I was wondering if it is possible to uncouple engines. I am doing time table work in the sand patch, and had a 'collision' with another pair of AI driven engines. Causing them to become coupled to my double engines. I could not find a way to decouple them from my engines, so I was forced to take them along for the ride. Luckily this happened at the end of the 3rd timetable thing.
There are a couple of ways to uncouple, one from the F4 HUD by clicking on the coupler at the bottom left of the HUD. Another way is to press the 8 key to go into the free-roaming outside view and move to the coupler when you put your mouse pointer on the coupler it should change into a coupler icon and then click on it and that should uncouple your loco.
I will give that a try next time it happens. I should probably clarify that I play on xbox. So some things might be a little different.
Are you playing TSW2? If so you need this forum https://forums.dovetailgames.com/forums/xbox-discussion.85/