1997 Layout CT for Routes from 112 and point 306)

[Peter]

I have attached the CT for P303 but am really unsure abut how I have written the control for the swinging overlap.
Thanks in advance
Ian

I have had a look at your table for 303 and I think you have done reasonably. In the Set by column, I think you missed 124 in the N>R (they would be called for flank protection) and similarly 122B(M) in the R>N (flank again). 107A(W) would call 303 R (not N as you have it) because the ROL is shown going round the corner. You put 112B(S) which should be 112B(M) (there is no shunt route).

I am on shaky ground as I cannot confess to be a natural on swinging overlaps, but you have got the essence right for the bit that you did (you missed the R>N entry). I think that maybe BK should also be in the TC clear for the release (but I'm open to persuasion on that) and remember that a train stopping in the platform could be on BG or BH, so TC OCC should have (BG or BH) for time. My stab at the R>N entry would be
- TC Clear ----------- TC Occ -Time-TC clr- Pts--- Route N
DJ DB (BR BF BG BH | BG OR BH | t ) | BK | 206N | 107A(M)

You also put 107A(M) as calling R>N. If we have just been discussing the swinging O/L for main routes up to 111 (ie 107A(M)) this would not call it one way or the other, unless the O/L was not available so I think you should have entries like N>R 107A(M) w 306R and R>N 107A(M) w 305R.

Any thoughts from others?

Peter

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Many thanks for your comments much appreciated and hopefullt they have sunk in. May I submit P301 for your perusal..many thanks.

I would have missed 122. the route from 112 is 112B(M) not 112A(M), but you have the tracks right.
The routes exiting into 108 lock 301 points as part of the overlap. You should consider releasing the overlap point locking after BG occ for time. This would allow the route 108B(S) to be able to set.
I wonder if there is a (small) flank protection benefit for 202A(S) to call 301 normal? A spad at 107 can always get through the trailing point to 202A(S), but may help from a spad at 201?
Someone else might like to comment here. It looks good to me.

If 108 has an alternative overlap with 302N, the requirement to call 301 with routes up to 108 would, on the face of it, depend on the lie of 302. However, given the nature of 301 (ie from the siding) you would probably want them N whichever overlap was selected.

You would indeed need to time off the overlap via 302N on occupation of BH or BG to be able to route the train anywhere else meaningful in the up direction.