I just found out something truly profound from ex-BN employee Bob Stafford (and after digesting articles in the OPSIG magazine “the Dispatcher’s Office”). The official Timetables only contained the official “schedules” that could be used by dispatchers to reduce the number of train orders that needed to be written, to improve safety, in the days before radios were widely used. There weren’t very many schedules listed in the timetables, by my modeled era of the early 1970's. But there were lots of (extra) trains that ran at the same time, with the same purpose, each day. Each train had a “Train Brief (TB)” - a document that listed which blocks of cars would be switched in and/or out at each station along the route, and the estimated time at each station. This TB was followed every day that train was run, until it was changed. All of the TB’s together constituted the “Operating Plan” (OP), which was distributed to all stations in the district, and available to operators, yardmasters, etc. to know what to plan for all day. (on the Santa Fe the OP was called the Train Service Plan (TSP)). In my era, every 4 hours the dispatcher, after consulting with the train master, would issue updates to the OP to each station operator, who would make up, or revise, the “lineups” to give to the yardmasters, engine foremen, etc.
The reason this is profound, is because it makes clear that, for yardmasters at least, the “Timetable” is actually a document of secondary importance to the OP. What I call “train instruction cards” on my layout (see photo shown above) are actually summaries of a more detailed Train Brief, and what I call a “lineup of trains” is actually more of a sequential list of trains I would like to run, but mostly without meaningful departure or arrival times, or blocking information. I don’t even bother with a “Timetable”, because only the passenger trains used it, by 1973, so I just put their official times in their train instruction cards. But I am sadly missing the entire point, which is to have a master Operating Plan, which lists which trains are going to set out which blocks, where and when. Without this, it is basically chaos. It doesn’t matter if on a particular day the blocks themselves are 10 cars long or empty. The point is that everyone knows what time to expect what to happen, whether or not (mostly not) a train will use a particular "schedule" in the official "Timetable." If a train is “late”, it usually is in reference to the OP, not the Timetable, unless that train is using a schedule listed on the Timetable.
The larger context of Bob’s comments to me about my Interbay Switching video, is that in a real yard, the yardmaster can plan ahead for many hours which track he is going to use for which blocks. On a model yard, without an OP and/or lineup, along with copies of the Train Briefs, the yardmaster is just dealing with one emergency after another.
The following diagram is a graphic that the late Doug Walters designed for my layout to help yardmasters figure out which blocks could be placed on which trains. Now I can see that this information should also be part of my "train instruction form", and should be available to the dispatcher in some form as well, as part of a coherent "Operating Plan". Almost regardless of whatever schedules are shown on the official "Timetable".