Every time I respond to the 'does the direction of track direction matter', and I say it does, I get bashed. But I will say it again, it does matter.
It's possible to prove that track direction matters for AI, at least for some cases.
Create a new route with a straight section of track. Create two passing loops, one each side, starting and ending at the same junctions (that is, two three-way junctions). Make them as identical as you can manage. Lay one passing loop in one direction and the other passing loop in the other direction. Make sure the junction switches are set to straight-ahead.
Use the copy tool to copy and paste the section of track so the second one is alongside the first, but rotate it 180 degrees ([[) before pasting.
So you should now have two separate identical sections of track that differ only in their orientation in the world.
Place a consist on each centre portion between the passing loop junctions. One consist will have to be turned around, so that they face the same direction.
Start driver and issue a 'Run Around Train' command for each consist. AI will have to decide which side to run around on. If train facing or world orientation was the controlling factor, then the two trains would run around on the same side - either to left or to right.
But they don't - they run around on opposite sides. That is, the side selected seems to be dictated by track direction because that's what got reversed in the copy process.
A similar test can be done with only the central track laid in the opposite direction. The result suggests that the difference is created when the AI searches for a route, and meets a junction. It appears that the track direction controls which side of the junction is searched first. But the selection is not affected by the direction in which the passing loop is laid, so the effect of track direction is much more subtle than might be first thought, and perhaps that's why people deny that it exists.
Note that this test applies to the Run Around Train rule only - it shows that track direction
can matter. It doesn't prove anything about how track direction affects other AI rules. However it is reasonable to assume that any rule that needs to search for a train, and possibly any rule that needs to search for anything, will be affected by track direction if there are multiple paths.