235 Points
The thing about these points is that they give passenger lines trapping protection from the run round siding.
1. NR would give these a "restoration alarm" to remind the signaller that they had been left reverse or even "autonormalise"- this should be noted in the Remarks column.
2. All routes over 236N should be calling 235 normal as flank, but in addition to this routes over 239N should also be calling 235 normal to ensure that passenger line gets trapping protection. Note that this applies even if 235 are made to be auto-normalising (there is always a chance that signaller leaves keyed reverse etc). Alex has done this and indeed for good measure has decided also to call trap for those moves into Down Yard. This is a good idea but I think that I'd make these routes a "soft call" such that they would take the points if free, but could still set if they weren't. I certainly (and this would show not here but on the route & aspect CT for the relevant routes) would NOT detect 235 so that the PLs could clear even if detection was not achieved for some reason.
3. When points are called as trapping, then trains on those routes may never reach the "deadlocking" tracks so the usual rule (recorded i/c/w 233 above) needs slight modification. Trapping needs to be maintained until a train on the route has passed beyond the place where a collision with errant vehicle would be possible. hence for routes such as 146D(S) then the route locking tracks would be BL, BK, SG.
4. Certainly for routes such as 146B(S), the route locking tracks should be BL, BK, SF, SE. SE is certainly FOUL (as can be seen by the placement of the CP arrow and indeed the general rule that joint is close to the convergence than the switch tongues on the parallel line presumably at 6ft spacing). This is where comparison with the deadlocking track column would avoid such an error, since SE is correctly included in it.
5. Whilst looking at column 2, there is an error here. SF track is the track over the points and thus should ALWAYS lock them; the "or 236N" condition on the N to R locking is incorrect.
6. Now returning to columns 5-7 to look at the locking of the points when in overlap.
Alex has followed Signalling Plan and provided locking after 109B(S) and has correctly shown it timing out. Mention of SE is superfluous as this is an overlap track that deadlocks anyway.
However the entry for 113A(M) is right to include the overlap tracks as well as those in line of route; because 235 are trapping points not adjacet to the route then BJ, BK are not deadlocking and thus must be in the maintained locking. Note the listing of the tracks has to be out of sequence so that occupation of BH for a time does not override the locking on these tracks as well- the bracket excludes.
However 113A(W) should NOT lock the points as the ROL is situated at the BJ/BK joint. It would appear that the principal reason for providing the ROl on this layout is to permit a passenger train to be drought into Down platform simultaneously with a movement into / out of the Yard via 239R and if 235 are locked N then moves from that particularsiding could not be made (and of course 238A serves a similar role in providing trapping and thus would be given the equivalent locking). Even if there was a SPAD at 129, the train would not be endangered until it had passed beyond the ROL that had been reserved for it, so trapping is not required.
One route that might have been worth considering is 109A(S) that could have called and locked 235N, except when a forward route set from 133. In this particular case I don't think worth the complexity and Alex's approach of making routes over 238R call 235N (pseudo point-to-point) is probably the better. However on a different layout having traps at the end of a Goods Loop off a mainline, this would be more appropriate; if your practice (NR's current practice) is to give overlaps even for freight moves on Goods Lines then you'd need to consider whether there is a sufficient overlap into a spur with the trapping points normal, you may need to call reverse and direct the overlap back out onto the mainline until the train is safely stopped and then the trap points can be normalised.
7.The 158A(S) entry is wrong. The clearance of 158 purely relates to the move as far as 146- there is no overlap shown. The route box specifies that it requires 146 off; i.e. a driver will not (except in unusual failure conditions) encounter 146 at danger. It is practice in such situations to allow the signaller to be able to set the routes in either order but the order of aspect clearance is first 146, then 158. The approach locking lookback of 146 is designed to be taken back to 158; there is no need therefore for a concept of am overlap beyond 146 since the route is being held via the locking of 146 itself. 146 has some routes that call 235N and others that call 135R so it should be obvious that 158 must not lock them (as it wouldn't know which way!). So when doing point CTs if you see that a route demands as a pre-requisite another signal off, this is probably a hint that it ISN'T necessary to include it on the CT, because the other one has already imposed any requisite locking. If the stated requirement is just that it needs another route set, then similarly there is no poiint calling to worry about, but you do need to consider how the locking is being maintained.
Overall Alex would get good marks for this CT as has clearly demonstrated that understood the significance of the trapping protection being afforded by 235- probably a contrast with many candidates whose CTs would have been somewhat lacking in entries as they thought it was an easy point!
