing rather than indirectly opposing, but indirectly opposing is possible from signals falling beyond one's route. However it wasn't very clear and you also confuse when state that locked by "aspect control", when surely it would also be at route level. The question really wasn't asking for an explanation of why indirectly opposing locking is needed- you dwelt too long on this; however it was good that you provided a diagram to demonstrate the need to look beyond one's overlap for opposing route locking.

At least you remembered to mention point detection within the overlap; I think that the examiner would be minded now to regard the omission in the previous section as a sily slip rather than a fundamental oversight.


section iii):
I think that a diagram here would have been beneficial to support your words; you could have used it to show how point flank protection is related to conditionally foul tracks and indeed the provision of flank track or overrun detection protection where the layout does not feature points which can be used to provide flank. Should also have mentioned trapping.

===================================================================
Now look again at the question set:

The proving of a route prior to issuing a movement authority (or proceed aspect) needs to consider items of infrastructure within, beyond and adjacent to the route.

List the items you would expect to be considered within the route with brief reasons. [7 marks]

Discuss what items of infrastructure could be included beyond the route and the reasons for inclusion or exclusion. [9 marks]

Discuss what items of infrastructure adjacent to the route may need to be proved, with reasons for consideration. [9 marks]


Did you give reasons for the things you included in section i)?
Did you give any arguments for inclusion / for exclusion for elements within section ii or section iii?

Generally not, but at least you tried in the odd instance. Hence you (and indeed the others who attempted what seemd to be a favourite question) really only tackled the half of it. The thrust of the question was surely that there is little debate regarding what controls ought to be applied from signal post to signal post [ok if you are from a railway without level crossings then your standards won't include them, similarly there are very few NR lines where the position of flood doors are relevant considerations]; however there can be much debate whether the extra complication and unreliablilty etc of adding layers of locking to address relatively low risks are actually worth it. That's what the examiners were trying to draw out; hence why there were more marks for the "beyond the signal" and the "adjacent to the route" sections than the "plain and simple post-to-post".

So perhaps 3.5 marks for section i), 3.5 for section ii), 4 for section iii) is the most I'd feel able to give. A shame because what was written was generally OK- BUT it was rare that it fully addressed the question.
this lesson is applicable to many attempts at questions in any of the modules....
PJW
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#3
(04-05-2010, 09:10 AM)Andrew Lockyear Wrote: My answers to Module 3 are attached

You should use your first sheet that lists some $ refs also to define the standards which you are following.
In particular I think you should explain here various assumptions e.g.
re whether certain track joints are at clearance,
the way routes read (418C could be via 249R or indeed via 249N
whether shunt routes have overlaps

Particularly since you have chosen not to signal the swnging overlaps that the plan depicts, you should draw this to attention "up-front".

Also you have done something pretty unconventional re providing a single Control Table for 365A(M/W/C) and have annotated certain entries to which classes they apply, but in the absence of annotation then an entry applies to all. I know why you took this approach, but it doesn't make them easy to read or to mark- the least you can do is take a little time to explain your presentation rather than expect the examiner to work it out, particularly when you are simply adding a C or W to an entry!

Also suggest you should define abbrieviations such as SRL.
------------------------------------------------------------------------
----------------------------------

Point Control Tables

1. No value in the disconnect facility box and entry.

2. Foul Tracks!
235RtoN needs to be locked by BT
I also suggest 235NtoR needs to be locked by [BU or 236N]
Similarly AF, DR and BT all appear to be conditionally foul TCs for 236 and therefre should be included in tthe relevant track circuit dead locking.

3. This has implications also for the extent of the route locking which needs to be imposed by relevant routes.

4. 235 are trailing points within the overlap for 412A(M) as well as 416A(M)- the fact ou got one and not the other looks like careless oversight.

5. Overlap route locking needs to list ALL tracks between the entrance signal and the exit signal, but the SRL on both the platform tracks should be overriden if either of them has been occupied for the relevant time to prove train at stand on their combined length. Route locking in the overlap is only required if the track is not itself a dead-locking track and any such locking should not be overidden by platform track(s) occupied for time.
e.g. for locking on 235 after 416A(M)
DH, DJ, DK, [DL, DN or (DL or DN) occ for 45s], DP
However this expression doesn't fit easily into the standard column layout so therefore generally written:
TCs clear after route used_______or TC occ for t
DP, DH, DJ, DK [DL, DN ...............(DL or DN) 45]

6. Route locking on 235 after 378C(M) is BT BU (i.e. the foul track) rather than BT DR (since the route doesn't read that way and this is locking holding 235 in N)

7. You seemed to overlook 365 completely re 235 points.

8. Even if you are not going to have NR style swinging overlaps, then I don't think that you can simply ignore that there are alternative overlaps beyond 378 towards the Up Main and also towards the Up Branch- it'd be very restrictive only to have the one. A lot of railways would permit the signaller to select one of the possible overlaps (e.g. by keying the facing points prior to route setting) and then locking it until trin has passsed or alternatively been timed to stand.

9. 236 points. You seem to have missed 265 again; similarly 351! It is perhaps arguable whether 351A(M/W/C) should set and lock 236R as switch diamonds tend not to provide useful flank but I think I'd include. Certainly 351B(M/C) reads directly over them so that has got to be an omission.

