I've been playing with 10.2 a bit, and so far so good... I wonder if you could clarify the intended use cases of keep orders and inherit orders for me. For a locomotive at the head of the train that 'runs around' to the other end at end of line, everything is clear and works fine. For a second locomotive that attaches to front or rear of the train for just a portion of the journey, it is unclear to me how orders will be handled after that decoupling -- that is, can the parts of a decoupled train go on to do distinct actions, or will the 'orphaned' part of the train always just dumbly await coupling? I am trying to use this to pull trains out of terminus tracks, but I think the common case would be 'banking' engines (extra locomotive attaches at bottom of hill, detaches after pulling train over hill, awaits next train to help while the original continues per orders). In this case, after the decoupling, the original train needs to retain its ongoing orders, and the banking engine needs to retain its "wait to help" orders. Is this possible?
Use case for dividing orders is entering terminus station in reversed state (the loco pushing wagons) and then the loco can go somewhere else. It's meant for small cargo terminus stations. Or it can be used for some kind of shunting yard.
Autonomous banking engines and shunting train out of "passanger" terminus station by other engine
is not possible with current orders. Those orders as they are just prepare ground for the future update.
Edit: the terminus shunting with other engine is currently not supported because of how train looks for other train. It allows only one train in station platform. This is planned to be changed too, there wasn't use case for this so far.
To support those operations, we will need arbitrary orders for both decoupled parts. There was suggestion to make it in a faster "hack" way with "contitional jump", but I personaly dislike those hacks in gui, it's annoying for gameplay and usually brings unwanted special cases. Basically what should solve all this is implementation of independent orders list, which I call global order list, that could store future orders of both train parts. But it will take a while to implement.
Another issue I've noticed are odd gaps in the timetable, not just immediately around coupling movements. In the attached image, I understand why there is no time given between arriving at the station and the decouple order (underlined in blue), as these happen at the same time. However, I am not clear on why travelling from the previous station to the station where the decoupling happens (red) is also not timetabled.
Separate from this, trains seem to be getting a lifespan of 0 years when reversing, then returning to normal after reversing again
Thanks for reporting bugs.
Timetables are not handled at all at current implementation, they need support in source code. I'll add it to bug list and fix it later.
Lifespan of vehicle in trunk is too simple, it's just first vehicle's property, it wasn't updated in this patch yet. The topic is actually breakdowns, which is currently inconsistent too. It's another bigger future fix.