2009 Q4 STOPPING TRAIN IN EMERGENCY

[KonduriRaghavakumar]

I had attempted this question with respect to the railway rules that I am presently working. please check it and give suggestions.

[PJW]

I had attempted this question with respect to the railway rules that I am presently working. please check it and give suggestions.

I think you should start with a sentence explaining which railway's practice you are assuming in your answer. Perhaps extend this to two sentences if need to explain something pertinent to the context of your answer.
Without this the examiner thinks: "Doesn't seem as if candidate answering the question asked. It said colour light signalling with secure radio system; answer seems far more like small mechanical signalboxes without any form of radio system."
Now obviously can have small signalboxes (VDUs, panels or levers) with colour light signals and there are a reasonable number of them in the UK but isn't particularly typical and therefore seems an odd way of answering question- if however the candidate is from elsewhere then advisable to explain this.
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You were asked for 3 different methods; you appear to have given 4 which would be a waste of your valuable time. There would be 5 marks for each description so expect to take 5 minutes on each and in that time you need to cover (presumably pretty evenly):
a) description of method
b) manner control received by driver
c) effectiveness of the control,
d) impact on operation of unaffected part of railway
So perhaps the marking scheme is 1 mark for each and another mark which is available to be added to the most appropriate section depending on what was actually selected as some options may have more to say in one bit than others.

Looking at your methods
i) replacing signal is the obvious one but good that you considered not only the direct visual observation but also any automatic effect on the train via ATP etc. You therefore covered a) ok though briefly, b) partially, but c) and d) not at all.

ii) operating detonators at minimum braking distance. I think you need to explain how this is achieved- it sounds like having motorised detonator placers in conjunction with operation of caution aspect of distant signal. This would be possible but not a practice I am familiar with, but I could understand that it might be on another railway. Not quite clear why you mention adequate time- this sounds rather more like a signaller having to go trackside a long way from their signalbox to place detonators by hand- doesn't seem to be what you'd do if having a secure radio system. So I am left wanting more re a) but this time you did cover b) and c), though still omitted d).

iii) Examiner by now knows you are not talking re UK railways for sure, but yes a perfectly reasonable way to attempt t stop a train in some contexts no doubt. Again wonder if really appropriate with colour lights and radio system. So you gave info re a) and hinted at b) and said something about c) but not d) at all.

iv) Certainly a possible method but the sad thing is that examiner has no mark allocation left to give. The best you can hope for is that you'll be given credit for the 3 best of your 4 answers.

So you didn't write enough and certainly didn't answer all that you were asked, so your marks would be mediocre. There are some good ideas here about stopping trains in emergency but a feeling that it really wasn't quite the type of railway that the question was envisaging. The fact that you never mentioned radio at all, reinforced the feeling that not really addressing question asked. You do need to make sure that you make clear to the examiner that you are; if you feel that your railway's environment doesn't allow you to answer the question then you have a choice to make:

1. If very fundamental to the question then need to choose a different one

2. If not critical, then tackle the issue head on and in your introduction state that your railway doesn't have the benefit of such a radio system, describe two methods of stopping train in emergency and then say that if it did have the luxury of such a system then this would obviously be another good method in certain contexts- you are showing your broader awareness and that you are attempting to answer the question given your experience.
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You now have 5 minutes to tackle the second part. I don't think that you said enough for the first sentence- you need to expand on what you said on procedures re how guidance is given to get the signaller to attempt in a certain priority order or what key factors would be relevant in choosing one method over another in certain circumstances. You did rather better on the second sentence of this bit of the question.

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Again you had 5 minutes for the last portion and you only wrote 4 lines which isn't nearly enough I am afraid.

The question was also about the signaller stopping trains in emergency and you were implying the driver contacting the signaller. You could certainly have made use of this by explaining that if the driver had an emergency (e.g. had discovered brakes ineffective) they could contact signaller who might then be able to set appropriate routes for the train or contact others to attempt to get them to stop instead. Also your understanding of a secure radio system seems to differ from mine; you i think mean that only railway have access to that frequency but it is a common channel, whereas in my context it means that the communication van be restricted between just one driver and one signaller at a time and so each knows precisely with whom they are communicating
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SUMMARY

Overall it was on the right lines but too short; I think it needs to be at least twice the length.

It was however very clearly laid out so I knew which bit of the question you were attempting to answer at all times.

You need to address each little bit of the question consistently; where there are several elements within each portion then you really do need to do them all- they are not there as alternatives to do one or the other as seems appropriate.

Your railway context is rather different to what I am familiar with, but this need not be a disadvantage particularly if you explain a little more.

