2007 Aspect Sequence Chart

[Suganthy]

Sir,
I have tried the 2007 Aspect Sequence. Kindly review.

V.Suganthy

[Peter]

Can't find a copy of the 2007 layout 3, so in the meantime has anybody else got any comments or can someone get me a copy.

[PJW]

Sir,
I have tried the 2007 Aspect Sequence. Kindly review.

V.Suganthy

Quite an easy layout I feel in 2007 so probably the examiners would mark harshly; however you'd have done quite reasonably as it is neat clear, well presented and mainly accurate.

The biggest mistake was the sequence of 182 reading up to 138; you fell into what seems to be a deliberate trap. I suspect that the examiners arranged things to try to determine who really understood what they were doing and who could be misled by a red herring. Full marks for reading the plan and noticing that 138 can only be approached when it has a forward route set; however you seem to have misunderstood the rationale. Also it was a bit of a give away that you draw the aspect sequence chart in the direction that a train runs and had therefore got a Y+SI"X" at 182 that didn't seem to be required as you believed that 138 could not show Red [actually it can!].
The rationale for the control is to mitigate the risk of SPAD at 138 by ensuring that 233 is locked Reverse and thus inhibiting other routes in the area. Should a running SPAD occur then the result will not be a high risk junction collision but just a rear end collision at relatively low speed and hence lower risk. It is possible that 138 could be at Red due to the presence of an occupied track ahead of it etc. and thus the signal in rear must show appropriate aspect. If you think about it, since you are happy that 182 shows a Green with a route indication for the route up to 114 at Red, why wouldn

[Suganthy]

Thank you for the review and comments. I will keep a note of all your comments in future attempts. But I am little bit worried on the warning about change in question style. I will try to concentrate much on it.

V.Suganthy

[dorothy.pipet]

Another attempt for comments please.
(untimed and open book)

Dorothy.

[PJW]

Another attempt at 2007 with my comments is attached

[asrisaku]

Another practice

Thanks, Arnut