So I've been messing with a specific route for a while and in one session I have a long coal train pulled by 4 SD40-2's (UP) (built in). In this session I would pull the cars through a coal loader and load them, then decouple head for fuel and sand and recouple for the return trip. BUT since SP1 (HF2) for some reason the loco's don't want to recouple. I can watch it closely and see what the problem is, but I don't know how to fix it. Heading back from fuel the 4 loco's (AI control) are in reverse (driver in back). It approaches a searchlight 06 RD to re-enter the siding to attach to cars. The siding has multiple tracks and the outermost is empty so the light shows yellow. All good. BUT as the first loco passes the light it flashes red (duh right...?) but now the announcement window says driver passed a danger signal and halts for 2 minutes. Why? I can change the commands to wait for x seconds so that the driver will change ends but really, he is backing into the siding as he should. Also if I do a wait for x seconds before heading into the siding and he does couple up now the driver is technically in the middle of the train and I've seen where that can really confuse the AI. I'd really prefer to have it work more prototypically and back into the siding to recouple. So after that long tale, what am I seeing that is wrong?