2010 Q9 Degraded working at mechanical signalbox

[Hort]

Hi,

I have attempted Q9 of 2010 paper. I have attached the layout as well.

[Jerry1237]

Hello,

Your answer seems to address a couple of methods of degraded working. However, there are a few things I'd like to add.
1) It is mentioned to add an FPL to 22. Simplistically, the need to degraded working is often short notice (as in this case) and fitting of additional kits is prohibitive due to time/cost/effort. However, in this situation, note the comment under the 'box stating all points are motor driven. Therefore, it is a reasonable assumption there is an internal FPL!
2) Often the simplest methods are overlooked. There is no mention in the answer about ticket working, pilot working, clipping and scotching point ends, cancelling or re-routing trains etc.

Also, method 1, risk 4 is no different to normal operation and therefore, I would suggest, irrelevant to this answer.

Arguably, for me, the risks are (not a full list):
* crossing trains
* delaying the service (assumption on the level of service and having to wait to ensure trains have stopped due to the increase in potentially conflicting/head-on movements)
* speed of trains approaching 27 signal
* speed of trains approaching 6 signal (i.e. unexpected, not-normal routes and aspects)
* potential train crew confusion
* potentially having no overlap on 18 signal for passenger moves
* increased workload for signaller (possible fatigue dependant upon when in shift it occurs and at what time of day
* abnormal working adding to increased workload for signaller
* potential conflicts for access of platform (passenger trains from both directions passing).
* etc.

Fundementally, the site is fully signalled/interlocked and the risks appear to be more about human error than weakness is signalling. It being module 1 (safety), a technical answer isn't really necessary. Have a think and reply to this thread with brief skeleton suggestions of alternative answers that could be provided.

However, some of the above are alluded to in the answer and I feel your answer has the basis for being great. The trick of the IRSE Exam (don't tell everyone) is to read the question, understand the question, confirm your understanding is in the context of the paper (i.e. safety = safety) and re-read the question to double check what you think the examiner is after actually matches how you intend to answer the question.

Look forward to your comments.

Jerry

[PJW]

The point machine may have an internal FPL but that certainly is an assumption that would need to be stated by the candidate.

In this sort of layout I would not be in the slightest surprised that there would NOT be; a guess would be that when initially converted to motor operation that there would have been no FPL (signal engineers in say the 1960s were - to our eyes- very parsimonious and keen to keep to the minimum the "initial first cost" even at the expense of greater "whole life cost". We should not criticise them for this since the world was different then- labour was relatively cheaper compared to equipment than nowadays; also the poor man actually often does not have the wherewithall to invest to save money long term, even if they know that theoretically they should be so doing. Actually many such places may well since have acquired FPLs by default, as should there have been a need to replace the point machine, nowadays we have standardised only on machines with internal FPL).

Slightly out of context, but be aware that London Underground is as part of the current upgrade to Circle / District / Hammersmith & City / Metropolitan lines is needing to upgrade some 30 machines to allow reversible use of the infrastructure (albeit I think that it is more of a question of fitting additional Ground Locks than FPLs, but conceptually it is the same issue).

This demonstrates that it is important to realise that some signalling standards are in reality perpetuated somewhere for at least a generation after they have officially been superseded for new work. One of the things that one only learns from experience.

Therefore I think that the identification in the answer that the points may well not have an FPL was entirely valid, although I agree with Jerry that in the scenario given the solution would have been "scotch the open switch, clip the closed switch and padlock"

Hello,

Your answer seems to address a couple of methods of degraded working. However, there are a few things I'd like to add.
1) It is mentioned to add an FPL to 22. Simplistically, the need to degraded working is often short notice (as in this case) and fitting of additional kits is prohibitive due to time/cost/effort. However, in this situation, note the comment under the 'box stating all points are motor driven. Therefore, it is a reasonable assumption there is an internal FPL!

[Hort]

Thanks for your comments

to be honest, I overlooked the fact that all points are motor worked and saw a mechanical layout and automatically thought FPL.

Jerry
I can't see the benefit of pilot working etc if a signalled route was available; you would incurr delays in waiting for the pilotman to arrive and also delays in the signaller having to communicate with the pilotman. Also this method of working is also inherently riskier than signalled moves. However, I accept that to describe one degraded method involving signalled moves and another with pilotworking would display a greater depth of knowledge to the examiner rather than two fairly similar method of working.

Re the risks, you are right that there are marks to be gained for mentioning 'unseen' risks such as fatigue, unusual working pattern etc which I missed.

With risk No. 4 the point I was trying to make was that train might regularly be coming in and out of the siding with the Up Loop unoccupied, degraded working mens a greater chance of the Up Loop being occupied with a train being signalled out of the siding in error.

