(14-06-2010, 05:57 AM)greensky52 Wrote: As you mentioned above, I attach my attempt on Point 203 & 211, which were finished last week, before getting your explanation...so there were still some errors we juse discussed, please do not mind...
(14-06-2010, 10:47 PM)PJW Wrote: I'll look at in the next few days and then respond; I note that you did before recent comments.A little later than advertised.......
please find attached some annotations on your Control Tables.
They are certainly quite good, but note:
1. Be careful that you don't "slip" yourself when looking at single or double slips- I think that you got confused between 211 and 212 for one route.
2. Where the points are in the overlap, once the train has been proved stopped at the protecting signal then the points must be released again. For some reason you got this right for 203 but wrong for 211.
3. Be consistent when doing route locking; if your standards are to include the dead locking tracks within the limits of the route locking (as NR current practice), then include any foul tracks within the route locking also. However it is usual that any overlap route locking extends only up to (i.e. not including) the dead track.
4. You had 135A(S) calling 211 the wrong way.
5. You did get a little confused re the swinging overlap locking for 203, but at least you had an attempt. I think that you muddled this a bit with the "time of operation locking"; this also applies to facing points in a swinging overlap but is subtly different regarding its imposition and role (although I accept it looks somewhat similar and will actually be released simultaneously- after all it is the same train coming to a stand at the same signal on the same track).
In essence TofOp is about locking points that are only a short distance beyond a signal just in case the train SPADs at the time they are moving- the imposition of the lock is only as a train gets close[/]; if the points are more than 50m beyond then no such locking is needed.
Conversely the entry for "swinging overlap" is what I still prefer to call "counter-conditional" as this explains better what it is for; this is needed when there is an [i]"OR" condition involving these points in the aspect level of the reelvant signals having these points within their swinging overlaps [see attachment]. This is needed therefore as soon as the route is set and indeed applies to any facing point within overlap, irrespective of distance from protecting signal.
Basically for this locking you put in far too many points; you only put in those points that are to be included within the overlap you wish to swing towards which are not within the overlap that you already have.
Similarly for tracks, except that you also don't need to include those tracks which deadlock your hinge points anyway.
Well done for recognising that 107 and 142B(M) oppose, but note that the locking on the points is only from N to R (i.e. Normal is OK as the overlaps are parallel, Reverse wouldn't be as the overlaps would conflict). Also the two entries are related; there are different ways of depicting, but a good way is basically as you have shown BUT not as two completely separate lines of entry but link them in an OR condition; the points can be swung Reverse if one overlap or the other overlap is in use, but not if both are.
I have added another sheet of my own that attempts to explain the sort of entries needed and what the locking is attempting to achieve- which I think you haven't grasped.
Overall though, pretty reasonable attempts!
PJW