The thing about these points is that they give passenger lines trapping protection from the run round siding.
1. NR would give these a "restoration alarm" to remind the signaller that they had been left reverse or even "autonormalise"- this should be noted in the Remarks column.
2. All routes over 236N should be calling 235 normal as flank, but in addition to this routes over 239N should also be calling 235 normal to ensure that passenger line gets trapping protection. Note that this applies even if 235 are made to be auto-normalising (there is always a chance that signaller leaves keyed reverse etc). Alex has done this and indeed for good measure has decided also to call trap for those moves into Down Yard. This is a good idea but I think that I'd make these routes a "soft call" such that they would take the points if free, but could still set if they weren't. I certainly (and this would show not here but on the route & aspect CT for the relevant routes) would NOT detect 235 so that the PLs could clear even if detection was not achieved for some reason.
3. When points are called as trapping, then trains on those routes may never reach the "deadlocking" tracks so the usual rule (recorded i/c/w 233 above) needs slight modification. Trapping needs to be maintained until a train on the route has passed beyond the place where a collision with errant vehicle would be possible. hence for routes such as 146D(S) then the route locking tracks would be BL, BK, SG.
4. Certainly for routes such as 146B(S), the route locking tracks should be BL, BK, SF, SE. SE is certainly FOUL (as can be seen by the placement of the CP arrow and indeed the general rule that joint is close to the convergence than the switch tongues on the parallel line presumably at 6ft spacing). This is where comparison with the deadlocking track column would avoid such an error, since SE is correctly included in it.
5. Whilst looking at column 2, there is an error here. SF track is the track over the points and thus should ALWAYS lock them; the "or 236N" condition on the N to R locking is incorrect.
6. Now returning to columns 5-7 to look at the locking of the points when in overlap.
Alex has followed Signalling Plan and provided locking after 109B(S) and has correctly shown it timing out. Mention of SE is superfluous as this is an overlap track that deadlocks anyway.
However the entry for 113A(M) is right to include the overlap tracks as well as those in line of route; because 235 are trapping points not adjacet to the route then BJ, BK are not deadlocking and thus must be in the maintained locking. Note the listing of the tracks has to be out of sequence so that occupation of BH for a time does not override the locking on these tracks as well- the bracket excludes.
However 113A(W) should NOT lock the points as the ROL is situated at the BJ/BK joint. It would appear that the principal reason for providing the ROl on this layout is to permit a passenger train to be drought into Down platform simultaneously with a movement into / out of the Yard via 239R and if 235 are locked N then moves from that particularsiding could not be made (and of course 238A serves a similar role in providing trapping and thus would be given the equivalent locking). Even if there was a SPAD at 129, the train would not be endangered until it had passed beyond the ROL that had been reserved for it, so trapping is not required.
One route that might have been worth considering is 109A(S) that could have called and locked 235N, except when a forward route set from 133. In this particular case I don't think worth the complexity and Alex's approach of making routes over 238R call 235N (pseudo point-to-point) is probably the better. However on a different layout having traps at the end of a Goods Loop off a mainline, this would be more appropriate; if your practice (NR's current practice) is to give overlaps even for freight moves on Goods Lines then you'd need to consider whether there is a sufficient overlap into a spur with the trapping points normal, you may need to call reverse and direct the overlap back out onto the mainline until the train is safely stopped and then the trap points can be normalised.
7.The 158A(S) entry is wrong. The clearance of 158 purely relates to the move as far as 146- there is no overlap shown. The route box specifies that it requires 146 off; i.e. a driver will not (except in unusual failure conditions) encounter 146 at danger. It is practice in such situations to allow the signaller to be able to set the routes in either order but the order of aspect clearance is first 146, then 158. The approach locking lookback of 146 is designed to be taken back to 158; there is no need therefore for a concept of am overlap beyond 146 since the route is being held via the locking of 146 itself. 146 has some routes that call 235N and others that call 135R so it should be obvious that 158 must not lock them (as it wouldn't know which way!). So when doing point CTs if you see that a route demands as a pre-requisite another signal off, this is probably a hint that it ISN'T necessary to include it on the CT, because the other one has already imposed any requisite locking. If the stated requirement is just that it needs another route set, then similarly there is no poiint calling to worry about, but you do need to consider how the locking is being maintained.
Overall Alex would get good marks for this CT as has clearly demonstrated that understood the significance of the trapping protection being afforded by 235- probably a contrast with many candidates whose CTs would have been somewhat lacking in entries as they thought it was an easy point!
PJW