2008 Aspect Sequence Chart

[sugavanam nagarajan]

I have attempted aspect sequence chart for 2008 layout, expecting your valuable reply.

-Sugavanam

[Peter]

I have attempted aspect sequence chart for 2008 layout, expecting your valuable reply.

-Sugavanam

I think that you have done well on this. There are a couple of general comments and a few specific items below, but there is nothing particularly substatial.

1. I was not quite sure from the question what they actually wanted. It says "[...] down direction including to and from East Junction in the down direction". Given the nature of the triangle, at what point are they considering "downness" starts. For instance, you included 161 as it is fairly clearly in the down direction in respect to the main line, but what about 149 on the North curve. If that reads up to a down signal, should that be included. Then the slippery slope starts, does that mean that we should include 124. Although it is on the Up East Branch, the B route reads away from East Junction towards down direction signals.
I'm not saying what you did was wrong, but perhaps a note explaining what you have taken the question to mean might help them give you the benefit of the doubt in the case where they think you have missed something they wanted where you have taken a deliberate decision that it is not in the scope of the question.

2. You took good care to make it clear the direction of travel when lines converge (eg where 157 and 161 read up to 165). However, where you have chosen to show 131, the angles you put on the lines implies that 131 reads up to 135 and not 123. The junctions are in the right place, just the angles pointing the wrong way.

3. Very well done for reading the route boxes on 152. The symbol only shows a pos 4 JI on the signal (for the B route) but the route box shows that the A route has a pos 1 JI which you showed on the chart. The paper clearly has an error on it. I personally think the error is in the route box as wherever they have shown JIs, they have taken care to show the type of junction control and in this case, it is omitted.

4. Another area where you have followed what the route box says is for 109B. They clearly say that this will show YY. However, given that the junction is 50km/h, as is the line beyond giving full BD from 109 to 135 and there is full BD 135 to 123, showing YY on 109 when 123 is Red gives you 1310m braking where, for 50km/h, the table notes 445m is needed, well over 150%!

5. For the divergance on 109, you have shown Y+J4 twice. I think what you are trying to convey is that whatever is ahead, you will get Y+J4 and then when #1 is satisfied, it will show what it can, depending on the aspects ahead, including staying on Y+J4 if 135 is red. You normally only ever show each aspect once (the notable exception which you had just above is with a warner class route). So omitting your top Y+J4 and moving the #1 down to the line between the Y+J4 and YY+J4 would give you the right conditions without repeating the aspect and the extra lines to 135's Y and G.
One other point on that one, you showed the conditional parts for non flashing and the warner route with dotted lines (the way I was taught to show it), but you used solid lines for the conditions for stepping up the Y+J4 to anything else. I would have used dotted there too. For the Y on 107 to the onward junction sequence, you put the #1 below the junction of the first horizontal branch. I would try to keep the note of the condition near the point at which it leaves the "main" line - on this case the line between 107Y and 109R, just so that it is clear that the whole dotted branch is dependent on that condition.

6. Your layout is quite clear and (depending on how quickly you were doing this) quite neat. One tip I was given was to get in the habit of putting a box round each signal to make it clear what the aspects belong to. The case here is 109 where there are three distinct parts with some separating lines between. In this case, there is little to get confused with but sometimes, a box can help make it clear what goes with what.

I hope that helps and well done on what I think is a pretty good shot at it. If you have any queries, please feel free to ask.

Peter

[sugavanam nagarajan]

Thank you for your comments.

Please clarify,
1.Signal having POL, Reduced overlap to be noted near R with # notes?
2.Before MAY occurs in the case of 109, condition of 135 need not to be shown in aspect sequence?

-Sugavanam

[Peter]

Thank you for your comments.

Please clarify,
1.Signal having POL, Reduced overlap to be noted near R with # notes?
2.Before MAY occurs in the case of 109, condition of 135 need not to be shown in aspect sequence?

-Sugavanam

1. Are you confusing POL with ROL. POL stands for Phantom Overlap (see the notes on the plan) and in this case is of the correct length to be the full overlap. POLs are not often used and are where the point of the end of the OL does not coincide with a convenient track joint. Since it represents a full OL here, I do not think there would be any mention on the aspect sequence chart.

2. I think what you are asking can be explained as follows: Think of the approach to the signal first and then the onward route. The FY up to the signal is simple as it goes to Y+J4. After the release condition, the signal can show Y+J4 to R; YY+J4 to Y and G+J4 to G. You do not need to show the Y+J4 as two entries.

