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+----- Thread: 1994 Question 2 (/showthread.php?tid=1951)
1994 Question 2 - MikeMurphy - 16-08-2015
Hi,
This is my first attempt at answering an IRSE question and I have attempted to answer a question on 'the principal purpose of a signalling system' and I'm just looking to get some advice guidance on;
Have I understood the question correctly
If so is the content enough to justify the marks for it
How could I improve my answer
Thanks
Mike
RE: 1994 Question 2 - PJW - 17-08-2015
[*]MikeMurphy
[quote pid='5878' dateline='1439753918']
Hi,
This is my first attempt at answering an IRSE question and I have attempted to answer a question on 'the principal purpose of a signalling system' and I'm just looking to get some advice guidance on;
Have I understood the question correctly
If so is the content enough to justify the marks for it
How could I improve my answer
Thanks
Mike
[/quote]
[*]
Mike,
You don't say (and I haven't investigated) the module in which asked but I assume mod3 given the section in which posted. The wording does sound a bit mod 7ish though and I would certainly answer it in terms of "functional requirements" but aligning to Signalling Principles. Hence I would say the 10 principal purposes would be:
1. Centralise control so the various points can rapidly be set to the required position for a movement and the driver then given the movement authority (conveying all necessary information about the movement to be made) so that the train may proceed without any undue delay.
2. Prevent conflicting movements from taking place simultaneously so as to provide safety at junctions and avoid the possibility of head on collisions occurring; a special case of this can be protection of engineering possessions of the line.
3. Ensure that all relevant (including "line of route", "flank", "trapping", "overlap") infrastructure (points, Ground Frames, many level crossings, bridges, Patrolman Lock Outs etc.) is proved in the correct position and locked prior to authorising the train to proceed.
4. Provide adequate warning of train approach (other level crossings, trackside annunciation systems) such that people can clear the track sufficiently prior to the arrival of the train.
5. Ensure adequate separation between trains such that the following one gets adequate warning to brake to a stand in the event of the first train stopping.
6. Provide adequate information to the driver so that they may control (or preferably the signalling system itself enforce) train speed such that infrastructure speed restrictions (including junction turnouts, permanent and temporary speed restrictions, approach to buffer stops etc,) are respected.
7. Provide facilities to warn the driver of an emergency so that they may stop the train
8. Provide a "degraded mode" means of running trains in the event of a failure within the signalling system (e.g. noticeboards, rules, verbal communications with signaller, axle counter reset-restore, POSA).
9. Permit the efficient use of the railway infrastructure (maximum number of trains using it to full speed potential, ) by effective train regulation etc.
10. Provide train running information to a plethora of other systems associated with the running of the railway and interface to the public.
Your answer gave some of these, but not all were expressed clearly (very few actually stated a "purpose")
There were some definite "red herrings"- for example "maintainable and reliable" system is certainly important but it isn't a functional requirement of a signalling system (i.e. what is there FOR) but is a non-functional requirement (i.e. in this case HOW well it has to perform those functions).
Your answer was rather too short; my answer above is far too short and each heading needs a range of sub-bullets to give more examples and explanation but should give a suitable skeleton structure on which to build. What I have tried to do is ensure that the 10 items cover the full range and consider emergency / degraded/ abnormal modes of railway operations as well as normal use.
If I get a chance I'll review your answer in more detail later on this week
RE: 1994 Question 2 - MikeMurphy - 17-08-2015
Hi Peter,
Yes the question is for module 3. I have taken it from the IRSE study guide July 2015 (Module 3 Study Guide 1 [Attached]).
Thanks for your quick reply and after reading the chapter and comparing the two answers, I can see where I'm having trouble in answering questions.
Chapter 2 in the study guide can be quoted as:
"The following fundamental requirements support the overall purpose of a signalling system. They are an amplified set of the requirements set out in the IRSE's Signalling Philosophy Review."
I can clearly see I missed the use of "purpose" in answering some of the 10 topics. I am struggling (although I understand the importance) the link between some of your points to the content the IRSE have provided in the study chapter and why they have not included these points.
For Example
"point 10 - Provide train running information to a plethora of other systems associated with the running of the railway and interface to the public", they have included no reference to providing interface to the public.
Thanks for you help
Mike
RE: 1994 Question 2 - PJW - 18-08-2015
(17-08-2015, 04:40 PM)MikeMurphy Wrote: Hi Peter,
Yes the question is for module 3. I have taken it from the IRSE study guide July 2015 (Module 3 Study Guide 1 [Attached]).
Thanks for your quick reply and after reading the chapter and comparing the two answers, I can see where I'm having trouble in answering questions.
Chapter 2 in the study guide can be quoted as:
"The following fundamental requirements support the overall purpose of a signalling system. They are an amplified set of the requirements set out in the IRSE's Signalling Philosophy Review."
I can clearly see I missed the use of "purpose" in answering some of the 10 topics. I am struggling (although I understand the importance) the link between some of your points to the content the IRSE have provided in the study chapter and why they have not included these points.
For Example
"point 10 - Provide train running information to a plethora of other systems associated with the running of the railway and interface to the public", they have included no reference to providing interface to the public.
Thanks for you help
Mike
Firstly I must admit that I did not consult the Study Guide and had even forgotten that it had such a section.
Secondly there is no one right answer to an IRSE question.