[Jerry1237]

Hort,

My point is that everything regarding the answer is an assumption and that it is entirely possibly the errant freight train has disabled some of the interlocking or its functionality; that there are sometimes simpler ways of achieving an end than a technical solution and that risk is not what kills people - it is the poor management or lack of attention to mitigation of risk that does.

M1 is about safety and the exam is about the student showing the examiner they understand the problems, issues and hazards. More marks are gained for depth of knowledge and preciseness. There is no time in the exam to discuss detailled risk analysis but stating pilot working is possible but would have an impact to the timetable plus adds additional (not necessarily worse) risks would show depth of knowledge.

I would argue about pilot working being "inherently riskier" than signalled working. However, I would be curious to hear your arguement to validate the point. If you do, I'll add my rebuttal and it would be a useful discussion for the forum I feel.

Jerry

[PJW]

A few comment from me on your answer:

Not sure your initial sentence did much other than repeat the question.

Method 1.

Sensible and well described; displaying knowledge of mechanical signalling, but some observation:

a. 7 is not a switch diamond but a single slip; however apart from nomenclature, the item is valid.

b. Given that there is an advanced starter,26, then it would seem more sensible to let the Up train proceed to wait there, since this would also mean that it could proceed as soon as the line is clear, rather than being delayed by the crossing move. You could have displayed a little more knowledge by assuming that there are some long trains for which there would be insufficient standage for that and thus needed to be held at 27.

c. The issue re FPL provision had been discussed earlier in this thread. Fitting a FPL is not a five minute exercise and is not something that is going to be practicable whilst the incident is disrupting the railway; you could mention it as something to consider at such sites, in case there is a

[Hort]

Thanks for the comments.
Please note that when answering this question i did not mean to suggest that infrastructure changes would be made at the time of the incident. If my answer implies this them that is obviously my failing.

Re safety of pilot working v signalled moves; my argument would be that the 'human' element involved in pilot working ie communication between signalles an pilot man increases the risk.

[Jerry1237]

Hort,

Something to think about. The human element is involved in signalled, degraded signalled and pilot moves including communication. Personally, I'd suggest whilst the highest risk is communication based as you suggested, it is the abnormal method of working, i.e. human factors, that is the true hazard. Specifically, the communication between pilot and signaller is mitigated by the pilot acting as a token/annetts key and trains cannot move without them! Three competent people (signaller, pilot, driver) ensuring safe movement of trains rather than just two in degraded signalling. Whereas the degraded mode, i.e. use of non-normal routes, especially in complex P&C, has the potential to cause greater confusion.

There is an increased SPAD risk especially for trains not expected to stop there normally BUT there are mitigation methods for that as well. An example is stopping the trains at the previous block and reminding them they will stop at the next box.

Pilot working slows traffic down (dependant upon levels) and has the disadvantage of one pilot who would need to travel if two trains needs to go in the same direction sequentially without an opposite direction move.

Therefore, there is a suggestion that pilot operation is not more risky but is operationally less than desirable. Remember, risk is a combination of hazard assessed against frequency and severity. Risk can always be mitigated but is the mitigation itself tolerable (complexity, cost, effort) versus the decrease of the risk (read Wikipedia: ALARP), i.e. cost:benefit ration.

Well done though.

Jerry

[PJW]

Just a minor point.
Unless the rules have changed in recent years, I believe I am correct when I say that the pilotman does not necessarily need to travel on all trains. Therefore if it is known initially that two or more trains need to travel in the same direction, the pilotman having shown himself to and instructed a driver can dispatch the train into the section and then follow on the last train of the "flight".
Like "train staff and ticket" working.

Anyone sufficiently keen to check up what the current Rulebook actually says?

Hort,

Pilot working slows traffic down (dependant upon levels) and has the disadvantage of one pilot who would need to travel if two trains needs to go in the same direction sequentially without an opposite direction move.

Jerry

[Peter]

Just a minor point.
Unless the rules have changed in recent years, I believe I am correct when I say that the pilotman does not necessarily need to travel on all trains. Therefore if it is known initially that two or more trains need to travel in the same direction, the pilotman having shown himself to and instructed a driver can dispatch the train into the section and then follow on the last train of the "flight".
Like "train staff and ticket" working.

Anyone sufficiently keen to check up what the current Rulebook actually says?

Yes and no. The relevant module is P1 and section 7.1 says what you describe

7.1 Travelling with the driver Unless there is another train to follow, you must ride with the driver in the leading cab.
If there is more than one locomotive, you must ride with the driver of the leading locomotive.

but section 6.2, Additional instructions for wrong-direction movements, says

[quote]b) Accompanying the train
If there is no handsignaller to control movements back to the proper line, you must accompany the train and instruct the driver to stop the train: