2009 Q7 TRAIN OVERRUN SIGNAL

[KonduriRaghavakumar]

I just attempted this question with basic background  from my maintenace side 3 years experience.  I am not able to complete fuly the answer.

[Peter]

I just attempted this question with basic background from my maintenace side 3 years experience. I am not able to complete fuly the answer.

Your answer is reasonable first stab. I have some observations:

I think the first section is about the very immediate actions. You have out some things which fall into this, but I think that one action needs to be about protecting the the and preventing any other trains from approaching the area because the report (if true) indicates that the signalling may be defective. This needs to be done with care so as not to affect the state of important equipment. Perhaps you mean this by "lock the control panel".

Collecting information from volatile sources is then important - go for the items that are likely to change or be affected by subsequent actions. Hence your point about noting positions of switches and indications is good.

Photographs are good. Data loggers give you the luxury of some time - the tend to keep several days of data. As an aside, in any incident, check what data loggers are available. After one accident near London about ten years ago, a claim was made later about something that was done to protect things, but this could not be verified as no one immediately involved with the investigation knew that there was a logger associated with the piece of equipment in question so no one recovered it, so it got overwritten a week later.

For the second section, you have described high level statements and run out of them - the question specifically asked for 5 which you clearly read as you have put five numbered bullets. Perhaps thinking of some of the next level down would have given you some more to talk about (eg Wrong side failure of train detection, wrong side failure of interlocking, SPAD because of degraded aspect (sunlight, dirt etc)). Another thing to note is the distribution of the marks. You have written more for a) than b), but b) has double the marks available. I think they are looking for some more explanation of the items in here - give a description of what may have failed and how this would have led to the events given in the question.

In the final section you appear to have listed a series of things to be checked rather than describing the process. You have referred back to the types of failure, as it asked in the question, but not quite in the structured way that I think the examiner would be looking for. I note that you say that you are from a maintenance background. Does your employer or railway authority have a process for managing wrong side failures? This would be a good place to look for inspiration on this. Set out the stages involved and the objective of each stage. What are the criteria for moving from one stage to the next and, as the question asks, what levels of authority are needed to move from one stage to the next, or indeed at the end if you conclude the signalling WAS working OK and you are going to say the driver is in error, what authorisation is required to bring the signalling back into use. In the UK, there is a process called Signal Failure Investigation which it may be worth you trying to get a copy of if you do not have anything from your own railway.

I hope this is useful and if you do not understand any of the comments, please come back and ask.

Peter

[KonduriRaghavakumar]

Thank you, I will try to get the copy of Signal failure investigation of UK. Actually I didnot known any of such process. I will try to develop this one. I would like to clarify wrong side failure means that failing of the interlocking which results to unsafe, generally we employ only the fail safe sytems, hence there may be error in wiring or circuit.

[PJW]

I would like to clarify wrong side failure means that failing of the interlocking which results to unsafe, generally we employ only the fail safe sytems, hence there may be error in wiring or circuit.

Remember that systems that are designed to be failsafe do not always do so. This may be due to an error in design that got through check and test. It may be through a completely unanticipated (or perhaps incorrectly judged to be incredible) failure mode of a piece of equipment perhaps arising through age derioration, being subjected to greater than anticipated stress etc. There is aways the possibility of failure induced unintentionally by careless maintenance.

Possibly a failure may result from an error in circuit design or in data in particular through some start-up or other unusual transitory condition that hadn't been adequately considered. Can be problems at interfaces between different systems, particularly in unusual failure modes.

Never overlook the human; sod's law dictates that when something has been designed to be fool-proof that evolution eventually ensures that a more complete class of fool evolves to bypass any precaution. In the quoted example the train detection could be assumed to be via axle counter and this could have been inappropriately reset; hence the section, though occupied, would be showing clear. In the UK now we ensure that the protecting signal is still held at danger for the first train on the affected route(s) after any such reset; however this wasn't always the standard.......This is called "Aspect Restriction Following Restoration" and there seem to be some places where this is regarded as a nuisance and a means to "get rid of it quickly" by running a train around the layout to do the bare minimum to satisfy the locking (whilst not actually achieving all of the prime objective to physically prove the totality of routes are clear of foul vehicles) has become practice!!

[cmcvea]

Peter i have attempted Q1 from the 2009 paper. it took slightly more than the 30 minutes to complete....

You have done well in the sense that you have clearly read the question. .....

Your generic process is very concise which is good.

Peter

i have just completed question 7 any feedback would be welcome.

[PJW]

I have just completed question 7 any feedback would be welcome.

Looks like we have two attempts at this as Hort has also posted (I have transferred attachment to this post) so I will review together.

The one from cmcvea was the fuller answer; for part a) there were 11 bullet points, so one can immediatelyly see that be able to award 0.5 marks for each and thus the answer would get off to a flying start.  I'd have liked a sentence of intro re railway context and abbrieviations to be explained and some of the entries to have been slightly fuller- e.g. "Signalling Equipment Secured" could well be misinterpreted etc.  However the key points were certainly there:
1) protect the situation to ensure railway is safe,
2) escalate the issue to the appropriate authorities (incident investigation, decision what train services can still operate, rearrangement staffing, alternative travel arrangements)
3) ensure the preservation of evidence relating to the incident at the actual site and at the signalling control centre and potentially other places where it might be,
4) ensure that drugs and alcohol testing of staff is initiated,
5) arrange for independent investigation to be initiated,

Obviously the question can be interpreted slightly differently re the word "immediate" and also it leaves vague "by whom"; it is for that reason that starting off by explaining that you are answering  in the context of undertaking a particular role is useful to help the examiner interpret your answer.  You may consider yourself to be the signalling maintenance engineer at the control centre, an IRSE memner just happening to be at the station witnessing it occuring or indeed the appointed investigating officer; the answer you give would therefore be different in each case.

My incident investiation experience is not in recent times and in the past it was less formalised / procedurised than it is nowadays; indeed there were less separate parties and possible litigation involved.  My instincts are still to get as much of the perishable evidence just as soon a possible- i.e. take photographs, get people to write statements before memories fade or get contaminated and this looked to me to be the main omission.  I think I'd have answered with the 5 headings (as above) but have made them fuller by giving examples- indeed I'd have used many of the 11 bullets given, but arranged in groups to support the relevant heading.

I think that cmcvea's abswer would have scored pretty well though (perhaps as much as 4/5) as it is; Hort's answer was much weaker- there was not much written and the wording seems to assume that there hd been a SPAD and fails to recognise that the fact that the driver has made a claim about having received a proceed aspect strongly suggests that the train has come to a stand and that a conversation with the signaller has taken place.  I fear that 1/5 is all that would be awarded.
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There were then 10 potential marks for 5 possible causes so I'd have given 5 and written enough relevant on each hopefully to earn my quota of 2 marks apiece.  It is good policy to make them as different as possible (displays knowledge, may make answering remaining part of question easier), so perhaps I'd have chosen
a) train detection showing clear when occupied.  Potential causes could be for e.g. poor train shunt lightweight vehicle / rusty rails, erroneous line circuit operation due to poor cable insulation / earth fault; inappropriate reset of axle counter section whilst vehicle still within limits
b) interlocking fault.  Potential causes could be for e.g. wires touching due to wire degradation affecting insulation, silver migration at relay plugboard, relay failed to release, circuit design wiring error,
c) incorrectly illuminated signal aspect.  Potential causes could be for e.g. physically damaged cable cores, testing strap left inserted in error,
d) phantom aspect.  Potential cause could be sunlight angle / reflection causing driver to be misled re what aspect was actually being displayed
e) misreading of signal by driver.  Potential cause could be reading a signal on a parallel running line instead, correctly observing previous signal but the failing to realise that had passed the platform protecting signal.

cmcvea's answer was similar and had a good range.  I liked particularly the idea in bullets 5&6 that nothing untoward may have happpened at all but in one way or another the report of it having occured was incorrect.  This very much suggests knowledge acquired from personal involvement in such incidents.  I think I'd have grouped these bullets together as two examples of "false alarms" and similarly I'd probably have grouped bullets 1&4 as reasons why a driver believed signal showing proceed when in fact it wasn't as by itself bullet 4 needs a bit more explanation.  Also putting down 7 bullets when asked for 5 inherently is not good exam technique- it seems to send the message that not too sure so putting down a couple of extras "just in case".  However this section was certainly good and although it is quite compact I'd probably award it very nearly full marks- say 8 or 9/10 to reflect a feeling that I'd have liked just a little more description re how staff working in the area may have caused the fault and more precision re wromgside failure of equipment.

Hort did list 5 posible causes but in most cases, the words could not really be said to describe.   Also the selection seemed too focussed on the driver rather the signalling- they were all true but didn't demonstrate as well a wide understanding.  I'd feel mean not to award 5 marks, but certainly wouldn't give more and would probably only give 4 since bullets 3&5 certainly need to explicitly say what they only imply.

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The last section asked for a procedure to manage the investigation of THIS scenario with reference to one or more of your POSSIBLE CAUSES.

cmcveas's answer covered a generic procedure quite well but failed to relate it to the earlier parts of the question.  It certainly displayed knowledge of the relevant source material and was clearly and concisely presented. but didn't address completely what was actually asked.  It was also I think too brief regarding actions and authority if faulty equipment is found / if it is not.

Hort's answer did go a little bit further relating to the scenario and possible causes, but I feel still not enough- however this may be partly down to not having selected a better selection in the initial part of the question.  This answer tended to describe more the various investigations rather than A PROCEDURE TO MANAGE THE INVESTIGATION- ironically it was rather better re managing the situation after the results of the investigation.  Another deficiency wa that it did not address at all the situaton of a failure not being identified (other than what seemed to be an implicit assumption that it must be the driver at fault).  I think that the emphasis given in the answer to "finding the party responsible for the deficiency" is a sad (but I fear accurate) reflection on the current industry environment.

Both answers had a lot of good bits and very little that I regarded as wrong.  I hope though this comparison serves to show how important it is to study the question, see where the marks are and have a strategy for obtaining them.  You don't actually have to write a lot provided that what you do write is targetted and ha enough substance so that not only is the nail hit on the head but it is fully driven home.  

Overall cmcvea did this pretty well, but the last section wasn't as good.  May well have still got a Credit though.

Hort's answer seemed to start poorly and was quite sketchy throughout, but actually got better as it progressed.  In fact the examiner would have been able to award the marks that seemed to have been missed in part a) on the strength of some of the material that was written in c).  I don't think it would have been a Pass but it wasn't that far away and given the the exam is still a fair time off there is plenty of time to practice more and get more used to tackling such questions to be able to score the marks.

[cmcvea]

I have just completed question 7 any feedback would be welcome.

Looks like we have two attempts at this so will review together.

Overall cmcvea did this pretty well, but the last section wasn't as good. May well have still got a Credit though.

Peter, thanks for your constructive comments, it is much appreciated.

[Hort]

P & P,

Thanks for your comments.
Certainly something for me to build on re questions 5 & 7. Generally I found that I need to be more descriptive when discussing certain terms and abbreviations.

As for Q2... I completely fluffed it! Looking at it again I realise that the question requires the candidate to demonstrate knowledge of how the railway is operated and in part calls for some regurgitation of the rule book. So the best advice to take away from that is to not answer that type of question!

Cheers
H

[PJW]

[quote]
I know it

[Peter]

[quote='PJW' pid='2222' dateline='1285791205']
[quote]
I know it