Dwarf Fortress Bug Tracker - Dwarf Fortress
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0006189Dwarf FortressDwarf Mode -- Interface, Depot Accesspublic2012-09-10 07:192014-07-22 12:08
king doom 
0006189: Wagons of different races cannot pass each other.
There are a few reports of people complaining caravans wont trade and race X takes too long to load/unload and you can't trade because of it, and I've just worked out what is happening. Wagons cannot pass by each other the same way all other creatures can. They cannot share a tile with a wagon from another race and keep moving.

I know this because on the road outside my fort, the human caravans wagons and the dwarven caravans wagons just collided, and both have stopped moving. Both wagons are on a road, so nothing has grown up underneath them, there are no obstacles and the human caravan had finished trading at my depot and had just finished packing up, so they have a path to/from the depot.
Build a depot with one entrance that guarantees two caravans of different races are going to collide going to/from it, and ensure there are two caravans of different races trying to leave/visit the depot at the exact same time.

The bug may not occur if all caravans are inside the depot at the same time, I've observed it occuring only when they are on the road or half in/out of the depot.

Save file showing the problem:
http://dffd.wimbli.com/file.php?id=6899 [^]
related to 0005351resolved Toady One Wagons don't unload fast enough to allow trading, may need NO_THOUGHT_CENTER_FOR_MOVEMENT 
Issue History
2012-09-10 07:19king doomNew Issue
2012-09-10 07:21king doomTag Attached: pathing
2012-09-10 16:40QuietustNote Added: 0023548
2012-09-10 18:34PetWolverineNote Added: 0023549
2012-09-11 04:12king doomNote Added: 0023551
2012-09-11 20:51FootkerchiefRelationship addedrelated to 0005351
2012-10-26 16:32HiEvNote Added: 0023682
2012-10-27 18:13kwielandNote Added: 0023686
2012-11-18 12:31arclanceIssue Monitored: arclance
2013-01-07 17:08QuietustNote Added: 0023825
2014-03-07 21:40AltF4Note Added: 0024592
2014-03-08 12:41FootkerchiefAssigned To => Footkerchief
2014-03-08 12:41FootkerchiefStatusnew => acknowledged
2014-07-22 12:08ButtonNote Added: 0027221

2012-09-10 16:40   
Under normal circumstances, it's highly unusual for two caravans to be on the map at the same time - caravans typically only stay for a month or so, and then it's another 2 months before the next one shows up. Did you lock the Human caravan inside your fortress for a prolonged period of time, or did they just take several months to load up their goods?
2012-09-10 18:34   
I have two caravans at the same time on a regular basis. In fact, right now in my current fort, it's mid-winter and the humans are just now leaving; I've long since finished trading with the dwarves and they're still packing up. It's a result of trading a huge number of small, low-value items to them - in the case of my current dwarven caravan, nearly 200k worth of tattered clothing and bone and stone crafts.
king doom   
2012-09-11 04:12   
PetWolverine is correct - if you trade large amounts of items that aren't in bins, usually because you can't spare the bins due to lack of wood, the caravans can take months to pack everything up after trading has finished.
2012-10-26 16:32   
Sounds like the description in bug 0005687 to me.
2012-10-27 18:13   
Related should be the capacity of wagons.

I've noticed that two wagons from the SAME caravan can block each other. I had a fort with an entrance path with a two-way entry. It seemed that the caravans would choose randomly which way to go. The paths ultimately came back together, and the wagons happened to meet in the middle of the union/tee would result in the two wagons just stalling out there. Eventually they would "die" and dump all their stuff where they were.
2013-01-07 17:08   
If caravans are taking more than 2 months to pack up, there's almost definitely something wrong - past versions of the game didn't have this problem.

Incidentally, the "place designations while paused to instantly pack up" exploit (which could be used to avoid this problem) was fixed in version 0.34.11 - perhaps the fix introduced another bug which makes caravans load far more slowly than they used to...
2014-03-07 21:40   
I had this happen in the area surrounding my fortress. No where near any tunnel.
2014-07-22 12:08   
I had this problem in 0.40.03 with two wagons of the *same civilization*. The trade route runs through a courtyard, and they took different paths around the traps in the center, and then collided head-on at the place where their paths re-joined.