What about half-full cancelled trains?

[i-make-robots]

Trains loaded with material are cancelled by LTN and returned to depot. then they are reassigned and the train goes to a station with an unfiltered miniloader that proceeds to pollute my factory. How do I get the system to recognize that it's either

(a) cancelling too soon or
(b) still got stuff in the train car that should be unloaded before reassignment?

Thank you, and have a great day!

[robot256]

In my LTN build I made every depot unload the trains to active provider chests. The inactivity condition on the depot schedule prevents the train from leaving until it is fully empty. This is normally a rare occurrence.

Why are your deliveries being cancelled? Do they time out during unloading? The intention of LTN is for requesters to be circuit controlled and only request a train when there is enough buffer space to unload it. You might need more/faster inserters for items with large stack sizes.