(11-09-2010, 08:09 AM)alexgoei Wrote: Hello PJW,
This is Part 2 of the posting with the layout on 5 A3 size sheets.
Thank you once again
Cheers
Alex
Route Boxes
113A(M) Mention Auto facility in comments
113A(W) Approach release is AG occ but don't say MAR as that means Main Approach Release from Red which is applicable to (M) and junction signalling, not (W) routes
117A(M) Wouldn't have a route indicator as it is the straight, highest speed route.
117A(C.) A call-on traditionally always has a route indication to distinguish it from a shunt (well this always was the standard- recently there have been some changes but probably best to ignore for exam purposes!); hence MARI "U".
117B(M) If assume that points 210, 203 & 207 are all 75km/h (again the exam info is somewhat ambiguous but I think that this is what must have been meant) then the SARI should have been PLJI as suitable for greater approach viewing distance and speed.
117C(M) Interseting that you had this as PLJI 5 that would rather imply 117B(M) would have been PLJI pos 4; note that the plan shows no PLJI at all so you have been rather inconsistent! However I agree pos 5 appropriate here.
119A(M) OK. But in the exam if short of time, hardly worth doing signals with only one route.
121A(M) OK
121
B(S) Note nomenclature. Actually not convinced that need 305 signal, so would have this read directly into turnback siding.
128A(M) OK
128B(M) Signal ahead is 126 rather than 122- think you must have changed your mind re numbering! Well done for recognising that the junction speed of210, 211 is such that would be MAY-FA. You could have added in the comments box the need for signal 126 to be displaying proceed for MAY-FA to be effective.
122A(M) OK
122B(S) Why have a PL into one platform and a ain aspect into the other? I'd have made this 122B(M). If you felt that there could be a need to join a 100m passenger train with another 100m passenger train then could have provided a PL as well and thus 122A(C.) and 122B(C.) but I can't see anything in the specificarion that even hints at this, so best omitted; if however you feel that there is some hint that such a facility might be needed then provide and put a justifying note why you have decided that.
120A(M) OK
120B(M) Interesting that you have now assumed that all these points are 75km/h and thus provided MAY-FA. I agree but you have been inconsistent with yourself earlier.
Note that it is not permissible for a signal to show both a flashing yellow for one divergence and a double flashing yellow for another divergence, but it is acceptable (but relatively unusual) for a junction signal to display a flashing aspect for another divergence, so your layout is indeed OK.
118A(M), 118B(M) both OK
The 3 aspect head and SARI are fine since trains strating from rest. Well done for reading notes and providing this signal as requested.
116A(M) OK
116B(S) OK but I am not actually convinced that need LOS 302; however it is perfectly correct and 113 has been made a controlled signal so it is only a matter whether there is operational justification for it as well as GPL 301.
116C(S) OK
114A(M), 114B(S), 114C(S) all OK, similar comments as previous signals
301A(S), 301B(S) both OK but the MARI are not necessary; indeed you have not actually provided any on the plan and I think that is correct for this scenario
303A(S), 303B(S) both OK, but again I'd not have provided any route indicators. Had the freight been running in the down direction from the siding rather than just puling forward to be run around, then a main aspect would have been appropriate, but for this scenario I agree with your choice
305. Don't think we need the sugnal at all; it isn't actually wrong, just not required and therefore superfluous. If you have it then 121A(M) would need to pre-set it as indeed you have shown in that route box.
Typically all GPLs would be last wheel replaced; in terms of route boxes don't need to write the track conditions, just L in a circle and define that symbol as "last wheel replacement"
Basically the operation of a turnback siding is that passengers de-trained at C then train draws forward using a PL aspect into siding. Driver shuts down front cab, walks therough multiple unit to open up the other cab and waits there until time to return to platform.
306A(S) OK. You were correct to provide this GPL so that a train terminating in this platform can then access turnback siding.
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I have a nightshift to do tonight ("3rd time lucky" we hope for Twyford which seems to be jinxed); hope I will have time to give further comments on the layout tomorrow pm