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Points and route controls
#1
Hi All,
Please can you provide some feedback on the 2013 control tables attached.

Regards

TF


Attached Files
.pdf   2013_CT.pdf (Size: 570.96 KB / Downloads: 11)
.pdf   2013_PTS_CT.pdf (Size: 506.34 KB / Downloads: 5)
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#2
(28-08-2019, 02:42 PM)tfly86 Wrote: Hi All,
Please can you provide some feedback on the 2013 control tables attached.

Regards

TF
I think you need to look a bit at the points. The basic bits are right (deadlocking and the routes that require them in positions).

However, your understanding of the "locked after..  until.." part needs some work.
Thinking about your entry for the points being locked after route set 112B(M). You have given the release condition of DJ clear or DH OCC for time. Given that, at the time of setting 122B(M), DJ is likely to be clear, what does your entry achieve? Also DH is on the approach to 112 so having set 112B(M) the train is on DH as it approaches the signal and the points. That does not sound like a occupation condition that you would want to be able to release the points that the train is about to move onto!

One thing that you have not mentioned is that the overlap for routes up to 112 can go either way through the points. If this is to be provided as a swinging overlap then given its simple arrangement, there is not really anything to record on this table, but I think it would be worth adding a note that you have spotted this. Alternatively, if the overlap is to be set and locked whichever way it lies when the route up to it is set, that would be a matter for recording on this table. So it is not wrong that you have not included it, but the examiner would not know whether that is your omission or your knowledge that has led to that. Give them the opportunity to give you marks!

As for the signals:105A(M)
This has an alternative class of route from the same signal (105A(W)) and this needs to be proved normal - although it is in the same direction, this goes in the opposing locking section under Route Normal.
Points called and detected - it is normal to list each end of points detected (214 A and B; 215 A and B). Same for the other route table.
In the tracks for the aspect, you have listed those in the route correctly, but I am not sure why you have put CB OCC for 180s. This would give approach release which is a) not called for in the layout and b) in this case would be 3 minutes before the signal clears which is an incredibly long time for A/L so indicates to the examiner that you have not really understood about how A/L timings are derived!
A small detail on the aspect sequence - Y->R is good, G->Y is good, but not the whole story. You have omitted the G->G.
In the approach locking section, I think this form of table is records the number or name of the route in the "Signal Cleared / Route Set". It is not a binary option of one or the other. The next column is for the look back conditions if comprehensive approach locking is provided - just having the berth track in here is not sufficient. If you are not sure what this means, look for some information on Approach Locking Lookback.
For the approach locking release, I think you have the right idea but have not recorded it right in this column form. The condition is "first and second track occupied THEN first clear and second occupied". You have written the first condition across the two columns and then done the same with the second condition below. So if you look down the column for first condition yours reads "CD OCC CD CLR" which is clearly impossible and the second condition reads "CE OCC CE OCC" which is tautologous! Same comment applies for other route.

As noted above, several of the same points apply to the other route. Here are a couple of other specific points:
Not strictly necessary, but it is likely that 219 and 217 points would be called normal as flank protection.
It is not stated on the layout, but you have assumed that the call on requires DA OCC and DB CLR. Depending on the operational context, the call on may be for a light engine in which case both occupied my be valid. What you have put here is not wrong, but again, you could clarify the assumptions that you have made.
Also, you have put DA being occupied for 30s before the aspect clears yet you already have the requirement that a route that has taken a train in there has DA timed for 30s before the route locking releases.

