I can't help with the first part, so will leave that to Reuben
OFZ-BA is the nomenclature that is uused in SSI data to teflect the element of locking imposed when a route is et which has its overlap extending over track section FZ; it is called a "sub-overlap".
Just as route locking in RRI is either in the Up or Down direction, there is a need to specify the directionality. The various ends of the track section are given a reference in alphabtical order in a clockwise direction- on plain line sections there are directions AB, BA; for a section with a single point end there could be dirctions AB, BA as well as AC, CA and if there is more than a single point end then there can be even more ends and corresponding numbers of sub overlaps.
The most recent form of NR control tables for SSI and SSI derivative interlockings use such nomenclature. However would not follow this approach for IRSE Exam CTs as can only use this short cut on point and signal control tables if provide another type of Control Table regarding the route locking and you won't have time to do so.
OFZ-BA is the nomenclature that is uused in SSI data to teflect the element of locking imposed when a route is et which has its overlap extending over track section FZ; it is called a "sub-overlap".
Just as route locking in RRI is either in the Up or Down direction, there is a need to specify the directionality. The various ends of the track section are given a reference in alphabtical order in a clockwise direction- on plain line sections there are directions AB, BA; for a section with a single point end there could be dirctions AB, BA as well as AC, CA and if there is more than a single point end then there can be even more ends and corresponding numbers of sub overlaps.
The most recent form of NR control tables for SSI and SSI derivative interlockings use such nomenclature. However would not follow this approach for IRSE Exam CTs as can only use this short cut on point and signal control tables if provide another type of Control Table regarding the route locking and you won't have time to do so.
(17-08-2013, 12:19 PM)taxcel Wrote: Dear Reuben
I also attempted 2011's control table, and I noted you mentioned you have a "model answer", may I know where it is posted? I couldn't find it on this website.
In addition, would you explain what is "OFZ-BA "
PJW