Indeed you could have made more re the fusee by saying that it can be quite effective in a relatively rural area with good long range visibility but not appropriate in city areas etc where there are many more obstructions/ distractions or where a station is approached around a sharp bend or through a tunnel. I think that the fusee must be some form of fixed signal at the signalbox (although I at first wondered if it was a form of rocket firework) but I am intrigued by the flame being ABOUT 101.6mm dia"! Presumably it applies to all lines and all directions and any driver should stop just as soon as they can having seen it (but you did not state) and thus there would be something for you to say re d) as it would therefore affect every train within visual range. You say it lasts for up to 7 hours but not that the signaller can easily extinguish it more quickly once the potential emergency has passed. You did mention the lessened effectiveness in bright sunlight but you did not say anything about the distance over which it might be visible compared with the train braking distance and never indicated the speed of traffic either. Remember this is a "Signalling Principles" paper and therefore concentrate on that; an effective warning in an emergency is surely one capable of stopping a train before an accident occurs at all, failing that a means to lessen the severity of an accident by having achieved a significant reduction in collision energy is the next best thing.

So I think you can see that I have lots of unanswered questions arising from just that little bit of your answer; had your answer addressed some more of these I'd have felt that your description was adequate and awarded more marks- because I am left wondering, I am left unsatisfied and therefore you'd get less marks.

So well done for having a go; it is only by practice that you can improve. This wouldn't have been a pass but it wasn't a disaster either. Hopefully you can now see some areas where you could have made an improvement by actually writing down what you knew anyway and perhaps understand a bit more about really reading very little bit of the question and working out here the marks are allocated within it- as that is part of the secret in passing the exam.

[KonduriRaghavakumar]

Thank You Sir for your valuable suggestions, I just made one correction that fusee lit for only 7 minutes. Can you guide me what is the impact of operation on unaffected part of railway which i didn't understand.

[PJW]

Thank You Sir for your valuable suggestions, I just made one correction that fusee lit for only 7 minutes. Can you guide me what is the impact of operation on unaffected part of railway which i didn't understand.

If I had known about a fusee then I may have guessed that you used the wrong word; because I didn't, I had to take your words meaning what they appeared to. I am afraid that this is a disadvantage that you face. However you do have a corresponding advantage; your description may be slightly wrong but provided it is plausible I'd go with it; however I'd be far more critical of a UK student as I would be far more certain that they were wrong if they wrote something incorrect.

I know understand that a fusee is a form of flame torch carried by track workers as a means of stopping trains in emergency.

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Replacing signals to danger can be entirely selective; the signalman will only give the message to stop to those trains which are considered endangered by the emergency and those which could still run safely would not be affected.
The same could be true using radio message to stop one secific train; however a general "Emergency Stop" call would not cause the stopping of those trains wanted but also others as well.
Examples:
a) Perhaps the incident only affected one direction running line; train in the opposite direction would also be stopped.
b)Perhaps the incident affected a bridge- in this case trains in both directions would need to be stopped, but those that already had passed over the bridge and going away from it would also be stopped unnecessarily.
c) Perhaps the incident had occurred on the branch line just beyond the junction at the signalbox; there would be no need to stop trains on the mainline but a red flag or fusee at the signalbox would stop trains heading for the mainline as well as those heading for the branch. It would not protect trains coming from the branch as it would be encountered too late, yet trains from the mainline would see it and then stop even though they were not destined for the line with the incident.

Your method re stopping trains by cutting the power supply would have been a good one to illustrate this with; it is unlikely that the electrical contol has very precise remote switching and any urgent disconnection may well affect a wide area and thus be a "blanket outage" rather than able to be "targetted" to the incident area itself.

This gives another esson re doing these wrotten questions; "look for the hidden question" and address it. In this case it is
1. to recognise that there are a range of reasons for stopping trains in emergency; for e.g.
- is it to protect the train or
-is it to protect somone from the train
2. to recognise that the best means to use may depend upon the type of incident.
A candidate demonstrates their railway experience to the examiner by seeing the things which lie beneath the surface of the question and bringing them into the discussion. You make it relevant to what was "actually asked" by using a typicl range of incidents to address the art of the question asking abot "effectiveness" and "operation of the unaffected part".

You should have asked yourself: what emergency? what incident? which trains in that case would I want to stop? and which trains need not have been stopped?

So you may have considered incidents such as-
a) derailment on train on adjacent track which may be foul
b) member of public fallen off platform at station
c) underbridge hit by road vehicle
d) broken rail
e) staff attending broken down train on the runnuing line adjacent to other tracks
f) fire at a factory close to the tracks
g) terrorist alert at a major station
h) lorry stuck on automatic level crossing
j) herd of cows broken through fence and wandering around the railway track

Think of a list and then choose appropriate ones to illustrate elements of your answer to give you more concrete examples to talk about in order to explore the things that the examiners were asking you about

[PJW]

