1997 Layout CT for Routes from 112 and point 306)

[PJW]

One of the issues which i was interested in was understanding the case of route 124A(M) in relation to 107A(M) - you are right it shoudn't prevent the latter from setting but i put it there just because i did not know other way to provide flank protection for it when 303 was normal.

124 sets and locks 303R to give itself flank; thus if 107A(M) is requested then the only way its overlap can go is via 303R. Should there have been no overlap defined in that direction for some reason then the route would request 303N but then find it unavailable so the route would be unable to set.

The other issue is timing the tracks - i understand it is for permissive routes (shunts) but also i know that when there are points in the O/L especially in platform areas one want to release them soon as possible from operational reasons - this is why i timed out 122A(M) and 112A(M) - however i can say i am not very sure when is to be applied and when not; for example, would it be necessary in case of call-on routes from these two signals?

Two separate (but related) issues:

a) Points locked within any overlap do need to be released after train has come to stand at exit signal; this is shown on the Control Table for the points concerned- not relevant to route Control Tables

b) Opposing locking does need to time out to allow a permissive route to be able to be set onto a train which has timed to a stand at the opposing signal; this is shown on the route Control Tables for 'Call-on' and 'shunt (when permissive as I suggest you usually assume)' class routes. Opposing locking should not time out for a non-permissive route such as 'Main' or 'Warning' and therefore the opposing locking is shown without the 'track(s) occupied for time' condition on those Control Tables.