Simply put, which station?
(And "skipped due to fork in the track", etc.)
On Network trains, if I don't catch the issue within seconds of it happening, there's often no clear indicator of exactly what station it had a problem with. In this case, the diesel train probably skipped the station whose diesel intake I'm in the middle of remodeling, but a lot of times- particularly with a many-station product like diesel- I just have to wait for the next train to have the issue as well, and hope I catch it quickly.
It would also be nice to be able to look at this train of vegetables, for instance, and discover where it came from (aside from the fact that there's only one vegetable source station on my network), even if it's only a station name:
Or this mine-approaching rock train, and know where it's planning on taking the rock (there's an obvious answer on my network, but when it's picking up a product of which there's a shortage- maybe steel, vehicle parts, or electronics, though I don't have any shortages right now- it's annoying to have to click through all the potential receiver stations to find which one's got inbound, to decide if that job needs to be redirected while the train's still moving to pickup, or actively loading):
Something like this might be nice for trucks too. "Hey wait, where did you get that waste from?" click "Huh, why is that mine producing waste?"
Speaking of unexpected waste, when belt ramps or rails are left unsupported by deconstruction or collapse, they take anywhere from an instant (belt ramps) to about two seconds (rails) at 3x to collapse, so it's very easy to miss the collapse warning and end up with a pile of trash in an unknown location. There also doesn't seem to be a persistent "this building collapsed" warning, and the "train destroyed by collapse" warning times out way too fast, so it's very easy to miss those destructions until the trucks are seen hauling waste from mine nearby ore sorters to the belt-fed incinerator. If there happens to be one in place to absorb the damage, at least.
In cases where there isn't source information, I think it'd be okay for the vehicle to declare that it got the resources from itself, since it doesn't know where they came from.