[sugavanam nagarajan]

Thank you for the information.
-Sugavanam

[dorothy.pipet]

Another attempt for comments please
(untimed and open book)

Dorothy

[PJW]

A good attempt in general, but some comments:

1. Biggest error was the omission of the flashing aspect sequence; the symbol for the flashing yellow is on 107 and 109B route box shows MAY-FA. However it does seem odd that they have not shown more signals on the approach! Also to current standards (post Colwich) it seems improbable that one would permit a flashing sequence up to 135 at red (but actually, since the overlap extends sufficiently to lock out conflicts, then a SPAD at 135 would at least be safe). I suppose that giving a train a flashing aspect up to a red does ensure that the Main lines are cleared quicker, but I doubt whether would provide it in reality unless the train was to run non stop around the curve.

2. It is ambiguous how the lines which are broken at the break marked A-A are supposed to join up- "top to top" or "wrapped around the curve".
You have followed the route box for 109, but would have been worth a note, since the single yellow at 135 would be enough braking to stop at 123 so strictly could have given a green.

3. Hadn't specified a value for t4- it would be low or even zero depending on whether there is risk of seeing the main aspect before PLJI readable.

4. Do suggest that using dashed lines for approach release and greater clarity where aspect sequence lines join where there are both 3 and 4 aspect sequences converging does make the chart far clearer.

5. You did not interpret which signals to include / exclude the same as I did. I don't think the wording is entirely clear, but I think if you re-read question paper then you will see that your answer doesn't completely match. Feel you also applied #1 to wrong portion.

Another attempt for comments please
(untimed and open book)

Dorothy

[asrisaku]

Dear Railway Signal Engineers

I have just done the aspect sequence year 2008. I studied dorothy's attempt and I found out some need more clarification.

161
it should have shown Y+JI1 and G+JI1

Transition from 3 to 4 aspect
Route 161-165, 149-157, 143-157 might be wrong. I am not sure. Please help clarify.

Also I don't understand that why sugavanam did not show the signal 149.

Any comments on my attempt? Please help.

[PJW]

Sorry, in the host of things to do I find that I overlooked this one. I'll get onto it when I get a chance but in the meantime here are my comments in the attachment on another one received recently.

Be aware that it isn't possible for me to spend enough time to check in all regards all attempts and so some things may pass me by when looking at an effort. Other times it may be that I actually only choose to point out the more important errors and adjust level according to the overall quality of that which received- the better it is, the more detailed the check and pickiness of comments.

I feel that it is more important for me to point areas that indicate a systematic lack of understanding or suggest a way of improving presentation generically than to detect every lack of perfection for a specific layout. The aim is to help students in the exam which is to come and therefore concentrating on the broad themes is more relevant than comparing with a particular model answer- obviously if there are a number of "oversight" issues arising then this may be indicative of why someone might lose marks in exam and so show "a leak that should be be plugged", but from an education perspective these are of less importance for this Forum than those items that betray a lack of understanding. The former are "random faults" whereas the latter are "systematic" and if not corrected the individual will do reliably exactly the same wrong thing in the the exam.

Dear Railway Signal Engineers

I have just done the aspect sequence year 2008. I studied dorothy's attempt and I found out some need more clarification.

161
it should have shown Y+JI1 and G+JI1

Transition from 3 to 4 aspect
Route 161-165, 149-157, 143-157 might be wrong. I am not sure. Please help clarify.

Also I don't understand that why sugavanam did not show the signal 149.

Any comments on my attempt? Please help.

[asrisaku]

Sorry, in the host of things to do I find that I overlooked this one. I'll get onto it when I get a chance but in the meantime here are my comments in the attachment on another one received recently.

Apologies for my uploaded attempts. I just would like to make sure that I practice the variety of aspect sequence enough for my exam preparation. Unfortunately the exam center is not established in my country and I don't want to waste my own money with fly cost and a lot of accommodation outside. Trying the best with a fail result is acceptable for me. And if you do not have time reviewing my all attempts, I understand that. Just pick some that look interesting.

Be aware that it isn't possible for me to spend enough time to check in all regards all attempts and so some things may pass me by when looking at an effort. Other times it may be that I actually only choose to point out the more important errors and adjust level according to the overall quality of that which received- the better it is, the more detailed the check and pickiness of comments.

I understand that. Yes I agree with that. My point is that it might be good for other people to see some awareness.

I feel that it is more important for me to point areas that indicate a systematic lack of understanding or suggest a way of improving presentation generically than to detect every lack of perfection for a specific layout. The aim is to help students in the exam which is to come and therefore concentrating on the broad themes is more relevant than comparing with a particular model answer- obviously if there are a number of "oversight" issues arising then this may be indicative of why someone might lose marks in exam and so show "a leak that should be be plugged", but from an education perspective these are of less importance for this Forum than those items that betray a lack of understanding. The former are "random faults" whereas the latter are "systematic" and if not corrected the individual will do reliably exactly the same wrong thing in the the exam.

THANKS for your gigantic contribution. and sorry for chaos.