Trains hard-lock en route under a schedule with specific station request limits

Issue description

I've noticed this continues to be a problem (first noticed on launch release); you need a line with a list of stations and multiple trains under these specific conditions;

• one waypoint station (no modules), no limits
• one source station, no limits
• multiple destination stations, each with "if all modules empty" limit, and also a fixed number limit above 1
• multiple trains on line
• each stop set to only depart with train fully empty or loaded

what will happen is when a station with all-empty and hard cap of 2 trains becomes available, two trains will load and go en-route to that station
when both arrive there, the first train will unload and leave, the second train will begin to enter the station as the first train leaves
this station's state changes because the modules now have contents, now normally this isnt a problem, the next train just goes in anyway

BUT; heres the problem, if another station becomes available, this second train then either switches to attempting to path to that new station while already within both reserved and no-stop rails AND the previous station, or, the train's state just seems to get completely corrupted and isnt recoverable

methods to work around this are not exactly straightforward since this seems to be a hard-lock condition, if you manually tell the train to move to a different rail section it usually just ignores you, if you recover it to depot it often gets locked inside the depot, it also doesnt attempt to recover itself either, about the one thing that works reliably is to remove the train from the route and then unity recover+pause it to the depot

long-term the only option seems to just not set up a line like this or simply set each station to hard cap at one train

Reproduction steps

Game version and build number

0.7.7 and prior

Operating system

Windows

Attachments

there does seem to be some weird cases where the train suddenly resets itself and returns to entering the station it was already entering, but it seems like for that to happen both that station must now be empty of any cargo, and the secondary station that triggered the bug has to also have been filled up by another train, which would also have required its reservation to be removed from the broken train for that to happen, so in some cases the train may be able to reset in this manner but rarely so

oh one extra thing i feel is noteworthy is the trains in general still want to hold on to the last single track connected to the station where they came in from, this doesnt seem like it would really be related but maybe its indicative of another issue, so for all of my stations i add an additional two rail tiles before the split to parallel, because without this the train will do a strange shimmy-in-place before backing out of the station, despite the train not being long enough for it to be necessary to move forward

changed the location of a station and despite it running fine for a long time now, the bug popped up again

train knows exactly where to go, but has completely forgot what its even doing

basically it behaves as if the whole physical station itself nolonger exists and thus the train cant physically move to the station or even simply through it, every time you tell it to manually go to the station it hangs for a bit and repeats the "cannot find path" message, even though of course with the navigation UI open it clearly has the route physically and visually mapped

a really weird bit about this as well, I have multiple lines configured exactly like this, but its with this specific line that the bug seems to continue to pop up with on occasion

but there is a catch here; this problem line also happens to be the very first line ever made and also still in use, just that every station, section of rail and each train have been completely wiped and replaced over time, so in theory the behavior should be the same as if it were a whole new line created after the previous one was deleted, but maybe the bug only occurs specifically when the first line in the list gets updated? as in the timing of the update cycle of each line is important

Can't reproduce - would need a save. From what I can tell from the description it's a case of a train "forgetting" it's target station, which should never happen. Potentially, it was fixed in v0.7.8, as some sections that would cover this issue were changed. If you have a repro on the latest version, please file a new issue and attach your save file.