Preserving previous travel schedule after completing it

[Xeizzen]

After doing some pick-ups and drop-offs a train is stopping at a depot station, which clears its schedule and putting the train to "stand-by" mode.
But what if I don't want its schedule to be removed for debugging reasons? Because sometimes trains arrive at depot not empty, and I need to investigate of why this is the reason, and where I requested more stuff when I actually able to store. So having a sort-of backtracking of its schedule would be extremely handy, because it can point me to a station that can have a problem so I can fix it.
So, is it possible to somehow keep the schedule of the train after it completed its route as it arrive at a depot station?

[Optera]

If you keep "Delivery resets at requester" disabled you can build circuit controlled signal contraption with Inventory sensor in your depots that only lets empty trains pass to the actual depot stop.
If you add in a speaker you can also get a notification for it.