Point CT for Point no 139 Module 3 - 2011 layout

[Murugesan india]

Dear Members,

I have solved and attached the point control table for Module 3- 2011 layout and also i have attached the module 3 layout.

UK mainline practice is followed,
for swinging controls i have added two boxes extra in the notes column, Kindly have a look and give your valuable comments, Kindly correct me if I’m wrong.


Regards,

Murugesan

[reuben]

Dear Murugesan

Thanks for your posting - here are some comments.

Track circuit dead locking - good, both foul track circuits identified.

Calling and locking by routes (except swinging overlap conditions)

Good. One omission is that the points also need to be called and locked reverse by routes 214A(M) & B(S) for flank protection. this is easy to miss, but you did identify this for 347A(M) & ©.

Swinging Overlap conditions

The additional track circuit clear + points set or free conditions have been correctly specificied

What you've missed (and it's very unpleasant to even think about, let alone write down..!) is the fact that track circuit FZ is also an area where there can be a directly opposing swinging overlap used by routes up to 347 or 349 signals. To express this, you would an extra control to 139 N to R controls as follows:

Requires
All routes up to 212 and SRL normal OR
[(all routes up to 347 and SRL normal Or 132 R (S or F) or (134N,133N S or F) AND
(all routes up to 349 and SRL Normal or 133N (SorF) or 135R (SorF)) ]

where SRL = Sectional Route Locking
SorF = set or free

This set of extra conditions prove that there is either no opposing overlap set up to FZ, or that it is free to swing to another non-conflicting lie.

It should be noted that this horrendous piece of login doesn't have a set of contro, table columns to write it in, but you can create it either by joining enties together with brackets, dashes & OR statements, or writing it out separately on a continuation page


Overall, a good attempt; the points I have corrected are unlikely to lose many marks

Reuben

[Murugesan india]

Hi Reuben,

Thankyou verymuch for your valuable comments, i will update it, i have one question about the point control table format which will be provided by IRSE,
for swinging overlap conditions and Time of opeation locking there is no separate column in that format, if people are following UK mainline line practice then this question comes, for these two functions (ie Swinging overlap conditions & Time of operation locking),
can we add the extra boxes in the notes column or how we can proceed, could you please clarify regarding this issue.

Regards,

Murugesan

[Peter]

You are free to add whatever extra columns or lines you wish to the sheet issued. You are also free to draw up your own in the exam or bring your own version of a template to use (they will be checked by the invigilator to confirm there is no illicit help information on them).

Peter

[PJW]

Sorry for the lengthy time it has taken me to respond; life has been very busy!

I think your additions to the format for the swinging overlap are good.
However as Reuben remarked you overlooked that the overlap over 139R may in fact not be available; for example there is a chance that there is simultaneously a route in progress from 327B(M) which has overlap beyond 349 over 133R and thus conflicting for the length of FZ. You could show this on your Control Table by the use of brackets to link the expression logically together as one combined statement that ANDs the need for the controls you have stated with
the absence of route locking after {327B(M): [GE, FK, FZ (CF, DA, FG - - - or FG - - - -occ for 30)] - - - or - - - 133N}, showing this in the relevant columns underneath your existing entry.

As you say Time of Op would be needed if 139 close to the BP/BS joint; in this layout it might be reasonable to make the assumption that there is sufficient length (>50m) that it is just not needed. however to show it I think it is a good idea to create a specific row between the N to R and R to N ones to make it clear that it applies BOTH WAYS and your headings should emphasise that the locking is not imposed by the route locking but only by the occupation of the berth track in the presence of that route locking, and that occupation for time (say 30sec) releases it.

You are free to add whatever extra columns or lines you wish to the sheet issued. You are also free to draw up your own in the exam or bring your own version of a template to use (they will be checked by the invigilator to confirm there is no illicit help information on them).

Peter