Peter
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#3
Hi Peter, As always thanks for the reply. Just so I can clear a few things up, in regards to the PTS 212 controls.Having DJ clear, would that not prove that 1. train has not entered the route or 2. train has entered the route but has cleared the deadlocking track and points are free to move to allow the A route set. (I would not usually repeat deadlocking track in this section, probably just the fear of putting nothing in the box). I have put DH for time, as I believed this would prove that the train has occupied the TC section for a time that gives the assumption it has come to a stand and is not likely to enter the route. (am I thinking too much about route controls here)I should have included some reference to the overlap, this was a mistake. Given that there is a swinging overlap then the points locked section is void. But what I have stated for DJ clear and DH occ for time, would this not stand  for points locked in general. The release being train is now clear of danger point, or train no longer needs points in that position (new route set)For the Signals, so in signal cleared/route set column, this should be represented by the route identification? In other types of control forms there was a box where you needed to identify when cleared or when set, it thought this may just be an identical input to that. If this could be clarified that would be great, as it could be easy marks lost(or gained)Not sure why I put CB occ for 180s, probably a bit of confusion on my behalf while doing it, thinking I was in the approach release section maybe.Now that you have pointed it out, the CAL section seems obvious, just a little concerning the size of the column provided, as I remember these can be quite extensive for some signal look backs.And thanks for highlighting the locking release section mistake as well. Force of habit writing in that format, rather than looking at what the boxes actually say. Another few easy marks that could have been lost. Really appreciate the feedback, the next four weeks are ironing out these issues and a few mock exams that will be posted on completion also.CheersTF Wrote:
tfly86 Wrote:Hi All,
Please can you provide some feedback on the 2013 control tables attached.

Regards

TF
I think you need to look a bit at the points. The basic bits are right (deadlocking and the routes that require them in positions).

However, your understanding of the "locked after..  until.." part needs some work.
Thinking about your entry for the points being locked after route set 112B(M). You have given the release condition of DJ clear or DH OCC for time. Given that, at the time of setting 122B(M), DJ is likely to be clear, what does your entry achieve? Also DH is on the approach to 112 so having set 112B(M) the train is on DH as it approaches the signal and the points. That does not sound like a occupation condition that you would want to be able to release the points that the train is about to move onto!

One thing that you have not mentioned is that the overlap for routes up to 112 can go either way through the points. If this is to be provided as a swinging overlap then given its simple arrangement, there is not really anything to record on this table, but I think it would be worth adding a note that you have spotted this. Alternatively, if the overlap is to be set and locked whichever way it lies when the route up to it is set, that would be a matter for recording on this table. So it is not wrong that you have not included it, but the examiner would not know whether that is your omission or your knowledge that has led to that. Give them the opportunity to give you marks!

As for the signals:105A(M)
This has an alternative class of route from the same signal (105A(W)) and this needs to be proved normal - although it is in the same direction, this goes in the opposing locking section under Route Normal.
Points called and detected - it is normal to list each end of points detected (214 A and B; 215 A and B). Same for the other route table.
In the tracks for the aspect, you have listed those in the route correctly, but I am not sure why you have put CB OCC for 180s. This would give approach release which is a) not called for in the layout and b) in this case would be 3 minutes before the signal clears which is an incredibly long time for A/L so indicates to the examiner that you have not really understood about how A/L timings are derived!
A small detail on the aspect sequence - Y->R is good, G->Y is good, but not the whole story. You have omitted the G->G.
In the approach locking section, I think this form of table is records the number or name of the route in the "Signal Cleared / Route Set". It is not a binary option of one or the other. The next column is for the look back conditions if comprehensive approach locking is provided - just having the berth track in here is not sufficient. If you are not sure what this means, look for some information on Approach Locking Lookback.
For the approach locking release, I think you have the right idea but have not recorded it right in this column form. The condition is "first and second track occupied THEN first clear and second occupied". You have written the first condition across the two columns and then done the same with the second condition below. So if you look down the column for first condition yours reads "CD OCC CD CLR" which is clearly impossible and the second condition reads "CE OCC CE OCC" which is tautologous! Same comment applies for other route.

As noted above, several of the same points apply to the other route. Here are a couple of other specific points:
Not strictly necessary, but it is likely that 219 and 217 points would be called normal as flank protection.
It is not stated on the layout, but you have assumed that the call on requires DA OCC and DB CLR. Depending on the operational context, the call on may be for a light engine in which case both occupied my be valid. What you have put here is not wrong, but again, you could clarify the assumptions that you have made.
Also, you have put DA being occupied for 30s before the aspect clears yet you already have the requirement that a route that has taken a train in there has DA timed for 30s before the route locking releases.

Peter
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