Finished some timetable run to Bad Vilbel and continued it on foot mode. Just before Gronau bridge got error that service failed due to derailment. Even if it is some specific problem for particular route or AI service, a bit of protective programming would help for all cases. If I am not driving a train and just walking around enjoying nice scenery, I really do not care that some invisible AI service passed at red signal or derailed due to other bugs. This can be fixed in core game.
I arrived to Bad Vilbel driving 7079. It is supposed to stay at Platform 2, wait for 7083, couple together and leave as 7084. However the AI driver of 7083, after stopping before the red shunting signal, goes wild and derails the waiting unit; see stream snippet.