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Hi Guys,

I have had ago at 2012 Q11 from Module 3. I would appreciate if anyone could look into my attempt and come with comments. I have some doubts for signal 105 reading at 207 signal using flashing yellow.
Many thanks in advance.
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At first sight it looks a good presentation, drawn either site of the IRSE's layout and from that perspective worked out quite nicely. However:

1. What were you doing with 107 and 207?
Without red aspects, there really is no value of having those signals on the layout. Also read Q11 text- it distinctly says that the signals on the layout all have stop aspects. Therefore you haven't answered the question that was set.

2. You have not declared your practices (I guess modern UK mainline), nor listed any assumptions relating to braking distances, sighting distances or overlaps (you will note that diagram had dimensioned distances from certain signals to the CPs, but you made no reference).

3. You did not "list all the aspects, combination of aspects, indicators and their meaning to the train driver".

Hence you have actually thrown a large number of the marks away. This is a real shame because it does look as if you could have otherwise done an aspect sequence question quite well.

I certainly have my doubts whether one would sensibly provide a flashing aspect sequence from 105 for the divergence at 209 back onto the line that the train had originally come from.
I am not sure the meaning of your depiction of the junction of the aspect sequence lines between 205 and 207 to tell whether105 would be showing G+pos1 up to the FY as well as the YY/G. Actually of course since you have drawn 105 & 205 as 4 aspect signals they would need to show FYY when 207 displaying FY.

However I don't know why you have made them 4 aspects, albeit without a red. You depict 107@YY for 109@Y and 111@R, yet there is full braking from 109 to 111 so 107 should be G- although you have given it a green aspect your sequence diagram never utilises it.

Conversely you have 205@G for 207@YY and 209@R; this must be wrong as the signal prior to a Red should always be Yellow and since the signal spacing is less than 450m then there would need either to be a YY on the previous signal to give an earlier caution signal, or signal 207 would need to be approach released when 209 at Red but in that case you'd also have to deal with the problem that the distance 205 to 207 is only 300m which again is less than braking.

Therefore even if I go with your layout as drawn having 107/207 without red aspects, the aspect sequence drawn in this area of the layout still does not make sense.

If we now look at the separate area of under-braking between 101 and 103, I see that you have made 101 always approach released. This is unnecessarily restrictive; what you should have done was implement "modified 3 aspect sequence" and made 101's Yellow approach released but permit 101 to show Green whenever 103 at a proceed aspect.

So overall I am afraid that you would not have done well on this question. You would get some credit for demonstrating what you know about flashing aspects and the Warning class route, but should have shown the MAR better.
Also at least you recognised that there were some under-braked signal sections (that some people would not),yet you really did not demonstrate that you knew how to deal with the problems and ended up having made some silly errors.
Above all you weren't answering all the question that was set.
I reckon that you might have got 7 or 8 marks out of 25.


(30-08-2013, 09:06 AM)adobe Wrote: [ -> ]Hi Guys,

I have had ago at 2012 Q11 from Module 3. I would appreciate if anyone could look into my attempt and come with comments. I have some doubts for signal 105 reading at 207 signal using flashing yellow.
Many thanks in advance.
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Peter,

Thank you very much for your precious comments.

Kind Regards,
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Dear Professional railway engineers

Another go for my attempt. Could you please kindly review?

Thanks,
Arnut