DAP 2009 Q4: Stopping Trains in Emergency

One of a set of three questions undertaken in mock exam conditions

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Part a) option 1
Careful with wording “only affects one signal”- obviously every signal within aspect sequence range reverts accordingly; it may have been worth making more of this by stating if train far enough away then it should stop at the protecting signal normally but is otherwise likely to SPAD, dependent upon its position when the driver first becomes aware of the more restrictive sequence, its speed and rail head conditions etc.  In the case of continuous ATP then the information can be conveyed to the driver before the changed signal itself becomes visible; indeed in this scenario the driver is actually likely to be alerted to the situation by the braking initiated by Automatic Train Protection.
Part a) option 2
ESOC is not necessarily implemented via the crude method of cutting the power to the central interlocking; for example a WESTLOCK cubicle has a directly wired input and if this feed is lost the OPT file is no longer processed (so all signals go to red) but the indications remain valid and normal working can be resumed immediately once input is restored.  The essence of the control is
i) a single quick action to revert all signals within a defined area (as you stated)
ii) a means that does not rely upon the operation of the VDU control system in order that there is a diverse means to place the signalling into a safe state even should this freeze up or become inoperative for some other reason (indeed it was when these systems were a novel replacement for the trusted panel directly wired to a relay interlocking that it was felt that there was a need for ESOC).
Your text was fine for SSI and SMARTLOCK and indeed it gave you more to discuss- it would however have been better if your answer had recognised the distinction between the “concept” and “particular implementation”.
Part a) option 3
I admit that I am not sure of the details of the GSM-R Global Emergency Stop; I suspect you are correct that there is no positive feedback of receipt as it is a broadcast call to anything that happens to be in the selected area (normally a particular GSM-R cell and all of its neighbours, although this is configurable) and indeed can be initiated by any driver as well as the signaller.  I don’t believe that there is any direct tie up, but for ETCS L2 (and above) the train position and speed is reported back to the RBC; on the Cambrian lines the signaller has a supplementary display provided primarily for the imposition/ removal of Temporary Speed Restrictions on which the train is depicted at its longitudinal position compared to the signalling plan and supplementary details of its status, such as speed, can be viewed.
Despite comments above, part a) was basically well answered and of appropriate length.  Perhaps you could have said a little more about effectiveness and particularly for option 3 have included more discussion regarding the area affected.  Being based on radio cell coverage it is inevitable that there will be instances of far more trains being affected than ideally would be.  The primary problem is when there are two operationally all but independent railways in the same radio cell and therefore two logically separate routes are interconnected; for example places such as Tamworth where one mainline crosses another at a different level, places such as Willesden/Old Oak Common where completely separate lines actually run extremely close together and radio propagation effects mean that some places on a line might have better coverage from a cell for the other line, place such as Richmond where the terminal platforms of the London Overground/ District Line are operationally nothing to do with the through platforms on the line to Waterloo.
Even without such issues, the area of a railway within a GSM-R cell is unlikely to match precisely those signals which would be chosen to be replaced in an emergency.  Typically a Railway Emergency Call is given to all trains within not just the cell but also to all neighbouring cells in an attempt to stop trains from getting into the danger area- however this can mean that the effect is quite widespread.  Conversely a definite safety advantage is that all drivers become immediately aware even if between signals and also that the REC can be initiated by any driver from their cab; this can of course have some disadvantages; there was an instance not long ago of a telecoms technician attending to a fault on radio equipment in a tamper repeatedly bringing the operating railway to a stand whilst installing a replacement piece of equipment in its cab and being blissfully unaware of the chaos being created by their antics.



Part b)
Good answer, but it would have been worth bringing into the discussion the likelihood of signallers being faced with different arrangements within the disparate areas all gathered together within a large Rail Operating Centre- the signalling technology hat has been re-controlled to it and indeed the geography of the various lines within a large operating area could be very different.  There are still a lot of individual signalboxes left extant and certain signallers may be passed out for many which could be quite different from each other and which they actually operate very rarely (e.g. relief signallers, MOMs).  The RAIB have recently issued an accident report into the derailment at Knaresborough which relates to a signallers unfamiliarity which was the principal cause of the derailment, but also the driver not selecting correctly the REC in the immediate aftermath and therefore not achieving the level of mitigation that should have been possible; both elements are salient here.




Part c)
As I understand it, when using GSM-R, all emergency stop communication must be to all trains within a specific radio cell and those neighbouring cells which have been pre-defined in the design as associated with it.  This is both to get a good speed of response and to maximise the probability of driver reaching the message. 
Whereas the radio system certainly allows a normal call to be routed to a particular train, this does rely on accessing several central databases (to associate an entered train description with the train at a particular signal, to associate that train identity with the particular rolling stock and indeed the currently being used cab within that formation, to associate this cab with a particular SIM card in order to know what number to ring).  Clearly obtaining this information takes time and if any of the requested information is absent or invalid, then the call would not succeed; in addition there is unlikely to be enough capacity within the cell to simultaneously initiate separate calls to all the different trains which might be within it.  Hence the approach taken is the broadcast emergency call to anything within the area; it is not reliant upon the driver correctly having completed registration etc.
Whereas I thought your answer was broadly reasonable generically, I don’t think it fully reflected the specific of GSM-R functionality in the UK (one could argue that it didn’t need to and I am certainly also out of my comfort zone here.)



Overall though I felt this was n answer that would be a Credit.