Thirdly my comments are just my opinion of how I might have answered it; like everyone else I may not always be completely right. Given the constraint of finding just 10 items and on the basis that I feel it is best in the exam to err to covering as wide an area as the question will permit, then I prioritised this item rather than put in something else which I felt partially overlapped another; for example I'd have preferred to have split item 3 into its various constituent elements but I had to lump in level crossing and protection lockouts with locking the points in route. I had to ration myself and felt that it was important to have item 1 as CENTRALISATION and then item 2 ROUTE LEVEL so I really had to make item 3 ASPECT LEVEL and whereas I might have wanted to continue with ASPECT SEQUENCE and then APPROACH LOCKING, I was obviously going to exceed the 10 items if I wanted to include some of the other "wider interpretation" things, so attempted to work these in implicitly within another item so as to economise; I would have placed Approach locking as something which contributes to item 2 and Aspect Sequence as something which contributes to item 5).
Another person (or even me on a different day) might select a slightly different set when arriving at what they considered the best compromise in the circumstances; the wording of the question to me suggested a mod 7 element that made me particularly keen that my answer reflected abnormal / degraded / emergency modes of operation as well as normal operational scenario and if I had instead relegated these to be non principal then clearly there would have been more ability to separate some of those which I had combined together.
Fourthly the Study Pack wording I think dates from more than a decade ago, and things evolve.
- Although NR has yet to change in a meaningful way towards ETCS it is definitely far closer than it was and London Underground already has a significant percentage of transmission based signalling in operation now.
- NR is very keen (well it was until recently when the money ran out) to make rapid progress towards having Traffic Management Systems based in just about a dozen Route Operation Centres for the entire network and should link the train position on the layout with the rolling stock information and the train crew diagrams. In the immediate future there are things like Driver Advisory System (some isolated ones already in use and an essential part of the Thameslink programme for 2018) to help drivers to regulate speed prior to getting to congested areas to make best use of capacity and save fuel costs and excessive braking,
- Also you can probably get more accurate train running information from your Smartphone now than is displayed on the station indication screens; this would have been unthinkable a decade ago when even Cab Secure Radio was pretty novel.
- NR now has a national wide fibre optic network (indeed is just upgrading from FTN to FTNx) and GSM-R radio virtually everywhere, so what we now mean by "signalling" has changed quite a bit
Fifthly, an answer will depend on the specific railway's context. For example there are metros where the signalling display has the facility to indicate the approximate passenger loading of every car in a consist based on weight of the vehicle so that the regulator can tell which trains are very crowded {and indeed that the front of one is very crowded but the rear relatively empty and therefore appropriate advice can be given prior to arrival at subsequent stations to help balance the loading}. Similarly integration with the traction power system can be important to prevent this being overloaded in circumstances following a delay on the line which resulted in a temporary hold of trains in stations, so that the resumption of running is slightly staggered (preventing the attempted simultaneous acceleration from rest of all trains when the reason for that hold is removed). At the other end of the spectrum perhaps a principal role of the signalling on various heritage tourist lines could be non-functional; very rudimentary signalling could satisfy the safety requirement yet far more complex signalling is provided really to add to the interest and historic atmosphere to "enhance the visitor experience"; the vast majority of the other purposes which I have listed would not be in the slightest relevant to that environment.
Therefore don't worry about being able to trace every bit of my outline to that in the Study Guide, because there will not actually be a link in all cases. Having just scanned the extract you provided, I do think overall there is a good level of correspondence between my answer and those items listed even if we express a bit differently or have altered emphasis. Clearly there is more detail in the guide and the wording more honed than me just dashing off a set of essentially 1 or 2 sentence paragraphs late at night.
Conversely I wrote based on 2015 and deliberately making as wide as I felt the interpretation of the question could reasonably stretch; certainly if answering in the exam you would want to add some flesh onto the bones of the framework I sketched out and I believe that you ought to find that you could work in practically anything within that section of the Study Pack under one of my headings, but I do agree that there may be some of my headings for which there is little content within that Study Pack section. It would probably be educational for you to do that exercise and then find other sources to be able put some meat on the remaining bits of the skeleton.
Do not fall into the trap of thinking the exam is set on the basis of the Study Pack; it is set on the basis of the syllabus and indeed this was updated at the end of last year, again reflecting the gradual evolution of the industry.
For similar reasons the most relevant Past Papers for students are, at least in most modules, those set in the last 3 years, then slightly less relevant those set up to say 6 years ago and then those which are older. Papers set more than a decade ago may well still have some relevant questions within them, but overall are becoming increasingly dated. It is appreciated that similar has happened to the Study Packs (for example mod1 refers to the UK's CDM Regulations but the terminology is that of the older (2003?) law which was superseded in 2007 and has now been changed again in 2015) and it is hoped they will be refreshed for 2016. However even if they are, remember they are GUIDES to form an introduction to the areas of studying, not exam SET BOOKS.
Hope this puts your mind at rest; there is nothing to struggle about.
PJW
RE: 1994 Question 2 - MikeMurphy - 19-08-2015
Hi Peter,
Thank you for your detailed response and appreciate the time you put into to it.
It gives a clear view of how to approach the question and with your response how it answers the question but also how another answer could be valid also.
I know it's from over a decade ago but I feel its a good question for any to be aware of what the signalling system fully takes into consideration and now makes you aware of other questions moving forward.
Thanks for your responses
Mike