Hi,
AI switching moves are a bit tricky, but they should work on the VNHRR like on any other route (at least that's my experience with it).
The most common error source is I think that AI trains can only couple to cars that belong to a stationary consist that was there at the start of the scenario. I.e., if another AI or the player dropped the cars somewhere, the AI will refuse to couple to them. The only exception I've found to this is if the dropped cars belonged the AI's own starting consist, but even then it still failed sometimes.
Also, it is crucial to place the "stop markers" at the exact location of the coupling spot (ideally just a tiny bit behind where the coupler faces should meet). Place them too far inside the car, and the AI will crash and terminate the scenario on a derailment. Place it too far ahead of the coupler, and the AI will not be able to make the coupling connection.
I have uploaded a "railfan" scenario to the Workshop that includes some AI switching if you want to have a look "under the hood" (AI arrives, splits its train, drops front half at a siding, picks up rear part again, moves off):
viewtopic.php?f=47&t=20640Cheers
Michael