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Post Watford- Points CT
#1
A few people had attempted the Control Tables for the panel layout given- the time on the panel was spent illustrating some things as samples and we never finished an entire point or route CT. I know that several needed to revisit their CTs from what they learnt; it'd be good to see the various revised offerings posted here for comparison.

I was asked to give details of the points CT that I used as a blank on the wipe board (note that some suggested "Simplified NR 11202" and "column" style are already in the mod3 section). Hence the attachment.

This is based on NR 11202 but with some slight differences.
There is often confusion created by this style with the points N to R and points R to N split vertically. I feel one reason for this is that the traditional column order lists tracks in the first column, then the calling routes, then the locking imposed by routes. Since the locking is in the OPPOSITE sense to the calling it is obvious that the route entries need to be diagonally transposed- what is calling in one direction must be locking from moving away from that position to the opposite. My belief is that putting the track locking separate to the other locking confuses the situation- thus I have changed the column order i.e.

col 1: those routes which, having first ensured the points are available (=correct or free to go), then places a call on them

col2: those tracks that ALWAYS lock the points (i.e. those immediately over the point end(s) and those that are foul of the points (lock the points in one direction and not the other- sometimes whether or not a track is foul is conditional on the lie of ANOTHER set of points)

col3: those signal routes which when approach locked must lock the points (since a train may be unable to stop prior to the signal that had been cleared but has now been replaced)

col4 etc: those tracks that are situated between the protecting signal and the points that must impose locking on the points once a train has been signalled and entered the route. Points beyond the exit signal must be released once the berth track has been occupied for the relevant time, but if there are track circuits beyond the signal prior to the points these must not be so bypassed and hence "outside the brackets"

Special Locking. I don't feel that it is worth putting Time of Operation loking and Swinging Overlap (aka counter conditional) locking on the blank. Hence the wide right-hand column for all this stuff as required. Indeed it would also be the place to show point-to-point (for example the GF and the trap points on the Watford example). For illustration the blank I show has drawn the entry for T of Op, but I'd only do so on a particular exam example if it were actually needed on that point; I have placed it halfway down the page as the obvious place to me for specifying locking that applies to points both ways (N to R and R to N) as it saves writing in a lot of identical stuff twice.


Attached Files
.doc   Blank Point Control Table.doc (Size: 33.5 KB / Downloads: 47)
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