Hi Bluebelly, to answer your question, I am assuming that you were not applying time against anyone and like you state, all rules were properly complied with prior to leaving your originating point. If you simply went in the clear and no superior opposing trains were due by SN from the time you originally went in the clear to the time you occupy the main at SN, you would not need an "A" Card.
You stated that you already have an "A" Card properly representing superior opposing trains so you already know that any train that was due to have left SN has done so because all trains have made it to Montauk. If they made it to Montauk, they left SN. If any train that was due through SN prior to your arrival had not made it to Montauk, you would have already known this when applying Rule S-83 in order to not violate Rule S-87 against that train(s). Once going in the clear at SN, you would have reviewed your timetable and if no other train was due to arrive, then there is no train to represent therefore no "A" Card being necessary.
Hope this helps. If I can be of further assitance just private message me. Also, I will pass on the compliment to 2716's Engineer
M.A.R.I.A. in my opinion was always a poor acronym to describe representation of trains. To fully understand what I am saying you have to look at the history of our rules. Imagine yourself a telegrapher in Montauk a century ago. You were looking for equipment to represent the schedule of particular trains. That is where the term "representation" comes from. If a train is annuled they are telling you that it cannot be represented. If a train is meeting you, they are telling you that you will represent them at the meeting location, not where you are getting your original information. If you have right-over a train, you are now the superior train and do not have to represent particular trains that lost their superiority to you. The only way you truly represent a train is by IDing them from a train order of some sort or being issued an "A" Card stating "None" with the times of the "A" Card encompassing the train schedules that you are trying to represent. The Training Department should stop using this acronym because it becomes very confusing because it leads some to believe that they can receive an "A" Card stating "None" even with a schedule annulment due to believing that the Train Order annuling the schedule represents that train and the "A" Card represents everyone else. SK2MY, please don't think I am bashing anything you are saying. Your posts are very informative and I enjoy reading them. I just don't think Training should teach it the way they do.
Cool beans!