I spent the past few hours or so applying this guide to the lumber mill in my route. Using triggers, it's removed a lot of the AI mess from the equation. Since consists are handled exclusively from their front end, by both the switcher and their locomotive, run-arounds are completely eliminated. If the locomotive needs to reach the other end of the consist for a return trip, I use triggers to make it cross through the A/D leg from eastbound parking to westbound parking, once the switcher has moved the cars out of the way. It can then recouple to the back end of the consist and depart back up the route once the cars have been returned to the A/D.
Trains enter, decouple from their consists on the arrival/departure leg, and move on to parking, getting them out of the way. When they enter parking, they trigger the yard's switcher, who retrieves the consist, unloads/loads it, and returns it to the departure leg. Once the switcher returns to its parking spot, another trigger signals the locomotive to leave parking and recouple to the consist, then continue along its route.
There are little quirks however, mainly in dealing with multiple trains at once. In order for this to work, the yard needs a dedicated switcher for each train that will interact with the yard. (Unless there's a way to save each train's instructions to a schedule and have the switcher change its directions accordingly.) To avoid traffic jams due to irregular timing, I imagine one would also need separate A/D legs for each incoming or outgoing train, as well. On my lumber mill, which only has a single train, trading logs for lumber and continuing down the line, this isn't an issue, and things run very smoothly.
