Don, that wasn't exactly the way it worked. They may have had certain tracks where they generally yarded inbound trains, and generally built outbound trains, but that wasn't set in concrete. Depending on the requirements of the business on any given day, any of the yard tracks could be used for anything.
For example. they might usually build the south local in track #6 (or whatever) because it was a short track, but today they had alot of extra cars so they might build it in track #2. Then #70 arrives, and they normally yard him in track #2 because it is a long track, but the local was late getting called because of power problems, so they might have to yard #70 in track #4, and have him double over to track #7 because he wouldn't fit in track #4.
To understand railroading you need to accept that things weren't the same day after day after day. They were always changing depending on the requirements of the service on any given day. Yes, there were certain tracks that they preferred to use for certain moves when things were running normally, but they usually weren't running normally, so they adjusted accordingly.
Another thing to consider was that some tracks were used for certain moves on one shift, but not the other shifts. Case in point was the scale track at McDoel. They would always yard the South Stone Train in track #13 because that's where the scale was, but the SST usually came in late on 1st. shift or early on 2nd. Then, they weighed the stone on 2nd. shift, switched it out, and after that #13 could be used for anything until the next day. If the next day was Saturday or Sunday, it all changed again because the SST was a five day job.
As far as the caboose track was concerned, they usually had a designated track where the cabooses could be serviced, and back in the old days when the train crews slept on the caboose, it was located where the crews wouldn't be disturbed. Same thing for the rip track where they made running repairs on cars. / Ron