10. Unclear why you claim 418B(S) should lock 236 yet 414B(S) should not
------------------------------------------------------------------------------------------------------------
PJW
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#4
(04-05-2010, 09:10 AM)Andrew Lockyear Wrote: My answers to Module 3 are attached


Your CT headings are too sketchy in general.
e.g. You do not distinguish between point availability at route level and points being proved set, locked and detected at aspect level.
also in the TC occupied column at aspect level it is not very clear that the numbers refer to occupancy times.

As per points, I suggest you omit reference to the aspect disable facility- it won't get you any credit and just costs space and time.

If you are not mentioning AWS and TPWS on each Control Table, then you should cover by a general note on your front sheet.

365A
You are only permitting an overlap over 242N- not really what the plan implies, so as a minimum you should explain / justify.

Sectional route locking:
you seem to have missed
a) 371A(S) as a pre-set shunt
b) 414C(S), 418D(S) as train from these routes could be in the platform for example. These would give you a problem showing with your CT presentation since the opposing locking would be "neat" in the M and W but would permit the C to set once timed to a stand. The available space on the CT is already too small for the number of routes- if you need multiple alternative lines of entry then this constraint is made worse
c) the moves to the LOS from 382A(S), 378B(S), 376B(S), 374B(S)
Also you have generally listed AF in the SRL. Whereas this would be locked by routes requiring overlap beyond 382, this would result in 238 locked N. Since 365A requires (R or free), the listing of AF is superfluous.

Main / Warning / Shunt
No reference to the manner of selection of the different route classes
No reference to conditions which would initiate and those that would permit the W route to step up to M

Pre-set shunt
No reference to pre-setting at route level, nor proving that the GPL is controlled off at aspect level

Call-on tracks.
Again your presentation method gives you difficulty; you have not conveyed the fact that the C does not require AH and AJ clear (as per M and W)
Also at both route and aspect level, what you have written as AJ occ should be (AH or AJ) occ

Auto
My interpretation of plan is that one route (at least) from 365 is to work Auto; has surely got to be either 365A(M) and/or 365A(W)

Aspect sequence
Again your presentation isn't clear- almost looks like PL is route indication

Approach locking
Heading fails to make reference to "tracks" and doesn't really make sense.
If plan doesn't go far enough for you to complete entry then you should explain.
A/L times: seem to be saying that M is 60s, whereas W and C are 180s??????

416BB
Generally similar comments, but specifically:

Opposing locking: you got 373A(S) but didn't include 351B(C.), 353B(S), 371B(S), 365B(S). Also you listed in the SRL tracks: BN, BL but you only need SRL to BP as BN deadlocks 243 and it is quite legitimate for 416B to set with train on BL in down direction.

Flank points: what about 246, 249?

Approach Release- look at route box and plan for signal in rear- the route is MAY, not MAR!

Route Indication:
PLJI pos 4 for M and MARI "B" for C; again the route box tells you this.

A/L time:
A PL (C or S) would generally be 30s, although in RRI it would probably adopt the same time value as the associated M class route. I seem to reber that one of the NR standards or the RGS is very badly written and that is probably from where you are getting the fallacious 60s

416BB
Again some similar.

This time you correctly put 237R as flank, but what about 238N
Again missed the opposing to the LOS

Also route locking against 365D(M/C) as the point locking is compatible but don't want to be able to set both routes simultaneously.

Shunt routes from GPLs are not in general approach released, but do have comprehensive A/L just on their berth track.
A/L time would be 30s
Also are last wheel replaced, but your TC's clear don't indicate this. I also would have omitted the proving of ED and recorded an assumption that they could well be an operational need to signal a train into an occupied bay (it says it is used for stabling so perhaps a locomotive going to rescue a "cripple" that has previously been removed from a train , or perhaps multiple tampers / on-track machines for engineering work prior to possession).

-------------------------------------------------------------------------------------------------
If you feel that any of my comments conflict with those which you used to produce the Control Tables, then I apologise, but since you didn't tell me I had to guess and seeing as things seemed broadly in line with NR current standards then that is the default I used. I could have been even more picky ad have looked for you to be 100% compliant with things like GK/RT0044 locking, signal overrun protection etc. particularly as you seemed to have adopted shunt overlaps, but I stopped short of that.
==============================================================

So overall they weren't too bad, but you still have quite a bit more work to do.
You must ensure that you get right the key areas:
FOUL TRACKS
FLANK POINTS
OPPOSING ROUTE LOCKING
CONSISTENCY WITH THE ROUTE BOXES GIVEN

Also your ides of using one CT for the different classes of route perhaps could be made to work, but it needs a bit more thought how you are going to achieve this with clarity.
A suggestion that one student made was that they could do a CT for say the W route and then ask for it to be photocopied twice. Then each sheet could be amended, one for the M (mainly addition but perhaps a crossing out or two) and one for the C (some addition, some crossing out). Haven't actually tried this, but may be worth a trial.

Of course one of the disadvantages is that you'd be waiting for the copies to be returned during which time you'd have to be doing other routes etc before revertig back to the previous mindset. so if you are contemplating such a strategy then practice in exam like conditions to make sure you can actually cope.
PJW
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