2011 Mod 3 Control Table attempt

[asrisaku]

Dear Guys

216A(M)
I don't understand opposing routes. Why don't we need 327A(M), 327B(M) and 343A(M)?
I saw overlap sharing on FZ. Could u explain why? I am confused.

Thanks in advance.

Best wishes, Arnut

[Peter]

Dear Guys

216A(M)
I don't understand opposing routes. Why don't we need 327A(M), 327B(M) and 343A(M)?
I saw overlap sharing on FZ. Could u explain why? I am confused.

Thanks in advance.

Best wishes, Arnut

In the case of 216A(M) up to 212, 212 has two possible overlaps (via 139 N or R), so a given overlap may not be available by the fact that a route is set up to 349 with the overlap on FZ, but that would not prevent 216A(M) being set with the overlap from 212 through 139N.

[asrisaku]

Thanks Peter

I agree with you your explanation above. However, there is a possibility that 327B(M) w 133R,135R can be set while 216A(M) calling 139R can be set also. Did I miss something? can you help explain more?

Best regards, Arnut

[Peter]

Thanks Peter

I agree with you your explanation above. However, there is a possibility that 327B(M) w 133R,135R can be set while 216A(M) calling 139R can be set also. Did I miss something? can you help explain more?

Best regards, Arnut

Ah, I see what you are asking. I must caveat my comment here that you are stretching the depths of my knowledge on swinging overlaps here, but I think it is the case that in order to be able to select the overlap for 327B(M) as you suggest (133R and 135R), this would not be possible with 139R, and similarly, if the route from 216A(M) is attempted, the conditions for 139 to swing R would be precluded by the overlap not being available since FZ is, as you say, already being used for the overlap of 327B(M). Since this combination of routes would never be possible because of the swinging overlap conditions, there is nothing to show in the opposing route locking for the signals. I hope someone with a bit more depth on swinging overlaps can confirm or correct this.

Swinging overlaps quickly make things very complicated, one of the reasons that, unless there is a very good reason to require them, the current NR practice is to avoid them.

Peter

[asrisaku]

Yes now you see what I tried to ask. I think that other years of exam have tricky layouts also regarding swinging overlaps. If we just ignore it, we might not get the good score I guess.

[Peter]

Yes now you see what I tried to ask. I think that other years of exam have tricky layouts also regarding swinging overlaps. If we just ignore it, we might not get the good score I guess.

You are absolutely right!