I've seen this too, details here viewtopic.php?p=695463#p695463

Is it even only about interruptions? I have several trains that get stuck like this (see image). There is no limit on the destination station, there is no train blocking the route. It's already kind of going (there is the stop-button). When I press that button, it starts actually going immediately ...

I believe there is at least one race condition when changing the quality of a train which results in the train being stuck.

One reliable way to reproduce this is to trigger the upgrade while a train is unloading such that it will finish unloading before the bots upgrade the train. When the bots ...